AP Biology Final exam SG
Semester 1 2011
Biochemistry:
Nucleotides: Building block of nucleic acids, made of a 5 carbon sugar,
phosphate group and a nitrogen base
pH: measure of the concentration of H+ ions, each value is 10x smaller that
the previous value; the more H+ ions the stronger the acid
why is water cohesive: H bonds form between the oxygen end of 1 water
molecule and the hydrogen end of another; separation of charges is because
oxygen is more electronegative
energy source for cells: hydrolysis of ATP
how can you determine the rate of enzyme reactions: measure the
disappearance of the substrate or the production of the product
what is the C source for plants: carbon dioxide taken in and “fixed” in
photosynthesis
proteins: made of chains of amino acids at the ribosome
carbohydrates: made of glucose units; monosaccharides, disaccharides,
polysaccharides (cellulose, chitin, glycogen)
nucleic acids: carry the genetic code
lipids: made of glycerol and fatty acids, used for insulation and long term
energy storage
steroids: lipids that are used to make cholesterol and hormones
coenzymes: non-protein helper molecules, needed for some enzymatic
reactions to take place
competitive inhibitors: block the active site of an enzyme
characteristics of enzymes: made of chains of amino acids,
specific, not used up, have optimal temperature and pH ranges, decreases
the activation energy to start a reaction, combine with a substrate to help a
reaction
Cells:
endosymbiotic theory: mitochondria and chloroplasts used to be free living
organisms; both have their own DNA
prokaryotes vs eukaryotes: P: no nuclear membrane or membrane organelles,
single circular chromosome, E: has a nucleus and membrane organelles; both
have DNA and ribosomes
chloroplast: site of photosynthesis
golgi: packages proteins for transport
nucleus: contains the DNA
nucleolus: makes ribosomes
lysosomes: contains digestive enzymes
mitochondria: site of cellular respiration
ER: tranports proteins in the cell
Ribosomes: make proteins
Tonoplast: membrane that surrounds the central vacuole
Osmosis: movement of water from a high concentration to a low
concentration
active transport: movement from a low concentration to a high
concentration; requires energy
facilitated diffusion: movement from high to low using a transport protein, a
type of passive transport
plasmodesmata: pores in the cell wall that allow plant cells to communicate
with each other
tight junctions: connections between animal cells that don’t allow passage of
materials
desmosomes: anchoring intercellular junction between animal cells
osmotic pressure: the higher the solute concentration the higher the
osmotic pressure
animal vs plant cells: plant cells have a large central vacuole and cell walls
difference between cancer cells and normal cells: cancer cells have a shorter
cell cycle and can stop at any place; no control mechanisms
hypertonic: solution that has more solutes (less water) than another; cells
will shrink in this solution
hypotonic: solution that has less solutes (more water) than another; water
always goes hypo to hyper; cells will swell in this solution
isotonic: equal concentration of solutes; no net movement of water or change
in cells
Photosynthesis and Cellular Respiration:
Light reactions vs Calvin Cycle: ATP and NADPH are made in the light
reactions and used in the Calvin Cycle
end products of light reactions: light energy is captured by pigment
molecules and the energy from the excited electrons is stored as ATP and
NADPH; some of the energy is used to split water to release oxygen
enzymes in Calvin Cycle: Rubisco fixes carbon from carbon dioxide
C3 vs C4 plants: C4 plants are better at “fixing” carbon since they have to
store it until the plant is ready for photosynthesis
reactants and products of each set of reactions—where do the products
come from: Light reactions: use water, produce ATP, NADPH, and oxygen
(comes from the water); Calvin cycle: uses carbon dioxide, ATP, NADPH,
produces glucose
best wavelength light for photosynthesis: red light
chloroplast vs mitochondria: both have DNA, carry out chemiosmosis to make
ATP, are double membrane organelles,
ways to increase rate of photosynthesis: increase carbon dioxide levels, use
optimal temperature, increase stomata number, increase # of enzymes
glycolysis: occurs in the cytoplasm, splits glucose into 2 pyruvate molecules,
produces 2 ATP, 2 NADH and 2 pyruvate molecules, uses the energy from 2
ATP to get started
Krebs cycle (Citric Acid cycle): occurs in the mitochondria; uses acetyl CoA
to produce 2CO2, ATP, NADH and FADH2
ETC: occurs in the inner mitochondrial matrix, makes 32-34 ATP per glucose
Chemiosmosis: uses a H+ ion concentration gradient to make ATP, occurs in
the mitochondria and chloroplast
Cytochromes: proteins in the electron transport chain in both
photosynthesis and cellular respiration
FADH2: carries electrons to the ETC in Cellular Respiration; adds them at a
lower energy level than NADH
NAD+: picks up electrons and H ions to form NADH in Cellular Respiration
and carries them to the ETC; drops them off at the top of the ETC
NADP+: picks up electrons and H ions to form NADPH in photosynthesis;
used to power the Calvin cycle
oxygens role in cellular respiration: final electron acceptor to form water;
most ATP is made if oxygen is present
Cell respiration—steps: Glycolysis, Krebs cycle, ETC
reactants and products of each: see above answers
why/what forms most ATP in CR: chemiosmosis and ETC
substrate level phosphorylation: adds P from molecules; forms ATP in
glycolysis and Krebs Cycle
pyruvic acid: same as pyruvate, formed in glycolysis
acetyl CoA: 2 carbon fragment that enters the Krebs cycle
proton gradient: concentration difference of H+ ions across a membrane,
when they even out they move through ATP synthase and make ATP
why is ATP a good energy source: its energy is easily stored and released
ATP structure: ribose, adenine, 3 phosphate groups
Fermentation (anaerobic respiration): produces only 2 ATP (those produced
in glycolysis), products can enter aerobic respiration when oxygen becomes
available; 2 types: alcoholic fermentation and lactic acid fermentation
Genetics:
polygenic inheritance: controlled by many genes, examples are eye color and
skin color in humans
genetic problems: monohybrid, dihybrid, sex-linked, blood types, fruit flies:
see the practice genetics problems page
probability rules: having a boy = ½, having 2 boys in a row = ½ x ½ = ¼
testcross: allows you to determine the genotype of an organism; mating an
organism with a dominant phenotype but unknown genotype with a
homozygous recessive organism; if any recessive offspring are produced the
parent is heterozygous
dominant vs recessive: if you get 1 dominant gene you show the dominant
trait; you need 2 recessive alleles to show the recessive trait
linkage: genes are found on the same chromosome
epistasis: 1 gene influences the expression of another; usually a 9:3:4 ratio in
the offspring
locus: location of a gene on a chromosome
Evolution:
heterozygote advantage: heterozygote is better off than either of the
homozygotes; example: sickle cell anemia—heterozygote is resistant to
malaria but doesn’t show the symptoms of sickle cell
punctuated equilibrium: long periods of no evolutionary change followed by
periods of rapid change
gradualism: slow steady change in a species over time
species: group of organisms that can mate and produce fertile offspring
under natural conditions
Hardy-Weinberg problems: see lab #8
why are hybrid organisms sterile: hybrids are normally sterile due to
chromosome differences
convergent evolution: organisms that are not closely related evolve similar
structures because they are advantageous in their environment; for
example—fins/flippers in dolphins, fish and penguins
divergent evolution: speciation
reproductive isolation: keeps gene pools separate and allows species to
become or remain separate
temporal isolation: differences in timing of reproduction
habitat isolation: live in the same place but don’t meet so cant mate
behavioral isolation: species-specific mating rituals
geographic isolation: populations are separated by a geological formation
(mountains, streams, etc) that keep their gene pools separate; can lead to
allopatric speciation
adaptive radiation: a population can evolve into many different species in a
relatively short period of time given enough variation in the population and
time
Hardy-Weinberg conditions: large population, no mutation, no migration,
equal reproductive success, random mating
Microevolution: change in allele frequency of a population over time
homologous structures: similar structures in closely related organisms;
examples—forelimbs of mammals
feeding response: a mother bird regurgitates her meal at the sight of her
offspring
altruism: aiding another organism at your own expense
Kin selection: altruism among related organisms
genetic drift: change in allele frequency due to random chance; affects a
small population more than a large one
polyploidy: containing more than 2 sets of chromosomes; can explain some
speciation events in plants
allopatric speciation: speciation when groups are geographically separated
from each other
,sympatric speciation: speciation without geographic separation
Mutation: change in the DNA sequence of an organism
sexual selection: female selection for the best genes in her mate; can lead to
extreme forms in the males like in peacocks
Natural Selection—statements: variation exists in organisms, there is
competition for resources, more individuals are born than can survive,
evolution takes long periods of time, individuals best adapted to their
environment survive, reproduce and pass on their genes to the next
generation
gene flow: movement of genes into or out of a population
bottleneck event: most organisms in a population die, those that are left may
not have the same allele frequency as the original population but they are
the only ones to create the next generation
hybrid sterility: there are barriers to reproduction between different
species
Plants:
Mesophyll: middle layer of the leaf, site of photosynthesis
Transpiration: evaporation of water from the stomates, with cohesion allows
water to move to the top of trees
angiosperm reproduction—microspore: male gametophyte, becomes the pollen
grain
megaspore: produces the female gametophyte (embryo sac)
gametophytes: haploid structure that produces gametes
why are angiosperms so successful: don’t need water for fertilization,
produce flowers for pollination, produce fruit for seed dispersal
endosperm: triploid food in seeds for embryonic plants
hypocotyl: in dicots the first part of the stem to be visible above ground
ovary: contains ovules, becomes the fruit
auxin (IAA): hormone that is responsible for elongation of shoots and apical
dominance in plants
gibberellins: hormone that is responsible for germination
cytokinens: hormone responsible for cell division
phytochromes: protein isomers that control flowering in short day plants
ethylene: hormone that controls ripening of fruit, only hormone that is a gas
what controls flowering in short day plants: see above answer
double fertilization: in angiosperms 1 sperm nucleus fertilizes the egg, the
other fertilizes the diploid cell to become the triploid endosperm
pollen tubes: produced by the pollen tube nucleus, allows the sperm nuclei to
reach the embryo sac
fruit function: seed dispersal
root hairs: increase surface area for absorption of water and minerals
Casparian strip: controls entry of substances into the vascular cylinder of a
root
root cap: protects the apical meristem
zone of maturation: plant takes on its adult function here
apical meristem: produces new plant cells for the life of a plant, allows a
plant to have indeterminant growth
translocation: movement of sugars in plant phloem vessels
companion cells: found outside sieve tube element cells, controls their
functions
tracheids: xylem vessel cells, dead at functional maturity
trichomes: small hairs on a plant that help control water loss and prevent
herbivory
sieve tube elements: phloem vessel cells, are alive at maturity
vessel elements: xylem vessel cells
cohesion: attraction of water to other water molecules, contributes to water
movement up a plant
root pressure: movement of water a short distance into a root
capillary action: movement of water a short distance into a narrow tube
why do stems bend toward the light: auxin causes elongation of the cells in
the dark
why does sugar move: pressure and osmotic differences between the source
and the sink
results of stomates closing: reduction in CO2 levels in the plant so a
decrease in photosynthetic rate
parenchyma: general plant cell, gives rise to all other types
sclerenchyma: forms xylem vessels, contains lignin for extra support of the
plant
collenchyma: support cells in young plants
xylem: transports water and minerals
phloem: transports sugars
what factors increase transpiration: heat, wind, dry conditions
gymnosperms: “naked” seed plants, conifers
mosses: gametophyte generation is dominant, produces a sporophyte
consisting of a stalk and a capsule containing a sporangium
ferns: most primitive vascular plant
algae: water-dwelling autotrophs