Chapter 7 Cell Structure and Function

7-1 Life is Cellular

7-2 Cell Structure

7-3 Movement Through the Membrane

7-2 The Cell as a Factory

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-

strong layer around the cell membrane in plants, algae, and some bacteria.

Nucleus- 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-

single-celled microorganism that lacks a nucleus.

Eukaryote- 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 pointsA. 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 nucleii. 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- granular material visible within the

nucleus; consists of DNA tightly coiled around proteins.

Chromosome- 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

Nuclear envelope- double-membrane layer that surrounds

the nucleus of a cell. Cytoskeleton-

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- long, thin fiber that functions in the

movement and support of the cell. Ribosome-

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- stack of membranes in the cell in

which enzymes attach carbohydrates and lipids to proteins.

Lysosome- 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 Cell Structure Vocabulary

7-2 Notes Cell Structures1. 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

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Plants Yes

Animals NO

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 Apparatusa. Stack of membranes that receives

proteins from the rough ER

b. Enzymes attach carbohydrates & lipids to proteins

7-2 Notes Cell Structures

7. Chloroplastsa. 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. Mitochondriaa. Matrix where carbohydrates break down to

form CO2 and water

b. Use energy from food to make high-energy compounds (ATP) that the cell can use to power growth, development, and movement

7-2 Notes Cell Structures

Prokaryotes Eukaryotes

Cell membraneRibosomesCell wall

NucleusEndoplasmic reticulumGolgi apparatusLysosomesVacuolesMitochondriaCytoskeleton

Animal Cells Plant Cells

Lysosomes

Cell membraneRibosomesNucleusEndoplasmic reticulumGolgi apparatusVacuolesMitochondriaCytoskeleton

Cell Wall

Chloroplasts

Section 7-2

Venn Diagrams

Go to Section:

Plant Cell

Nuclearenvelope

Ribosome(attached)

Ribosome(free)

Smooth endoplasmicreticulum

Nucleus

Rough endoplasmic reticulum

Nucleolus

Golgi apparatus

Mitochondrian

Cell wall

CellMembrane

Chloroplast

Vacuole

Section 7-2

Figure 7-5 Plant and Animal Cells

Go to Section:

Animal Cell

Centrioles

NucleolusNucleus

Nuclearenvelope

Rough endoplasmic reticulum

Golgi apparatus

Smooth endoplasmicreticulum

Mitochondrian

CellMembrane

Ribosome(free)

Ribosome(attached)

Section 7-2

Figure 7-5 Plant and Animal Cells

Go to Section:

Cell membrane

Endoplasmicreticulum

Microtubule

Microfilament

Ribosomes Michondrion

Section 7-2

Figure 7-7 Cytoskeleton

Go to Section:

7-2 The Cell as a Factory

7-2 The Cell as a Factory

1. The Cell as a Factorya. One of the most important jobs in the

cellular “factory” is making proteinsb. 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 anotheri. ER

d. The control center sends out information and instructions to the rest of the cell, much like an assembly linei. Ribosomesii. DNA

e. Once the product is made, it is sent to get the final detailsi. Golgi Apparatus

f. The power supply in the factory fuels all these processesi. Mitochondria

7-2 The Cell as a Factory

7-2 The Cell as a FactoryComparing Cells

Eukaryotic CellsStructure Prokaryotic Cells

Animal PlantCell Membrane Yes

Cell Wall YesNucleus No

Ribosomes YesER No

Golgi Apparatus NoLysosomes NoVacuoles No

Mitochondria NoChloroplasts NoCytoskeleton No

Yes YesNo Yes

Yes YesYes YesYes YesYes YesYes No

Small or none YesYes YesNo YesYes 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-

double-layered sheet that forms the core of nearly all cell membranes

Concentration- 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.

Selective permeability- property of biological membranes that allows only

certain substances to pass through them. Osmosis-

diffusion of water through a selectively permeable membrane,

Facilitated diffusion- 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 Vocabulary

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. Polar molecules are on the outside of

the bilayaer ii. 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

7-3 Movement Through The Membrane

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel

Lipid bilayer

Carbohydratechains

Section 7-3

Figure 7-15 The Structure of the Cell Membrane

Go to Section:

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 Movement Through The Membrane

3.Osmosisa. 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

7-3

Cellmembrane

Higher Concentrationof Water

Lower Concentrationof Water

Water molecules

Sugar molecules

Figure 7-17 Osmosis

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

7-3

Lipid bilayer

5.Active Transporta.Sometimes material

moves across a membrane against the concentration gradient

b.Active transport: material moving from low concentration to high concentration and requires energy

7-3

Molecule tobe carried Low

Concentration

CellMembrane

HighConcentration

Moleculebeing carried

LowConcentration

CellMembrane

HighConcentration

Energy Energy