BASIC EDUCATION ASSISTANCE FOR MINDANAO SECOND YEAR – BIOLOGY CELL STRUCTURE AND FUNCTION USES OF CELL ORGANELLES/CELL ACTIVITIES AND TRANSPORT IN AND OUT OF CELLS Information about this Learning Guide

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Second Year - Biology

Cell Structure and Function

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Basic Education Assistance for Mindanao (BEAM) project. Prior approval must be

given by the author(s) or the BEAM Project Management Unit and the source must

be clearly acknowledged.

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Information about this Learning Guide

Recommended number of lessons for this Learning Guide: 8

Basic Education Curriculum Competencies

Second Year Science: Cell Structure and Function

• Understand how discoveries on cellular structures and functions have led to useful technologies

• Explain that the activities of certain cell organelles are used to promote food production and health

• Appreciate cellular exchange of materials with the environment • Explain osmosis as a type of diffusion

• Distinguish between active and passive transport

Objectives

• Explain that the activities of certain cell/cell organelles/secretions are used to promote food production and health.

• Define/describe diffusion and osmosis.

• Describe a cell when placed in a different types of solutions (isotonic, hypotonic and hypertonic).

• Demonstrate and describe endocytosis and exocytosis.

Essential concepts, knowledge and understandings targeted

• Cell membrane is defined as selectively permeable membrane that encloses all the cellular organelles. It allows some substances to pass through it.

• Some cell/cell organelles/secretions are used to promote food production and health. • Lysosomes play an important role in drug action.

• Smooth Endoplasmic Reticulum (SER) functions to detoxify (remove harmful effects of) many poisons and drugs such as barbiturates, amphetamine, morphine and codeine. • Eukaryotes and prokaryotes are important in food production.

• Hormones help regulates the breakdown and buildup of various substances in the body. • The process wherein substances are brought in and out of the cell is known as cellular

transport.

• There are two kinds of cellular transport: active and passive transport. • Passive transport includes the processes of diffusion and osmosis. • Active transport includes the processes of endocytosis and exocytosis. • The two common types of endocytosis are phagocytosis and pinocytosis.

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• In isotonic solution, the concentration of solutes and water outside the cell is the same as inside the cell. The movement of water in and out of the cell is therefore equal. • In hypotonic solution, the concentration of solutes is lower and water concentration is

higher outside compared to the inside of the cell. Water flows into the cell; the cell will swell up and may burst.

• In hypertonic solution, the concentration of solutes is higher and the concentration of water is lower outside the cell causing the cell to shrink and lose its shape.

• Cells are normal when placed in isotonic solution, develops turgor pressure in hypotonic solution and shrinks in hypertonic solution.

Specific vocabulary introduced

• Acetobacillus is a prokaryote that helps in the fermentation of sugar which produces acetic acid.

• Active Transport is the kind of cell transport that requires the cell to use its own energy in transporting substances into and out of the cell.

• Concentration is the measure of how much of a given substances there is mixed with another substances.

• Diffusion is a process by which molecules of a substance move from an area of greater concentration to an area of lesser concentration.

• Endocytosis is a kind of active transport wherein the cell membrane surrounds a substance and brings it into the cell.

• Exocytosis is a kind of active transport wherein a vesicle fuses with a plasma membrane and releases its content outside the cell.

• Flaccid (not firm or stiff) cell which means too much water has been lost or not enough water is available, a plant wilt. It is the exact opposite of turgid.

• Hypertonic solution is a solution with higher salt concentration than in normal cells of the body and the blood.

• Hypotonic solution is a solution with a lower salt concentration than in normal cells in the body or in the blood.

• Isotonic solution is a solution that has the same salt concentration as the normal cells of the body or in the blood.

• Lactobacillus is a bacteriun causes sourness in milk.

• Osmosis is the diffusion of water through a membrane. The movement of water is the same as simple diffusion.

• Passive Transport is a kind of cell transport that do not require the cell to use its own energy in transporting substances in and out of the cell.

• Phagocytosis is the process in which the materials that are taken into the cells are solid particles.

• Pinocytosis is the process in which the cells engulf liquids.

• Plasmolysis is a shrinking of cytoplasm away from the wall of the living cell due to the outward osmotic flow of water.

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• Solute is a substance dissolves in another substance, usually the component of solution in a lesser amount.

• Solvent is a substance usually liquid, that dissolves or can dissolve another substance. • Turgid (swollen or hard) cell is a plant cell whose vacuole contains the maximum

amount of water. The water has entered by osmosis, because the vacuole is hypertonic to the solution outside the cell.

Suggested organizational strategies

• Organization of groups and preparation of materials before the conduct of the activity.

Opportunities for Integration

• MAPEH - developing skills in arts and sportsmanship. • MATH - developing skills in solving mathematical problems. • E.P. - demonstrating values of cooperation and camaraderie.

Activities in this Learning Guide

Activity 1: Think About...Cell Membrane

Multiple Intelligences

• Verbal/Linguistic, Interpersonal

Skills

• Knowledge of major ideas, Observation and recall of information

Activity 2: Say It In Words! (Part 1)

Multiple Intelligences

• Verbal/Linguistic, Interpersonal

Skills

• Knowledge of major ideas, Grasp meaning, Observation and recall of information

Activity 3.1: Useful Technologies From Cell

Multiple Intelligences

• Verbal/Linguistic, Interpersonal

Skills

• Grasp meaning, Identification of components, Understanding information

Activity 3.2: Smelly Balloons

Multiple Intelligences

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Skills

• Grasp meaning, Observation and recall of information, Identification of components

Activity 3.3: (Option 1) - Osmosis In Gummy Bears

Multiple Intelligences

• Verbal/Linguistic, Visual/Spatial, Body/Kinaesthetic

Skills

• Recognition of hidden meanings, Grasp meaning, Solve problems using required skills or knowledge, Observation and recall of information

Activity 3.3: (Option 2) - Osmosis EggXactly

Multiple Intelligences

• Verbal/Linguistic, Visual/Spatial, Body/Kinaesthetic

Skills

• Grasp meaning, Solve problems using required skills or knowledge, Observation and recall of information, Understanding information

Activity 3.4: Awesome Osmosis

Multiple Intelligences

• Verbal/Linguistic, Interpersonal, Visual/Spatial, Body/Kinaesthetic

Skills

• Grasp meaning, Observation and recall of information, Understanding information

Activity 3.5: "Endo" and "Exo" Game

Multiple Intelligences

• Verbal/Linguistic, Interpersonal, Visual/Spatial, Body/Kinaesthetic

Skills

• Understanding information, Use information, Grasp meaning

Activity 4.1: Say It In Words! (Part 2)

Multiple Intelligences

• Verbal/Linguistic, Interpersonal

Skills

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Activity 4.2: Are You An Active or Passive Thinker?

Multiple Intelligences

• Verbal/Linguistic, Interpersonal, Visual/Spatial

Skills

• Knowledge of major ideas, Mastery of subject matter, Understanding information

Activity 5.1: Active and Passive Art

Multiple Intelligences

• Verbal/Linguistic, Interpersonal, Visual/Spatial, Body/Kinaesthetic

Skills

• Knowledge of major ideas, Mastery of subject matter, Use information, Interpret facts, compare, contrast, Translate knowledge into new context

Activity 5.2: Osmosis Everyday

Multiple Intelligences

• Naturalist, Interpersonal, Visual/Spatial

Skills

• Knowledge of major ideas, Mastery of subject matter, Use information, Solve problems using required skills or knowledge

Activity 6: My Active and Passive C.R.O.W.N

Multiple Intelligences

• Verbal/Linguistic, Intrapersonal

Skills

• Knowledge of major ideas, Mastery of subject matter, Use information

Key Assessment Strategies

• Paper - Pencil Test • Rubrics

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Mind Map

The Mind Map displays the organization and relationship between the concepts and activities in this Learning Guide in a visual form. It is included to provide visual clues on the structure of the guide and to provide an opportunity for you, the teacher, to

reorganize the guide to suit your particular context.

Stages of Learning

The following stages have been identified as optimal in this unit. It should be noted that the stages do not represent individual lessons. Rather, they are a series of stages over one or more lessons and indicate the suggested steps in the development of the targeted competencies and in the achievement of the stated objectives.

Assessment

All six Stages of Learning in this Learning Guide may include some advice on possible formative assessment ideas to assist you in determining the effectiveness of that stage on student learning. It can also provide information about whether the learning goals set for that stage have been achieved. Where possible, and if needed, teachers can use the formative assessment tasks for summative assessment purposes i.e as measures of student performance. It is important that your students know what they will be assessed on.

1. Activating Prior Learning

This stage aims to engage or focus the learners by asking them to call to mind what they know about the topic and connect it with their past learning. Activities could involve making personal connections.

Background or purpose

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The purpose of the activity is to describe a semi – permeable membrane and give its functions.

Strategies

Think.-Ink-Pair-Share (TIPS) is a strategy that allows groups to reach consensus, check understanding or as an introductory activity.

Peer Evaluation consists of student analysis and assessment of peer proficiency using either established or self-generated criteria. An activity must be very carefully structured if students are to receive valid feedback from their peers.

Materials

Student Activity Sheet 1, Think About...Cell Membrane, page 21

Activity 1: Think About...Cell Membrane

1. Have students choose their partner.

2. Distribute to each pair of students Student Activity Sheet 1, Think About...Cell Membrane, page 21.

3. Give students enough time to share their ideas.

4. When done, ask student volunteers to share their output in class. 5. Process the activity by asking students these questions:

• How do you describe semi – permeable membrane?

(Cell membrane is semi – permeable which means that some substances can pass across it and others cannot.)

• What is the function of cell membrane?

(Cell membrane controls what substance enters and leaves the cell. It also gives the cell its shape and protection.)

Formative Assessment

Peer evaluation rubric found on page 22 will be used to assess student's performance in doing the activity.

Roundup

Students should have:

• described a semi – permeable membrane. • given the function of cell membrane.

2. Setting the Context

This stage introduces the students to what will happen in the lessons. The teacher sets the objectives/expectations for the learning experience and an overview how the learning experience will fit into the larger scheme.

Background or purpose

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Strategy

Anticipation/Reaction Guide is strategy used to activate background knowledge before reading or doing an activity, stimulate interest and discussion, compare before and after decisions, reverse misconceptions, and assess students’ application of new knowledge and/or skills. Anticipation/ Reaction Guide is used before and after reading in a context area or conducting an investigation. The teacher prepares a list of statements about the topic for students to discuss before reading or beginning the investigation. Some of the statements should be true and some should be false. Students indicate if they agree or disagree and their reasons. After reading or completing the investigation, students again indicate if they agree or disagree and their reasons.

Materials

Anticipation/Reaction Chart (Student Activity Sheet 2, Anticipation/Reaction Chart, page 23)

Activity 2: Say It In Words! (Part 1)

1. Distribute Student Activity Sheet 2, Anticipation/Reaction Chart, page 23 and explain the instruction.

2. Have the students answer the activity sheet for 20 minutes.

3. Secure one copy of the Anticipation/Reaction Chart for recording. Have them come up with a consensus as to their stand to each of the statements by letting them raise their hands to express their opinion. Count the number of responses and record on the appropriate column under the “BEFORE” heading. Welcome all their opinions whether they agree or disagree. Leave the chart as it is and revisit in stage 4, Check for Understanding.

4. Inform the students that they will be finding the answers to the statements by performing different activities to help them understand about the topic on: cell/cell organelles/secretion used to promote food production and health and cell transport. Orient them with the objectives as well.

Formative Assessment

Behavior Checklist found on page 24 will be used to assess student's performance in doing the activity.

Roundup

Students should have expressed their views about some concepts related to: cell

organelles/cell activities used to promote food production and health, active and passive transport. They should have been oriented with the objectives as well.

3. Learning Activity Sequence

This stage provides the information about the topic and the activities for the students. Students should be encouraged to discover their own information.

Background or purpose

Agriculture and other industries use the products of cell organelles/cellular activities to improve the yield or to produce chemicals. Cells secrete certain substances during or after the cellular activity. Some cell secretion have been used by people to promote health as well as food production.

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obtained from food to move the molecules (or larger particles) through the cell membrane. Passive transport does not require such an energy expenditure, and occurs spontaneously.

Students will be engaged in performing series of activities where they will learn the concepts through discovery.

➢Activity 3.1 will help students explain that the activities of certain cell/cell organelles/secretions are used to promote food production and health. ➢Activity 3.2 will enable students to define/describe diffusion.

➢Activity 3.3 and 3.4 will enable students to describe a cell when placed in a different solutions (isotonic, hypotonic and hypertonic).

➢Activity 3.5 will help them demonstrate and describe endocytosis and exocytosis. These activities address the BEC learning competencies in Unit 2, Cell Structure and Function, 2.2.1 and 3.3.1 – 3.3.2 of the competencies.

Strategy 3.1

Small Group Discussion is a strategy that involves a smaller number of participants in each group. With this strategy, it is hoped, that all members of the group feel connected to each other in the accomplishment of a common goal, that each group member shares and collaborates with other members in ways that promote continued progress and that they develop social skills with support as their teacher.

Materials for Activity 3.1

Student Activity Sheet 3.1, Useful Technologies from Cell, page 25

Activity 3.1: Useful Technologies from Cell

1. Divide the class into about ten groups.

2. Distribute Student Activity Sheet 3.1, Useful Technologies from Cell, page 25.

3. Subdivide the information about food/medicine/health for them to read: golgi bodies and lysosomes, cytoskeleton and smooth endoplasmic reticulum (SER), soy sauce and patis and bagoong, nata and dairy products, insulin and cytoskeleton.

4. Ask students to choose a role within the group: leader, reader, recorder or presenter. Emphasize that the leader of each group needs to help the group in following the task. 5. Explain the role of every member:

• The recorder will write the idea of the group in the table. • The reader will read out loud the background of the activity.

• As a group use the material provided by the teacher to fill in the table and answer the questions.

• Work together to help the presenter practice his or her presentation to the class. The presentation includes the group’s answers to the table and question. He/she will present the group’s output to the class when it is the group’s turn.

6. Give students enough time to do the activity.

7. When done, have the presenter present their output to the class.

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• In what way do cell,cell organelles and cell secretion promote food production and health?

(Cell,cell organelles and secretion are important in promoting food production and health.)

Formative Assessment

Accuracy of students answer will be checked (Refer to Teacher Resource Sheet 3, Useful Technologies from Cell – Answer Key, page 28.)

Roundup

Students should have explained that the activities of certain cell, cell organelles and cell secretions are used to promote food production and health.

Strategy for 3.2

Hands On, Active Participation involves designing of activities so that students are actively involved in performing the activity. It is important as verbal participation in the activity.

Materials for Activity 3.2

4 Balloons vanilla/food extract dropper

Activity 3.2: Smelly Balloons

Advance Preparation:

• Using a dropper, place 4-5 drops of vanilla/food extract into each balloon. • Request student to blow up and tie, each balloon.

• Label the balloons A,B,C and D. 1. Divide the class into four groups. 2. Distribute the balloon to each group.

3. Provide students enough time to smell and identify the odor inside the balloon.

4. Go around, check if students are doing their work and guide them in doing the activity. 5. When done, conduct a debriefing by asking the following questions:

• How do odor molecules get out of the balloon?

(The odor molecules move/pass through the skin of the balloon.) • Which do you think has stronger odor, inside or outside the balloon?

(The odor inside the balloon is stronger than outside the balloon.)Why could you smell the odor?

(We could smell the odor because the molecules spread from the inside to the outside of the balloon.)

• How do molecules spread?

(The molecules spread from greater to lesser concentration.) Introduce the term diffusion. Ask:

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(Diffusion is the process where molecules move from greater to lesser concentration.)

Conduct a lecturette on diffusion. (Refer to Teacher Resource Sheet 4, Lecturette On Diffusion, page 30.)

Formative Assessment

Checking of students responses.

Roundup

Students should have defined/described diffusion.

Strategy for 3.3

Hands On, Active Participation

Materials for Activity 3.3 (Option 1)

2 plastic cups permanent marker tap water distilled water beaker/graduated cylinder ruler

platform balance

40% sugar solution 25% salt solution 3 Gummy Bears (different colors)/”growing animal” 2 aluminum or plastic screens (4"x4")/strainer

Student Activity Sheet 3.3, Osmosis In Gummy Bears, page 31

Activity 3.3: Osmosis In Gummy Bears (Option 1)

Advance Preparation:

• To make 100 mL of the 25% salt solution, add 25g salt to 75mL of water. Mix and then dispense into bottles.

• To make 100 mL of the 40% sugar solution, add 40g sugar to 60mL of water. Mix and then dispense into bottles.

1. Divide the class into desired number of groups.

2. Unlock words such as isotonic, hypotonic and hypertonic solution. You may refer to metadata page 4.

3. Build vocabulary such as solvent, solute and concentration (refer to metadata page 4). Show an example by dissolving 40 g of sugar in 60 mL of water. Ask the following questions:

• Which is a solute? (sugar) • Which is a solvent? (water)

• Based on the activity, how do you define solute? Solvent?

(Solute is a substance dissolved in another substance (solvent), usually the component of solution in a lesser amount.)

(Solvent is a substance usually liquid, that dissolves or can dissolve another substance.)

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4. Distribute Student Activity Sheet 3.3, Osmosis In Gummy Bears, page 31. 5. Make sure that students understand the instruction.

6. Provide students enough time to do the activity.

7. Go around, check if students are doing their work and guide them in doing the activity. 8. Process their observations on the activity. Ask:

• How could different solutions (distilled water, sugar solution and salt solution) affect the size of gummy bear?

(In distilled water, gummy bear remains the same; in sugar solution, gummy bear increases in size or swell; and in salt solution, gummy bear decreases in size or shrink.)

9. Conduct a lecturette on diffusion. (Refer to Teacher Resource Sheet 4, Lecturette On Diffusion, page 30.)

Formative Assessment

Accuracy of students output will be checked. ( Refer to Teacher Resource Sheet 5, Osmosis In Gummy Bears – Answer Key, page 33.

Roundup

Students should have described that: in distilled water (isotonic), cell is normal; in sugar solution (hypotonic), cell swells; and in salt solution (hypertonic), cell shrinks.

Strategy for 3.3

Hands On, Active Participation

Materials for Activity 3.3 (Option 2)

3 beakers or clear plastic cups vinegar

40% sugar solution 25 % salt solution

distilled water 3 eggs

platform balance 100 mL graduated cylinder ruler/tape measure aluminum foil

string

Student Activity Sheet 3.3, Osmosis EggXactly, page 34

Activity 3.3: Osmosis EggXactly (Option 2)

Advance Preparation:

• To make 100 mL of the 25% salt solution, add 25g salt to 75mL of water. Mix and then dispense into bottles.

• To make 100 mL of the 40% sugar solution, add 40g sugar to 60mL of water. Mix and then dispense into bottles.

1. Divide the class into desired number of groups.

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3. Build up vocabulary such as solvent, solute and concentration (refer to metadata page 4). Show an example by dissolving 40 g of sugar in 60 mL of water. Ask the following questions:

• Which is a solute? (sugar) • Which is a solvent? (water)

• Based on the activity, how do you define solute? Solvent?

(Solute is a substance dissolved in another substance, usually the component of solution in a lesser amount.)

(Solvent is a substance usually liquid, that dissolves or can dissolve another substance.)

• What is the concentration of sugar in a solution? (40 g of sugar) 4. Distribute Student Activity Sheet 3.3, Osmosis EggXactly, page 34.

5. Conduct a pre - laboratory discussion. Give the precautionary measure such as: • Proper handling and use of the beaker and graduated cylinder.

6. Make sure that students understand the instruction. 7. Provide students enough time to do the activity.

8. Go around, check if students are doing their work and guide them in doing the activity. 9. Process their observations on the activity. Ask:

• How could different solutions (distilled water, sugar solution and salt solution) affect the egg?

(In distilled water (isotonic), egg remains the same; in sugar solution (hypotonic), egg increases in size or swell; and in salt solution (hypertpnic), egg decreases in size or shrink.)

10.Have a post laboratory discussion to discuss the result of the activity.

11.Conduct a lecturette on osmosis. (Refer to Teacher Resource Sheet 7, Lecturette on Osmosis, page 37.)

Formative Assessment

Accuracy of students answer will be checked. (Refer to Teacher Resource Sheet 6, Osmosis EggXactly – Answer Key, page 36.)

Roundup

Students should have described that: In distilled water (isotonic), egg remains the same; in sugar solution (hypotonic), egg increases in size or swell; and in salt solution (hypertonic), egg decreases in size or shrink.

Strategy for 3.4

Hands On, Active Participation

Materials for activity 3.4

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5% salt solution 50% salt solution paper towel dropper

Student Activity Sheet 3.4, Awesome Osmosis, page 39

Activity 3.4: Awesome Osmosis

Advance Preparation:

• To make 100 mL of the 5% salt water solution add 5g salt to 95mL of water. Mix and then dispense into bottles.

• To make 100 mL of the 50% salt water solution add 50g salt to 50mL of water. Mix and then dispense into bottles.

1. Divide the class into desired number of groups.

2. Distribute Student Activity Sheet 3.4, Awesome Osmosis page 39.

3. Conduct a pre - laboratory discussion. Give the precautionary measure such as: • Proper handling and use of the microscope.

• Carefulness in handling sharp and breakable objects. 4. Make sure that students understand the instruction. 5. Provide students enough time to perform the activity.

6. Go around, check if students are doing their work and guide them in doing the activity. 7. Have a post laboratory discussion to discuss the result of the activity.

8. Conduct a lecturette on osmosis. (Refer to Teacher Resource Sheet 9, Lecturette on Elodea - Osmosis, page 41.)

Formative Assessment

Accuracy of students answer will be checked. (Refer to Teacher Resource Sheet 8, Awesome Osmosis – Answer Key, page 40.)

Roundup

Students should have described that: in distilled water (isotonic), cell is normal; in sugar solution (hypotonic), cell swells; in salt solution (hypertonic), cell shrinks.

Strategy for 3.5

Teacher Directed Instruction is highly teacher-directed and is among the most commonly used. This strategy is effective for providing information or developing step-by-step skills. It also works well for introducing other teaching methods, or actively involving students in knowledge construction.

Game is a strategy that stimulates student's active participation. The aim is for the students to have fun while learning.

Materials for Activity 3.5

Teacher Resource Sheet 10, “Exo” and “Endo” Game, page 42

Activity 3.5:”Endo” and “Exo” Game

1. Introduce “Exo” and “Endo” Game. Read the mechanics of the game. (Refer to Teacher Resource Sheet , “Exo” and “Endo” Game, page 42.)

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3. When done, conduct a debriefing by asking questions:

• Why is there a need to actively transport some substances into a cell? (Active Transport allows a cell to maintain conditions different from the surrounding environment.)

• How do you differentiate endocyctosis from exocytosis.

(Endocytosis involves the entry into the cell of materials that are too large to get in by mere diffusion while exocytosis, is the reverse of endocytosis, is the process by which a cell expels large molecules such as proteins, polysaccharides and insulin.)

4. Conduct a lecturette on lecturette on Active and PassiveTransport. (Refer to Teacher Resource Sheet 11, Lecturette on Active and PassiveTransport, page 43.

Formative Assessment

Students responses will be checked.

Roundup

Students should have:

• differentiated exocytosis from endocytosis.

• demonstrated and described exocytosis from endocytosis.

• explained that energy is needed to transport some substances into and out of the cell.

4. Check for Understanding of the Topic or Skill

This stage is for teachers to find out how much students have understood before they apply it to other learning experiences.

Background or purpose

The activities in this stage will help find out if students have learned the topic covering the following concepts: cell organelles used to promote food production and health, active and passive transport.

Strategy for 4.1

Anticipation/Reaction Guide

Materials for Activity 4.1

Anticipation/Reaction Chart ( partially completed in Stage 2 ) found on page 23

Activity 4.1: Say It In Words! (Part 2)

1. Revisit the Agree/Disagree Chart, page 23 previously answered in Stage 2.

2. Get the students to express their views once again. Find out if there are differences in their previous answers. Have them explain their answers using the concepts gained from the activities undertaken.

Strategy for 4.2

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Materials for activity 4.2

Student Activity Sheet 4.2, Are You An Active or Passive Thinker?, page 45

Activity 4.2: Are You An Active or Passive Thinker?

1. Divide the class into desired number of groups.

2. Distribute Student Activity Sheet 4.2, Are You An Active or Passive Thinker?, page 45 to each group.

3. Give students enough time to do the activity. 4. When done, let them present their output in class. 5. Facilitate checking of answers.

Formative Assessment

Accuracy of students output will be checked. (Refer to Teacher Resource Sheet 12, Are You An Active or Passive Thinker? - Answer Key, page 48.)

Roundup

Students should have:

• explained that the activities of certain cell organelles are used to promote food production and health.

• Identified situations showing osmosis and/or diffusion. • distinguished active and passive transport.

5. Practice and Application

In this stage, students consolidate their learning through independent or guided practice and transfer their learning to new or different situations.

Background or purpose

The concepts learned from previous stages will be applied to new but relevant situations in this stage. This will be done to enhance student's conceptual understanding of the topic.

Strategy for 5.1

Cartoon or Comic Strip is a series of drawings that read as a narrative, arranged together on the page of a newspaper, magazine, or book.

Materials for Activity 5.1

long bond paper pencil with eraser crayons

Activity 5.1: Active and Passive Art

1. Divide the class into groups with three members.

2. Have students draw a cartoon or comic strip to show the role of diffusion and osmosis in an everyday situation and usefulness of cell/ cell organelles/secretions to promote production of food and health.

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5. Once done, have them display their output for judging. Facilitate checking of outputs.

Formative Assessment

Students output will be assessed using rubric for comic strips. (Refer to Teacher Resource Sheet 13, Rubric for Comic Strip, page 51.)

Strategy for 5.2

Problem solving instruction

Materials for Activity 5.2

Student Activity Sheet 5.2, Osmosis Everyday, page 52

Activity 5.2: Osmosis Everyday

1. Divide the class into desired number of groups.

2. Distribute Student Activity Sheet 5.2, Osmosis Everyday, page 52. 3. Give students enough time to perform the activity.

4. When done gather their journals and use their responses in deciding for the next steps to be undertaken.

Formative Assessment

Accuracy of students answer will be checked. (Refer to Teacher Resource Sheet 14, Osmosis Everyday – Answer Key, page 53.)

Roundup

Students should have solved the problems applying uses of cell organelles and cellular transport concepts.

6. Closure

This stage brings the series of lessons to a formal conclusion. Teachers may refocus the objectives and summarize the learning gained. Teachers can also foreshadow the next set of learning experiences and make the relevant links.

Background or purpose

This is the stage where students sum up the learning experiences they had. They will be given an activity that will allow them to ponder on the concepts they learned in the topic.

Strategy

C.R.O.W.N. is a technique that encourages students to reflect on the completed topic. It is an acronym of the following ideas: C-communicate what you learned, R-reaction to what you learned, O-offer a sentence which sums up the topic, W-ways you could use on what you learned and N-note how well you did.

Materials

Student Activity Sheet 6, My Active and Passive C.R.O.W.N., page 54

Activity 6: MY ACTIVE AND PASSIVE C.R.O.W.N

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2. Explain that they need to think about the concepts they learned, communicate what they learned, react to what they learned, offer a sentence which sums up the topic, ways they could use on what they learned and note how well they did.

3. Discuss how the activity will be done.

4. Give them enough time to perform the activity.

Formative Assessment

You can ask some volunteers from the class to read their C.R.O.W.N.

Roundup

Students should have thought about the things they have learned, communicated what they learned, reacted to what they learned, offered a sentence which sums up the topics, ways they could use on what they learned and noted how well they did.

Teacher Evaluation

(To be completed by the teacher using this Teacher’s Guide) The ways I will evaluate the success of my teaching this unit are: 1.

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Student Activity Sheet 1

Think About...Cell Membrane

Questions What I Thought? What My Partner Thought? What We Will Share?

How do you describe a semi-permeable membrane?

What is the function of cell membrane?

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Teacher Resource Sheet 1

Peer Evaluation Rubric

CRITERIA Unsatisfactory (3 points) Satisfactory (5 points) Very Satisfactory (7 points) TOTAL

Initiator Peer shows a minimum of leadership skills; peer sometimes contributes a hopeful idea.

Peer is an active but not always effective leader; generally provides several useful ideas.

Peer a real leader; initiates work and gets others to accomplish tasks.

_____

Communicator Peer is an ineffective communicator; talks about everything except for the topic.

Peer is a good

communicator, but has difficulties expressing points.

Peer is able to

effectively and clearly communicate ideas of the topic.

_____

Listener Peer waits while others speak but is not really listening.

Peer is open minded, and is willing to listen to others.

Peer practices active listening, and can both reflect and sympathize with views of others.

_____

Critical Thinker Peer contributes minor

information of the topic. Peer contributes one or two complete information of the topic.

Peer is able to contribute an

influential or accurate information of the topic.

_____

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Student Activity Sheet 2

Anticipation/Reaction Chart

DIRECTIONS: Express your thoughts by checking the agree or disagree column under “BEFORE” heading. Support your answer by writing the explanation under “EXPLANATION” column.

STATEMENTS BEFORE EXPLANATION AFTER EXPLANATION

Agree Disagree Agree Disagree

1. Cell organelles are used to promote food production and health.

2. Molecules are always moving.

3. The cell will shrink when water gets out from it.

4. Movement of molecules in and out of the cell always requires energy.

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Teacher Resource Sheet 2

Behavior Checklist

DIRECTION: Please check the box that appropriately describes the behavior of the students while doing the activity.

Name of Students

Demonstrated productive character traits (e.g. patience, thoroughness, effort,self-reliance)

Displayed an adequate understanding of the task.

Turned in his/her work on time.

Allowed others to remain on task.

Respected opinion of others.

1

2

3

4

5

6

7

8

9

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Student Activity Sheet 3.1

Useful Technologies from Cell

DIRECTIONS: Read the information about food/medicine/health assigned to your group and fill in the corresponding column in the table below.

The study of cell structures and how they function is important to basic food production and maintenance of health.

CELL ORGANELLES

Golgi Bodies are believed to produce cellulose for the cell wall formation. Such cellular structures, as they normally function, will boost the cellulose products industry and help maintain rigidly protected plant cells.

Lysosomes play a role in drug action. An increase in the dosage of vitamin A may destroy lysosomal membranes, thus causing fractures and lesions in bones and cartilages. These are effects of intoxication. A substance with an opposite effect is steroids. Steroids stabilize lysosomes and therefore bring about an anti – inflammatory effect.

The cytoskeleton is made up of protein filaments and is equivalent to human bones. These filaments are useful in the detection of disorders. Of the three kinds of fibers making up the cytoskeleton, the

intermediate filaments have not been given sufficient attention in studies of cell structures. However, recent research has shown that they may be essential to the detection of cancer's possible origin. The smooth endoplasmic reticulum (SER), found in the liver of vertebrates, functions to detoxify (remove the harmful effects of) many poisons and drugs such as barbiturates, amphetamines, morphine and codeine. Most of such harmful drugs as cocaine and marijuana cause the cells and tissues of the body to deteriorate. Harmful damage is mostly concentrated in the brain, kidneys, liver and reproductive cells, bones and epithelial cells. The drugs alter their functions and ultimately destroy them.

CELL

Eukaryotics and prokaryotics are important in many industries. Yeast, an eukaryote, is used in making bread rise. Acetobacillus, a prokayote, helps in the fermentation of sugar which produces acetic acid. Vinegar is one kind of acetic acid solution.

Soy sauce.Soy sauce is one of the world's oldest condiments and has been used in China for more than 2,500 years. It is made from fermenting a mixture of mashed soybeans, salt, and enzymes. It is also made artificially through a chemical process known as acid hydrolysis. Traditionally fermentation in soy sauce making lasts from one to three hours and requires a temperature of 37oC. However, recent studies have established a good quality soy sauce needs

to be fermented for month at 40oC. Scientist use the salt – tolerant acid bacterium, Lactobacillus delbrueckii, a cell used to make a good quality of soy sauce. They have also discovered that mongo beans are good substitute for soybeans.

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Nata. Nata – making is a common cottage industry even in the modern world. Traditionally, nata is made from coconut water. Recent studies, however have yielded the other raw materials like pineapple juice and rice washings can be used. Makers of nata use Acetobacter aceti sp. xylinum in the synthesis of pellicles, a membranelike bacterial growth on the surfaces of a liquid medium.

Dairy Products. Lactobacillus, also a prokaryote, is used in the preparation of some dairy products. Cheese is produced naturally by the action of Lactobacillus. This bacterium causes sourness in milk products. Dairy production is dependent on the microorganisms involved. Specific organisms, like Lactobacillus acidophilus are added to milk after pasteurization. L.acidophilus produces sour milk cottage cheese.

CELL SECRETIONS

Some of cellular secretions widely used in medicine are the hormones and enzymes. Hormone helps regulate the breakdown and buildup of various substances in the body. Enzymes on the other hand, speed the breakdown of substances. In medicine, both prokaryotes represented by the bacteria and eukaryotes in the form of fungi have been used in the production of antibiotics Insulin is a hormone secreted by a group of cells in the pancreas. It helps regulate the breakdown of carbohydrates. The lack of insulin lowers the rate of carbohydrates' breakdown and raises the level of sugar in the blood. This results in an illness called diabetes. One of the important achievements of medical scientist is the discovery and extraction of insulin from the pancreas of animals. Insulin is now administered to human patients suffering from diabetes. However the amount of insulin obtained per animal for example cow, is limited.

Another advancement in medical science was the discovery of interferon in 1957. Interferon is a protein produced by virus-infected cells. Medical scientist believed that interferon slows down the growth of viruses. The substance also inhibits the transformation of normal cells to tumor cells. Interferon is currently used to treat certain types of cancer.

Food Products and Medicine/ Health

Cell/CellOrganelles/ Secretion

How the cell/cell organelles/secretion promote food production and health?

Soy Sauce

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Nata

Dairy Products

Insulin

Interferon

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Teacher Resource Sheet 3

Useful Technologies from Cell – Answer Key

DIRECTIONS: Read the information about food/medicine/health assigned to your group and fill in the corresponding column in the table below.

Food Products and

Medicine/ Health Cell/CellOrganelles/ Secretion How the cell/cell organelles/secretion promote food production and health?

Soy Sauce

Lactobacillus delbrueckii Used to make a good quality soy sauce.

Patis and Bagoong

Aspergillus oryzae

Streptomyces griseus

Produced an enzyme known as protease which accelerates/hasten fermentation process.

Nata

Acetobacter aceti sp.

xylinum Used in making nata de coco, pineapple, rice washings and other raw materials.

Dairy Products

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Insulin

Secreted by a group of cells in the pancreas of animals.

It helps regulate the breakdown of carbohydrates. The lack of insulin lowers the rate of carbohydrates' breakdown and raises the level of sugar in the blood. This results in an illness called diabetes

Interferon

A protein produced by virus-infected cells.

Interferon slows down the growth of viruses. The substance also inhibits the transformation of normal cells to tumor cells. Interferon is currently used to treat certain types of cancer.

Health

Golgi Bodies It produces cellulose for the cell wall formation and will boost the cellulose products industry and help maintain rigidly protected plant cells.

Lysosome Lysosome plays a role in drug action. Steroids stabilize lysosomes and therefore bring about an anti – inflammatory effect.

Cytoskeleton These filaments are useful in the detection of disorders.

Smooth Endoplasmic Reticulum (SER)

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Teacher Resource Sheet 4

Lecturette On Diffusion

Diffusion is the movement of molecules from a region in which they are highly concentrated to a region in which they are less concentrated. It depends on the motion of the molecules and continues until the system in which the molecules are found reaches a state of equilibrium, which means that the molecules are randomly distributed throughout the system. An important concept in understanding diffusion is the concept of

equilibrium. There are two types of equilibrium. Static equilibrium occurs when there is no action taking place. Dynamic equilibrium occurs when two opposing actions occur at the same rate. For example, consider a bucket full of water. It is in a state of static equilibrium because the water level stays the same. The water is not moving. If you were to poke a hole in the bottom of the bucket, water would leak out. This system would not be at equilibrium because there is action taking place - water is leaking out - and the water level in the bucket would drop. However, if you were to begin pouring water into the bucket at the same rate that it was leaking out, the water level in the bucket would stay the same because the rate at which the water is entering the bucket is equal to the rate at which it is leaking out. This is an example of dynamic equilibrium, and it applies to nearly everything that happens in the natural world.

Diffusion occurs when a system is not at equilibrium. As an example, suppose you drop one drop of ink into a glass of water. At first, all of the ink molecules are in a small space and they are moving around in a random way. They move in straight lines and change direction only when they collide with each other or the surrounding water molecules. Some of the ink molecules near the edge of the drop move away from the center of the drop. As a matter of fact, most of the molecules move away from the center of the drop.

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Student Activity Sheet 3.3 (Option 1)

Diffusion In Gummy Bears

PROCEDURE:

1. Obtain two plastic cups, one labelled with “ Distilled Water “, the other labelled “ Sugar Solution”.

2. Set aside one bear as control set – up.

3. Using ruler, measure the volume (length x width x height) of two gummy bears in cm. Record the volume of gummy bear in the data table below under “BEFORE” column.

4. Measure the mass of the two gummy bears. Record the mass of gummy bear in the data table below under “BEFORE” column.

5. Using the beaker/graduated cylinder measure the water enough to cover the gummy bear. Record the volume of water in the data table below under “BEFORE” column.

6. Separately submerge gummy bears in the cups (one distilled water and one sugar solution). 7. Place the cups on the counter away from direct sunlight. Let them sit overnight.

8. On the next day, gently pour the water over a screen into another cup. Measure the volume of liquid. Record the volume of water in the data table below under “AFTER” column.

9. While on the screen, measure the volume of the gummy bear. Record the volume of gummy bear in the data table below under “AFTER” column. Blot the screen dry by placing it on a paper towel. BE CAREFUL not to break gummy bears, they are very fragile.

10.Measure also the mass of the two gummy bears. Record the mass of gummy bear in the data table below under “AFTER” column.

11.Place the gummy bears back into their cups. Cover the gummy bears with saturated salt solution. Let them sit overnight.

12.Repeat steps 8 - 10. Find the volume and mass of the gummy bears. Measure also the volume of water. Record the volume and mass of gummy bear and volume of water in the data table below under “AFTER” column.

Table Observation

GUMMY BEARS

VOLUME OF BEARS VOLUME OF WATER MASS OF GUMMY BEAR BEFORE (cm) AFTER (cm) BEFORE (mL) AFTER (mL) BEFORE (g) AFTER (g)

Distilled Water Bear

Sugar Water Bear

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QUESTIONS:

1. In which solution, is bear volume the

a. largest? Why? _____________________________________________________________ ___________________________________________________________________________ b. smallest? Why? ___________________________________________________________ ___________________________________________________________________________ 2. Examine the volume data. In which solution, does volume of water

a. decrease? Why? ___________________________________________________________ ___________________________________________________________________________ b. increase? Why? ___________________________________________________________ ___________________________________________________________________________ c. remain constant? Why? _____________________________________________________

3. How did you know that water gets in and out of the egg?

______________________________________________________________________________ 4. How could the gummy bear represent a model of a cell with a semi – permeable

membrane? Explain your reason.

___________________________________________________________________________ ___________________________________________________________________________ 5. Which part of the gummy bear acts as a semi – permeable membrane?

___________________________________________________________________________ ___________________________________________________________________________ 6. Describe the direction of water movement when gummy bear is placed in the following

types of solutions?

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Teacher Resource Sheet 5

Diffusion In Gummy Bears – Answer Key

Questions:

( Note: Answers on the Data Table will vary, depending on the observation and data gathered by the students.)

1. In which solution, is bear volume the a. largest? Why?

Bear placed in sugar solution is the largest in volume because water molecules enter the bear which causes the bear to swell.

b. smallest? Why?

Bear placed in salt solution is the smallest in volume because water molecules move out of the bear which causes the bear to shrink.

2. Examine the volume data. In which solution, does volume of water a. decrease? Why?

Volume of sugar solution decreases because the water molecules move toward the bear.

b. increase? Why?

Volume of salt solution increases because water moves outside the bear. c. remain constant? Why?

Volume of distilled water remains constant because the water that moves inside and outside the bear is equal.

3. How did you know that water gets in and out of the egg? Through the difference in its mass.

4. How could the gummy bear represent a model of a cell with a semi - permeable membrane? Explain your reason.

The bear could be a model of a cell with a semi – permeable membrane because some substances can move in and out through it.

5. Which part of the gummy bear acts as a semi – permeable membrane?

The outer membrane/part of the gummy bear acts as a semi – permeable membrane. 6. Describe the direction of water movement when gummy bear is placed in

a. distilled water? Water moves in and out of the outer membrane of gummy bear. b. sugar solution? Water moves toward the gummy bear.

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Student Activity Sheet 3.3 (Option 2)

Osmosis EggXactly

PROCEDURE:

1. Using a flexible tape measure or a piece of string, measure the circumference of the 3 eggs. If you measure the eggs with a piece of string, follow these steps:

a. Wrap the string snugly around the egg at the equator, (but be careful not to cut into the egg’s membrane with the string).

b. Grasp the string between your thumb and finger exactly at the point where the end of the string meets the rest of the string after circling the egg.

c. Keeping your thumb and finger in place, lay the string straight on a ruler. d. Use a metric ruler to measure the distance from the end of the string to the

point where you are holding it.

Record the measurement in Table 1 and 2 below under “BEFORE” column. You may also record any other observations in Table 1 below under “BEFORE” column. 1. Place 3 eggs into a beaker of vinegar. Make sure that all the eggs are covered with the

vinegar. (Note each egg may also be placed into the cups and then covered with vinegar).

2. On day 2, pour off the vinegar and add ‘fresh’ vinegar so that the eggs are completely covered.

3. Let the eggs remain in the beaker for 3 days until the outer shell is dissolved.

4. On the 3rd day, remove the eggs from the vinegar. Rinse with water. (If necessary, gently

rub with your thumb the remaining shell off of the eggs under running water.) Repeat step 1. Record the measurement and observations in Table 1 under “AFTER” column. Table 1 Observations of Egg In Vinegar

Observations of egg in vinegar.

BEFORE AFTER

5. Place each egg into a separate beaker and cover one with 150mL of distilled water, another with 150 mL of corn syrup/sugar solution, and the last one with 150 mL of a 25% salt solution. Make sure that the eggs are fully submerged in the three types of solutions. Tightly cover the beaker with aluminum foil.

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Table 2 Observations of Egg in Different Solutions

Solution

Circumference

of the egg Mass of the egg Volume of liquids

BEFORE AFTER BEFORE AFTER BEFORE AFTER

Distilled Water

Corn Syrup/Sugar solution

Salt solution

Questions:

1. In which solution, is egg circumference the

a. largest? Why? _____________________________________________________________ ___________________________________________________________________________ b. smallest? Why? ___________________________________________________________ ___________________________________________________________________________ 2. Examine the volume data. In which solution, does volume

a. decrease? Why? ___________________________________________________________ ___________________________________________________________________________ b. increase? Why? ___________________________________________________________ ___________________________________________________________________________ c. remain constant? Why? _____________________________________________________ 3. How did you know that water gets in and out of the egg?

______________________________________________________________________________ 4. How could the egg represent a model of a cell with a semi - permeable membrane? Explain

your reason.

___________________________________________________________________________ ___________________________________________________________________________ 5. Which part of the egg acts as a semi – permeable membrane?

___________________________________________________________________________ ___________________________________________________________________________ 6. Which is the direction of the movement of water when egg is placed in

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Teacher Resource Sheet 6

Osmosis EggXactly – Answer Key

Questions:

( Note: Answers on Table 1 and 2 will vary, depending on the observation and data gathered by the students.)

1. In which solution, is egg circumference the a. largest? Why?

Egg placed in sugar solution is the largest in volume

because water molecules enter the egg which causes the egg to swell. b. smallest? Why?

Egg placed in salt solution is the smallest in volume because water molecules move out of the egg which causes the egg to shrink.g

2. Examine the volume data. In which solution, does volume a. decreases? Why?

Volume of sugar solution decreases because the water molecules move toward the egg.

b. increase? Why?

Volume of salt solution increases because water moves outside the egg. c. remain constant? Why?

Volume of distilled water remains constant because the water that moves inside and outside the egg is equal.

3. How did you know that water gets in and out of the egg? Through the difference in its mass.

4. How could the egg represent a model of a cell with a semi - permeable membrane? Explain your reason.

The egg could be a model of a cell with a semi – permeable membrane because substances can move in and out through it.

5. Which part of the egg acts as a semi – permeable membrane?

The outer membrane (part next to shell) acts as a semi – permeable membrane. 6. Which is the direction of the movement of water when egg is placed in

a. distilled water? Water moves in and out of the outer membrane of the egg. b. sugar solution? Water moves toward the outer membrane of the egg.

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Teacher Resource Sheet 7

Lecturette On Osmosis

A living cell is 75% water. It is a substance that can penetrate the cell membrane. Water molecules tend to move from an area of higher concentration of solvent and lower concentration of solute to an area of lower water concentration and a high concentration of solute. This movement of water across the membrane is called osmosis.

Osmosis is affected by by the concentration of solutes and solvents inside and outside the cell.

ANIMAL CELL

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The direction of water movement across a cell membrane depends upon the concentration of water on each side of the cell.

Isotonic solution is a solution that has the same salt concentration as the normal cells of the body and the blood. In an isotonic solution, the concentration of solutes and water outside the cell is the same as that inside a cell. The movement of water in and out of the cell is therefore equal.

Hypotonic solution is a solution with a lower salt concentration than in normal cells of the body and the blood. In hypotonic solution, the concentration of solutes is lower and water

concentration is higher outside compared to the inside of the cell. Hence water moves from the solution outside to the inside of the cell. Osmosis builds up pressure in the cell which is called

turgor pressure. A turgid (swollen and hard) cell is a plant cell whose vacuole contains the maximum amount of water. The water has entered by osmosis, because the vacuole is hypertonic to the solution outside the cell.

There is a limit to the amount of water that can enter the cell. The cell reaches this limit when the osmotic pressure attracting water into the vacuole is countered by the inward mechanical pressure exerted by the cell wall. A plant cell in a more hypotonic solution will absorb water by

endosmosis (the inward flow of fluid through a semi – permeable membrane toward a fluid of greater concentration), so that the increased volume of water in the cell will increase pressure, making the protoplasm push against the cell wall, a condition known as turgor. Turgor makes plant cells push against each other in the same way and is the main line method of support in non-woody plant tissue. Plant cell walls resist further water entry after a certain point, known as full turgor, which stops plant cells from bursting as animal cells do in the same conditions. This is also the reason that plants stand up right. Without the stiffness of the plant cells the plant would fall under its own weight. This is the same reason that when you pour water into a potted plant it perks up.

Hypertonic solution is a solution with a higher salt concentration than in normal cells of the body and the blood. In a hypertonic solution, the concentration of solutes is higher and the concentration of water is lower outside the cell. When plant cells are placed in a solution which has exactly the same osmotic strength as the cells they are in a state between turgidity and flaccidity. If a plant cell is placed in a hypertonic solution, the plant cell loses water and hence turgor pressure, making the plant cell flaccid. If too much water has been lost or not enough water is available, a plant will begin to wilt. When this happens the cells of a plant become

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Student Activity Sheet 3.4

Awesome Osmosis

Procedure:

1. Prepare a wet mount of an Elodea leaf with tap water. 2. Observe the leaf under Low Power Objective (LPO:10X).

3. Observe the leaf under High Power Objective (HPO:40X). Pay particular attention to the “green spots”, the chloroplasts. Draw the Elodea leaf and record your observations in the table below. Remove the slide from the stage of the microscope.

4. Place 2 drops of the 5% salt solution on the slide at the edge of the cover slip.

5. Return the slide to the microscope stage and repeat the observations of the cells under Low Power Objective (LPO:10X) and High Power Objective (HPO:40X). Draw the Elodea leaf and record your observations in the table below.

6. Repeat the above procedure with the 50% salt water solution. Draw the Elodea and record your observations/possible explanations in the table below.

Elodea Leaf as seen under the

microscope. What happened to the chloroplasts? Why?

Elodea leaf cell

Elodea leaf submerged in distilled water

Elodea with 5% salt solution

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Teacher Resource Sheet 8

Awesome Osmosis – Answer Key

Elodea leaf as seen under the microscope What happened to the chloroplasts? Why?

Elodea leaf cell

The chloroplasts are spread throughout the cell.

Elodea leaf submerged in distilled water

No change is observed in the elodea leaf. The chloroplasts are spread throughout the cell because movement of water inside and outside the cell is equal or balance.

Elodea with 5% salt solution

The chloroplasts swell or enlarge. Water moves toward the cell or inside the cell.

Elodea with 50% salt solution

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Teacher Resource Sheet 9

Lecturette on Elodea – Osmosis

Elodea is a common freshwater plant that is frequently used to decorate aquariums. The leaves of Elodea are only two cells thick and are ideal for the microscopic study of the effects of osmotic solutions. Freshwater is hypotonic to Elodea and maintains normal turgor (osmotic) pressure in the plant. A

hypotonic solution is a solution that contains less (hypo) solutes than the cytoplasm of the cell. Thus, a hypotonic solution has more water than the cell and water has a tendency to move (diffuse) into the cell. In plants this inward "pressure" produces rigidity of the cell as the plasma membranes are pushed against the cell walls. Plant cells do not rupture because the cell walls resist the outward expansion of the plasma membrane.

A hypertonic solution is a solution that contains more (hyper) solutes than the cytoplasm of the

cell. Thus, a hypertonic solution has less water than the cell and water moves (diffuses) out of the cell. As water moves out of the cells there is a loss of turgor pressure and the plasma membranes detach from the cell walls as the cells shrink.

A hypotonic solution contains less solute (thus, more water) than the cytoplasm of the cells. Thus, placing crenated Elodea cells into a

hypotonic solution (100% water) causes water movement into of the cells resulting in the swelling of the cells. The movement of water into the plasmolyzed cells results in an increase in turgor pressure and the cells expand and force the plasma membrane against the cell walls. The cells will not rupture because their turgor pressure is not strong enough to break the walls.

Internet Source:

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Teacher Resource Sheet 10

“Endo” and “Exo” Game

DIRECTIONS:

1. Have about 40 students form a circle (cell membrane) by holding hands.

2. Assign 5 students to act as a fat globules and fluids rich in proteins. (You may put labels to these students). In order for these fluids to get inside the cell, the cell membrane may

reshape and engulf these substances. Energy is required to do this process known as

endocyctosis.

3. One at a time, the students who act as a fat globule and fluids rich in proteins outside the cell says: “Little cell, Little cell, let me in”.

4. The cell membrane replies: “Not by Diffusion, not by Osmosis are you coming in? I hear you knocking but you can’t come in.” Then, the cell membrane will catch by engulfing these students (fat globules and fluids rich in proteins)

5. The students (fat globules and fluids rich in proteins) then breaks through the cell membrane joining the others inside, expending energy to get inside the cell. 6. Place 5 students inside a circle (cell membrane).These students will represent

proteins, polysaccharides and insulin.(You may put labels to these students). These large molecules must be spilled out of the cell. In order to move out of the cell membrane, a significant amount of energy, Adenosine Triphosphate (ATP) is required. The process is known as exocytosis.

7. As the teachers says “endo”....”exo”...then, a circle (cell membrane) will perform the process stated by the teacher.

8. The game continues until 5 students (fat globules and fluids rich in proteins) outside the cell could get inside the cell and the 5 students (proteins, polysaccharides and insulin) inside the cell could get out of the cell.

QUESTIONS:

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Teacher Resource Sheet 11

Lecturette on Active and Passive Transport

Cells require materials of various sizes and in varying concentrations. Consequently, cells have a number of mechanisms to transport materials across the membrane in or out of the cell. These mechanisms generally fall into two categories: 1) passive, and 2) active, using cellular energy.

Passive Transport

Passive Transport mechanisms act as a result of the inherent kinetic energy of molecules and therefore require no expenditure of cellular energy. Diffusion and osmosis are examples of passive transport mechanisms. Diffusion is the movement of a solute from an area where it is present in a high concentration, toward an area in which it is present in a lower concentration. Small molecules such as molecular oxygen and carbon dioxide can cross the membrane easily. Larger polar molecules such as glucose cannot cross the

membrane unless they are helped by a membrane protein. This latter mechanism is known as “facilitated diffusion”. Passive transport mechanisms move materials along a concentration gradient.

Active Transport

Active transport is movement of molecules across a cell membrane or membrane of a cell organelle, from a region of low concentration to a region of high concentration. Since these molecules are being moved against a concentration gradient, cellular energy is required for active transport. Active transport allows a cell to maintain conditions different from the surrounding environment.

There are two main types of active transport; movement directly across the cell membrane with assistance from transport proteins, and endocytosis, the "engulfing" of materials into a cell using the processes of pinocytosis, phagocytosis, or receptor-mediated endocytosis.

Transport proteins found within the phospholipid bilayer of the cell membrane can move substances directly across the cell membrane, molecule by molecule. The sodium-potassium pump, which is found in many cells and helps nerve cells to pass their signals in the form of electrical impulses, is a well-studied example of active transport using transport proteins. The transport proteins that are an essential part of the sodium-potassium pump maintain a higher concentration of potassium ions inside the cells compared to outside, and a higher concentration of sodium ions outside of cells compared to inside. In order to carry the ions across the cell membrane and against the concentration gradient, the transport proteins have very specific shapes, which only fit sodium and potassium ions. Because the transport of these ions is against the concentration gradient, it requires a significant amount of energy. It has been estimated that a full one third of the ATP used by a resting animal is used by the sodium-potassium pump.

The two processes of transporting materials in the cell by active means are by endocyctosis and exocytosis.

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pinocytosis and phagocytosis. Pinocytosis is the process in which cells engulf liquids. The liquids may or may not contain dissolved materials. Phagocytosis is the process in which the materials that are taken into the cell are solid particles.

With receptor-mediated endocytosis the substances which are to be transported into the cell first bind to specific sites or receptor proteins on the outside of the cell. The substances can then be engulfed into the cell. As the materials are being carried into the cell, the cell

membrane pinches in forming a vacuole or other vesicle. The materials can then be used inside the cell. Since all types of endocytosis use energy, they are considered active transport.

Exocytosis, the reverse of endocyctosis, is the process by which a cell expels large molecules, such as proteins and polysaccharides.

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Student Activity Sheet 4.2

Are You an Active or Passive Thinker?

Part A.

DIRECTIONS: Fill in the table below:

Food Products /

Medicine/ Health Cell/CellOrganelles/ Secretion How the cell/cell organelles/secretion promote food and health?

Soy Sauce

Patis and Bagoong

Nata

Dairy Products

Figure

Table Observation

Table Observation

p.31
Table 1 Observations of Egg In Vinegar

Table 1

Observations of Egg In Vinegar p.34
Table 2 Observations of Egg in Different Solutions

Table 2

Observations of Egg in Different Solutions p.35

References