Unit 2 Exam

Activator proteins bind to silencer sequences and repressor proteins bind to enhancer sequences (T or F)

False

Antibiotics can be designed to inhibit bacterial translation without affecting eukaryotic translation (T or F)

True

Constitutive genes are those that have constant levels of expression (T or F)

True

During elongation the polypeptide is removed from the tRNA in the P site and transferred to the amino acid in the A site. (T or F)

True

Transcription and translation may occur simultaneously in prokaryotic cells (T or F)

True

When a glucocorticoid hormone binds to the glucocorticoid receptor, HSP90 is released. (T or F)

True

Methylation typically occurs where a. CpG Islands b. Start codon of mRNA c. Histone tails d. Downstream of the promotor region

a. CpG Islands

Which of the following is a region in DNA that binds to a steroid receptor? a. GRE b. IRE c. CREB d. CRE

a. GRE

A histone variant is usually found at the +1 position of a transcriptional start site. What would be a useful characteristic of this histone? a. The histone variant is not tightly bound to the DNA, making it easier to remove b. The histone variant stabilizes the nucleosome c. The histone variant associates with other nucleosomes to create nucleosome clusters

a. The histone variant is not tightly bound to the DNA, making it easier to remove

How does signaling of a single type of hormone (such as glucocorticoid) result in the stimulation of many different genes simultaneously. a. There are many genes that have Glucocorticoid Response elements near their promotor, resulting in the stimulation of their transcription once the glucocorticoid complex binds. b. There are many different glucocorticoids, each one stimulates a single gene to be expressed. c. Glucocorticoid allosterically inhibits repressor proteins from a number of different gene. d. binding of clucocorticoid to the cell receptor sets of a signaling cascade, which activates many different transcription factors

a. There are many genes that have Glucocorticoid Response elements near their promotor, resulting in the stimulation of their transcription once the glucocorticoid complex binds.

Where does mRNA/tRNA codon-anticodon recognition take place? a.The surface between the two ribosomal subunits b. 50S c. 40S d. 30S

a. the surface between the two ribosomal subunits

How many promoter are in an operon? a. 2 b. 1 c. One for each gene in the operon d. 3

b. 1

What is the relationship between glucose and cAMP? a. There is no relationship between glucose and cAMP b. High glucose results in low cAMP c. High glucose results in high cAMP d. High cAMP increases the import of glucose into the cell

b. High glucose results in low cAMP

What is true according to the adaptor hypothesis? a. A given tRNA can carry any of the twenty amino acids. b. The position of an amino acid within a polypeptide is determined by the binding of mRNA with a tRNA carrying a specific amino acid. c. The anticodon and amino acid have no relationship. d. An amino acid recognizes the codon in mRNA

b. The position of an amino acid within a polypeptide is determined by the binding of mRNA with a tRNA carrying a specific amino acid.

Expression of ______ would inhibit X-inactivation. a. Tsix b. Xist c. Xic

b. Xist

What causes the black color of urine in alkaptonuria? a. build up of tyrosine b. build up of homogentisic acid c. build up of phenylalanine

b. build up of homogentisic acid

Mice with a paramutagenic allele of the kit gene (here called kit' ) have white feet and white spots on their tails. Mice with the paramutable kit allele have brown feet and a brown tail. If you cross mice that are homozygous for the paramutagenic allele with those that are homozygous for the paramutable allele, what will be the phenotype of the progeny? Assume that the kit' allele is very stable and very paramutagenic. a. All mice will have brown feet and tails. b. Mice will be in a 1:1 ratio of white feet and white spots on their tails : brown feet and brown tails. c. All mice will have white feet and white spots on their tails. d. Mice will be in a 3:1 ratio of white feet and white spots on their tails : brown feet and brown tails.

c. All mice will have white feet and white spots on their tails.

A deletion in an operon removes the promoter. How will that affect the transcript that is produced from the operon? a. The transcript will be produced, but shorter than normal b. The transcript will be produced and normal in length c. The transcript will not be produced d. The transcript will produced, but will contain a deletion e. The transcript will be produced, but longer than normal

c. The transcript will not be produced

On a tRNA molecule, where is the amino acid added? a.Stem loop b.Anticodon c. Acceptor stem d. Bulge loop

c. acceptor stem

In the lac operon, the CAP site is located next to the __________. When both lactose and glucose are present, this leads to a rate of transcription that is __________. a. promoter; high b. terminator; low c. promoter; low d. terminator; high

c. promoter; low

You perform a cell free translation experiment like Nirenberg and Matthaei, what percentage of your codons would be 5'-CGG-3' if you used a mixture of 40%G, 40%C and 20% U? a. 4% b. 3.2% c. 8% d. 6.4% e. 1.6%

d. 6.4%

CpG islands are associated with which of the following? a. Nucleosome location b. cAMP pathway c. Steroid hormone activity d. DNA methylation

d. DNA methylation

Genomic imprinting is a result of ___________. a. nucleosome location b. histone activation c. serine to leucine changes in the genetic code d. DNA methylation

d. DNA methylation

Which of the following recognizes response elements, control elements, and regulatory elements? a. Transactivation domains b. Mediator c. General transcription factors d. Regulatory transcription factors

d. Regulatory transcription factors

An enzyme catalyzes a substrate into a final product. When the concentration of the final product is high enough, it binds to a regulatory site on the enzyme. This binding at the regulatory site changes the shape of the enzyme, which prevents it from binding the substrate and prevents formation of more final product. This is an example of a/an __________. a. translational repressor b. methylation c. posttranslational modification d. feedback inhibition

d. feedback inhibition

An activator is present and results in the increase in transcription of the target gene. This is an example of _______________. a. feedback inhibition b. termination c. negative control d. positive control

d. positive control

A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene? a. activator + repressor b. activator + inhibitor c. repressor + co-repressor d. repressor + inducer

d. repressor + inducer

The peptidyl transferase is a component of _____ a. tRNA b. the protein being translated c. DNA d. mRNA e. the ribosome

e. the ribosome