Transcript Lecture #3 Date - local.brookings.k12.sd.us

AP BIOLOGY Chapter 6
Cell Structure & Function
WHAT’S NEW you didn’t learn in BIO I?
Slide shows combined and modified from:
http://gbs.glenbrook.k12.il.us/Academics/gbssci/bio/apbio/Lecture/lecture.htm;
http://www.explorebiology.com/
http://home.att.net/~tljackson/neville.html
NUCLEAR ENVELOPE
http://cellbio.utmb.edu/cellbio/nuclear_envelope.htm
DOUBLE MEMBRANE is
fused in spots forming
NUCLEAR PORES
NUCLEAR LAMINA- netlike array of protein
filaments on nuclear side of envelope that
maintains the shape of the nucleus
(Play a role in reforming nuclear membrane after cell division,
if you inject antibodies to lamina proteins, nucleus can’t
reform after mitosis)
NUCLEAR ENVELOPE
Nucleus
Nucleus
1 µm
Nucleolus
Chromatin
Nuclear envelope:
Inner membrane
Outer membrane
Nuclear pore
Pore
complex
Rough ER
Surface of nuclear
envelope.
1 µm
Ribosome
0.25 µm
Close-up of
nuclear
envelope
Figure 6.10
Pore complexes (TEM).
Nuclear lamina (TEM).
ENDOMEMBRANE SYSTEM
Regulates protein traffic and performs
metabolic functions in the cell
Includes:
Plasma membrane
Nuclear membrane
Endoplasmic reticulum
Golgi apparatus
Vacuoles
Lysosomes
INSULIN being released by pancreas cells
using exocytosis
http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x26.jpg
Golgi apparatus
Cisternae = Flattened membrane sacs
(look like stacked pancakes)
2 sides = 2 functions


cis = (receives vesicles by fusion)
trans = buds off vesicles to send to
other places (shipping face)
Animation from: http://www.franklincollege.edu/bioweb/A&Pfiles/week04.html
See a Golgi movie
EVERYTHING’S CONNNECTED!
LYSOSOMES
(common in animal cells but rare in plant cells)
Contain hydrolytic enzymes for intracellular
digestion
• Food (Phagocytosis)
See movie
• Damaged organelles
AUTOPHAGY
~ “eating self”
LYSOSOMES:
Uncontrolled release of lysosome contents into the
cytoplasm can also cause cell death (necrosis)
• APOPTOSIS (self-destruct mechanism)
“cell suicide”
Embryonic development
Removes damaged cells
Immune response
Cancer cells and AIDS virus override self-destruct
signals
WHITE BLOOD CELLS USE LYSOSOMES TO
DIGEST ENGULFED BACTERIA
(Phagocytosis)
http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x28.jpg
ANIMAL VACUOLES & VESICLES
“transport vehicles”
• FOOD VACUOLES
Phagocytosis/ fuse with lysosomes
• CONTRACTILE VACUOLES
Freshwater organisms pump
out excess water
http://www.microscopy-uk.org.uk/mag/imgjun99/vidjun1.gif
PLANT VACUOLES (Central Vacuole)
Surrounded by membrane
= TONOPLAST
Selectively permeable
– controls what goes in & out
STORAGE
• Water
• Stockpile proteins/inorganic ions
• Deposit metabolic byproducts
• Store pigments
• Store defensive compounds against herbivores
Other cell parts with membranes that
are NOT part of the Endomembrane
system:
– Mitochondria
– Plastids
– Peroxisomes
MITOCHONDRIADOUBLE MEMBRANE
Outer membrane
Inner membrane (CRISTAE)
increases surface area for
chemical reactions
Intermembrane space=
Space between inner membrane
& outer membrane
MATRIX = Space inside cristae folds
contains DNA, enzymes, ribosomes
Chloroplasts – site for
photosynthesis in plants
•DOUBLE MEMBRANE
•Has own DNA
• Thylakoids – membrane sacs
containing light-capturing pigments
•Grana –
closed compartments of stacked
thylakoid membranes
•Stroma – fluid surrounding thylakoids
PLASTIDS
CHLOROPLASTS- contain pigment
chlorophyll for photosynthesis
CHROMOPLASTS- contain pigments
that give fruits and flowers colors
AMYLOPLASTS- store starch (amylose)
in roots and tubers (colorless)
http://www.jonathanwald.com/800x600/images/Red-Apple.jpg
http://en.wikipedia.org/wiki/Image:Potato_-_Amyloplasts.jpg
Who else has a circular chromosome not
found within a nucleus?
Endosymbiotic Theory
http://en.wikipedia.org/wiki/Lynn_Margulis
• Originally proposed in early 1900’s
• Idea reintroduced in 1963 by Lynn Margulis
• Suggests that engulfed prokaryotes shared
symbiotic relationship with host cell
• Advantages for both:
~ one supplies energy
~ other raw materials & protection
ENDOSYMBIOTIC THEORY
See a movie about
ENDOSYMBIOTIC THEORY
http://www.mun.ca/biology/scarr/Endosymbiosis_theory.gif
Evidence for Endosymbiotic theory
1. Mitochondria and chloroplasts have circular DNA like
bacteria.
2. Mitochondria and chloroplasts have ribosomes whose size
and structure resemble bacterial ribosomes.
3. Mitochondria and chloroplasts replicate independently of
cell division using binary fission like bacteria.
4. Inner membranes of mitochondria and chloroplasts have a
composition similar to bacterial membranes.
PEROXISOMES
Other digestive enzyme sacs
in both plants and animals
NOT part of endomembrane system
(proteins come from cytosol)
In fat storing seeds (called GLYOXYSOMES)
Break down fatty acids → sugars
transport to mitochondria for energy
In LIVER CELLS
Help detoxify alcohol & other poisons
PRODUCE HYDROGEN PEROXIDE (also a TOXIN)
but have enzyme (CATALASE) to break this down
H2O2 → H2O + O2