Slide shows combined and modified from:
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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
AP BIOLOGY Chapter 6Cell Structure & Function
WHAT’S NEW you didn’t learn in BIO I?
NUCLEAR ENVELOPEDOUBLE MEMBRANE is
fused in spots formingNUCLEAR 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)
http://cellbio.utmb.edu/cellbio/nuclear_envelope.htm
NUCLEAR ENVELOPE
Figure 6.10
Nucleus
NucleusNucleolus
Chromatin
Nuclear envelope:Inner membrane
Outer membrane
Nuclear pore
Rough ER
Porecomplex
Surface of nuclear envelope.
Pore complexes (TEM). Nuclear lamina (TEM).
Close-up of nuclearenvelope
Ribosome
1 µm
1 µm
0.25 µm
ENDOMEMBRANE SYSTEMRegulates protein traffic and performs
metabolic functions in the cellIncludes:
Plasma membraneNuclear membraneEndoplasmic reticulumGolgi apparatusVacuolesLysosomes
INSULIN being released by pancreas cells using exocytosis
http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x26.jpg
Golgi apparatusCisternae = 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)
• Damaged organelles
AUTOPHAGY ~ “eating self”
See movie
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 TODIGEST ENGULFED BACTERIA(Phagocytosis)
http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x28.jpg
ANIMAL VACUOLES & VESICLES“transport vehicles”
http://www.microscopy-uk.org.uk/mag/imgjun99/vidjun1.gif
• FOOD VACUOLES Phagocytosis/ fuse with lysosomes
• CONTRACTILE VACUOLES Freshwater organisms pump out excess water
PLANT VACUOLES (Central Vacuole)
Surrounded by membrane = TONOPLASTSelectively 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
MITOCHONDRIA- DOUBLE MEMBRANE
Outer membrane Inner membrane (CRISTAE)
increases surface area for chemical reactions
Intermembrane space=Space between inner membrane & outer membrane
MATRIX = Space inside cristae foldscontains 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
PLASTIDSCHLOROPLASTS- 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.jpghttp://en.wikipedia.org/wiki/Image:Potato_-_Amyloplasts.jpg
Who else has a circular chromosome notfound within a nucleus?
Endosymbiotic Theory
• 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
http://en.wikipedia.org/wiki/Lynn_Margulis
ENDOSYMBIOTIC THEORY
http://www.mun.ca/biology/scarr/Endosymbiosis_theory.gif
See a movie about ENDOSYMBIOTIC THEORY
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.
PEROXISOMESOther digestive enzyme sacs
in both plants and animalsNOT 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 CELLSHelp detoxify alcohol & other poisons
PRODUCE HYDROGEN PEROXIDE (also a TOXIN)but have enzyme (CATALASE) to break this down
H2O2 → H2O + O2