Notes 10-26-07:
1.4.1: Draw a diagram of the fluid mosaic model:
• Show bilayer, cholesterol, glycoprotein, integral and
peripheral proteins.
Peripheral
hydrophilic
Hydrophobic
proteins
are on the
outside
layer…
just draw
one…
(Integral protein)
hydrophilic
1.4.2: Label the hydrophobic and hydrophilic portions and
explain how phospholipids maintain the structure of cell
membranes.
Phospholipids have a polar ‘head’ (phosphate group) and a non-polar
hydrocarbon chain. Polar likes water and is near the water. The nonpolar lipid chains stay together away from the water.
Make sure that you are on ‘View’
and ‘Slideshow’ for the rest of the
activity
Prokaryotes
do not have
membranebound
organelles
like ER,
Golgi,
Mitochondria
etc…
Prokaryotes
•
•
•
•
•
‘Pro’ means ‘before’
‘Kary’ means kernal
Prokaryotes are cells without a nucleus!
They are SMALL
Example: Bacteria
Some prokaryotes that cause disease
Neisseria gonorrhoeae - coccoid
prokaryote; causes gonorrhea
Staphylococcus aureus,
a Staphylococcus
prokaryote
Anthrax! Bacterial disease.
(caused by a prokaryote)
Impetigo, common
bacterial disease
Leprosy, bacterial
disease
Other famous prokaryotic diseases:
•Gonorrhea
•Acne
•Syphilis
•Typhoid fever
•Staph infection
•Gangrene
NOT in prokaryotes! (Why?)
A cell with a golgi apparatus
Prokaryotes don’t have organelles
with membranes around them!
Monkey cell infected containing roughly twenty Coxiella burnetii
Why is Coxiella
burnetii NOT a
prokaryote?
Each cell that is infecting
has a nucleus!
Go to this site and play one of the
games
http://www.quia.com/mc/65947.html
Mitochondria and
chloroplasts have
their own DNA…
(in fact it is one
of the pieces of
endosymbiotic
theory… they
originated on
their own first)
The more
specialized
organelles you
have, the bigger
you can be.
Plasmodesmota – channel between two
cells with a cell wall. ‘Pla’ and ‘Plant’
Gap junctions, channels between
cells with membranes only
Desmosome - They are like rivets that
hold two cells together. Necessary to
form tissues
Tight junctions – like a sewn seam
that keeps two cells together
If you are up to it, play this game… look at the
clues that the observers give you to know
which organelle to give to the guy going up the
ladder. The password is megacell.
http://nobelprize.org/educational_games/medicine/cell/
Microtubules,
microfilaments,
intermediate
filaments and
microtrabecular
lattice are part
of the
cytoskeleton.
Microtubules – large, and make up
cilia, centrioles, and flagella. They
are arranged in 9-2 format… 9
‘doublets’ surrounding a pair.
Microfilaments
• Small strings of globular
protein.
• Used especially in cell
division. (cleavage
furrow)
Peroxisomes-sacs of enzymes that come out of the
smooth endoplasmic reticulum. They are used to
detoxify things by adding oxygen to them. Different
from lysosomes – lysosomes have digestive enzymes
to break down food and old cell parts.
Glycoproteins and glycolipids are
used in cell recognition.
Phagocytosis:
endocytosis
where the
membrane wraps
around the
desired material
and ‘eats’ it.
Phago=eat
Pinocytosis:
endocytosis
where the cell
‘drinks’.
Pino=drink
Cotransport
proteins:
Bravo! Biologia!
Beisbol y biologia !
Dynein arms- ‘motors’ that cause
the doublets to pull together.
When they turn off and on it
makes the cilia or flagella move.
Surface to Volume ratio: When you look at the
following, notice that as volume increases,
surface area doesn’t increase as much…
Surface to volume with m and m’s
Diameter
(in mm)
Mini
m&m’s
4mm
Regular
m&m’s
8mm
Peanut
m&m’s
10mm
Radius
(1/2
diameter)
Surface Area:
(4r2)
Volume:
(4r3)
Ratio:
S.A./Volu
me
Questions regarding Surface:Volume
1. Describe how increasing the size of a cell
affects the ratio of Surface area to Volume
ratio.
2. Describe how increasing the size of a cell
affects the ability of the cell to diffuse
products into and out of the cell.
3. Why is smaller better for diffusion?
This scanning electron microscope picture demonstrates
HIV budding (arrows) from the surface of an infected
T-lymphocyte magnified 80,000X.