Cell Diversity
Cell Diversity Cells of different
organisms and even cells within the same organism are VERY diverse in terms of shape, size, and internal organization.
There are at least 200 different types of cells, ranging from flat cells to branching cells to round cells to rectangular cells!
Recurring Theme
One major theme in biology that occurs again and again is that form follows function!
In other words, a cells function influences its physical features.
Cell Shape
The diversity in cell shapes reflects the different functions of the cells
Compare the cells below. How does the nerve cell’s shape help it? The skin cell’s?
Cell Size
Cells differ in their size as well as their shape
Some nerve cells that extend from a giraffe’s spinal cord to the foot can be 2 m long!
Most cells are about 1/500th the size of the period at the end of a sentence.
Cell Size
The size of a cell is limited by the relationship of the cell’s outer surface are to its volume aka surface area-to-volume ratio
Cell Volume As a cell grows, the volume increases much
faster than the surface area
Important because the materials needed by a cell and the wastes produced must pass in and out of the cell through its surface
If a cell were to become very large, the volume would increase more than the surface area, so materials wouldn’t be able to enter or leave quickly enough
Cell Volume
Basic Parts of A Cell
Plasma Membrane
Cytoplasm
Control Center
Plasma Membrane
The cell’s outer boundary
Covers cell’s surface and acts as a boundary
Cannot be seen through a light microscope
Cytoplasm The region of the cell that
is within the plasma membrane and includes the fluid, the cytoskeleton, and all of the organelles
The cytosol is the part of the cytoplasm that includes molecules and small particles, but not membrane bound organelle
Control Center
Cells carry coded information in the form of DNA for regulating functions and reproducing themselves.
Some DNA floats freely in cells, other cells have a nucleus housing the DNA
Nucleus is a membrane-bound structure
Two Basic Cell Types
Prokaryotes Lack membrane bound organelles Have a nucleoid region where DNA
is located Bacteria and Archaea
Eukaryotes Organisms made up of one or more
cells and have membrane bound organelles
Much larger than prokaryotic cells
Prokaryotic Cell
Eukaryotic Cell
Cellular Organization
In multicellular organisms, cells organize into tissues, which organize into organs, then organ systems
Colonial organisms (colonies) are a groups of identical cells that live together in a connected group. These aren’t multicellular because their activities aren’t coordinated
Animal Cell
Nucleus
Nucleolus
Cell Membrane
Cytoplasm
Eukaryotic Cell Organelles and Function
1. Nucleus Nickname: “The Control Center” Function: holds the DNA Parts:
1. Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes
Animal Cell
Nucleus
Nucleolus Ribosomes
Cell Membrane
Cytoplasm
Eukaryotic Cell Organelles and Function
2. Ribosomes Function: makes proteins Found in all cells, prokaryotic and
eukaryotic
Eukaryotic Cell Organelles and Function
3. Endoplasmic Reticulum (ER) Nickname: “Roads” Function: The internal delivery
system of the cell
Animal Cell
Nucleus
Nucleolus
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Cell Membrane
Cytoplasm
Ribosomes
Endoplasmic Reticulum
2 Types:1. Rough ER:
Rough appearance because it has ribosomes
Function: helps make proteins, that’s why it has ribosomes
2. Smooth ER: NO ribosomes Function: makes fats or lipids
Animal Cell
Nucleus
Nucleolus
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Ribosomes
Golgi Complex
Cell Membrane
Cytoplasm
Eukaryotic Cell Organelles and Function
4. Golgi Complex Nickname: The shippers Function: packages, modifies, and
transports materials to different location inside/outside of the cell
Appearance: stack of pancakes
Animal Cell
Nucleus
Nucleolus
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Ribosomes
Golgi Bodies
Cell Membrane
Cytoplasm
Eukaryotic Cell Organelles and Function
5. Lysosomes: circular, but bigger than ribosomes)
Nickname: “Clean-up Crews” Function: to break down food into
particles the rest of the cell can use and to destroy old cells
Animal Cell
Nucleus
Nucleolus
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Ribosomes
Golgi Bodies
Mitochondria
Cell Membrane
Cytoplasm
Eukaryotic Cell Organelles and Function
6. Mitochondria Nickname: “The Powerhouse” Function: Energy formation
Breaks down food to make ATP ATP: is the major fuel for all cell
activities that require energy
Animal Cell
Nucleus
Nucleolus
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Ribosomes
Golgi Bodies
Mitochondria
Cell Membrane
Cytoplasm
Now let’s talk about structures only found in PLANT Cells!!
Plant Cell
Cell Membrane
Vacuole
Eukaryotic Cell Organelles and Function
7. Vacuoles Function: stores water
This is what makes lettuce crisp When there is no water, the plant wilts
Plant Cell
Cell Membrane
Vacuole
Chloroplasts
Eukaryotic Cell Organelles and Function
8. Chloroplasts Function: traps energy from the sun to
produce food for the plant cell Green in color because of chlorophyll,
which is a green pigment
Chloroplasts
Plant Cell
Cell Membrane
Vacuole
Chloroplasts
Cell Wall
Eukaryotic Cell Organelles and Function
9. Cell Wall Function: provides support and
protection to the cell membrane Found outside the cell membrane in
plant cells
Plant Cell
Cell Membrane
Vacuole
Chloroplasts
Cell Wall
Nucleolus
Nucleus
Rough ER
Smooth ER
Golgi Bodies
Mitochondria
Ribosomes
Cytoplasm
Comparing Plant and Animal Cells
Moon
AnimalPlant