Transcript The Cell - CCRI Faculty Web

The Cell
Chapter 4
Cells
Marks the boundary between the “living
and the dead”
 Structural and functional unit of an
organism
 Smallest structure capable of performing
all of the functions necessary for life
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What is a cell?

Why do we care?
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We have TRILLIONS of them!! (@65)
Every organism is composed of
one or more cells
Basic unit of structure and
function in organisms
All come from pre-existing cells
Cell Theory
All cells…….
Have an outer plasma membrane
 Contain DNA
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Enclosed within the cell somewhere
Contain cytoplasm
Plasma Membrane and Cytoplasm
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All cells surrounded by a
plasma membrane
 Phospholipid bilayer
material inside a cell is
the cytoplasm
 Everything between
the plasma
membrane and the
region of DNA
 Gives cells their
shape
 Assist in movement
of cell and organelles
Microscopes
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Compound light
microscope
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Multiple lenses increase
magnifying power
Two basic kinds of cells
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Prokaryotic
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Nothing separates the
DNA from
internal cell parts
Eukaryotic
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Contain organelle sacs
Nucleus – contains the
DNA
Eukaryotic Cells
Examples of Eukaryotic Cells:
Animal
 Plant
 Fungi
 Protozoa
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Cell Walls
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Plant cells
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Permeable
Protective
In addition to a plasma
membrane
Organelles
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Organelles act as their own separate
“organs”
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They physically isolate chemical reactions
inside cells
Animals and plants will differ in their
organelles
Nucleus
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Encloses the DNA of a
eukaryotic cell
Contains chromosomes
Functions:
 Prevents DNA from
getting entangled with
structures in the
cytoplasm
 Outer membranes act as
a boundary
Components of the nucleus
Nuclear pores
 Nuclear envelope
 Nucleolus
 Nucleoplasm
 DNA
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Chromosomes
Chromatin
Nuclear envelope
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Double-membrane
system composed of lipid
bilayer (with pores)
Bilayers surround the
fluid part of nucleus
(nucleoplasm)
Continuous with the
endoplasmic reticulum
Nucleolus
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Dense mass located
within the nucleus
Produces ribosomes
Ribosomes
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Site of protein
synthesis
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Occurs in the cytoplasm
Attached to the
endoplasmic reticulum
Differ between
prokaryotes and
eukaryotes
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Why is this important
from a health aspect?
Endomembrane System
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Helps modify proteins into final form
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Lipids are assembled
Compartmentalizes the cell
 Main components:
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1.
2.
3.
4.
Nuclear envelope
Endoplasmic reticulum (ER)
Golgi body
Various vesicles (transport)
1. Nuclear envelope
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Merges with the
membrane of the ER
Consists of
membranous channels
and saccules
2. Endoplasmic Reticulum
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Channel that snakes
through the cytoplasm
Lipids assembled and
polypeptide chains modified
into final proteins
Can be rough or smooth
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Dependant on the
attachments of ribosomes
Rough ER
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Processing and
modification of proteins
Smooth ER
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Synthesizes phospholipids
3. Golgi Body (Apparatus)
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Series of flattened
sacs
Collects, sorts,
packages, and
distributes materials
such as proteins and
lipids
Contain enzymes
that put the finishing
touches on proteins
and lipids
4. Vesicles
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Enzymes from golgi apparatus sort and
package the molecules into vesicles
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Tiny sac that moves through cytoplasm
Function in transport, storage, or digestion of
substances
Two main types:
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Lysosomes
Peroxisomes
Lysosome
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A lysosome is a
membrane-enclosed sac
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contains digestive
enzymes to break down:
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Macromolecules
damaged organelles
Put it all together……
Energy-Related Organelles
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organelles specialize in
converting energy to a
form that can be used
by the cell
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Chloroplasts
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Requires solar energy
Dissipates as heat
Use solar energy to
synthesize carbohydrates
Carbohydrates then
broken down in the…..
Mitochondria
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Produce ATP molecules
Energy-Related Organelles
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Photosynthesis
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Cellular Respiration
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The chemical energy of
carbohydrates is
converted at ATP
Cytoskeleton:
Cilia and Flagella - Movement
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Hairlike projections
Help in the movement
of cells
Some examples….
Why would we need
them?
Vacuoles
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Membranous sacs
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contractile vacuoles of protists
central vacuoles of plants
Prokaryotes
Archae
Bacteria
Prokaryotic Cells
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Cell Wall
Capsule
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Flagellum
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Plasma membrane
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Nucleoid
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Plasmids
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Ribosomes
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