Deck 17: Control of Gene

Question 1

Expression of specific genes in particular cells are regulated through the interaction of the genome with proteins. Both the regulatory regions of the genome and the primary structure of the regulatory proteins is conserved evolutionarily over many species.

A) Both sentences are true
B) Both sentences are false
C) The first sentence is true and the second sentence is false
D) The first sentence is false and the second sentence is true

Answer 1

Both sentences are true

Question 2

Genes that are not often transcribed in the presence of a specific metabolite are _____ and are called ____.

A) upregulated; repressible
B) upregulated; trans elements
C) downregulated; cis elements
D) downregulated; repressible
E) downregulated; inducible

Answer 2

downregulated; repressible

Question 3

The most prevalent mode of DNA-protein interaction is achieved with a(n) _____ that binds to the _____ groove of DNA.

A) $\alpha$ -helix; major
B) $\alpha$ -helix; minor
C) $\beta$ -sheet; major
D) $\beta$ -sheet; minor
E) $\beta$ -turn; major

Answer 3

$\alpha$ -helix; major

Question 4

Most commonly, proteins interact with DNA at

A) noncoding regions
B) introns
C) cis elements
D) gene regulatory regions
E) all of the above

Question 5

Which is NOT true of DNA promoter sequences?

A) They are commonly upstream of the gene
B) They are short
C) They may contain palindromic sequences
D) They are termed trans elements
E) Neither (A) nor (B) is correct

Question 6

A gene that undergoes positive regulation is called ___.

Question 7

Proteins with the amino acid sequence Arg-Arg-X-Ser or Arg-Arg-X-Thr would be expected to

A) interact with a palindromic cis element
B) form a leucine zipper
C) be phosphorylated
D) be methylated
E) help form a histone

Question 8

Consensus sequences

A) occur in proteins
B) occur in DNA
C) are also called palindromes
D) are commonly found in exons
E) Both (A) and (B) are correct

Question 9

___ is a motif commonly found among steroid receptors and PPARs.

Question 10

Which is NOT true of the helix-turn-helix motif?

A) It contains a complexed divalent cation
B) It is similar in structure to helix-loop-helix motif
C) It is one of the most common regulatory protein motifs
D) Its helices interact with DNA
E) It binds DNA through hydrogen bonding

Question 11

Responsible for proliferation and differentiation, this family of transcription factors has a relatively large DNA binding domain.

A) leucine zipper
B) homeodomain
C) POU domain
D) winged helix
E) zinc finger motif

Question 12

Which is true of the following?
5' - GCTATCGATAGC -3'
3' - CGATAGCTATCG - 5'

A) It contains tandem repeats
B) It is palindromic
C) It would be expected to be recognized by a POU motif
D) It is commonly found in exons
E) It commonly codes for tRNA

Question 13

What sugar is metabolized by the enzymes under the control of the lac operon?

A) sucrose
B) mannose
C) galactose
D) lactose
E) maltose

Question 14

What does allolactose bind?

A) lac operon
B) lac repressor
C) operator
D) promoter
E) all of the above

Question 15

To induce expression of the lac operon, _______ can be added to the cell medium.

Question 16

cAMP, highly conserved throughout evolution,

A) indicates cellular energy state
B) is involved in eukaryotic cell signaling pathways
C) activate energy mobilization pathways
D) is high in prokaryotes when glucose is absent
E) all of the above

Question 17

cAMP receptor proteins (CRP or CAP)
I. interacts with DNA through a leucine zipper motif
II. forms dimeric structure binding 2 cAMP molecules
III. bound to cAMP, interacts with DNA upstream of the lac operon operator
IV. forms a bend in DNA to inhibit RNA polymerase binding

A) I and II
B) II only
C) I, II and IV
D) II, III and IV
E) I, II, III and IV

Question 18

Tight control of tryptophan synthesis is advantageous evolutionarily in prokaryotes because

A) trp synthesis requires several enzymes
B) trp synthesis requires several different genes
C) trp serves as a precursor to prokaryotic coenzymes
D) trp is not always available to the organism
E) all of the above

Question 19

The trp operon differs from the lac operon in that

A) trp is important for energy metabolism, but lac is not
B) trp has a leader sequence immediately upstream of the structural genes
C) trp has a leader sequence immediately upstream of the operator
D) trp has three structural genes and lac has five structural genes
E) trp has five structural genes and lac has one structural gene

Question 20

The trp operon is like the lac operon in that

A) both constitutively express a repressor
B) both are repressed in a metabolite-rich environment
C) both rely on attenuation for control of expression
D) both (A) and (B) are correct
E) all of the above are correct

Question 21

In ___, gene expression is controlled by formation of complex secondary RNA structures.

Question 22

Attenuation is related to riboswitches in that

A) mRNA is involved in both
B) complex RNA secondary structures are involved
C) both rely only on translational control
D) both (A) and (B) are correct
E) all of the above are correct

Question 23

FMN participates in a riboswitch. When FMN is present
I. it binds the aptamer domain of the FMN riboswitch
II. it results in the formation of a terminator loop
III. it causes rho-dependent termination
IV. transcription proceeds

A) I only
B) I and II
C) III and IV
D) I, II and III
E) II and IV

Question 24

The TPP riboswitch (or THI element)

A) sequesters the Shine-Dalgarno sequence under times of high energy
B) inhibits translation of TPP (thiamine pyrophosphokinase)
C) regulates gene expression by altering ribosome binding site conformation
D) interferes with initiation factor binding
E) all of the above

Question 25

A self-cleaving ribozyme cleaves ___ resulting in prevention of ___.

A) mRNA; translation
B) mRNA; transcription
C) tRNA; transcription
D) tRNA; translation
E) rRNA; translation

Question 26

In eukaryotes, DNA is organized into "beads on a string," or ____, which are further organized into structures called ___.

Question 27

Humans have about the same number of genes as

A) E. coli
B) yeast
C) flatworm
D) colonial amoeba
E) none of the above

Question 28

Which is TRUE of structural maintenance of chromosome (SMC) proteins?
I. they help organize chromatin at the level of 30 nm fiber and above
II. they have braided helical structures that are hinged
III. they have ATPase domains
IV. they don't have homologs in prokaryotes

A) II only
B) II and III
C) I and IV
D) I, III and IV
E) I, II and III

Question 29

Cohesin complexes

A) are comprised of several proteins, including SMC proteins
B) are important during mitosis
C) are similar in structure to condensins
D) are important to chromatid separation
E) all of the above

Question 30

Cells that are able to differentiate into a limited number of cell types are

A) totipotent
B) pluripotent
C) terminally potent
D) chromosomally active
E) inducible

Question 31

What is common among the following: arg, his, lys?

A) all are basic amino acids
B) histones are enriched in these amino acids
C) all can interact with DNA through ionic and other weak interactions
D) both (A) and (B) are correct
E) all of the above

Question 32

Typically, addition of a(n) _____ group to certain lysine residues of a histone protein makes the region of chromatin transcriptionally _____; addition of a(n) _____ group to certain lysine residues makes the region of chromatin transcriptionally _____.

A) methyl; active; acetyl; active
B) acetyl; silent; methyl; active
C) phosphate; silent; methyl; silent
D) methyl; silent; acetyl; active
E) methyl; silent; phosphate; active

Question 33

The ______ proteins can undergo posttranslational modification by acetylation,
phosphorylation, methylation, and ubiquitination.

Question 34

Histone acetyltransferases (HATs) use ___ to acetylate histone proteins, while histone methyltransferase uses ___ to modify histone proteins.

A) S-adenosylmethionine; acetylCoA
B) acetylCoA; S-adenosylmethionine
C) acetylCoA; S-adenosylhomocysteine
D) acetylcholine; S-adenosylhomocysteine
E) acetylcholine; S-adenosylmethionine

Question 35

Post-translational histone modifications commonly

A) occur on histone tails
B) involve lys and arg residues
C) modulate histone/DNA interactions
D) both (A) and (B)
E) all of the above

Question 36

What type of modification is used to make CpG islands?

A) acetylation of guanine
B) methylation of guanine
C) phosphorylation of guanine
D) acetylation of cytosine
E) methylation of cytosine

Question 37

Both C/EBP (CCAAT/enhancer-binding protein) and CREB (cyclicAMP response element-binding protein) have a leucine zipper binding motif. Both are general transcription factors that are activated in the cytosol and translocate into the nucleus

A) Both sentences are true
B) Both sentences are false
C) The first sentence is true and the second sentence is false
D) The first sentence is false and the second sentence is true

Question 38

Which is NOT true of HOX genes?

A) They give rise to transcription factors containing a homeodomain
B) They were identified in Drosophila, and found to be highly conserved
C) Their binding motif is a zinc finger
D) Small mutations in HOX gene promoters have been found to significantly affect basic phenotype
E) Their position in the genome regulates their expression

Question 39

PPAR transcription factors

A) are mostly important to nervous system development
B) are of the leucine zipper type
C) in their inactive state can reside in the cytosol or nucleus
D) commonly forms homodimers
E) recognizes the DNA sequence 5' - TAAT - 3'

Question 40

The mechanism of action of drugs such as thiazolidine diones that treat diabetes, and some cholesterol lower drugs is binding and inactivation of transcripton factors such as

A) PPARs
B) HOX gene proteins
C) CREBs
D) SREBPs
E) C/EBPs

Question 41

Which is NOT true of sterol regulatory element-binding protein (SREBP)?

A) It is activated differently from most transcription factors
B) At low sterol hormone levels, it is bound to proteins in the ER membrane
C) One of its binding proteins acts as a sterol sensor
D) Still within the endomembrane system, its DNA binding domain is cleaved by proteases
E) Following translocation to the nucleus, it alters transcription

Question 42

G-protein coupled receptor signaling pathways are important to

A) PPARs
B) SREBPs
C) CREBs
D) HOX gene proteins
E) C/EBPs

Question 43

Nuclear hormone receptors
I. recognize DNA segments that contain repeated sequences separated by several bases.
II. interact with DNA via two zinc finger domains, and also have a hinged region.
III. are highly conserved sequences found in prokaryotic and eukaryotic cells.

A) I, II, III
B) I, II
C) II, III
D) I, III
E) II only

Question 44

RNAi is useful to experimental and therapeutic biochemistry because

A) it uses the cell's own machinery
B) it can affect many different genes
C) it can specifically silence a particular gene or a family of genes
D) it is relatively inexpensive and adaptable to varied experimental conditions
E) all of the above

Question 45

Eukaryotic posttranscriptional control of gene expression does NOT include

A) differential degradation of mRNA.
B) attenuation.
C) interference by RNA sequences.
D) splicing.
E) nuclear transport