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Cell and Molec > MD II Review > Flashcards

MD II Review Flashcards

1
Q
  1. The prokaryotic cells most commonly used to study transcription and translation are from
    a. E. coli.
    b. B. subtilis.
    c. S. cerevisiae.
    d. D. discoidium
A

E. coli.

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2
Q
  1. Eukaryotic RNA polymerase I genes code for
    a. mRNAs.
    b. tRNAs.
    c. small nuclear RNAs and small cytoplasmic RNAs.
    d. ribosomal RNAs.
A

ribosomal RNAs.

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3
Q
  1. Mitochondrial genes are transcribed by
    a. RNA polymerase I.
    b. RNA polymerase II.
    c. RNA polymerase III.
    d. a separate mitochondrial RNA polymerase.
A

a separate mitochondrial RNA polymerase.

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4
Q
  1. The first step in the formation of a transcription complex for mRNA transcription is the binding of _______ to the TATA box.
    a. TFIA
    b. TFIIA
    c. TFIIIA
    d. TFIID
A

TFIID

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5
Q
  1. The large multi-subunit complex that links the general transcription factors to the gene-specific transcription factors is called
    a. the transcription complex.
    b. Mediator.
    c. the operator.
    d. TBP.
A

Mediator.

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6
Q
  1. Release of RNA polymerase II to initiate transcription appears to be the direct result of the
    a. binding of TAFs to the polymerase.
    b. unwinding of the DNA by helicases.
    c. phosphorylation of RNA polymerase by a protein kinase.
    d. removal of the nucleosome occupying the promoter site.
A

phosphorylation of RNA polymerase by a protein kinase.

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7
Q
  1. A major difference between eukaryotic and prokaryotic RNA polymerases is that eukaryotic polymerases
    a. use a set of transcription factors to bind to and initiate transcription.
    b. use sigma () factors to initiate transcription.
    c. start from promoters.
    d. start from origins of replication.
A

use a set of transcription factors to bind to and initiate transcription.

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8
Q
  1. Enhancers usually are _______ sequences that require _______ to regulate a gene.
    a. cis-acting; other cis-acting sequences
    b. cis-acting; trans-acting factors
    c. trans-acting; trans-acting factors
    d. Both a and b
A

Both a and b

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9
Q
  1. Steroid hormone receptors recognize and bind to specific DNA sequences by _______ domains.
    a. zinc finger
    b. helix-loop-helix
    c. helix-turn-helix
    d. leucine zipper
A

zinc finger

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10
Q
  1. Helix-turn-helix transcription factor proteins are found
    a. only in insects.
    b. only in eukaryotes.
    c. only in prokaryotes.
    d. in both prokaryotes and eukaryotes.
A

in both prokaryotes and eukaryotes.

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11
Q
  1. DNA sequences that prevent enhancers from acting on promoters located in adjacent domains are called
    a. insulators.
    b. isolators.
    c. repressors.
    d. boundaries.
A

insulators.

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12
Q
  1. Aminoacyl tRNA synthetases are enzymes that
    a. synthesize transfer RNAs.
    b. attach amino acids to specific transfer RNAs.
    c. connect amino acids while they are held in place on ribosomes by transfer RNAs.
    d. attach the terminal CCA sequence to transfer RNAs.
A

attach amino acids to specific transfer RNAs.

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13
Q
  1. E. coli contains about _______ different tRNAs that code for _______ different amino acids.
    a. 62; 40
    b. 62; 20
    c. 50; 20
    d. 40; 20
A

40; 20

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14
Q
  1. The capacity for some tRNAs to recognize more than one codon in mRNA is explained by a phenomenon called
    a. redundancy.
    b. wobble.
    c. a reading frameshift.
    d. degeneracy.
A

Wobble

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15
Q
  1. Translation always occurs on which of the following structures?
    a. Ribosomes
    b. Endoplasmic reticulum
    c. Nuclear envelope
    d. Mitochondria
A

Ribosomes

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16
Q
  1. The combined sizes of prokaryotic and eukaryotic ribosomes are
    a. the same.
    b. 30S and 50S, respectively.
    c. 40S and 60S, respectively.
    d. 70S and 80S, respectively.
A

70S and 80S, respectively.

17
Q
  1. Which of the following statements is true and provides evidence that a certain component of the ribosome catalyzes protein synthesis?
    a. Ribosomes are inactive after protease digestion.
    b. Ribosomes are inactive after RNase digestion.
    c. Structural analysis shows that proteins occupy the catalytic site where peptide bonds are formed.
    d. Structural analysis shows that mRNA occupies the catalytic site where peptide bonds are formed.
A

Ribosomes are inactive after RNase digestion.

18
Q
  1. In translation, mRNAs are read in the _______ direction, and polypeptide chains are synthesized from the _______ends.
    a. 5ʹ to 3ʹ; carboxyl to the amino
    b. 5ʹ to 3ʹ; amino to the carboxyl
    c. 3ʹ to 5ʹ; carboxyl to the amino
    d. 3ʹ to 5ʹ; amino to the carboxyl
A

5ʹ to 3ʹ; amino to the carboxyl

19
Q
  1. During translation, the codons on the mRNA are recognized by complementary base pairing to the anticodon on the
    a. ribosome.
    b. transfer RNA.
    c. small cytoplasmic RNA.
    d. aminoacyl tRNA synthetase.
A

transfer RNA.

20
Q
  1. Eukaryotic ribosomes recognize and initially bind to what structure on the mRNA?
    a. A Shine-Dalgarno sequence
    b. The 7-methylguanosine cap
    c. A TATA sequence
    d. A CCAAT sequence
A

The 7-methylguanosine cap

21
Q
  1. Signaling by the steroid hormone estrogen is an example of _______ signaling.
    a. autocrine
    b. endocrine
    c. paracrine
    d. direct cell-to-cell
A

. endocrine

22
Q
  1. Signaling by neurotransmitters is an example of _______ signaling.
    a. autocrine
    b. endocrine
    c. paracrine
    d. direct cell-to-cell
A

paracrine

23
Q
  1. Stimulation of T lymphocytes, leading to their synthesis of a growth factor resulting in T lymphocyte proliferation, is an example of _______ signaling.
    a. autocrine
    b. endocrine
    c. paracrine
    d. direct cell-to-cell
A

autocrine

24
Q
  1. Steroid hormones usually act via receptors that
    a. are coupled to G proteins that activate adenylyl cyclase.
    b. activate tyrosine kinases.
    c. bind to DNA.
    d. activate phospholipase C.
A

bind to DNA

25
Q
  1. Which of the following signal molecules binds to nuclear receptors?
    a. Thyroid hormone
    b. Vitamin D3
    c. Retinoic acid
    d. Estrogen
A

Estrogen

26
Q
  1. Neurotransmitters act by binding to receptors that are
    a. ligand-gated ion channels.
    b. located in the cytoplasm.
    c. tyrosine-kinase receptors.
    d. not coupled to G proteins.
A

ligand-gated ion channels.

27
Q
  1. Peptide hormones and growth factors act on target cells by binding to cell surface and _______ receptors.
    a. endoplasmic reticulum
    b. cytosolic
    c. nuclear
    d. soluble extracellular
A

soluble extracellular

28
Q
  1. The G protein that activates adenylyl cyclase is a
    a. monomeric G protein in the Ras family that binds GTP.
    b. dimeric G protein that separates into  and  subunits.
    c. heterotrimeric G protein that separates into alpha and ßy subunits.
    d. heterotrimeric G protein that separates into  and subunits.
A

heterotrimeric G protein that separates into alpha and ßy subunits.

29
Q
  1. The GTP on the G protein that is linked to adenylyl cyclase is split to GDP and Pi
    a. in the inactive state.
    b. in the process of subunit separation.
    c. upon activation by the receptor.
    d. by the active subunit.
A

in the inactive state.

30
Q
  1. The major function of cAMP in animal cells is to activate
    a. adenylyl cyclase.
    b. protein kinase A.
    c. protein kinase C.
    d. tyrosine kinases.
A

protein kinase A.

31
Q
  1. Which of the following is not considered a second messenger?
    a. cAMP
    b. IP3
    c. Calcium
    d. Ecdysone
A

Ecdysone

32
Q
  1. Which of the following correctly describes how protein kinase A can activate genes?
    a. Nuclear protein kinase A is activated by cAMP to phosphorylate general transcription factors.
    b. Cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate CREB.
    c. Cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate general transcription factors.
    d. Nuclear protein kinase A is activated by cAMP to phosphorylate CREB.
A

Cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate CREB

33
Q
  1. Rhodopsin in the vertebrate retinal photoreceptor cells results in a change in the second messenger _______, leading to the opening of ion channels in the plasma membrane and the production of a nerve impulse.
    a. Ca2+
    b. cAMP
    c. cGMP
    d. IP3
A

cGMP

34
Q
  1. The first step in growth factor pathway activation is
    a. receptor dimerization.
    b. receptor phosphorylation.
    c. Ras activation.
    d. the binding of SH2-containing proteins.
A

receptor phosphorylation

Cell and Molec (5 decks)

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