Chemistry & Evolution
Cell cycle & cell communication
Genetics & gene regulation
Central Dogma
Cellular respiration & Photosynthesis
100
List the 4 important biological elements in order from greatest to least electronegativity
O > N > C = H
100
What is the purpose of a phosphorylation cascade?
To amplify a signal
100
What is it called when you cross 2 individuals that are both heterozygous for 2 genes?
Dihybrid cross
100
In what stage of the central dogma would the promoter region be utilized?
Transcription
100
What are the two ways by which ATP can be synthesized from ADP?
Substrate level phosphorylation and chemiosmosis
200
What biological molecule contains hydroxyl and phosphate groups?
Nucleic acids (DNA and RNA)
200
What are the 3 stages of interphase?
G1, S, G2
200
What is the difference between codominance and incomplete dominance?
Codominance is when both alleles are expressed at once.
Incomplete dominance is when the phenotype is an intermediate of the alleles.
200
Why does DNA replication require the enzymes helicase and topoisomerase?
To unwind the DNA and relieve supercoiling
200
What are the inputs and outputs of glycolysis?
Input: 1 Glucose, 2 ATP
Output: 4 ATP (net yield 2 ATP), 2 NADH, 2 pyruvate
300
Draw the structure of the functional group that is basic when ionized.
Amino group R-NH2 -> R-NH3+
300
At what stage in meiosis do cells become haploid?
Meiosis I when homologous chromosomes separate during Anaphase I. (After telophase/cytokinesis also acceptable since this is when 2 cells are formed)
300
Color blindness is an X linked recessive allele. Attached earlobes are a somatic recessive allele. If a man has color blindness and is heterozygous for detached earlobes, and marries a woman who is a carrier for color blindness and has attached earlobes, what is the probability that they will have a child who is male, has color blindness and detached earlobes?
1/8
300
A codon of mRNA reads 5’- CGU - 3’. What is the anticodon that would attach to this?
3’- GCA -5’
300
What is the flow of electrons through the light dependent reactions of photosynthesis?
Electrons are derived from the splitting of water. They go into photosystem II and then photosystem I. In photosystem II, the electrons are passed to P680+. Then they are passed onto PSI through the electron transport chain. The electrons are then energized again in PSI by P700. They pass through a second electron transport chain where they finally reduce NADP+ into NADPH where it can be used in the Calvin cycle.
400
A population of flowers has red individuals (RR), pink individuals (Rr) and white individuals (rr). If there are 20 red flowers, 25 pink flowers and 5 white flowers, what are the allele frequencies for this population?
Total alleles: 20x2 + 25x2 + 5x2 = 40 + 50 + 10 = 100 alleles
R= 20x2 + 25 = 65/100 = .65
r= 25 + 5x2 = 35/100 = .35
400
If a cell during G1 has 20 chromosomes, how many sister chromatids would you expect to find during prophase of meiosis II?
40 sister chromatids. S phase = 20x2 = 40 chromosomes= 80 sister chromatids. After mitosis, 40 sister chromatids.
400
How does the presence of tryptophan affect the trp operon?
Tryptophan is an effector that acts as a corepressor. The repressor cannot bind to the operator unless it is changed to the correct shape, which tryptophan does by allosterically binding to the repressor.
400
What are the 3 sites of the large ribosomal subunit and what is the purpose of each?
A site: Entry site for charged tRNA where the next codon is prepared to be read
P site: Polypeptide site where the amino acid is added to the growing polypeptide chain.
E site: exit site where uncharged tRNA leaves the ribosome.
400
400: Compare and contrast chemiosmosis in photosynthesis versus cellular respiration.
Both involve electron transport chains that carry excited electrons down energy levels, where the potential energy is used to create a proton gradient. This gradient is used to turn the rotor of ATP synthase to produce ATP from ADP. Photosynthesis uses NADP+ and NADPH while respiration uses NAD+ and NADH. Photosynthesis chemiosmosis takes place between photosystems II and I while respiration chemiosmosis takes place during oxidative phosphorylation.
500
A population of lizards are either blue or green. Blue (B) is dominant to green (b). You find 230 blue lizards and 80 green lizards. Assuming the population is in Hardy Weinberg equilibrium, what are the genotype frequencies of the population?
p^2 + 2pq + q^2=1
P = dominant allele frequency
q= recessive allele frequency
310 total lizards
q^2= 80/310 = .258
Sqrt .258 = .507 = q = allele frequency of b
1-.507 = .493 = P = allele frequency of B
2pq = 2(.507)(.493)= .499
P^2=.243
BB= .243
Bb= .499
bb= .258
500
Name & briefly describe the 3 cell surface receptors.
G protein coupled receptors: Signaling molecule binds to the receptor which triggers the attachment of GTP to a G protein, activating it and allowing it to send a cellular response.
Receptor tyrosine kinase: Signaling molecule causes the receptor to form a dimer, at which point molecules undergo phosphorylation by using ATP. The molecules are then activated and can send a signal onto relay molecules.
Gated ion channel: Signaling molecules causes the shape of a channel to change and open/close it.
500
How does the presence of cAMP affect the lac operon?
cAMP is released when glucose levels are low. This will bind to the cAMP receptor protein which acts as an activator for the operon, increasing the rate of transcription (positive regulation). This promotes the breakdown of lactose over glucose.
500
Given the following DNA molecule, what is the amino acid sequence that would result?
DNA: 3’- TAC CGG TGT AAA ACT -5’
mRNA: 5’- AUG GCC ACA UUU UGA -3’
Amino acids: Met Ala Thr Phe
500
Draw a diagram of the Calvin cycle, labeling the important components.
