AP Bio Ch 17 Test

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals with Aa genotype? 0.4 0.5 0.32 0.8

0.32

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.4. What is the percentage of the population that is homozygous for this allele? 64 48 40 16

16

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the percentage of the population that is heterozygous for this allele? 41 18 81 90

18

A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be (Picture) 3' AAC-GAC-GUC-AUA 5'. 3' AAA-GAA-TAA-CAA 5'. 5' TTG-CTA-CAG-TAG 3'. 5' AUG-CTG-CAG-TAT 3'.

3' AAA-GAA-TAA-CAA 5'.

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is 3' UCA 5'. 3' UCA 5'. 5' TCA 3'. 3' UGA 5'.

3' UCA 5'.

An Okazaki fragment has which of the following arrangements? primase, polymerase, ligase 3' RNA nucleotides, DNA nucleotides 5' 5' DNA to 3' 5' RNA nucleotides, DNA nucleotides 3'

5' RNA nucleotides, DNA nucleotides 3'

identify a 5' --> 3' sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe-Pro-Lys. 5'-UUUGGGAAA-3' 5'-AAAACCTTT-3' 5'-CTTCGGGAA-3' 5'-GAACCCCTT-3'

5'-CTTCGGGAA-3'

A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants. What proportion of the population is probably heterozygous (Aa) for this trait? 25 33 75 50

50

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules? C = T A = G A + G = C + T A + T = G + T

A + G = C + T

In the year 2500, five male space colonists and five female space colonists (all unrelated to each other) settle on an uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their offspring randomly mate for generations. All ten of the original colonists had free earlobes, and two were heterozygous for that trait. The allele for free earlobes is dominant to the allele for attached earlobes. Which of these is closest to the allele frequency in the founding population? 0.1 a, 0.9 A 0.5 a, 0.5 A 0.8 a, 0.2 A 0.2 a, 0.8 A

0.1 a, 0.9 A

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals with Aa genotype? 0.8 32% 0.32 0.4

0.32

A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2? 0.21 0.42 0.3 0.7

0.42

A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants. What is the estimated frequency of allele A in the gene pool? 0.25 0.75 0.5 0.05

0.5

In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population? 0.80 0.75 0.08 0.15

0.80

In the year 2500, five male space colonists and five female space colonists (all unrelated to each other) settle on an uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their offspring randomly mate for generations. All ten of the original colonists had free earlobes, and two were heterozygous for that trait. The allele for free earlobes is dominant to the allele for attached earlobes. If one assumes that Hardy-Weinberg equilibrium applies to the population of colonists on this planet, about how many people will have attached earlobes when the planet's population reaches 10,000? 10 100 400 800

100

Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? 38 72 12 24

12

Which enzyme catalyzes the elongation of a DNA strand in the 5' --> 3' direction? DNA ligase primase helicase DNA polymerase III

DNA polymerase III

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized? The origins of replication occur only at the 5' end. Helicases and single-strand binding proteins work at the 5' end. DNA polymerase can join new nucleotides only to the 3' end of a growing strand. Polymerase can work on only one strand at a time.

DNA polymerase can join new nucleotides only to the 3' end of a growing strand.

A new DNA strand elongates only in the 5' to 3' direction because DNA polymerase can only add nucleotides to the free 3' end. replication must progress toward the replication fork. DNA polymerase begins adding nucleotides at the 5' end of the template. the polarity of the DNA molecule prevents addition of nucleotides at the 3' end.

DNA polymerase can only add nucleotides to the free 3' end.

Which of the following is not true of RNA processing? it does not occur in eukaryotic cells Nucleotides may be added at both ends of the RNA. Exons are cut out before mRNA leaves the nucleus. A primary transcript is often much longer than the final RNA molecule that leaves the nucleus.

Exons are cut out before mRNA leaves the nucleus.

Using RNA as a template for protein synthesis instead of translating proteins directly from the DNA is advantageous for the cell because mRNA molecules are subject to mutation but DNA is not. tRNA, rRNA and others are not transcribed. RNA acts as an expendable copy of the genetic material. only one mRNA molecule can be transcribed from a single gene, lowering the potential rate of gene expression.

RNA acts as an expendable copy of the genetic material.

In which of the following actions does RNA polymerase differ from DNA polymerase? RNA polymerase is much more accurate than DNA polymerase. RNA polymerase uses RNA as a template, and DNA polymerase uses a DNA template. RNA polymerase does not need to separate the two strands of DNA in order to synthesize an RNA copy, whereas DNA polymerase must unwind the double helix before it can replicate the DNA. RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.

RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.

When does translation begin in prokaryotic cells? after a transcription initiation complex has been formed as soon as transcription has begun as soon as the DNA introns are removed from the template after the 5' caps are converted to mRNA

as soon as transcription has begun

Alternative RNA splicing is a mechanism for increasing the rate of transcription. is due to the presence or absence of particular snRNPs. can allow the production of proteins of different sizes from a single mRNA. increases the rate of transcription.

can allow the production of proteins of different sizes from a single mRNA.

The anticodon of a particular tRNA molecule is catalytic, making the tRNA a ribozyme. the part of tRNA that bonds to a specific amino acid. complementary to the corresponding triplet in rRNA. complementary to the corresponding mRNA codon.

complementary to the corresponding mRNA codon.

Same as 19

cringe monkey

Same as 29

darn heelflips cuh

Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes union with ribosomes. linkage to histone molecules. fusion into circular forms known as plasmids. excision of introns.

excision of introns.

A mutation in which of the following parts of a gene is likely to be most damaging to a cell? 3' UTR intron All would be equally damaging. exon

exon

What are the coding segments of a stretch of eukaryotic DNA called? introns exons replicons UTR's

exons

What are polyribosomes? aggregations of vesicles containing ribosomal RNA groups of ribosomes reading a single mRNA simultaneously multiple copies of ribosomes associated with giant chromosomes ribosomes containing more than two subunits

groups of ribosomes reading a single mRNA simultaneously

Which of the following separates the DNA strands during replication? topoisomerase primase ligase helicase

helicase

What kind of chemical bond is found between paired bases of the DNA double helix? phosphate hydrogen covalent ionic

hydrogen

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? unwind the parental double helix stabilize the unwound parental DNA join Okazaki fragments together synthesize RNA nucleotides to make a primer

join Okazaki fragments together

You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent lagging strands and Okazaki fragments. Okazaki fragments and RNA primers. leading strands and Okazaki fragments. leading strands and RNA primers.

leading strands and Okazaki fragments.

Which of the following covalently connects segments of DNA? helicase topoisomerase DNA Polymerase II ligase

ligase

A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that there are termination exons near the beginning of mRNA. many noncoding stretches of nucleotides are present in mRNA. there is redundancy and ambiguity in the genetic code. many nucleotides are needed to code for each amino acid.

many noncoding stretches of nucleotides are present in mRNA.

What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3' (picture) met-glu-arg-arg-gln-leu met-arg-glu-arg-glu-arg met-ser-ser-leu-ser-leu met-ser-leu-ser-leu-ser

met-ser-ser-leu-ser-leu

What is the sequence of a peptide based on the following mRNA sequence? 5' . . . UUUUCUUAUUGUCUU 3' (Picture) phe-ser-tyr-cys-leu cyc-phe-tyr-cys-leu leu-pro-asp-lys-gly leu-cys-tyr-ser-phe

phe-ser-tyr-cys-leu

Which of the following synthesizes short segments of RNA? topoisomerase primase helicase ligase

primase

What is the function of topoisomerase? elongation of new DNA at a replication fork by addition of nucleotides to the existing chain unwinding of the double helix the addition of methyl groups to bases of DNA relieving strain in the DNA ahead of the replication fork

relieving strain in the DNA ahead of the replication fork

What determines the nucleotide sequence of the newly synthesized strand during DNA replication? the nucleotide sequence of the template strand the particular DNA polymerase catalyzing the reaction the primase used in the reaction the arrangement of histones in the sugar phosphate backbone

the nucleotide sequence of the template strand

Introns are significant to biological evolution because they correct enzymatic alterations of DNA bases. they are translated into essential amino acids. their presence allows exons to be shuffled. they protect the mRNA from degeneration.

their presence allows exons to be shuffled.

What is the function of DNA polymerase III? to add nucleotides to the end of a growing DNA strand to seal together the broken ends of DNA strands to unwind the DNA helix during replication to degrade damaged DNA molecules

to add nucleotides to the end of a growing DNA strand

Which of the following is a function of a signal peptide? to signal the initiation of transcription to translocate polypeptides across the ER membrane to bind RNA polymerase to DNA and initiate transcription to terminate translation of the messenger RNA

to translocate polypeptides across the ER membrane