AP BIOLOGY Chapter 6 Cell Structure & Function 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

Prokaryote and eukaryote The basic structural and functional unit of every organism is one of two types of cells: prokaryotic or eukaryotic Only organisms of the domains Bacteria and Archaea consist of prokaryotic cells Protists, fungi, animals, and plants all consist of eukaryotic cells

Prokaryotic and eukaryotic cells Basic features of all cells Plasma membrane Semifluid substance called cytosol Chromosomes (carry genes) Ribosomes (make proteins)

Prokaryotic cells Prokaryotic cells are characterized by having No nucleus DNA in an unbound region called the nucleoid No membrane-bound organelles Cytoplasm bound by the plasma membrane

Eukaryotic cells Eukaryotic cells are characterized by having DNA in a nucleus that is bounded by a membranous nuclear envelope Membrane-bound organelles Cytoplasm in the region between the plasma membrane and nucleus Eukaryotic cells are generally much larger than prokaryotic cells

DOUBLE MEMBRANE is fused in spots forming NUCLEAR PORES http://cellbio.utmb.edu/cellbio/nuclear_envelope.htm NUCLEAR ENVELOPE 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 Figure 6.10 Nucleus 1 µm Nucleolus Chromatin Inner membrane Outer membrane Nuclear pore Rough ER Pore complex Surface of nuclear envelope. Pore complexes (TEM). Nuclear lamina (TEM). Close-up of nuclear envelope Ribosome 1 µm 0.25 µm Figure 6.10

Ribosomes are particles made of ribosomal RNA and protein Ribosomes carry out protein synthesis in two locations In the cytosol (free ribosomes) On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes)

ENDOMEMBRANE SYSTEM Regulates protein traffic and performs metabolic functions in the cell Includes: Plasma membrane Nuclear membrane Endoplasmic reticulum - accounts for more than half of the total membrane in many eukaryotic cells Golgi apparatus Vacuoles Lysosomes

The smooth ER Synthesizes lipids Metabolizes carbohydrates Detoxifies drugs and poisons Stores calcium ions

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

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 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

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 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 any organelles, in the cytoplasm of plant cells, containing pigment or food. 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?

Originally proposed in early 1900’s http://en.wikipedia.org/wiki/Lynn_Margulis 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

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