1. CELLS
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2. The Cell Theory
The Cell Theory arose after hundreds of years of observation, and many scientists. A few key scientists involved in the cell theory are Hooke, Schleiden, Schwann and Virchow.
Robert Hooke- The first scientist to describe what he saw as “cells” when viewing samples of cork under the microscope in 1665.

3. The Cell Theory
Nearly 200 years later, Matthias Schleiden viewed living plant specimens under the microscope and discovered they were made up of cells.
Around the same time as Schleiden, Theodor Schwann viewed nonliving animal parts under a microscope and realized that they, too were made up of cells.

4. The Cell Theory
Finally, Rudolf Virchow witnessed cell division under the microscope and learned that all cells arise from preexisting cells.
The findings of these scientists, among others, lead to the cell theory, which states:
All living things are made of cells.
Cells are the basic unit of structure and function of life.
Cells come from preexisting cells.

5. TYPES OF CELLS 1. Eukaryotic cells 2. Prokaryotic cells
Defined by having a
nucleus.
Defined by having
complex organelles.
Plant and animal cells.
2. Prokaryotic cells
Defined by NOT having
a nucleus
Bacteria cells.

6. Common Cell Features Both prokaryotic and eukaryotic cells contain:
DNA
A cell membrane (protects cell and allows things in and out of the cell).
Ribosomes (protein making factories).
Cytoplasm (water-based substance inside the cell).
These are typically the only similarities between the two different types of cells.

7. There are approximately a dozen different organelles!
Plant cell
Eukaryotic Cells
Eukaryotic cells contain organelles, a word that literally means “little organ”.
Organelles have specific
functions that they employ
throughout the cell.
There are approximately a dozen different organelles!
Animal Cell

8. 1. Nucleus
What is it? a large, central membrane-bound organelle which contains D.N.A. Where is it found? All eukaryotic cells! (BOTH plant and animal cells have a nucleus). What does it do? Protects the DNA!

9. 2. Nuclear envelope
What is it? A porous membrane that encases the nucleus. These “nuclear pores” allow certain substances to pass into and out of the nucleus. Where is it found? In all eukaryotic cells; BOTH plant and animal. What does it do? The nuclear envelope protects the nucleus.

10. 3. Nucleolus
What is it? A structure contained within the nucleus. Where is it found? Inside the nucleus of eukaryotic cells. What does it do? It is responsible for making ribosomes.

11. 4. Endoplasmic Reticulum
What is it?
A tunnel-like
network
of membranes.
Where is it found?
Connected to the nucleus and branching out into the cytoplasm of all eukaryotic cells.

12. Endoplasmic Reticulum con’t
What does it do?
Transfers substances within the cell, as well as many different chemical reactions including protein modification and distribution. ER is like the highway system of the cell!
Smooth E.R.
(free of ribosomes) TW O
TYPES
Rough E.R. (contains ribosomes)

13. 5. Golgi body (sometimes called the “Golgi apparatus”)
What is it?
A membrane-bound
organelle, which
processes and
packages proteins.
Where is it found?
The cytoplasm of
all eukaryotic cells.

14. Golgi Body con’t
What does it do? Acts like a post office by packaging proteins in vesicles and delivering them to other parts of the cell.
Vesicles containing proteins exit the Golgi body and are sent to parts of the cell that need them.

15. 6. Lysosomes What are they? Vesicles that contain powerful
digestive enzymes.
Where are they found?
In all eukaryotic cells.
What do they do?
Break down old cell parts and fight off invading bacteria.
*Peroxisomes are identical to lysosomes, except they contain hydrogen peroxide.

16. 7. Mitochondria
What is it? A unique, double membrane-bound organelle, which contains its own DNA. Where is it found? All eukaryotic cells.

17. Mitochondria con’t.
What does it do? Generates A.T.P. (cellular energy) *Think “Power House”
Mitochondria have two membranes; an inner and an outer. Unique because these organelles have their own DNA (known as Eve’s DNA).

18. 8. Vacuoles (vak-u-oles)
Vacuoles differ among plant and animal cells.
PLANT CELLS
ANIMAL CELLS
There is ONE, LARGE central vacuole.
The central vacuole of plants stores water and nutrients, and also aids in cellular digestion.
There are multiple, small vacuoles.
The vacuoles of animal cells do not store water or nutrients, but rather waste as they aid in cellular digestion.

19. 9. Vesicles
What are they? Small membrane bound sacs. Where are they found? Eukaryotic Cells What do they do? Transport various items around the cell.

20. 10. The Cytoskeleton of Eukaryotic Cells
Cytoskeleton: A network of protein fibers which help the organelles and cell move, and assist in cell division. The cytoskeleton maintains cell shape, as the name implies.

21. Cytoskeleton continued
The main components of the cytoskeleton: -microtubules -actin filaments (or microfilaments) -intermediate fibers

22. 11. Microtubules Help move proteins and vesicles throughout the cell.
What are they?
Small tubular structures
made up of protein filaments;
part of the cytoskeleton.
Where are they found?
All eukaryotic cells.
What do they do?
Help move proteins and vesicles throughout the cell.

23. 12. Centrioles
What are they? Nine triplets of microtubules. Where are they found? IN ANIMAL CELLS ONLY! What do they do? Assist during nuclear division.

24. 13. Chloroplasts
What are they? Membrane-bound organelles that contain light-absorbing pigments. Where are they found? PLANT cells only! What do they do? Harvest energy from the sun for photosynthesis.

25. 14. Cell Wall Where is it found? What is it?
A structure consisting of cellulose that surrounds
the cell membrane.
Where is it found?
Within eukaryotes the cell
wall is ONLY found in plant
cells, however all prokary-
otes also have a cell wall.
What does it do?
Protects the cell and maintains homeostasis.

26. 15. Cell Membrane AKA: Plasma Membrane
Controls what enters or leaves the cell
Made of a phospholipid bilayer and proteins
Surrounds outside of ALL cells
Outside
of cell
Inside
(cytoplasm)
Cell
membrane
Proteins
Protein
channel
Lipid bilayer
Carbohydrate
chains

27. 16. Cytoplasm Jelly-like or watery substance that holds the organelles
Enclosed by the cell membrane