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AP Biology

Ch 7:

Cell Structure and Functions

The Cell Theory

1. All living things are made of cells.

2. New cells come from existing cells.

3. Cells are the basic units of structure and function

of living things.

Cell types to know:

Prokaryotic

Eukaryotic

plant cells

Prokaryote -No organelles

-No nucleus

-Have ribosomes

Eukaryotes - Have membrane bound organelles, a true

nucleus and ribosomes

bacteria

cells

animal cells

Types of Cells

What differences can you see between these cells?

Cell size comparison

Bacterial cell

Animal cell

micron = micrometer = 1/1,000,000 meter

diameter of human hair = ~20 microns

most bacteria

1-10 microns

eukaryotic cells

10-100 microns

Viruses are smaller

than bacteria and

they are NOT ALIVE!

Prokaryotic Cells Smaller than eukaryotic

Less complex than eukaryotic

No nucleus, mitochondria,

vacuoles, or chloroplasts

Circular DNA strands called plasmids

Have Ribosomes

Have DNA and RNA

Eukaryotic Cells Larger

More complex

Have nucleus, mitochondria,

vacuoles, or chloroplasts

Have Ribosomes

Have DNA and RNA

Now we are going to look at

the parts of the eukaryotic cell

Cell parts (organelles) to know:

Nucleus

Ribosomes

Vacuole

Mitochondria

Chloroplast

Plasma or cell membrane

Cell wall

Model Animal Cell

Organelles = membrane bound

structures inside a cell that perform

specific functions required by the

cell.

If they each perform

specific functions, will

they all have the same

structure?

Cytoplasm = jelly-like filling that holds organelles

Surface Area: Volume Lab http://www.biologyjunction.com/cell_size.htm

Nucleus

Function

control center of cell

contains most of the DNA

instructions for building proteins

Structure

Surrounded by

nuclear membrane – that

contains nuclear pores that

allows particles to pass in

and out of the nucleus

Where is the nucleus in a bacterial cell?

Ribosomes on ER

Ribosomes Function

Site of protein synthesis

Where instructions are read to build proteins

from DNA

Structure

2 subunits

some free in cytoplasm

some attached to ER large

subunit

small subunit

Ribosomes get their protein directions from the

DNA sequence

DNA RNA Proteins Specific Traits

Bacteria – have a few thousand ribosomes

Human cells – have a million ribosomes

The more protein a cell needs to make =

the more ribosomes it will have

Vacuoles – storage

structures

plant cells

contractile

vacuoles

protist

central vacuole

food vacuoles

Vacuoles – storage structures

Stores water, salts, proteins, and carbohydrates in a

cell

Plant cells have a single, large vacuole to store water

Keeps the plant upright; provides

support

without water = plant will wilt

Many small vacuoles are found in some animal cells

Powerhouse of the cell

Structure

double membrane

Function

make ATP energy

cellular or aerobic respiration glucose + O2 water +

CO2 + ATP

fuels the work of life

Mitochondria

ATP

Mitochondria Inner fold increases the surface area so that the

mitochondria can produce more energy in less space

In humans, nearly all inherited come from the egg

(contains their own maternal DNA)

The more energy a certain cell type needs =

the more mitochondria it will have

Chloroplasts – where

photosynthesis occurs

Uses sunlight to make glucose

(sugar)

Converts light energy chemical

energy

H2O + CO2 Glucose + O2

Sugar (glucose) = stored energy

build leaves & roots & fruit

out of the sugars

Chloroplast – Plant Cells Only

sugar

Mitochondria are in both cells!

animal cells plant cells

mitochondria

Chloroplast

Chloroplasts are only in plant cells.

Organelles work together to get the jobs

of the cell done

Examples in

plants:

chloroplast make

glucose for the

cell;

mitochondria use

glucose to make

energy that cell

can use

Another Example:

DNA codes for

proteins which are

assembled by the

ribosomes and

used as enzymes

for energy

production at the

mitochondria

Homeostasis and the Cell Membrane Video

Cell MEMBRANE

lipid “tail”

phosphate “head”

Structure

thin, flexible membrane

around all cells

double layer of fat

phospholipid bilayer (water tolerant end so that it can function with water on the inside and outside of the cell)

Proteins transport molecules

Do oil and water mix?

Cell MEMBRANE (cont.)

FUNCTIONS of the Cell Membrane:

1.Separates the inside of the cell from the outside environment.

2.Control what enters and leaves the cell (selectively permeable)

3.Carbohydrates act like chemical identification cards, allowing

individual cells to identify one another.

Structure:

•Strong, supporting layer

•Found in plants, algae, fungi, and many prokaryotes

(NOT found in animal cells)

•Found outside of the cell/plasma membrane

•Made of carbohydrates (cellulose in plants)

Function:

•Provides protection and support

•Porous – allows water, O2, CO2, and other substances

to pass through easily

•Not selective (doesn’t regulate what goes in and out)

Cell Wall-

cell membrane

cell boundary

controls movement of materials in & out

cytoplasm

jelly-like material holding organelles in place

vacuole

storage

mitochondria

make ATP energy from sugar + O2

nucleus

protects DNA

controls cell

ribosomes

builds proteins

1

2

3

4

5

6

Which two structures ONLY

occur in plant cells?

Animal Cell

Plant Cell

1. What type of cell is shown below? (Plant or Animal)

2. What type of cell is shown below?

(Eukaryote or Prokaryote)

3. What type of cell is shown below?

(Plant, Animal or Bacteria)

Microscopes used to see cells

Types:

Scanning Electron: more

detail

Electron Transmission:

more detail

Light

Total Magnification

Objective x Eyepiece

AP Biology

Prokaryotic vs Eukaryotic Cells

https://www.youtube.com/watch?v=ruBAHiij4EA