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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