RNA, transcription and translation Flashcards
(95 cards)
1
Q
The four main types of RNA
A
mRNA, tRNA, rRNA, small RNAs
2
Q
RNA that encodes amino acid sequence of one or more polypeptides specified by a gene or a set of genes
A
mRNA
3
Q
RNA in ribosomes
A
rRNA
4
Q
RNA that reads information encoded in the mRNA and transfer the appropriate amino acid to a growing polypeptide chain during protein synthesis
A
tRNA
5
Q
The entire chromosome is transcribed to RNA. T/F
A
F
Only particular genes or groups of genes are transcribed at any one time, and some portions of the DNA genome are never transcribed.
6
Q
The sum of all the RNA molecules produced in a cell under a given set of conditions
A
Transcriptome
7
Q
Transcription requires a primer. T/F
A
F
RNA polymerase can directly initiate synthesis once it binds to a promoter
8
Q
Which ions does RNA polymerase require for transcription?
A
Mg, Zn
9
Q
RNA polymerase is most active when?
A
When bound to a double-stranded DNA
10
Q
Which enzymes synthesize RNA?
A
RNA polymerase
11
Q
The two strands of DNA is known as what during transcription?
A
Template strand and nontemplate strand (coding strand)
12
Q
Which DNA strand is complementary to the RNA strand?
A
Template strand/ antisense/ negative strand
13
Q
Which DNA strand is identical to the RNA strand, except U is in place of T?
A
Coding strand/nontemplate strand/ sense/ positive strand
14
Q
RNA polymerases have a separate proofreading 3’ to 5’ exonuclease active site. T/F
A
F
Transcription is less accurate than DNA replication.
15
Q
RNA synthesis is initiated at which specific sequences?
A
Promoters
16
Q
Which polymerase synthesizes the precursors for rRNA?
A
RNA polymerase I (Pol I)
17
Q
Which polymerase synthesizes tRNA?
A
RNA polymerase III (Pol III)
18
Q
Which polymerase synthesizes mRNA?
A
RNA polymerase II (Pol II)
19
Q
The RNA strand produced from a DNA template
A
Primary RNA transcript
20
Q
Noncoding tracts on the RNA that break up the coding regions of the transcript
A
Introns
21
Q
The coding segments of RNA
A
Exons
22
Q
What is splicing?
A
The process where introns are removed from the primary transcript and the exons are joined to form a continuous sequence that specifies a functional polypeptide
23
Q
Most eukaryotic mRNAs are capped at which end?
A
5’
24
Q
What molecule is the 5’cap?
A
7-methylguanosine
25
The methyl groups of 7-methylguanosine are donated by which molecule?
S-adenosylmethionine (sAM)
26
Introns and exons of the DNA are transcribed into RNA. T/F
T
27
Which group of introns are self-splicing?
Groups I, II
28
What does self-splicing mean?
No protein enzymes are involved in the removal of introns and the joining of exons
29
Which is the largest class of introns?
Spliceosomal introns
30
Which protein catalyzes the removal of spliceosomal introns?
Spliceosome
31
The spliceosome is a protein complex made up of specialized RNA-protein complexes known as what?
Small nuclear ribonucleoproteins (snRNPs)
32
Each snRNP is made up of eukaryotic RNAs, 100 to 200 nucleotides long, known as what?
Small nuclear RNAs (snRNAs)
33
Eukaryotic mRNAs have which distinctive 3' end structure?
poly(A) tail
34
The process by which mRNA is utilized as a template to direct the synthesis of a polypeptide
Translation
35
The triplet sequence of nucleotides on the mRNA molecule
Codon
36
the complementary triplet on the tRNA molecule
Anticodon
37
The stem-loop structure on a tRNA
Anticodon loop
38
Stop codons
UAA, UAG, UGA
39
Start codon
AUG
40
Where does the attachment of amino acids to tRNA for protein synthesis occur?
Cytosol
41
The mRNA with the polypeptide code binds to which structures to initiate protein synthesis?
Small subunit of the ribosome and initiating aminoacyl tRNA
42
Which cytosolic proteins promote initiation of protein synthesis?
Initiation factors
43
The arms of a tRNA
D arm, amino acid arm, anticodon arm, TψC arm
44
The first stage of protein synthesis occurs in which part of the cell?
Cytosol
45
Which enzyme esterify the 20 amino acids to their corresponding tRNAs?
Aminoacyl-tRNA synthetases
46
AUG codes for which amino acid?
Met
47
Which of the following statements is INCORRECT?
A. Replication of double-stranded DNA is a semiconservative process.
B. DNA synthesis is continuous on the leading strand.
C. DNA synthesis is discontinuous on the lagging strand.
D. For RNA synthesis, the sense DNA strand serves as the template.
D
48
Which of the following statements is INCORRECT?
A. Every codon is a triplet nucleotide sequence.
B. Every amino acid is coded for by at least one codon.
C. Every codon codes for exactly one amino acid.
D. The start codon codes for exactly one amino acid.
C
49
Which of the following statements is CORRECT?
A. Both DNA and RNA can serve as template for synthesizing both DNA and protein.
B. Both DNA and RNA can serve as template for synthesizing both RNA and protein.
C. Both DNA and RNA can serve as template for synthesizing both RNA and DNA.
D. Protein can serve as template for synthesizing RNA.
C
50
The process of transcription requires several important proteins to proceed. These proteins generally belong to the class of RNA polymerases. Which of the RNA polymerases is responsible for initiating transcription of all protein-coding genes?
A. RNA polymerase I
B. RNA polymerase II
C. RNA polymerase III
D. RNA polymerase IV
B
51
Transfer RNAs are very important in protein translation. Which of the following initiate transcription of tRNA genes?
A. RNA polymerase I
B. RNA polymerase II
C. RNA polymerase III
D. RNA polymerase IV
C
52
Which of the following statements regarding gene transcription is FALSE?
A. The raw materials for the new RNA are ATP, CTP, GTP, and UTP.
B. Transcription proceeds in a 5’to 3’ direction.
C. New bases are added to the free 3’ OH group.
D. Transcription needs a primer to build on mRNA.
D
53
Which of the following processes involved in gene transcription is INACCURATE?
A. Various other proteins, called transcription factors, help RNA polymerase bind to the DNA.
B. Other DNA sequences further upstream are also involved.
C. RNA polymerase unwinds a small section of the DNA (coding strand) which it uses as a template to synthesize RNA.
D. The coding strand is actually read from 5’ to 3’ direction.
D
54
The primary RNA transcript needs further processing before it can be translated. The process is called RNA processing. Which of the following is part of this process?
A. Addition of a cap to the 5’ end
B. Addition of a poly-A tail to the 3’ end
C. Splicing out of the introns
D. All of the above
D
55
Which of the statements below regarding introns is INCORRECT?
A. Introns are stretches of DNA which get transcribed but not translated.
B. Introns code for amino acids in the protein.
C. Introns tend to be much longer than exons.
D. Removal of introns is done with the spliceosome.
B
56
Which statement does NOT accurately differentiate the process of transcription from DNA replication?
A. The RNA strand remains hydrogen-bonded to the DNA template.
B. The RNA molecules that are produced are released from the DNA template as single strands.
C. The RNA molecules are much shorter than the template DNA molecules.
D. The enzymes involved are called RNA polymerases.
A
57
Which of the following statement/s accurately describe/s the role of ribosomes in protein translation?
A. Translation of mRNA into protein is accomplished by the ribosome, which is an RNA/protein hybrid.
B. Ribosomes bind to the translation initiation sequence on the mRNA.
C. Ribosomes move down the RNA in a 5’ to 3 direction.
D. All of the above
D
58
Which of the following statements about transfer RNAs (tRNAs) is INCORRECT?
A. tRNAs contain nucleotides which are modified, like pseudouridine and ribothymidine.
B. Each tRNA has 3 bases that make up the anticodon.
C. Each tRNA has its corresponding amino acid attached to the 5’ end.
D. Aminoacyl tRNA synthetases are the enzymes that “charge” the tRNA with the proper amino acid.
C
59
Which of the following is the usual initiation sequence on the mRNA?
A. AUG
B. UAG
C. UAA
D. UGA
A
60
What is the usual amino acid that is coded by the initiation sequence of the mRNA in eukaryotes?
A. Valine
B. Methionine
C. Formyl-methionine
D. Leucine
B
61
In the elongation phase of protein translation, several processes are involved. Which of the following is/are TRUE?
A. The initial tRNA with its attached amino acid binds to the P site.
B. The new tRNA corresponding to the next codon on the mRNA binds to the A site.
C. The ribosome catalyzes the transfer of the amino acid from the P site onto the amino acid at the A site.
D. All of the above
D
62
Which of the following statements regarding the termination of translation is FALSE?
A. STOP codons do not code for any amino acid.
B. tRNA molecules bearing no amino acid bind to the STOP codons.
C. Binding of the release factor releases the polypeptide from the ribosome.
D. The remaining portion of the mRNA after the STOP codon is not translated.
B
63
Which of the following statements regarding the genetic code is FALSE?
A. 3 bases comprise a codon which codes for a particular amino acid.
B. The 69 codons are allocated to 22 different amino acids.
C. Wobbling is the amino acid’s property of having several codons.
D. Three codons do not code for amino acids but signal for stop.
E. The genetic code is generally applicable to living
organisms with some exceptions.
B
64
Which of the following statements is/are FALSE?
A. Both DNA and RNA can serve as template for synthesizing both DNA and RNA.
B. Both DNA and RNA can serve as template for
synthesizing DNA.
C. Protein can serve as template for synthesizing RNA.
D. Both A and C.
D
65
Which of the following is/are FALSE?
A. All introns function as noncoding sequences.
B. All untranslated regions (UTRs) function as coding sequences.
C. All untranslated regions (UTRs) form introns or parts thereof.
D. Both B and C.
D
66
Which of the following is not involved in translation?
A. messenger RNA
B. ribosomal RNA
C. transfer RNA
D. snRNA
D
67
During translation, which ribosomal site is the entry point of
aminoacyl-tRNAs?
A. D site
B. A site
C. E site
D. P site
A
68
What would be the anticodon sequence on the tRNA for the first amino acid added during translation?
A. 5’ AUG 3’
B. 5’ GUA 3’
C. 5’ CAU 3’
D. 5’ UAC 3’
C
69
On the DNA template strand, which among the following does not code for a stop codon?
A. 5’ TCA 3’
B. 5’ CTA 3’
C. 5’ TTA 3’
D. 5’ AAT 3’
D
70
Which among the following is not part of the modifications in mRNA processing?
A. Excision of exons
B. Polyadenylation of the 3’ end
C. Capping of 5’ end with 7-methylguanosine
D. Lariat formation
A
71
Which of the following is not needed for basal transcription of genes?
A. TATA Box
B. RNA Polymerase
C. Enhancer
D. GC/CAAT Box
C
72
What is in the proteins synthesized in the rough endoplasmic reticulum that is not present in the proteins synthesized in the cytosol?
A. leader sequence at 5’ end
B. f-methionine as the first amino acid in the protein
C. Kozak sequence at the 5’ end
D. Polyubiquitination sites
A
73
Which among the following describes the eukaryotic ribosome?
A. 30S + 50S = 70S
B. 60S + 40S = 80S
B
74
What does the 5’ AAUAA 3’ sequence in the mRNA for?
A. Polyadenylation site
B. 5’ exon-intron boundary
C. 3’ intron-exon boundary
D. 3’ end cleavage site
A
75
Where are the amino acids attached to the tRNA?
A. 5’ end
B. 3’ end
C. Variable loop
D. Anticodon loop
B
76
The central dogma of molecular biology is applicable to almost all organisms, with few exceptions, made possible by the reverse transcriptase enzyme. Which of the
following are sequences of DNA that make RNA copies of themselves, which then get reverse transcribed into DNA and inserts into new locations in the genome?
A. Complementary DNA
B. RNA viruses
C. Retrotransposons
D. Provirus
C
77
Enzyme for tRNA gene transcription
A. Pol I
B. Pol II
C. Pol III
D. Pol IV
C
78
True for mRNA production:
A. Untranslated 5’ end is leader sequence
B. Coding sequence specifies amino acids to be translated
C. Untranslated 3’ region may contain info regarding stability of mRNA
D. AOTA
B
79
There is a cap which protects the ends of the mRNA from being degraded by enzymes. Which modified nucleotide consists this cap?
A. Adenine
B. Guanine
C. Thymidine
D. Uracil
B
80
Which of the following is the reason why nucleotides in codons are read only once?
A. The genetic code is triplet.
B. The genetic code is non-overlapping.
C. The genetic code is almost universal.
D. The genetic code is degenerate.
B
81
Which of the following events about protein translation is
INACCURATE?
A. The initial tRNA with attached amino acid goes into the P site
B. The aminoacyl-tRNA that is able to base pair with the next codon in the mRNA arrives at A site
C. The source of energy during translation is ATP
D. The ribosomes catalyzes the transfer of the amino acid from the P site into the amino acid at the A site
C
82
What does not happen during translation?
A. There may be one or more stop codon
B. For the stop codon, there is no tRNA with an attached AA
C. The stop codon reads a release factor
D. None of the above
D
83
Which of the following statements applies to normal human genetic code?
a. Every codon sequence codes for exactly 1 amino acid.
b. Every amino acid codes for exactly 1 codon sequence.
c. Exactly one codon sequence normally codes for the start sequence.
d. Exactly one codon sequence normally codes for the stop sequence.
c
84
Which of the following statements does not follow from the central dogma of molecular biology?
a. DNA can function as template for the synthesis of new RNA
b. RNA can function as template for the synthesis of new DNA
c. RNA can function as template for the synthesis of new protein
d. Protein can function as template for the synthesis of new RNA
d
85
Which of the following is not a genome-encoded part of the mRNA?
a. UTR
b. Hogness box
c. Poly-A tail
d. Exons
e. AAUAA
c
86
5’ AGG AGG ACA GCU AUG GGU GGU UCC GCC GCC UGA AAA AAA UAA3’
a. Arg-Arg-Thr-Ala-Met-Gly-Gly-Ser-Ala-Ala
b. Arg-Arg-Thr-Ala-Met-Gly-Gly-Ser-Ala-Ala-
Cys-Lys-Lys
c. Met-Gly-Gly-Ser-Ser-Ala
d. Met-Gly-Gly-Ser-Ala-Ala
d
87
Which of the following is true about transcription?
a. synthesis in 3’ 5’ direction
b. template DNA is the sense strand
c. 400 base per second, 1x109
d. A binds with U instead of T error rate
d
88
Which protects mRNA from degradation by nucleases as it moves from the nucleus to the cytoplasm?
a. 5’ end
b. 3’ end
c. Poly A tail
d. None of the above
c
89
On which part of the RNA is the 7-methylguanosine attached?
5' end
90
The polyadenylation signal sequence
AAUAAA
91
The base sequence of the strand of DNA used as the
template for transcription has the base sequence GATCTAC . What is the base sequence of the RNA
product? (All sequences are written according to stan
dard convention.)
```
A. CTAGATG
B. GTAGATC
C. GAUCUAC
D. CUAGAUG
E. GUAGAUC
```
E
92
The first aminoacyl-tRNA in translation
Initiator tRNA
93
During translation, a ribosome can accomodate two tRNAs at any given time. At which sites does each of the tRNA bind?
Peptidyl site (P site) and the aminoacyl site (A site)
94
Which of the following statements is/are TRUE regarding protein synthesis?
(a) The genetic code provides for the possibility of an individual codon coding for more than one amino acid residue.
(b) The start codon codes for the first amino acid residue to be incorporated into a polypeptide chain.
(c) The stop codon codes for the last amino acid residue to be incorporated into a polypeptide chain.
(d) All of the above
(e) (a) and (b) only
b
95
Which of the following statements is/are TRUE regarding the central dogma of molecular biology in its most comprehensive form?
(a) It provides for the possibility of synthesizing new RNA using RNA as a template.
(b) It provides for the possibility of synthesizing new protein using RNA as a template.
(c) It provides for the possibility of synthesizing new RNA using protein as a template.
(d) All of the above
(e) (a) and (b) only
b
