CELL STRUCTURE AND FUNCTION

(1)

CELL STRUCTURE AND

FUNCTION

(2)

Cell Theory

 In 1665, Englishman Robert Hooke used an early light microscope to look at a thin slice of cork.

 Under the microscope, cork seemed to be made of thousands of tiny,

empty chambers.

 Hooke called the chambers “cells”.

After the rooms of monks that were

called cells.

(3)

Cell Theory

 By 1855, it was clear that cells were the basic units of life, and the Cell Theory was born. The cell theory states:

1 All living things are made of cells

2 Cells are alike in structure and function.

3 New cells are produced from existing cells.

4 Cells need instructions in order to

survive.

(4)

LEVEL OF ORGANIZATION

 The levels of organization in multicellular organisms:

 Cells g tissues g organs g

organ systems g organism

(5)

Quiz

 1) What are the 4 parts of the cell theory?

 2) What are the levels of

organization from cells to organisms?

(6)

TWO MAJOR TYPES OF CELLS

 Cells fall into 2 major categories:

prokaryotes and eukaryotes.

(7)

Prokaryotes

 (pro = before, karyon = nucleus), so literally “before nucleus”

 Generally smaller than eukaryotes.

 Lack a nucleus and membrane bound organelles.

 Prokaryotes are bacteria

(8)

Prokaryotes

 Store genetic material in one circular DNA molecule called a nucleoid.

 Have a cell wall made of

peptidoglycan.

(9)

(10)

Quiz

 3) What does “PROKARYOTE” mean?

 4) What is function of a nucleoid?

(11)

Eukaryotic

 Eu = true

 Karyon = nucleus

 So literally means true nucleus

 Generally larger than prokaryotes

 Have a nucleus, organelles and

cytoplasm.

(12)

Eukaryotes

 Have membrane bound organelles

(literally “little organs”) that carry

out different functions.

(13)

PARTS OF THE CELL

 A eukaryotic cell is like a microscopic factory. It is filled with organelles,

each of which has its own job.

 Most biologists divide the cell into

two major parts: the nucleus and the cytoplasm.

 The cytoplasm is the part of the cell

outside of the nucleus.

(14)

Quiz

5) What does “EUKARYOTE” mean?

6) What do “organelles” do?

(15)

Eukaryotes

 Generally bigger than prokaryotes

 Have a nucleus and cytoplasm (gel

like material inside)

(16)

(17)

(18)

Cell Structure Type of Cell Structure Function

Nucleus All cells except

prokaryotes In the center of the cell,

surrounded by a nuclear

envelope.

Envelope has pores, which allow things to move in and out of the nucleus.

 Controls all of the cell’s

activities

 Contains the genetic

material for the cell

(chromatin/ch romosomes) Plasma

Membrane

(19)

Cell Structure Type of Cell Structure Function

Plasma

Membrane ALL cells Made of a lipid bilayer, with proteins

embedded

inside and carbs attached to the proteins. “Fluid Mosaic Model”

 Regulates what enters and leaves the cell.

 Provides protection and support.

Cell wall

(20)

Cell Structure Type of Cell Structure Function

Plasma

Membrane ALL cells Made of a lipid bilayer, with proteins

embedded

inside and carbs attached to the proteins. “Fluid Mosaic Model”

 Regulates what enters and leaves the cell.

 Provides protection and support.

Cell Wall Plants Fungi

Prokaryotes

Outside of the plasma

membrane.

Made of cellulose in

plants, chitin in fungi,

peptidoglycan in prokaryotes.

 Structural

support (grow tall)

 Protection

 allows H

2

O, O

₂

, CO

₂

to diffuse in &

out of cell

(21)

Quiz

7) What is the function of the nucleus?

8) What is the function of the plasma Membrane?

9) What is the function of the Cell

Wall?

(22)

Cell Structure Type of Cell Structure Function

Ribosome ALL cells Small particles of RNA and protein found throughout the cytoplasm or attached to the Rough ER.

 Synthesize (make)

proteins.

Mitochondria

(23)

Cell Structure Type of Cell Structure Function

Ribosome ALL cells Small particles of RNA and protein found throughout the cytoplasm or attached to the Rough ER.

 Synthesize (make)

proteins.

Mitochondria All eukaryotic

cells Shaped like a

peanut, it has a double

membrane, the inner membrane has folds called cristae.

 Converts

energy stored in food into

energy used in

the body (ATP)

in a process

called cellular

respiration.

(24)

Cell Structure Type of

Cell Structure Function

Endoplasm

Reticulum Eukaryotic

cells Rough ER has ribosomes

attached to its surface, smooth ER does not.

 Helps with protein synthesis

 Where lipids in the cell are made

Golgi Apparatus

(25)

Cell Structure Type of

Cell Structure Function

Endoplasm

Reticulum Eukaryotic

cells Rough ER has ribosomes

attached to its surface, smooth ER does not.

 Helps with protein synthesis

 Where lipids in the cell are made

Golgi Apparatus Eukaryotic

cells Stacks of

flattened sacs  Modifies, sorts, and packages

proteins and other materials made in the cell.

 Helps to “ship”

materials out of

the cell.

(26)

Cell Structure Type of Cell Structure Function

Vacuoles Plant cells have one big vacuole Animal cells have smaller vacuoles (called vesicles)

Fluid filled sacs Largest

organelle in plant cells

 Store materials like

carbohydrates water, salt, and proteins.

 Structural

support in plants.

Chloroplasts

(27)

Quiz

 10) What is the function of the ribosome?

 11) What is the function of the Mitochondria?

 12) What is the function of the Endoplasmic reticulum?

 13) What is the function of the Golgi

Complex?

(28)

Cell Structure Type of Cell Structure Function

Vacuoles Plant cells have one big vacuole Animal cells have smaller vacuoles (called vessicles)

Fluid filled sacs Largest

organelle in plant cells

 Store materials like

carbohydrates water, salt, and proteins.

 Structural

support in plants.

Chloroplasts Plant cells Contain chlorophyll (green)

Have small stacks of thylakoids called grana

 Capture energy from sunlight and convert into

chemical energy

(photosynthesis)

(29)

Cell Structure Type of Cell Structure Function

Lysosomes Eukaryotic cells Small organelles filled with

enzymes

 Breaks down large food molecules into smaller molecules for the cell

 Breaks down

old cell parts

Cytoskeleton

(30)

Cell Structure Type of Cell Structure Function

Lysosomes Eukaryotic cells Small organelles filled with

enzymes

 Breaks down large food molecules into smaller molecules for the cell

 Breaks down old cell parts Cytoskeleton Eukaryotic cells Made of protein

filaments

Microfilaments (actin) and

microtubules (tubulin)

 helps the cell to maintain its shape

 helps with

cell division

(31)

Quiz

 14) What is the function of Vacuoles?

 15) What is the function of the Chloroplast?

 16) What is the function of the Lysosome?

 17) What is the function of the

Cytoskeleton?

(32)

Cell Specialization

 Organisms that are made up of many cells are called multicellular

 Each multicellular organism is made

up of different cells.

(33)

 Each of the specialized cell types

found in the adult develops from the

same fertilized egg cell.

(34)

 Cells throughout an organism

develop in different ways to perform

different tasks. This process is called

cell specialization.

(35)

 Different types of cells have a)

different types of shapes and b)parts

so that they can c)perform different

functions.

(36)

 During the process of differentiation, only specific parts of the DNA are

activated. The cells will produce

different proteins.

(37)

 Because all the cells in an organism contain the same DNA, they initially have the potential to become any type of cell; however, once a cell

differentiates, the process cannot be

reversed.

(38)

Quiz

 18) What is “ Cell Specialization?”

 19) How do cells specialize?

(39)

SPECIALIZED CELLS

 Neuron – cells that carry messages

throughout the nervous system.

Have an axon to send electrical

impulses over long distances and

dendrites to pass and receive

messages from

other nerve cells.

(40)

 Red Blood cells – have a small disc like shape to increase the surface

area for oxygen absorption;

hemoglobin binds and carries

oxygen; no nucleus to make more

space for the hemoglobin

(41)

 Muscle cells - A muscle cell is generally elongated and elastic containing mitochondria in large

number. The elongated and elastic feature helps muscle tissues to

contract; the mitochondria make

more ATP for the cell.

(42)

Quiz Answers

1 1) All living things are made of cells

2 Cells are alike in structure and function.

3 New cells are produced from existing cells.

4 Cells need instructions in order to survive.

2) Cells g tissues g organs g

organ systems g organism

(43)

Quiz Answer

 3) Before Nucleus

 4) The nucleoid contains the DNA of the prokaryote.

 5) True Nucleus

 6) carry out different functions.

(44)

Quiz Answers

 7) Controls all of the cell’s activities

 Contains the genetic material for the cell (chromatin/chromosomes

 8) Regulates what enters and leaves the cell.

 Provides protection and support

 9) Structural support (grow tall)

 Protection

 allows H ₂ O, O ₂ , CO ₂ to diffuse in &

out of cell

(45)

Quiz Answers

 10) Synthesizes (makes) proteins

 11) Produces energy

 12) Helps with protein synthesis and produces lipids.

 13) Modifies, sorts and packages proteins. Helps ship materials.

 14) Stores materials.

 15) Photosynthesis

(46)

Quiz Answers

 16) Breaks down food molecules into smaller molecules. Breaks down old cell parts.

 17) Helps the cell maintain its shape and helps with cell division.

 18) Cells throughout an organism

develop in different ways to perform different tasks. This process is called cell specialization.

 19) Cells produce different proteins.