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The Cell
Structures & Functions
AG BIO - McKee
What is “Cell Theory”?

The idea that all living things are made up of cells.
What’s so special about cells?

Cells are the smallest working units of all living things.
Yeast Cells
Where do cells come from?

All cells come from
preexisting cells
through cell division.
Bean Cells in Mitosis
Definition of the Cell

A cell is the smallest unit that is capable
of performing life functions.
Would you like to see
some examples?
Even if you don’t, too bad.
Remember…

These are magnified
images taken with
microscopes

Some cells have been
stained with color so you
can see them better.
Nerve Cell
Bacteria Cell
Tree cells from the stomach of a possum.
Brain Cell
Cornstalk Cells
Mammalian Tissue
•Smooth muscle are structurally the simplest muscle cells
•Provide contractile forces for most internal organs
•Controls flow of blood through vessels and moves food
through digestive tract.
Two Types of Cells
Prokaryotic
 Eukaryotic

Prokaryotic

One-celled organisms

Example: Bacteria

Few internal structures
surrounded by
membranes
Cells Dividing: Bacteria from a Taxi Cab
Eukaryotic


Contain organelles surrounded by membranes
Most living organisms
Plant
Humans & Animals
“Typical” Animal Cell
“Typical” Plant Cell
Cell Parts and Functions
Cell Wall
Plant, not animal cells
Outer layer, rigid, strong, stiff
Made of cellulose
Cell Parts and Functions
Cell Membrane
Plant & animal cells
Protects the cell
Lets things in and out of the cell
Location: around the cell
Cell Parts and Functions
Nucleus
 Plant & animal cells
 Large & oval
 Control center
 Location:


Inside the cell,
Near the center
Cell Parts and Functions
Nucleolus (Nucleoli)
Plant & animal cells
Makes ribosomes
Location: inside the nucleus
(dark spot)
Nuclear Membrane
Plant & animal cells
Protects around nucleus
Lets things in/out of nucleus (pores)
Selectively permeable
cell
Cell Parts and Functions
Cytoplasm
 Plant & Animal
 Clear, thick, jellylike
 Holds all organelles in cell
 Location: in cell
Cell Parts and Functions
Chromatin/Chromosomes
 In Plant & Animal Cells
 Contains genetic information/traits
 Location: In nucleus
Cell Parts and Functions
Endoplasmic Reticulum (E.R.)





Plant & animal cells
Network of tubes and membranes
Transports materials and sends messages to all parts of the cell
Two types: smooth and rough (has ribosomes)
Location: attaches from cell membrane to nuclear membrane
Rough E.R.
Cell Parts and Functions
Ribosome
 Plant & Animal Cells
 Makes proteins
 Small circular shape
 Location:


In Cytoplasm or
Attached to E.R.
Mitochondria
 Plant & animal
 Bean shaped with inner membranes
 Makes energy/powerhouse
 Breaks down sugar into energy
 Location: In Cytoplasm
Mitochondria
Cell Structure & Function
Vacuole
Plant = few/large
Animal = small
Fluid filled sacs
Stores food, water & waste
Location: In cytoplasm
Vacuole

What does a vacuole remind you of?
Golgi Bodies or Golgi Apparatus
 Located in Plant & Animal Cells
 Packages and secretes
 Gets rid of waste
 Location: in cytoplasm

What does a Golgi Body remind you of?
GOLGI APPARATUS
Cell Parts and Functions
Lysosome
Plant & Animal Cells
Contains digestive enzymes
Destroys bacteria, old cell parts…
Location: in cytoplasm
Centrioles
Plant & Animal Cells
Helps the cell to divide
Location: in cytoplasm
Cell Parts and Functions
Cilia
Most Plant, Animal & Bacteria Cells
Short hair-like projections
Used for movement
Location: outside of cell
Flagella
Most Plant, Animal & Bacteria Cells
Long whip-like tail
Used for movement
Location: outside of cell
What’s
that?
?
Cell Structures and Functions
Chloroplast
Only in plant cells
Contains chlorophyll
Makes plants green
Traps light energy from the sun
Light Energy = Chemical Energy
(Where photosynthesis occurs)
Chemical Energy = Food for the Plant
Cell Structures and Functions
Plastids
 Found in Plant Cells
 Stores extra food
 Located in cytoplasm
Can you name these plant cell parts?
A.
B.
C.
Cell Parts and Functions
Cytoskeleton
Also called Microfilament
Plant & Animal Cells
Made of thin hallow tubes
Like a spider web
Supports & transports
“Super Highway”
Microfilament (cytoskeleton) of mouse embryo
fibroblasts, stained with FITC-phalloidin (100fold magnification.)
Can you name these animal cell parts?
Cell
#1
Membrane
#2
Rough E.R.
#3
Ribosome's
Cytoskeleton or
Microfilaments
#4
#5
Mitochondria