Chapter 4 Student 2 Notes.doc

Name:

Period:

C

4

A Tour of the Cell

Chapter Objectives

Explain what is unique about the cellular level of biological organization.

Introduction to the Cell

4.1 Compare the designs of and images produced by a light microscope, a scanning electron microscope, and a transmission electron microscope. Distinguish between magnification and resolving power.

4.1 Describe the two parts of cell theory.

4.2 Explain why there are upper and lower limits to cell size.

4.2 Describe the hydrophobic and hydrophilic components of a plasma membrane and relate these regions to the functions of the plasma membrane.

4.3 Distinguish between the structures of prokaryotic and eukaryotic cells.

4.4 Explain why compartmentalization is important in eukaryotic cells.

4.4 Compare the structures of plant and animal cells. Note the function of each cell part.

4.4 Describe the structures and functions of the four compartments of eukaryotic cells.

The Nucleus and Ribosomes

4.5 Describe the structure and functions of the nucleus and nucleolus. Explain how DNA is packaged inside of the nucleus.

4.6 Describe the functions of ribosomes. Explain why some ribosomes are free in the fluid of the cytoplasm while others are bound to the endoplasmic reticulum or nuclear envelope.

The Endomembrane System

4.7–4.12 Describe the structures and functions of the components of the endomembrane system, including smooth and rough endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes.

Energy-Converting Organelles 4.13–4.15

4.13–4.14 Compare the structures and functions of chloroplasts and mitochondria.

The Cytoskeleton and Cell Surfaces 4.16–4.22

4.16 Compare the structures and functions of microfilaments, intermediate filaments, and microtubules.

4.17 Relate the structure of cilia and flagella to their functions.

4.18 Describe examples of environmental and genetic causes of infertility in men.

4.19 Relate the structure of the extracellular matrix to its functions.

4.20 Compare the structures and functions of tight junctions, anchoring junctions, and gap junctions.

4.21 Relate the structures of plant cell walls and plasmodesmata to their functions.

4.22 Describe the four functional categories of organelles in eukaryotic cells.

4.22 Describe the fundamental features of all organisms.

Key Terms

cell

theory-cell

wall-cellular

metabolism-central

vacuole-

centriole-

chloroplast-

chromatin-

chromosome-

cristae)-

cytoplasm-

cytoskeleton-electron

microscope-endomembrane

system-endoplasmic

reticulum-endosymbiont

theory-eukaryotic

cell-extracellular matrix

(ECM)-flagellum (plural,

flagella)-

glycoprotein-Golgi

apparatus-granum (plural,

grana)-

integrins-intermediate

filament-light microscope

lysosome-

microfilament-

microtubule-mitochondrial

matrix-mitochondrion (plural,

mitochondria)-nuclear

envelope-

nucleoid-

nucleolus-nucleus (plural,

nuclei)-

organelle-

peroxisome-plasma

membrane-plasmodesma (plural, membrane-

plasmodesmata)-prokaryotic

cell-

ribosome-rough endoplasmic

microscope-smooth endoplasmic

reticulum-

stroma-

thylakoid-transmission electron microscope

(TEM)-transport

vesicle-

vacuole-

vesicle-Lecture Outline

I. Introduction

A.Cells are the simplest collection of matter that can live.

B.Cells were first observed

by-C.Working with more refined lenses, Antoni van Leeuwenhoek later described

1.

2.

3.

D.Since the days of Hooke and Leeuwenhoek, improved microscopes have vastly

expanded our view of the cell.

II. Introduction to the Cell

1.A variety of microscopes have been developed for a clearer view of cells and cellular

structure.

2.The most frequently used microscope is the- like the one

used in biology laboratories.

a.Light passes through a specimen, then through glass lenses, and finally light is

projected into the viewer’s eye.

b.Specimens can be magnified up to- times the actual size of the

specimen.

3.

Magnification-4.Resolution-

In other words, it is the ability of an instrument to show two close objects as separate.

5.Microscopes have limitations.

a.The human eye and the microscope have limits of resolution—the ability to

distin-guish between small structures.

b.Therefore, the light microscope

cannot-6.Using light microscopes, scientists studied

a.

b.

c.

7. In the 1800s, these studies led to cell theory, which states that

b.

8.Beginning in the 1950s, scientists started using a very powerful microscope called the

electron microscope (EM) to view the ultrastructure of cells.

a.Instead of light,

EM-9.Electron microscopes can

a.resolve biological structures as small

as-b.magnify up

to-10. Scanning electron microscopes (SEM) study the detailed architecture of

cell-11. Transmission electron microscopes (TEM) study the details

of-12.Differential interference light microscopes amplify differences in density so that

structures in living cells appear almost three-dimensional.

B.4.2 The small size of cells relates to the need to exchange materials across the plasma

membrane

1.Cell size must

a.

2.The plasma membrane forms a flexible boundary between the living cell and its

surroundings.

3.Phospholipids form a two-layer sheet called a phospholipid bilayer in which

a.hydrophilic

heads-b.hydrophobic

tails-4.Membrane proteins are either

a.

b.

5.Some proteins form- that shield ions and other

hy-drophilic molecules as they pass through the hydrophobic center of the membrane.

6.Other proteins serve as pumps, using energy to actively transport molecules into or

out of the cell.

C.4.3 Prokaryotic cells are structurally simpler than eukaryotic cells

1.Bacteria and archaea

are-2.All other forms of life are composed of eukaryotic cells.

a.Prokaryotic and eukaryotic cells have

i.

ii.

b.Eukaryotic cells have a

i.

c. Prokaryotes have a nucleoid and no

true-3.The DNA of prokaryotic cells is coiled into a region called the- , but no

membrane surrounds the DNA.

4.The surface of prokaryotic cells may

a.be surrounded by a chemically

complex-b.have a- surrounding the cell wall,

c. have short projections that help attach to other cells or the substrate, or

d.have longer projections called- that may propel the cell

through its liquid environment.

D.4.4 Eukaryotic cells are partitioned into functional compartments

1.The structures and organelles of eukaryotic cells perform four basic functions.

a.The nucleus and ribosomes

are-b.The endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and

peroxi-somes are

involved-c. Mitochondria in all cells and chloroplasts in plant

cells-d.Structural support, movement, and communication between cells are functions of

the-2.The internal membranes of eukaryotic cells partition it into compartments.

-4.Almost all of the organelles and other structures of animals cells are present in plant

cells.

5.A few exceptions exist.

a.

b.Plant but not animal cells have

i.

ii.

iii.

III. The Nucleus and Ribosomes

A.4.5 The nucleus is the cell’s genetic control center

1.The nucleus

a.

b.

2.DNA is associated with many proteins in structures

called-3.The nuclear envelope

a.

b.

4.The nuclear envelope is attached to a network of cellular membranes called the

endo-plasmic reticulum.

5.The nucleolus is

a.

B.4.6 Ribosomes make proteins for use in the cell and export

1. Ribosomes are involved in the

cell’s-a.Ribosomes are synthesized

from-b.Cells that must synthesize large amounts of- have a large number of

ribosomes.

2.Some ribosomes are free ribosomes; others are bound.

a.Free ribosomes are

i.

ii. typically involved in

making-b.Bound ribosomes are

i. attached to the- (ER) associated

with the nuclear envelope and

ii. associated with proteins packed in certain organelles or exported from the cell.

IV. The Endomembrane System

A.4.7 Overview: Many cell organelles are connected through the endomembrane system

1.Many of the membranes within a eukaryotic cell are part of the endomembrane

system.

2.Some of these membranes are physically connected and some are related by the

trans-fer of membrane segments by tiny- (sacs made of membrane).

3.Many of these organelles work together in the

a.

c.

4.The endomembrane system includes

a.

b.

c.

d.

e.

f.

B.4.8 The endoplasmic reticulum is a biosynthetic factory

1.There are two kinds of endoplasmic reticulum—smooth and rough.

a. Smooth

ER-b. Rough ER

-c. Although physically interconnected, smooth and rough ER differ in structure and

function.

2.Smooth ER is involved in a variety of diverse metabolic processes.

a.Smooth ER

produces-b.Other enzymes help process drugs, alcohol, and other potentially harmful

sub-stances.

c. Some smooth ER helps store calcium ions.

3.Rough ER makes

a.additional membrane for itself and

C.4.9 The Golgi apparatus

finishes-1.The Golgi apparatus serves as a molecular warehouse and finishing factory for

prod-ucts manufactured by the ER.

a.Products- in transport vesicles from the ER to the Golgi apparatus.

b.One side of the Golgi apparatus functions as a receiving dock for the product and

the other as a shipping dock.

c. Products are modified as they go from one side of

the-D.4.10 Lysosomes are digestive compartments within a cell

1.A lysosome is a membranous sac

containing-a.The enzymes and membrane are produced by the ER and transferred to the Golgi

apparatus for processing.

b.The membrane serves to safely

isolate-2.Lysosomes

help-a.A food vacuole binds with a lysosome.

b.The enzymes in the

lysosome-c. The nutrients are

then-3.Lysosomes also help remove

or-a.The damaged organelle is first enclosed in a membrane vesicle.

b.Then a lysosome

i.

iii.

E.4.11 Vacuoles function in the general maintenance of the cell

1. Vacuoles are large vesicles that have a variety of functions.

a.Some protists have contractile vacuoles that help to eliminate water from the

protist.

b.In plants, vacuoles may

i.

ii.

iii.

F. 4.12 A review of the structures involved in manufacturing and breakdown

V. Energy-Converting Organelles

A.4.13 Mitochondria

harvest-1. Mitochondria are organelles that carry

out-2.Cellular respiration converts the chemical energy in

foods-3.Mitochondria have two internal compartments.

a.The intermembrane space is the narrow region between the inner and outer

membranes.

b.The mitochondrial matrix contains

i.

ii.

B.4.14 Chloroplasts

convert-1. Chloroplasts are the photosynthesizing

organelles-2.Photosynthesis is the conversion of light energy from the

sun-3.Chloroplasts are partitioned into compartments.

a.Between the outer and inner membrane is a thin intermembrane space.

b.Inside the inner membrane is

i. a thick fluid called- that contains the chloroplast DNA,

ri-bosomes, and many enzymes; and

ii. a network of interconnected sacs

called-iii.In some regions, thylakoids are stacked like poker chips. Each stack is

called-C.4.15 EVOLUTION CONNECTION: Mitochondria and chloroplasts evolved by

endosymbiosis

1.Mitochondria and chloroplasts have

a.DNA and

b.ribosomes.

2.The structure of this DNA and these ribosomes is very similar to that found in

prokaryotic cells.

3.The endosymbiont theory proposes that

b.

VI. The Cytoskeleton and Cell Surfaces

A.4.16 The cell’s internal skeleton helps organize its structure and activities

1.Cells contain a network of protein fibers, called the- , which

functions in structural support and motility.

2.Scientists believe that motility and cellular regulation result when the cytoskeleton

interacts with proteins called motor proteins.

3.The cytoskeleton is composed of three kinds of fibers.

a. (actin filaments) support the cell’s shape and are involved in

motility.

b. reinforce cell shape and anchor organelles.

c. (made of tubulin) give the cell rigidity and act as tracks

for organelle movement.

B.4.17 Cilia and flagella move when microtubules bend

1.While some protists have- that are important in

locomo-tion, some cells of multicellular organisms have them for different reasons.

a.Cells that sweep mucus out of our lungs

have-b.Animal sperm

are-2.A flagellum, longer than cilia,

propels-3.Cilia work more like

the-4.Although differences exist, flagella and cilia have a common structure and

5.Both flagella and cilia are made of- wrapped in an extension of

the plasma membrane.

6.A ring of nine microtubule doublets surrounds a central pair of microtubules. This

arrangement is

a.called

the-b.anchored in a basal body with nine microtubule triplets arranged in a ring.

7.Cilia and flagella move by bending motor proteins called dynein feet.

a.These feet attach to and exert a sliding force on an adjacent doublet.

b.The arms then release and reattach a little further along and repeat this time after

time.

c. This “walking” causes the microtubules to bend.

C.4.18 CONNECTION: Problems with sperm motility may be environmental or genetic

1.In developed countries over the last 50 years, there has been a decline in sperm

quality.

2.The causes of this decline may be

a.environmental chemicals or

b.genetic disorders that interfere with the movement of sperm and cilia. Primary

cil-iary dyskinesia (PCD) is a rare disease characterized by recurrent infections of the

respiratory tract and immotile sperm.

D.4.19 The extracellular matrix of animal cells functions in support and regulation

1.Animal cells synthesize and secrete an elaborate extracellular matrix (ECM) that

a.helps hold cells together in tissues and

2.The ECM may attach to a cell through glycoproteins that then bind to membrane

proteins called integrins. Integrins span the plasma membrane and connect to

micro-filaments of the cytoskeleton.

E.4.20 Three types of cell junctions are found in animal tissues

1.Adjacent cells communicate, interact, and adhere through specialized junctions

between them.

a. prevent leakage of extracellular fluid across a layer of

ep-ithelial cells.

b. fasten cells together into sheets.

c. are channels that allow molecules to flow between cells.

F. 4.21 Cell walls enclose and support plant cells

1.A plant cell, but not an animal cell, has a

rigid-a. skeletal support that helps keep the plant upright against

gravity and

b.is primarily

composed-2.Plant cells have cell junctions called- that serve in

communi-cation between cells.

G.4.22 Review: Eukaryotic cell structures can be grouped on the basis of four basic

functions

1.Eukaryotic cell structures can be grouped on the basis of four functions:

b.

c.