Download AP Study Guide Exam 3

AP Study Guide Exam
Cell Cycle
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Unicellular-Reproduction, Multicellular- Growth and Repair
Represents the life of a cell from origin until cell division
Interphase is where cell spends 90% of its life.
During interphase, the cell is doing its everyday job (Making RNA, Proteins, etc)
Interphase is divided into 3 parts: G1, S, and G2
G1= Cell doing its everyday job, and growing
S= DNA being copied
G2= Preparation for division, Cell growth, making organelles, proteins, and membranes
G0= A non-dividing state. Most human cells in G0. Nerve and muscle cells highly
specialized and never divide.
10. Liver cells are special they can be in G0 and be called back into division.
11. Cells divide at different rates depending on cell type. Ex- Skin=frequent, liver=seldom,
nerves & muscles= never
12. Cell cycle is controlled by checkpoints (to make sure that the cell is dividing properly)
13. There are two irreversible checkpoints (Replication, and separation of sister chromatids)
14. Checkpoints controlled by Stop and Go chemical signals
15. 3 Major Checkpoints G1, G2, and M
16. G1= Can DNA synthesis begin (Important See Below). G2= has DNA been made correctly
and mitosis is happening. M Phase= spindle checkpoint, and did the sister chromatids
separate correctly?
17. G1- Critical checkpoint. Primary decision point. If cell gets “go” then it divides. If it does
not, it exits cell cycle and enters G0 phase (Non-Dividing)
18. Cell communication= signals in the form of proteins (Activators & Inhibitors)
19. Go signals= Internal (promoting) or external (growth)
20. Promoters= Cyclins (regulatory proteins), Cdks= Cyclin-dependent kinases (enzyme
activates cellular proteins) MPF= used for G2 checkpoint (maturation/mitosis promoting
factor), APC= used for M checkpoint( Anaphase promoting complex)
21. CDK’s and Cyclin drive cell from one phase to the next in cell cycle. These proteins have
been highly conserved through evolution. See same genes in yeast, insects, plants, and
animals(Yes humans too)
22. External Signals= Growth factors (External signals that say grow and stop). Signals that
are released by body cells to get cells around them to divide.
23. Two categories of factors= Density-Dependent Inhibition- Crowded cells stop growing,
mass of cells use up growth factor, not enough factor to continue division. Anchorage
dependence- cells must attach themselves to a substrate in order to divide.
24. Cancer= a failure to control cell division. What does this mean? No off switches in the
cell cycle. Checkpoints are no longer. Major gene is the p53 gene which is in charge of G1
checkpoint. Most cancers shut down p53.
25. p53 protein halts cell division if it detects damaged DNA, stimulates repair enzymes to
fix DNA, forces and keeps cell in G0 resting stage, and causes apoptosis (Death) of
severely damaged cell.
26. Cancer only develops if there are 6 key mutations (“hits”)
 unlimited growth
 ignore checkpoints
 escape apoptosis
 immortality = unlimited divisions
 promotes blood vessel growth
 overcome anchor & density dependence
27. Mutagens= Stuff that causes mutations. Ex. UV radiation, Chemical exposure, Radiation,
Cigarette smoke.
Cell Division
28. DNA is organized into chromosomes (tightly coiled packages of DNA). Makes it easier to
handle during cell division.
29. 2 sister chromatids together= chromosome (chromatids held together by centromere)
30. Structure of a chromosome= DNA, Nucleosome, Coil, Supercoil, and Chromosome
31. 2 stages of cell division= Mitosis, and Cytokinesis
32. Mitosis divided into 4/5 stages PMAT (5th is Prometaphase)
33. Prohase
 Chromatin condenses (visible chromosomes)
 Fibers extend from centromeres
 Centrioles move to opposite poles
 Mytotic spindle is formed (Actin/Myosin)
 Nucleolus disappears
 Nuclear Membrane breaks down
34. Prometaphase
 Proteins attach to centromeres (kinetochores)
 Microtubles attach to kinetochores (Connect centromeres to centrioles)
 Chromosomes begin migrating to equator
35. Metaphase
 Chromosomes align across the equator
 This occurs on metaphase plate (ensures proper chromosome separation)
36. Anaphase
 Sister chromatids separate at kinetochores
 Pulled by motor proteins (chromatids “walk” along microtubules)
 Increased production of ATP at this time.
37. Telophase
 Chromosomes at opposite ends of poles
 Two nuclei form
 Chromosomes disappear
 Spindle fibers disperse
 Cytokinesis begins
38. Cytokinesis
 Animals and plants differ
 Animals- form a cleavage furrow (Ring of Actin). Microfilaments (Myosin) form
around the equator. Tightens down and eventually breaks cell into two. (Like a
drawstring)
 Plants- Ridged cell wall does not allow for pinching. Vessicles move to the
equator to form a primer for cell plate. Cell plate is the template to forming the
cell wall to split the cells into two.
39. Evolutionary Link- Mitosis evolved from binary fission (Bacterial Reproduction). Simpler
forms of mitosis seen in protists.
Homeostasis
40. 2 evolutionary paths for organisms. Regulators or Conformers
41. Regulators- maintain constant internal conditions
42. Conformers- allow internal conditions to fluctuate with external changes
43. Hierarchy of structure in multicellular organisms. Cells, tissues, organs, organ systems
44. Homeostasis- keeping internal balance. Multiple things (systems) happening at once. Ex.
Temperature, blood sugar, water balance. Body has to maintain stability.
45. Negative feedback- stimulus triggers control mechanism. Reversing what is going on. Ex.
Body Temp
46. Positive feedback- amplifying process (Not common) Ex. Permafrost and Greenhouse
gas
47. Feed-Forward- Changing the set point for equilibrium Ex. Deer and Driver
48. Ectotherms- animals that rely on environment for body temperature
49. Endotherms- organisms that can maintain their own body temperature
50. Heterotherm- Can be both at times (Hibernating Animal)
51. BMR- minimum amount of energy to carry out basic functions
52. Thermoregulation- controlling body temp. Vasodialation decrease temp (blood moving
closer to skin), and Vasoconstriction increase temp (blood being moved away from skin)
53. Osmoregulation- Water balance. Fresh water hypotonic to fish must get rid of diluted
urine. Salt water is hypertonic to fish must maintain salt in urea in order to stay
balanced. Land animals conserve water because they lose it through processes
(Breathing and Waste)