Bio 213 Midterm 2 Questions

b

A multi-gene family is composed of _____. A) multiple genes whose products perform the same cellular functions B) genes whose sequences are very similar and that probably arose by duplication C) a gene whose exons can be spliced in a number of different ways D) identical genes that are found in different species E) genes that perform similar functions but evolved from different ancestor genes

d

A population in Hardy-Weinberg equilibrium: a. Is undergoing natural selection b. Has changes in allele frequencies between generations c. Has individuals migrating in d. Is not evolving e. Can have mutations occurring

c

An enhancer ____________ and a promoter-proximal element _______________. A) is a transcription factor; is a DNA sequence B) increases transcription; inhibits transcription C) can be distant from a promoter; is always close to the promoter D) is a DNA sequence; is a protein E) binds a repressor; binds an activator

e

Genes encoding eye color are found in: a. Sperm cells b. Iris (eye) cells c. Liver cells d. A and B only e. A, B and C

b

Here is a non-template strand of DNA: 5'-ACTTGC3'. What will the resulting mRNA look like? a. 5'-ACTTGC-3' b. 5'-ACUUGC-3' c. 5'-TGAACG-3' d. 5'-UGAACG-3' e. 5'-GCAAGU-3'

c

Here is an mRNA: 5'-ACUUGC-3'. What was the DNA sequence of the template strand? a. 3'-ACTTGC-5' b. 3'-ACUUGC-5' c. 3'-TGAACG-5' d. 3'-UCAACG-5' e. 5'-TCAACG-3'

d

How do eukaryotes coordinate control of multiple genes that must be turned on simultaneously? a. The genes are all co-located on one specific part of the chromosome. b. The expression of one of these genes triggers the expression of the next one. c. There is no coordination of gene expression d. Activator proteins recognize common control elements (e.g. steroids, hormones, etc.) and bind to them, resulting in simultaneous transcription. e. Transcription occurs independently but the activator proteins hold the mRNA until all are transcribed, then the proteins are made simultaneously during translation via ribosomes.

c

How is gene expression permanently regulated at the start of development? a. Once turned on genes cannot be turned off. b. It cannot be permanently regulated. c. Through methylation patterns being passed on in successive cell division. d. Through histone acetaylation.

e

How is translation initiated? See Concept 17.4 (Page 350) a. The small ribosomal subunit binds to the mRNA. b. The tRNA bearing methionine binds to the start codon. c. The large ribosomal subunit binds to the small one. d. The start codon signals the start of translation. e. All of the above.

d

In a population in Hardy-Weinberg equilibrium, there are 100 total individuals. If 36 display the recessive trait, how many are heterozygotes? a. 0.6 b. 0.4 c. 16 d. 48 e. I don't know.

c

In a population in Hardy-Weinberg equilibrium, there are 100 total individuals. If 36 display the recessive trait, how many of individuals are homozygous dominant? a. 0.4 b. 0.6 c. 16 d. 48 e. I don't know.

a

Microevolution includes genetic drift. a. True b. False

a

To transcribe a gene, histones need to be __________ and DNA ___________. a. Unmethylated : Acetylated b. Deacetylated : Methylated c. Methylated : Deacetylated

b

Under natural selection, organisms intentionally acquire new beneficial mutations that they need to evolve and survive: a. True b. False

a

All of the following could repress lop1 expression (in absence of silk) except: a. Acetylating histones b. miRNA binding to mRNA c. Transcription factors binding to silencers d. Methylation of DNA

a

Aminoacyl-tRNA synthetases are enzymes that ________. a. link tRNAs to amino acids b. remove introns from pre-RNA transcripts c. detach RNA polymerase from DNA d. polymerize RNA complementary to DNA template strand

c

DNA and RNA differ in: a. The type of bond that links their monomeric units b. The types of purine bases used in their synthesis c. The presence of a hydroxyl group at the 2' position of ribose d. DNA is hydrophilic and RNA is hydrophobic e. The types of amino acids used in their synthesis

c

In the case of the Bombina frogs given in your text, there was evidence of hybridization because B. variegata (yellow-bellied toads) genes were present in the B. bombina (fire-bellied toads) in the hybrid zone but the frequency decreased across the hybrid zone with distance from the yellow-bellied toad range. What would you expect to happen to the allele frequencies in the case of fusion? a. The allele frequencies would continue to remain the same across the hybrid zone. b. Allele frequencies would stabilize with all B. bombina frogs having no B. variegata frog alleles and vice versa. c. Allele frequencies would converge into a common number (50%) of alleles in both B. variegata and B. Bombina.

d

What is NOT needed for evolution by natural selection to occur? a. Variation in a population b. Non-random survival based on adaptation c. More individuals born than can survive d. Organisms develop helpful traits in their lifetimes that are passed along to progeny e. Genetic basis for traits (inheritance)

a, b, c, and d

What is a way that speciation can occur? a. Migration b. Genetic Drift c. Sexual selection d. Natural selection

e.

What is found near a promoter? a. proximal control elements b. transcription start site c. transcription factors d. RNA polymerase e. all of the above

a

What is the correct order of the translation initiation complex? a. A, P, E b. E, A, P c. A, E, P d. P, A, E

a

What is the function of RNA polymerase? See Concept 17.2 (Page 342) a. It unwinds the double helix and adds nucleotides to a growing strand of RNA. b. It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule. c. It relies on other enzymes to unwind the double helix. d. It adds nucleotides to the 5' end of the growing mRNA molecule. e. All of the above.

d

What is the function of the release factor during translation in eukaryotes? a. It releases the amino acid from its tRNA to allow the amino acid to form a peptide bond. b. It releases the ribosome from the ER to allow polypeptides into the cytosol. c. It supplies a source of energy for termination of translation. d. It binds to the stop codon in the A site in place of a tRNA.

c

What occurs immediately after a peptide bond forms between amino acids attached to tRNAs in the P and A sites of the ribosome? A) Initiation of tRNA synthesis B) Reading of the next codon of mRNA C) Translocation of tRNAs and mRNA within the ribosome D) The tRNA in the A site binds to a new codon in the mRNA E) A new amino acid is added to the tRNA in the P site

c

What type of noncoding DNA comprises the largest portion of multicellular eukaryotic genomes? See Concept 21.4 (Page 448) a. gene regulatory sequences b. centromeric sequences c. transposons d. introns e. pseudogenes

b

Where does RNA polymerase begin transcribing a gene into mRNA? See Concept 17.2 (Page 342) a. It starts at one end of the chromosome. b. It starts after a certain nucleotide sequence called a promoter. c. It looks for the AUG start codon. d. The ribosome directs it to the correct portion of the DNA molecule. e. Transfer RNA acts to translate the message to RNA polymerase.

b and e

Which of the following are intrinsic sources of DNA mutation? Select all that apply. a. Mutagenic chemicals (like EMS) b. Errors during DNA replication c. Errors during transcription d. Ultraviolet (UV) light e. Spontaneous chemical modification of bases

c

Which of the following are not found at (or near) a promoter? a. TATA box b. Transcription start site c. Transfer RNA d. Transcription factors e. RNA polymerase

c

Which of the following are true ONLY when a population is in Hardy-Weinberg equilibrium? A. The two alleles for that gene have an equal frequency (p=q=0.5) B. The frequency of heterozygotes and both types of homozygotes = 1 C. The genotypes for that gene are predicted by the Hardy-Weinberg equation D. There are twice as many heterozygotes as either type of homozygotes E. A and B are both true

b

Which of the following describes the most likely order of events in allopatric speciation? a. divergence, genetic drift, genetic isolation b. genetic isolation, genetic drift, divergence c. genetic isolation, divergence, genetic drift d. genetic drift, genetic isolation, divergence

e

Which of the following is not necessary for natural selection to occur? A) Variation in traits among individuals in a population B) Variation in traits must be heritable C) Reproductive success is NOT random D) Competition for finite resources E) Variation among individuals caused by environmental factors

d

Which of the following is true about gene transcription, but not about DNA replication? a. Strands of DNA helix are separated b. Initiates at defined sites with the genome c. Polymerase synthesizes nucleic acid 5' 3' d. Only one strand of DNA serves as a template e. Nucleic acid synthesis proceeds in both directions along DNA

d

Which of the following is true about gene transcription, but not about DNA replication? a. Strands of DNA helix are separated b. Initiates at defined sites with the genome c. Polymerase synthesizes nucleic acid 5' --> 3' d. Only one strand of DNA serves as a template

a

Which of the following statements correctly describes the function of a signal peptide? a. It helps target a protein to the ER. b. It signals the initiation of transcription. c. It directs an mRNA molecule into the cisternal space of the ER. d. It terminates translation of messenger RNA.

f

Which one of the following is true of tRNAs? See Concept 17.4 (Page 348) a. There are four types of tRNA. b. Each tRNA binds a particular codon. c. tRNAs carry special sequences known as codons. d. tRNAs are double-stranded. e. All of the listed answers are correct. f. None of the listed answers is correct.

e.

Which part of a transfer RNA (tRNA) is covalently bonded to an amino acid? A) The anticodon B) Both arms of the cloverleaf structure C) The small subunit D) The codon E) The 3' end