AP Biology
Final Exam Study Guide
Semester 1 2012
Unit 1
Levels of protein structure, what causes each
Primary: order of amino acids, determined by nucleotide sequence, covalent bonds (peptide) hold the
molecule together
Secondary: alpha helices and beta pleated sheets, held together by R groups between adjacent amino
acids
Teriary: 3-D structure, held together by interactions between the R groups—ionic bonds, H bonds,
hydrophobic interactions
Quartenary: bonding of 2 or more polypeptides together
What elements are in each type of biological molecule
Carbs: C, H, O in a 1:2:1 ratio
Lipids: C, H, O with very few O’s
Proteins: C,H,O,N,S
Nucleic Acids: C,H,N,O,P
Unit 2
What is compartmentalization? What are the advantages?
Each organelle has a memebrane that keeps its contents separate from the cytoplasm so it can have
different concentrations of molecules inside; can increase surface area for reactions; increases efficiency of
reactions
SA/V ratio—what does it affect?
The higher the ratio the easier it is to move substances across the membrane
Cell membrane
phosopholipid bilayer; has different molecules facing the inside and outside of the cell because they have
different functions
Photosynthesis—Light Reactions/Calvin Cycle—What are the inputs and products of each?
Light reactions: water and sunlight go in, ATP, NADPH, oxygen is produced; water is split into electrons,
H+ ions and oxygen
Calvin Cycle: ATP, NADPH, carbon dioxide go in; CH2O is produced (sugar building block)
Glycolysis—which organisms do it? What is this evidence of?
All living things carry out the reactions; evidence of a common ancestor
Osmolarity in solutions/cells; what happens to red blood cells in each type of solution?
The higher the osmolarity of a solution, the more solutes it has.
Hypertonic: more solutes in the solution, rbc’s shrink
Hypotonic: less solutes in the solution, rbc’s swell
Isotonic: same amount of solutes, no change in rbc’s
Rbc’s: 99.1% water
Review Cell respiration Lab; how does CR differ in endotherms vs. ectotherms?
Oxygen is consumed but carbon dioxide is produced in equal volumes. To measure you need a substance
to remove the carbon dioxide.
Endotherms: maintain body temperature; metabolic rate increases as it gets colder to help organism keep
warm.
Ectotherms: body temperature depends on the environment; metabolic rate increases as it gets warmer
Na+/K+ pump—found in what cells? What’s its purpose?
Found in neurons, carries electrical impulses
Relationship and similarities between mitochondria and chloroplasts
Both contain electron transport chains that create H+ ion gradients to produce ATP using ATP synthase
Both have their own DNA and ribosomes and replicate themselves.
Endomembrane system—what organelles? What is the order?
REribosomesGolgivesiclesplasma membrane
Enzyme function and inhibition
Active site: where substrate fits; site of catalytic reaction; binding can cause a change in shape of an
enzyme
Inhibition: competitive—fits in the active site preventing the substrate from binding
Non-competitive—binds somewhere else but changes the shape of the active site so substrate can’t fit in
Unit 3
Base pairing rules
A-T with 2 H bonds (weaker)
C-G with 3 H bonds (stronger)
Lac operon parts and functions of each
Study diagram on pg 355
Promoter: DNA sequence where RNA polymerase binds to start transcription
Operator—site where repressor attaches to prevent transcription
Repressor—protein that attaches to the operator to stop transcription
Lactose—inducer—binds to repressor to prevent it from binding the DNA
Genetic crosses—monohybrid and dihybrid expected outcomes, what could cause unexpected ratios?
Monohybrid: Aa x Aa 3:1, Aa x aa 1:1
Dihybrid: AaBb x AaBb 9:3:3:1
Unexpected outcomes could be caused by linkage, epistasis, multiple genes, cytoplasmic influence
Sickle cell anemia
One amino acid difference changes the way hemoglobin molecules interact; causes them to bind together
Viruses
Retroviruses (HIV) uses reverse transcriptase to make DNA from RNA; high mutation rate because there is
no proofreading of RNA viruses
What is the universal genetic code evidence of?
A common ancestor of all living things
DNA replication—leading vs. lagging strands
Leading strand is replicated continuously towards the replication fork in the 5’ to 3’ direction
Lagging strand is replicated in pieces in the 5’ to 3’ direction then are fused together
Bacterial transduction—define, what are the results?
Transfer of information from 1 bacteria to another using a vector; once the new genes are inside the
bacteria genetic recombination can take place which can change the genotype of the bacteria.
What effects crossing over frequency?
The distance between the genes on the same chromosome. The closer the genes, the lower the
recombination frequency
Features/activities of homologous chromosomes
Contain information about the same traits; you get one from each parent; during mitosis they act
independently of each other; during meiosis 1 they synapse and crossing over can occur; they line up in pairs on
the metaphase plate and separate during anaphase 1
Calculate and analyze recombinant frequency
See grid in problems
Unit 4
Conditions on early Earth; result of oxygen release
Atmosphere: water vapor, methane, ammonia, no oxygen; the molecules essential to life could have
formed from these precursors
Oxygen produced through the first photosynthesis by bacteria cause oxidation
Natural Selection—what causes phenotype/allele frequency changes over time?
Phenotype/genotype changes: there has to be variation in the population which the environment can
select for or against and change the relative allele frequencies and can result in speciation given enough time.
Be familiar with the peppered moth story; what is it based on?
The allele frequency changed as the environment changed; variation existed; predators did the
selecting.
What are the statements in the Theory?
Variation exists; more are born than can survive; there is competition for resources; the best competitor
passes on their genes and has the most offspring (are most fit) Note: organisms cannot choose to adapt to
environmental change.
How do organisms evolve as a result of Natural Selection?
Organisms evolve as the environment selects for or against phenotypes which can change allele frequency
over time.
What is it’s effect on populations?
Change in environment can cause poorly adapted organsims to die while well adapted ones survive and
leave more offspring, which changes allele frequency.
Analyze phylogenetic trees/cladograms
Fossil location/superposition/ age
The oldest fossils are in the lowest layers of sediments
Hardy-Weinberg conditions—what do they indicate
No mutation, no migration, equal reproductive success, population is very large, random mating occurs; if
there is no change in the gene pool the population is in Hardy-Weinberg equilibrium
Solve Hardy-Weinberg problems
See grid in problems.
Artificial Selection
Humans choose what organisms to mate based on desired characteristics
MRSA
Methicillin-resistant Staph aureus—bacteria that normally grows on skin but can cause infection if it gets
into your body; has become a problem because of overuse/misuse of human produced antibiotics that have killed
those bacteria that are susceptible and allowed the survival of those that were resistant
What are the sources of genetic variation? What does it allow?
Fertilization, mutation, crossing over, independent assortment, sexual reproduction (main source in
humans); allows natural selection to act on the population
Types of selection—disruptive, stabilizing, directional recognize graphs and examples
Disruptive: selection towards the 2 extremes
Stabilizing: selection towards the mean (average) trait
Directional: selection toward one extreme or the other
Types of Isolating mechanisms—recognize examples of each type of prezygotic barrier
Isolating mechanisms—keep gene pools separate from each other
Prezygotic—gametic: gametes are not compatable
Mechanical: parts must fit together to deliver the gametes
Habitat: they live in the same place but don’t run into each other
Behavioral: they don’t know the mating rituals
Temporal: the timing of gamete production doesn’t match
Postzygotic—hybrid inviability: mating occurs but no offspring is produced
Hybrid sterility: mating occurs, offspring is produced but offspring is sterile
Hybrid breakdown: hybrid has offspring but they don’t survive
Types of speciation
Sympatiric: without geographic isolation
Allopatric: with geographic isolation
Punctuated equilibrium vs. gradualism
Punctuated equilibrium: long periods of stability followed by periods of rapid change
Gradualism: slow steady change over time
Sequence of events in the origin of life on Earth
Organic monomers polymersprotobiontsDNA based systems
What did the first genes originate from?
RNA that could copy itself
How do we know prokaryotes evolved before eukaryotes?
The oldest fossils look like prokaryotes; mitochondria and chloroplasts have similar membranes and
ribosomes
Adaptive radiation—define, what are the results?
Small founding population (founder effect) can take advantage of available niches and become many new
species from 1 ancestral species if there is enough variation in the population, enough available niches and lack of
predators
What do molecular homologies and homologous structures indicate?
A common ancestor; the closer he match, the more recent the ancestor
Grid in: chi square, Hardy-Weinberg, recombination frequency, water/solute potential, Q10
See grid in problems