CELLS
Structure and Function
Cell = smallest unit of life
Two Major Cell Types
Cell Type
Prokaryotic
Eukaryotic
Example
Archaea
Bacteria
Protists
Fungi
Plants
Animals
Prokaryotic Cell
Eukaryotic Cell
(protist, animal)
Eukaryotic Cell
(plant)
Components Common to All Cells
• Plasma Membrane
boundary surrounding the cell
• Genetic material: DNA
found in one or more chromosomes
• Cytoplasm
Fluid containing enzymes and
organelles
Differences Between Cell Types
Prokaryotic Cell
Single circular
chromosome
Chromosome found in
a cytoplasmic region
called the nucleoid.
No internal membranes
Some infolded plasma
membrane
Eukaryotic Cell
Multiple linear
chromosomes
Chromosomes found in
a membrane-bound
nucleus.
Extensive network of
internal membranes
Specialized areas
called organelles
Features of All
Prokaryotic Cells
Structure
Plasma
Membrane
Nucleoid
Function
Regulates flow of substances
into and out of cell
Cytoplasmic region containing
genetic material
Cytoplasm Cytosol: fluid
Ribosomes—produce proteins
Enzymes—assist in reactions
Features of Some
Prokaryotic Cells
Structure
Cell Wall
Capsule or
Slime Layer
Infolded Plasma
Membranes
Function(s)
Supports cell
Maintains shape
Protects from drying
Protects against white
blood cells
Metabolism
Cell division
Features of Some
Prokaryotic Cells
Structure
Bacterial
Flagellum
Plasmid
Pilus
Function
Movement
Small circular DNA
Replicates independently
Genes for antibiotic resistance?
Surface projection used for
transfer of genetic material
Applying Your Knowledge
1.
2.
3.
4.
5.
Nucleus
Ribosome
Capsule
Cytoplasm
Nucleoid
A. Which feature is unique to prokaryotic
cells?
B. Which feature is unique to eukaryotic
cells?
C. Which feature(s) do prokaryotic and
eukaryotic cells have in common?
Features of Eukaryotic Cells
Structure
Function(s)
1. Regulates passage of
Plasma
Membrane materials
2. Cell-Cell Recognition
Cell Wall 1. Controls cell shape, protects,
supports
(algae,
plants, fungi) 2. Made of carbohydrate
Features of
Eukaryotic Cells
Structure
Cilia and
Flagella
Function(s)
1. Cell movement in protists,
animal sperm
2. Move substances across cell
surface in lungs, fallopian
tubes
Motion of cilia and flagella
Features of
Eukaryotic Cells
Structure
Centriole
Function
Gives rise to basal bodies that
produce cilia or flagella
Features of
Eukaryotic Cells
Structure
Nucleus
Function(s)
1. Carrier of genetic material
DNA + protein = chromatin
2. Governs cell activities
3. Directs cell reproduction
4. Surrounded by Membrane =
nuclear envelope
5. Contains nucleolus—produces
ribosomes
Eukaryotic Cell Nucleus
DNA + protein = chromatin
Chromosomes are composed of chromatin.
Chromatin appears diffuse during most of the cell cycle.
Features of
Eukaryotic Cells
Structure
Function(s)
Nucleolus
1. Site of ribosome assembly
(inside nucleus)
Ribosomes
1. Site of protein synthesis
2. Can be free in cytoplasm or
attached to membranes
Features of
Eukaryotic Cells
Structure
Function(s)
Rough
Endoplasmic
Reticulum (rer)
1. Produces proteins
2. Prepares proteins for export
Smooth
Endoplasmic
Reticulum (ser)
1. Lipid Synthesis
2. Drug detoxification
3. Transport of proteins from rer
Rough Endoplasmic
Reticulum
Features of
Eukaryotic Cells
Structure
Golgi
Complex
Function(s)
Collects, modifies, packages
and distributes proteins from rer
Features of
Eukaryotic Cells
Structure
Function(s)
Lysosome
Contains digestive enzymes
to digest food in protists or
destroy aging organelles
Features of
Eukaryotic Cells
Structure
Function(s)
Vacuole
1. Central vacuole (plants) stores
waste, maintains turgidity.
2. Contractile vacuole (protists)
maintains water balance.
3. Food vacuole (protists) fuses
with lysosome for digestion.
Features of
Eukaryotic Cells
Structure
Peroxisome
Function
Removes harmful oxidants
from cells
Applying Your Knowledge
1.
2.
3.
4.
5.
Cilium
Rough ER
Golgi apparatus
Smooth ER
Lysosome
A. Which organelle produces proteins that
will be exported from the cell?
B. Which organelle contains digestive
enzymes?
C. Which site acts as a protein packaging
and distribution center?
Features of
Eukaryotic Cells
Structure
Chloroplast
Function
Photosynthesis: Uses light
energy to produce organic
molecules in plants and
protists
Features of
Eukaryotic Cells
Structure
Mitochondrion
Function
Produces energy by breaking
down organic molecules
Found in all eukaryotic cells
Features of Eukaryotic Cells
Structure
Cytoskeleton
Function(s)
1.
2.
3.
4.
Maintains cell shape
Allows for cell movement
Anchors organelles and proteins
Directs transport of materials
Thought Questions
1. What are similarities for
a. eukaryotic and prokaryotic cells?
b. animal and plant cells?
2. What are differences between
a. eukaryotic and prokaryotic cells?
b. animal and plant cells?
Comparing Animal and Plant Cells
Animal
Cell
Centrioles
Chloroplasts
Mitochondria
Golgi
Nucleus
Endoplasmic
Reticulum
Plant
Cell
Comparing Animal and Plant Cells
Animal
Cell
Nucleolus
Ribosomes
Central Vacuole
Cell Wall
Plant
Cell
Analogy
If the cell were a factory
the ____________________ would be
(name a cell component)
a _____________________________.
(name a part of a factory)