1. AP BIOLOGY Chapter 6 Cell Structure & Function
Slide shows combined and modified from:

3. 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

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

5. 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

6. 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

8. DOUBLE MEMBRANE is fused in spots forming NUCLEAR PORES
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)

9. 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

13. 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)

14. 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

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

17. INSULIN being released by pancreas cells using exocytosis

20. Golgi apparatus Cisternae = Flattened membrane sacs (look like stacked pancakes) 2 sides = 2 functions

21. Animation from: http://www.franklincollege.edu/bioweb/A&Pfiles/week04.html
See a Golgi movie

22. EVERYTHING’S CONNNECTED!

23. 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

25. 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

26. WHITE BLOOD CELLS USE LYSOSOMES TO DIGEST ENGULFED BACTERIA (Phagocytosis)

28. ANIMAL VACUOLES & VESICLES “transport vehicles”
FOOD VACUOLES Phagocytosis/ fuse with lysosomes
CONTRACTILE VACUOLES Freshwater organisms pump out excess water

29. 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

30. Other cell parts with membranes that are NOT part of the Endomembrane system:
Mitochondria
Plastids
Peroxisomes

33. 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

36. 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

37. 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)

38. Who else has a circular chromosome not
found within a nucleus?

39. Originally proposed in early 1900’s
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

40. ENDOSYMBIOTIC THEORY See a movie about ENDOSYMBIOTIC THEORY

41. 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.

42. 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