Cell Diversity
• Cell Shape
– A cell’s shape reflects its function.
•www.cellsalive.com
I. Cell Diversity
A. Cell Shape
1. Cells shape helps it to perform its function
B. Cell size
1.Cells have volume and surface area.
a. as it grows:volume increases faster than surface
area
b. if it is too big it can’t import or export correctly so it
stays smaller
• III. Cellular Organization
A. Colonial organization- genetically identical but stay
together and don’t function together
B. Multicellular- one life with 1+ cells
Cells
Tissue
Organ
Organ systems
Organelles
• Cell Size
– Cell size is limited by a cell’s surface area–tovolume ratio.
Cellular Organization
• In multicellular eukaryotes, cells organize into tissues,
organs, organ systems, and finally organisms.
A. Plasma Membrane aka cell
membrane
1. cell’s outer boundary,
2. covers a cell’s surface
3. acts as a barrier between the
inside and the outside of a cell.
4. consist of a phospholipid bilayer.
a. Contains protein embedded
in the bilayer
there are Receptor proteins in the cell
membrane that recognize and bind to other
substances on the outside of the cell.
Transport Proteins help substances move
across the cell membrane.
b. fluid mosaic- It
acts more like a liquid
than a solid.
5. The plasma membrane allows
certain particles to pass into or
exit the cell.
. The membranes of eukaryotes contain
lipids called sterols.
These are located between the tails of the
phospholipids.
Sterols make the membrane more firm, and
keep it from freezing in low temperatures.
B. The region of the cell that is within the plasma
membrane and that includes the fluid, the
cytoskeleton, and all of the organelles except the
nucleus is called the cytoplasm.
C. The nucleus is a membranebound organelle that contains a
cell’s DNA.
• directs the cell’s
activities
1. Prokaryote cells
lack a nucleus and
membrane-bound
organelles.
Bubonic Plague-14th century Versinia Pestis 1347-52.
25 million in Europe (flea bites/ direct contact)
2. Eukaryote cells have a nucleus and membranebound organelles. ( most plants and animals)
• The nucleus is surrounded by
a double membrane called
the nuclear envelope.
• The nucleolus is the
place where DNA is
concentrated when it
is in the process of
making ribosomal
RNA.
D. Mitochondria harvest energy
from organic compounds and
transfer it to ATP.
1. Highly active cells have hundreds of
mitochondria, such as muscle cells
2. Fat storage cells are less active and have fewer
mitochondria
3. Structure
• Mitochondria have a inner and outer phospholipid
membrane
--Separates mitochondria from cytosol
• Inner membrane
– Have folds called cristae
• Cristae- contain protein that carry out energy
related chemical reactions
4. Mitochondria have their own DNA
5. They reproduce by the division of existing
mitochondria
E. Ribosomes
• Small roughly spherical organelles that are
responsible for building protein
• They do not have a membrane
• Made of protein and RNA molecules
• Ribosome assembly begins in the nucleolus and
ends in the cytoplasm
• A large subunit and a small subunit come together to
form a function
• Some are free in cytosol and some ribosome
attached to the rough ER
F. Endoplasmic Reticulum
The Endoplasmic Reticulum is
a system of membranous
tubes and sacs that are used
in the cell to act as the
intracellular highway for
molecules. The amount of
Endoplasmic Reticulum
(abbreviated E.R for short) is
found in different amounts
depending on the cell type.
Smooth Endoplasmic Reticulum
The smooth Endoplasmic
Reticulum has no ribosomes,
which gives it it’s smooth
appearance. It’s main function is
to produce lipids. An example of
a lipid produced by Smooth E.R
is cholesterol. An example of
Smooth E.R found in the body is
E.R in the body is in the liver
and kidney. The E.R protects
the liver and kidney from drugs
and poisons.
Rough Endoplasmic Reticulum
There are two types of E.R, rough
and smooth E.R. The Rough
E.R is covered in ribosome.
Rough Endoplasmic produces
phospholipids and proteins.
Rough E.R is usually found in
places that produce large
amounts of protein. An example
of this would be cells in the
digestive glands.
Parts of the Endoplasmic Reticulum
G. Golgi Apparatus
• processes and packages proteins.
Golgi Apparatus- another system of flattened
membranous sacs.
• Sacs nearest the nucleus receive vesicles from the
ER containing newly made proteins or lipids.
– A. vesicles travel from one part of the Golgi
Apparatus and transport substances as they go.
– B. stacked membranes modify vesicles as they
move.
– C. Modifies many cellular products and prepares
them for export.
Golgi Apparatus
H. Vesicles
• Small , spherically shaped sacs that are surrounded
by a single membrane and that are classified by their
contents.
• A. migrate to and merge with the plasma
membrane, when they do they release their
contents to the outside of the cell.
Vesicles Chart
Vesicle type
functions
Lysosomes
-Contain digestive enzymes: break
down unused large molecules
Peroxisomes
-Neutralize free radicals, break down
toxins in the body and kill bacteria.
Glyoxysomes
-Break down stored fats in seeds.
Endosomes
-Engulf material to take to the
lysosomes to digest.
Food vacuoles
-Store nutrients.
Contractile vacuoles
-Contract to expel excess water from a
cell.
Vesicle
• Vesicles, including lysosomes (digestive enzymes)
and peroxisomes (detoxification enzymes), are
classified by their contents.
http://highered.mcgrawhill.com/sites/0072437316/st
udent_view0/chapter5/anima
tions.html#
• Protein Synthesis
– The rough ER, Golgi apparatus, and vesicles work
together to transport proteins to their destinations
inside and outside the cell.
Processing of Proteins
http://www.exploratorium.edu
/traits/cell_explorer.html
H. Cytoskeleton
• is made of protein fibers that help cells move and
maintain their shape.
• includes microtubules, microfilaments, and
intermediate filaments.
1. Microtubules
• Hollow tubes made of a protein called tubulin.
• They radiate outward from a central point called the
centrosome.
2. Microfilaments
• Long threads of beadlike protein actin and are linked
end to end and wrapped around each other
– Like two strands of a rope
• Contribute to cell movement
– Includes the crawling of white blood cells and the
contraction of muscles
3. Intermediate Filaments
• Rod that anchors the nucleus and some other
organelles to their places in the cell
• Maintain the internal shape of the nucleus
• Hair-follicle cells produce large quantities of
intermediate filament proteins
• Make up most of the hair shaft
http://www.northland.cc.mn.u
s/biology/biology1111/animati
4. Cilia and Flagella ons/flagellum.html
• Hair-like structures that extend from the surface of
the cell wall
• They assist in movement
• Cilia are short and are present in large numbers in
certain cells
• Flagella are longer and are far less numerous in the
cells
• Have nine pairs of microtubules
5. Centrioles consist of two short cylinders of
microtubules at right angles to each other and are
involved in cell division.
Structure
Property
Microtubules
Microfilaments
Intermediate
Filaments
Structure
Hollow tubes made
of coiled protein
Two strands of
intertwined protein
Protein fibers coiled
into cables
Protein Subunits
Tubulin with two
subunits
Actin
One of several
types of fibrous
proteins
Main Function
Maintenance of cell
shape; cell motility
(in cilia and
flagella);
chromosome
movement;
organelle
movement
Maintenance and
changing of cell
shape; muscle
contraction;
movement of
cytoplasm; cell
motility; cell division
Maintenance of cell
shape; anchor
nucleus and other
organelles;
maintenance of
shape of nucleus
A. Plant Cells
1. have cell walls, central vacuoles, and plastids.
• 2. a rigid cell wall covers the cell membrane and for
support and protection.
• Made of cellulose
3. Large central vacuoles store water, enzymes, and
waste products and provide support for plant tissue.
4. Plastids store starch and pigments.
-chloroplast converts light energy into chemical
energy by photosynthesis.
B. Comparing Cells
• Prokaryotes, animal cells, and plant cells can be
distinguished from each other by their unique
features.
Comparing Plant and Animal Cells