Chapter 7
Cell Structure and Function
7-1 Life is Cellular
7-2 Cell Structure
7-2 The Cell as a Factory
7-3 Movement Through
the Membrane
7-1 Life Is Cellular
Interest Grabber

All living things are made up of cells. Some
organisms are composed of only one cell. Other
organisms are made up of many cells.

1. What are the advantages of a one-celled
organism?
2. What are the advantages of an organism that
is made up of many cells?

7-1 Vocabulary



Cell Collection of living matter enclosed by a
barrier that separates the cell from its
surroundings; basic unit of all forms of life.
Cell theory idea that all living things are composed of
cells and new cells are produced from
existing cells.
Cell Membrane thin, flexible barrier around a cell; regulates
what enters and leaves the cell.
7-1 Vocabulary

Cell Wall

Nucleus

strong layer around the cell membrane in
plants, algae, and some bacteria.
the center of the atom which contains the
protons and neutrons; in cells, large structure
inside some cells that contains the cell’s
genetic material (DNA) and controls the cell’s
activities.
Ctyoplasm
material inside the cell membrane- but not
including the nucleus.
7-1 Vocabulary

Prokaryote

Eukaryote

single-celled microorganism that lacks a
nucleus.
organism whose cells contain nuclei
Organelle
specialized structure that performs important
cellular functions within a eukaryotic cell.
7-1 Life is Cellular

1. Cell Theory states three main points
 A. All living things are composed of
cells.
 B. Cells are the basic units of
structure and function in living things.
 C New cells are produced from
existing cells
7-1 Life Is Cellular

2. Prokaryotes and Eukaryotes


A. Cells of Prokaryotes do not have
a nucleus, but cells of Eukaryotes
do.
B. Prokaryotes: have cell
membranes and cytoplasm but do
not contain nuclei
i. All bacteria are prokaryotes
7-1 Life Is Cellular

C. Eukaryotes: do
contain nuclei, a cell
membrane and
cytoplasm, plus
organelles (specialized
structures that perform
important cellular
functions)


i. Can be single-celled
organisms or large
multicellular organisms
ii. All plants, animals, fungi,
and many microorganisms
are eukaryotes
7-2 Cell Structure
7-2 Cell Structure
Division of Labor
A
cell is made up of many parts with different
functions that work together. Similarly, the parts of a
computer work together to carry out different
functions.
Working
with a partner, answer the following
questions.
1.
What are some of the different parts of a
computer? What are the functions of these computer
parts?
2.
How do the functions of these computer parts
correspond to the functions of certain cell parts?
7-2 Cell Structure
Vocabulary

Chromatin

Chromosome

granular material visible within the
nucleus; consists of DNA tightly coiled
around proteins.
threadlike structure within the nucleus
containing the genetic information that is
passed from one generation of cells to
the next.
Nucleolus
small, dense region within most nuclei in
which the assembly of ribosomes
begins
7-2 Cell Structure
Vocabulary

Nuclear envelope

Cytoskeleton

double-membrane layer that surrounds
the nucleus of a cell.
network of protein filaments within some
cells that helps the cell maintain its shape
and is involved in many forms of cell
movement.
Microtubule
hollow tube of protein that maintains cell
shape and can also serve as a “track”
along which organelles are moved.
7-2 Cell Structure
Vocabulary

Microfilament

Ribosome

long, thin fiber that functions in the
movement and support of the cell.
small particle in the cell on which
proteins are assembled; made of
RNA and protein.
Endoplasmic reticulum
internal membrane system in cells
in which components of the cell
membrane are assembled and
some proteins are modified.
7-2 Cell Structure
Vocabulary

Golgi apparatus

Lysosome

stack of membranes in the cell in
which enzymes attach carbohydrates
and lipids to proteins.
cell organelle filled with enzymes
needed to break down certain
materials in the cell.
Vacuole
cell organelle that stores materials
such as water, salts, proteins, and
carbohydrates.
7-2 Cell Structure
Vocabulary

Chloroplast

organelle found in cells of
plants and some other
organisms that uses
energy from sunlight to
make energy-rich food
molecules by
photosynthesis.
Mitochondrion
cell organelle that
releases energy from
stored food molecules.
7-2 Notes Cell Structures
1. Cell Wall
a. In plant cells, but not animal cells
b. Provides support and protection for the cell
C. Made mostly of cellulose: a tough
carbohydrate fiber
Animals NO
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Plants Yes
7-2 Notes Cell Structures
2. Nucleus
a. Controls most cell processes and contains the
hereditary information of DNA
b. Nucleolus
i. A small region where ribosome assembly
begins
c. Nuclear Envelope
i.
Double layer membrane with pores that
surrounds the nucleus
ii. Pores allow material to move into and out
of the nucleus
7-2 Notes Cell Structures
3. Cytoskeleton
a. Made of protein filaments and
helps maintain the cell’s shape
b. It also aids in many forms of cell
movement
4. Ribosomes
a. Where proteins are made
b. Follow coded instructions from the
nucleus
7-2 Notes Cell Structures
5. Endoplasmic Reticululm (ER)
a. Rough ER produces new proteins
including membrane proteins
b. Smooth ER: modifies or detoxifies
lipids using enzymes
6. Golgi Apparatus
a.
b.
Stack of membranes that receives
proteins from the rough ER
Enzymes attach carbohydrates & lipids
to proteins
7-2 Notes Cell Structures
7. Chloroplasts
a. Use the energy from the sunlight to make
energy-rich food molecules in a process known
as photosynthesis
b. Chlorophyll (green pigment) is located in the
photosynthetic membranes
8. Mitochondria
a.
b.
Matrix where carbohydrates break down to
form CO2 and water
Use energy from food to make high-energy
compounds (ATP) that the cell can use to
power growth, development, and movement
Venn Diagrams
Section 7-2
Prokaryotes
Eukaryotes
Cell membrane
Ribosomes
Cell wall
Animal Cells
Lysosomes
Go to
Section:
Plant Cells
Cell membrane
Ribosomes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Vacuoles
Mitochondria
Cytoskeleton
Cell Wall
Chloroplasts
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Figure 7-5 Plant and Animal Cells
Section 7-2
Smooth endoplasmic
reticulum
Vacuole
Ribosome
(free)
Chloroplast
Ribosome
(attached)
Cell
Membrane
Nuclear
envelope
Cell wall
Nucleolus
Golgi apparatus
Nucleus
Mitochondrian
Rough endoplasmic reticulum
Plant Cell
Go to
Section:
Figure 7-5 Plant and Animal Cells
Section 7-2
Nucleolus
Nucleus
Ribosome
(attached)
Nuclear
envelope
Mitochondrian
Smooth
endoplasmic
reticulum
Rough
endoplasmic
reticulum
Centrioles
Golgi apparatus
Animal Cell
Go to
Section:
Ribosome
(free)
Cell
Membrane
Figure 7-7 Cytoskeleton
Section 7-2
Cell membrane
Endoplasmic
reticulum
Microtubule
Microfilament
Ribosomes
Go to
Section:
Michondrion
7-2 The Cell as a Factory
7-2 The Cell as a Factory
1. The Cell as a Factory
a. One of the most important jobs in the cellular
“factory” is making proteins
b. Like a cell, a factory has a control center,
support structures, an assembly area, and a
power supply
c. A factory needs a transportation system to move
parts and machines from one building to another
i.
ER
7-2 The Cell as a Factory
d. The control center sends out information and
instructions to the rest of the cell, much like an
assembly line
i. Ribosomes
ii. DNA
e. Once the product is made, it is sent to get the
final details
i. Golgi Apparatus
f. The power supply in the factory fuels all these
processes
i. Mitochondria
7-2 The Cell as a Factory
Comparing Cells
Structure
Prokaryotic Cells
Cell Membrane
Cell Wall
Nucleus
Ribosomes
ER
Golgi Apparatus
Lysosomes
Vacuoles
Mitochondria
Chloroplasts
Cytoskeleton
Yes
Yes
No
Yes
No
No
No
No
No
No
No
Eukaryotic Cells
Animal
Plant
Yes
No
Yes
Yes
Yes
Yes
Yes
Small or none
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
7-3 Movement Through the
Membrane
In or Out?
How is a window screen similar to a cell membrane?
Read on to find out.
1. What are some things that can pass through a
window screen?
2. What are some things that cannot pass through a
window screen? Why is it important to keep these
things from moving through the screen?
3. The cell is surrounded by a cell membrane, which
regulates what enters and leaves the cell. Why is it
important to regulate what moves into and out of a
cell?
7-3 Movement Through The
Membrane Vocabulary

Lipid bilayer

Concentration

double-layered sheet that forms the core of nearly all
cell membranes
the mass of solute in a given volume of solution, or
mass/volume
Diffusion
process by which molecules tend to move from an area
where they are more concentrated to an area where they
are less concentrated.
7-3 Movement Through The
Membrane Vocabulary

Selective permeability

Osmosis

diffusion of water through a selectively permeable
membrane,
Facilitated diffusion

property of biological membranes that allows only
certain substances to pass through them.
movement of specific molecules across cell
membranes through protein channels
Active transport
energy-requiring process that moves material across
a cell membrane against a concentration difference.
7-3 Movement Through The
Membrane

1. Cell Membrane



a.
Regulates what enters and leaves the cell
b.
Provides protection and support for the cell
c.
Lipid bilayer: a double-layered sheet of lipids
in the cell membrane




i.
ii.
Polar molecules are on the outside of the bilayaer
Non-polar parts are on the inside of the bilayer
d.
Most membranes contain proteins that run
through the bilayer
E. Carbohydrate chains are attached to the protein’s
outer surface
Figure 7-15 The Structure of the
Cell Membrane
Section 7-3
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Go to
Section:
Protein
channel
Lipid bilayer
7-3 Movement Through The
Membrane
2. Diffusion
a. Diffusion: In a solution, molecules
move constantly and try to go from an
area of high concentration to an area of
low concentrated
b. No energy is required for diffusion to
happen!!
7-3
3.Osmosis
a. Cell membranes (biological membranes) are
selectively permeable: some substances can
cross and others cannot
b. Osmosis is the diffusion of water through a
selectively permeable membrane
Figure 7-17 Osmosis
Higher Concentration
of Water
Water molecules
Cell
membrane
Lower Concentration
of Water
Sugar molecules
7-3
4. Facilitated Diffusion
a. Protein channels allow certain molecules
to diffuse across the membrane but not
cross the lipid bilayer
b. Movement through the channels will only
occur if there is a difference in
concentrations surrounding the bilayer
Lipid bilayer
7-3
5. Active Transport
Molecule to
be carried
a. Sometimes material
moves across a
membrane against the
concentration gradient
b. Active transport: material
moving from low
concentration to high
concentration and requires
energy
Low
Concentration
Cell
Membrane
High
Concentration
Molecule
being carried
Low
Concentration
Cell
Membrane
High
Concentration
Energy
Energy