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