The Cell
All organisms are made of cells,
the organism’s basic unit of
structure and function.
Size range
of cells
The Nucleus
Nucleus—control center
- enclosed by nuclear
envelope
- contains most of the genes
that control the entire cell
- DNA organized with
proteins into chromatin
- nucleolus-produces
ribosomes
Mitochondria
–powerhouse
•energy transformers of cells- produces
ATP- energy for cell
+ double membranes
+ contain ribosomes/DNA
Mitochondrial DNA is only passed on
by mom
Ribosomes
Construction Crew
- make proteins
- free- float in
cytoplasm
- bound- attached
to endoplasmic
reticulum
Vacuoles
* Cell Closet
function in cell maintenance & storage
+ food vacuole
+ contractile vacuole- removes excess
water
+ central vacuole (pictured)- in PLANTS
Stores water & maintains cell shape
Endoplasmic reticulum
Endoplasmic reticulumIntercellular highway
•Transport cell materials
• two distinct regions
+ rough ER (ribosomes attached)
- manufacture proteins for
secretion
- membrane production
+ smooth ER
- synthesis of lipids
- carbohydrate metabolism
- detoxify drugs/poisons
- stores calcium ions
Golgi Apparatus
* Packaging &
shipping
• finishes, sorts, and
ships cell products
• two poles
+ cis face
+ trans face
Enzymes in the Golgi modify products of the ER in stages
as they move through the Golgi stack from cis to trans face.
Lysosomes
- clean up crew
contain hydrolytic enzymes- Primarily animal cells
• digestive compartments
+ intracellular digestion
+ recycle cell material
+ program cell destruction (apoptosis)
Apoptosis – programmed cell death
http://www.hhmi.org/biointeractive/disease/ctl_
video.html
The Cytoskeleton
Cytoskeleton
•provides structural support
for motility and regulation
+ network of fibers
- microtubules- thick &
Hollow (straw)
- microfilaments- thin &
Solid (toothpick)
- intermediate filamentsMedium & solid
Cilia & Flagella
-Cilia- short, hairlike, numerous. Cover
entire cell
-Flagella- long, only 1 or 2 on a cell
* Both function in movement
* Found on outside of ANIMAL cells
* Composed of microtubules
(cytoskeleton)
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Centrosomes
• Found in animals
primarily
• Produce microtubules
during cell reproduction
• Animal cells contain
centrioles which
contain 9 sets of 3
microtubules
Cell Membrane
Plasma Membrane- Bouncer
•boundary that separates living cell from
its non-living surroundings
+ 8 nm thick
+ selectively permeable
+ unique structure relates to function
+ phospholipid bilayer
Cell Wall
Cell Walls (1° & 2°)
Plant cells only*
- Brick wall
•cellulose fibers
•Middle lamella
Made of pectin
(sticky polysaccharide)
Cytoplasm/Cytosol
--cytosol--Gelatinous fluid that surrounds
organelles & holds cellular components (Na+, K+,
amino acids, etc)
Cytoplasm-everything in
Cell EXCEPT nucleus
Chloroplasts- site of
photosynthesis - Production crew* Only in PLANT cells
* Made of thylakoid stacks (grana)
where reactions occur
* green in color due to chlorophyll
Peroxisome
Break down large, branched
Fatty acid chains
•+ contain specialized
teams of enzymes
- peroxide-producing
oxidases and catalase
Leucoplast
* Basement/Cellar
Non-pigmented plastids
Bulk storage of starch,
commonly in roots
Chromoplast
* Crayons *
* Responsible for pigment synthesis and
storage
*Commonly found in fruit, flowers, & aging
leaves
* assist chloroplasts in absorbing suns energy
The Endomembrane System
Includes:
•nuclear envelope
•Endoplasmic reticulum
•Golgi apparatus
•Lysosomes
•Vacuoles
•Plasma membrane*
The organelles of the endomembrane system are related
through direct contact or by the transfer of membrane
segments as vesicles.
Endomembrane System Summary
Animal vs. Plant Cell
Unique to Plant Cells:
- cell wall
- large central vacuole
- Plastids
Unique to Animal Cells:
-Centrioles
-Lysosomes
- flagella and/or cilia
A Panoramic View of the Cell
Prokaryotic
+only in bacteria/archaebacteria
Eukaryotic
+no true nucleus/nuclear envelope
true membrane-bound nucleus
+genetic material in nucleoid region
genetic material in nucleus
+little to no organelles
many organelles
Protists, Fungi, Plantae, Animalia