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Biochemistry 2 > Questions 1 > Flashcards

Questions 1 Flashcards

1
Q

What is the main role of the above motif?
a) Oxygen binding
b) protein-protein interaction
c) Zn2+ chelating
d) DNA binding
e) Catalytic activity

A

d) DNA binding

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2
Q

Choose nucleic acids this nucleotide can be incorporated
a) genomic DNA
b) messenger RNA
c) mitochondrial DNA
d) transfer RNA

A

b) messenger RNA
d) transfer RNA

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3
Q

Choose a nucleotide that can pair with it in a single type of nucleic acid
a) dATP
b) ATP
c) dGTP
d) GTP
e) dCTP
f) CTP

A

b) ATP

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4
Q

if in a nucleic acid the content of this nucleotide is 40%, what would be the contents of guanylate?
a) 10%
b) 20%
c) 30%
d) 40%
e) 50%

A

a) 10%

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5
Q

Name elements of replication forks marked by letters A, B and C.

A

A: leading strand, B: Okazaki fragments, C: lagging strand

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6
Q

Name the basic rules of replication:
a) Semi-conservative
b) Starts at the ‘origin’
c) Synthesis always in one direction
d) Synthesis always in the 5-3’ direction
e) Semi-discontinuous
f) no primers required
g) RNA primers required
h) connected with ribosomes
i) performed by DNA replicase

A

a) Semi-conservative
b) Starts at the ‘origin’
d) Synthesis always in the 5-3’ direction
e) Semi-discontinuous
g) RNA primers required

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7
Q

What is the complementary DNA strand that is created from this template during replication? TEMPLATE: 5’-ATGCCGGGTAATCCA-3’
a) 5’-ATGCCGGGTAATCCA-3’
b) 5’-AUGCCGGGUAAUCCA-3’
c) 5’-TGGATTACCCGGCAT-3’
d) 5’-TACGGCCCATTAGGA-3’

A

d) 5’-TACGGCCCATTAGGA-3’

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8
Q

Arrange the following proteins in the proper order in which they participate in DNA replication
1 = Primase
2 = Helicase
3 = Single-strand binding proteins
4 = DNA polymerase
a) 2,4,3,1
b) 1,3,2,4
c) 2,3,1,4
d) 1,2,3,4

A

c) 2,3,1,4

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9
Q

DNA Pol alfa in Eukaryotic organisms:
a) has primase activity in one subunit and polymerization in another
b) does not have 3’ to 5’ proofreading
c) is highly processive
d) has primase activity
e) replicate a lagging strand

A

a) has primase activity in one subunit and polymerization in another
b) does not have 3’ to 5’ proofreading
d) has primase activity

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10
Q

Name three physical mutagens (environmental factors) that can cause a mutation:

A

UV light
Heat
Ionizing

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11
Q

ATTTGAGCC- Original ATTGAGCC - Mutated The example above is an example of a:
a) Insertion- Frameshift
b) Deletion- Substitution
c) Deletion -Frameshift
d) Inversion - Frameshift
e) All of the above

A

c) Deletion -Frameshift

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12
Q

Oncogenes:
a) mutated recessive-acting inhibitory genes that are inactive proliferation
b) mutated, dominant-acting stimulatory genes that cause cancer
c) genes encoding ONCO proteins
d) genes responsible for RNA degradation in tumor cells

A

b) mutated, dominant-acting stimulatory genes that cause cancer

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13
Q

Somatic mutations:
a) Arise in the somatic cells
b) Passed onto future generations
c) They occur in the cells that produce gametes
d) Passed on to other cells through the process of mitosis
e) Effect of these mutations depends on the type of the cell in which they occur
f) Are caused only by chemical agents

A

a) Arise in the somatic cells
d) Passed on to other cells through the process of mitosis
e) Effect of these mutations depends on the type of the cell in which they occur

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14
Q

The base composition of a virus was found to be 11% A, 32% G, 18% U and 39% C. Is it single-stranded or double-stranded?

A

single stranded

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15
Q

Transcription factors perform their function:
a) only during cell division
b) with other proteins in a complex
c) by promoting (as activators)
d) by blocking (as repressors)
e) only in the presence of ATP
f) in cells withouc cell wall
g) in Golgi system

A

b) with other proteins in a complex
c) by promoting (as activators)
d) by blocking (as repressors)

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16
Q

There are some differences between DNA and RNA. Select the features of RNA:
a) Mostly double stranded
b) Mostly single stranded
c) Ribose as sugar
d) Deoxyribose as suger
e) uracil, adenine, cytosine, guanine
f) thymine, adenine, cytosine, guanine

A

b) Mostly single stranded
c) Ribose as sugar
e) uracil, adenine, cytosine, guanine

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17
Q

RNA polymerase I (Pol I) in eukaryotes:
a) synthesizes mRNA and some specialized RNAs
b) corrects mistakes in RNA
c) is responsible for the synthesis of tRNA
d) is responsible for the synthesis of ribosomal RNAs
e) recognizes thousands of promoters

A

d) is responsible for the synthesis of ribosomal RNAs

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18
Q

Name the elements of tRNA marked by A and B:

A

A - amino acid binding site
B - anticodon loop

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19
Q

Select the features of the genetic code:
a) universal
b) specific
c) degenerated
d) unambiguous
e) endless
f) continuous
g) determined by deoxyribose order

A

a) universal
b) specific
c) degenerated
d) unambiguous
f) continuous

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20
Q

Initiation of translation begins when the:
a) large and small subunits link together, then bind to the mRNA.
b) ribosomal small subunit holding an initiator tRNA binds to the 5’ end of the mRNA.
c) ribosome binds to the start codon and an initiator tRNA enters the ribosome.
d) ribosomal large subunit merge with mRNA
e) initiator tRNA binds to the start codon, followed by binding of the ribosome large subunit.
f) tRNA binds ribosome

A

b) ribosomal small subunit holding an initiator tRNA binds to the 5’ end of the mRNA.

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21
Q

The Shine-Dalgarno sequence is:
a) trailer sequence
b) the reading frame of a gene
c) a short sequence that acts as a ribosomal binding site
d) there is no correct answer
e) tRNA binding site

A

c) a short sequence that acts as a ribosomal binding site

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22
Q

Amino-acyl tRNA synthetases:
a) are responsible for charging of the proper tRNA
b) may recognize multiple tRNAs for the same amino acid
c) are capable of editing incorrectly incorporated amino acid
d) synthesize peptide bond
e) do not require ATP

A

a) are responsible for charging of the proper tRNA
b) may recognize multiple tRNAs for the same amino acid
c) are capable of editing

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23
Q

Name the elements of lac operon marked by A, B and C:

A

promoter, operator, coding region

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24
Q

Genes that are always transcribed are called:
a) constitutive genes
b) transposons
c) stable genes
d) operator genes
e) operons

A

a) constitutive genes

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25
Q

Which of the following is the correct description of basic properties of a prokaryotic operon?
a) An operon contains exclusively genes that encode proteins involved in heat shock.
b) All genes in an operon have identical promoters.
c) An operon consists of multiple genes in a related pathway, organized between a single promoter and terminator.
d) An operon contains genes regulated strictly by feedback control of transcription.
e) An operon consist of genes responsible for lactose level regulation

A

c) An operon consists of multiple genes in a related pathway, organized between a single promoter and terminator.

26
Q

Where are promoters typically found in DNA?
a) In the 3’ UTR
b) In the middle of the coding region of a gene
c) Downstream of the coding region of a gene
d) Upstream of the coding region of a gene
e) In introns

A

d) Upstream of the coding region of a gene

27
Q

Where are promoters typically found in DNA?
a) In the 3’ UTR
b) In the middle of the coding region of a gene
c) Downstream of the coding region of a gene
d) Upstream of the coding region of a gene
e) In introns

A

d) Upstream of the coding region of a gene

28
Q

The effect of allolactose is:
a) Dissociation of RNA polymerase from DNA, terminating transcription of genes
b) regulated by the lac operon
c) Enhancement of binding of RNA polymerase to DNA, increasing gene transcription
d) Repression of the lac operon when glucose is present
e) Conformational change in the repressor protein, inducing the lac operon

A

e) Conformational change in the repressor protein, inducing the lac operon

29
Q

Name the way of regulation of gene expression presented on the scheme below:

A

alternative splicing

30
Q

Histone acetyltransferases (HATs) transfer acetyl groups from acetyl CoA to lysine residues on histones. What is the purpose of this transfer?
a) Prevent transcription factors from binding to DNA
b) Promote formation of euchromatin and increase gene expression
c) Facilitate phosphorylation of these lysines by kinases
d) Prevent DNA degredation by endonucleases
e) Signal for ubiquitin-mediated degredation of histones

A

b) Promote formation of euchromatin and increase gene expression

31
Q

Which of the following classes of histones are core components of the nucleosome?
a) H1
b) H2A
c) H2B
d) H3
e) H4
f) A1 Xber
g) DNA

A

b) H2A
c) H2B
d) H3
e) H4

32
Q

The most common form of control of gene expression in both the prokaryotic and eukaryotic organisms is:
a) RNA processing control.
b) Translational control.
c) Protein phosphorylation control.
d) Transcriptional control.
e) mRNA degradation control

A

d) Transcriptional control.

33
Q

Main mechanisms by which membrane-bounded organelles import proteins are:
a) Transport of proteins into the nucleus through selective gates called nuclear pores.
b) Transport of proteins into the ER, mitochondria, or peroxisomes by protein translocators located in the membrane
c) Transport of proteins to the cell envelope by cellular shuttels
d) Transport of proteins via the ATPase
e) Transport of proteins via the lipid derived rafts
f) Transport of proteins between the compartments using transport vesicles

A

a) Transport of proteins into the nucleus through selective gates called nuclear pores.
b) Transport of proteins into the ER, mitochondria, or peroxisomes by protein translocators located in the membrane
f) Transport of proteins between the compartments using transport vesicles

34
Q

Posttranslational modification of many eukaryotic proteins begins in the:
a) Endoplasmic reticulum
b) Mitochondria
c) Chloroplasts
d) Nucleus
e) Cell membrane

A

a) Endoplasmic reticulum

35
Q

Name the process presented below:

A

Crossing over

36
Q

Which of the following processes occurs between DNA molecules of very similar sequences?
a) Homologous genetic recombination
b) Site specific recombination
c) Non-homologous recombination
d) Phage lambda recombination
e) Replicative recombination

A

a) Homologous genetic recombination

37
Q

Which of the following contain only the sequences required for transposition and the genes for proteins that promote the process?
a) Insertion sequences
b) Complex transposons
c) Transposons
d) Chromosomes
e) Replicons

A

c) Transposons

38
Q

How many DNA duplexes are obtained from one DNA duplex after 5 cycles of PCR?
a) 4
b) 5
c) 8
d) 16
e) 25
f) 32

A

f) 32

39
Q

cDNA is synthesized from
a) miRNA
b) Protein chain
c) tRNA
d) mRNA
e) DNA
f) siRNA
g) ssDNA

A

d) mRNA

40
Q

Indicate a nucleic acid in which this nucleoside is very often incorporated:
a) snRNA
b) rRNA
c) tRNA
d) Mitochondrial DNA
e) Genomic DNA

A

c) tRNA

41
Q

Choose a sequence reverse complement to the following: 5’-GACTCA-3’
a) 5’-TGAGTC-3’
b) 5’-GACTCA-3’
c) 5’-CTGAGT-3’
d) 5’-ACTCAG-3’’

A

c) 5’-CTGAGT-3’

42
Q

What bonds link the adjacent nucleotides in the DNA strand?
a) Glycosidic
b) Hydroxyl
c) Phosphodiester
d) Hydrogen
e) Amide

A

c) Phosphodiester

43
Q

Link given mutation with their respective types:
G → A: a) Transition b) Transversion G → C: a) Transition b) Transversion T → C: a) Transition b) Transversion T → A: a) Transition b) Transversion

A

G → A: a) Transition
G → C: b) Transversion
T → C: a) Transition
T → A: b) Transversion

44
Q

Using Chargaff’s rule predict what percentage of G would be in a DNA containing 10% A
a) 10%
b) 20%
c) 30%
d) 40%
e) 50%

A

d) 40%

45
Q

Which of the following is true regarding these DNA repair mechanisms?
a) DNA damage from chemical reactions cannot be undone
b) Proofreading from DNA polymerase reduces the error rate in DNA to about 1 in 100 nucleotides
c) Copying errors not caught by the replication machinery can be corrected by mismatch repair
d) Non-homologous end joining is less likely to produce mutations than homologous recombination

A

c) Copying errors not caught by the replication machinery can be corrected by mismatch repair

46
Q

Which of the following correctly pairs the DNA replication enzyme with its function?
a) Topoisomerase works ahead of the replication fork preventing supercoiling
b) DNA I opens up the DNA at the replication fork
c) Helicase seals the gap between DNA fragments
d) DNA primase extends primers by adding nucleotides to the 3’-end

A

a) Topoisomerase works ahead of the replication fork preventing supercoiling

47
Q

___is a protein that synthesizes RNA primers on ___ during DNA replication
a) RNA polymerase .. both the leading and lagging strands
b) RNA polymerase … the lagging strand
c) Primase … the lagging strand
d) Primase … both the leading and the lagging strand

A

d) Primase … both the leading and the lagging strand

48
Q

Which of the following is not true for DNA replication?
a) Replication occurs in the 5’- to 3’-direction
b) The lagging strand is synthesized in short fragments, directed away from the replication fork
c) Replication occurs during prophase of mitosis
d) The DNA must be denatured at the replication fork

A

c) Replication occurs during prophase of mitosis

49
Q

Which prokaryotic polymerase is primarily responsible for filling in
a) Reverse transcriptase
b) DNA polymerase I
c) DNA polymerase III
d) RNA polymerase

A

b) DNA polymerase I

50
Q

Where does the eukaryotic DNA replication take place?
a) Nucleus
b) Ribosome
c) Cytoplasm
d) Golgi body

A

a) Nucleus

51
Q

DNA replication results in 2 DNA molecules:
a) Each with 2 original strands
b) Each with 2 new strands
c) One with 2 new strand and the other with 2 original strands
d) Each with one new strand and one original strand

A

d) Each with one new strand and one original strand

52
Q

Eukaryotic cells differ from prokaryotic cells in mechanism of DNA replication due to:
a) Use of DNA primer rather than RNA primer
b) Different enzyme for synthesis of lagging and leading strand
c) Unidirectional rather than semi-discontinuous replication
d) Discontinuous rather than semi-discontinuous replication

A

b) Different enzyme for synthesis of lagging and leading strand

53
Q

Which type of mutation results in sickle cell disease phenotype?
a) Conservative mutation
b) Frameshift mutation
c) Non-conservative missense mutation
d) Codon deletion

A

c) Non-conservative missense mutation

54
Q

A silent mutation is highly unlikely to affect protein because
a) The silent mutation does not cause a frameshift
b) The silent mutation substitutes the same type of amino acid
c) The dominant allele can compensate for the silent mutation
d) Multiple codons can code for the same amino acid

A

d) Multiple codons can code for the same amino acid

55
Q

Which of the following represents a transition?
a) G into A
b) T into A
c) A into T
d) G into C

A

a) G into A

56
Q

In a point mutation, this would have the worst effect on the function of the protein:
a) An insertion or deletion near the end of a gene
b) An insertion or deletion at the beginning of the gene
c) An insertion at the middle of the gene
d) A base substitution

A

b) An insertion or deletion at the beginning of the gene

57
Q

Which of the following can not cause mutations?
a) Chemical mutagens found in the environment
b) Transcription errors by RNA polymerase
c) Products produced by cells involved in chronic inflammation
d) Oxygen radicals produced by mitochondria
e) Radiation from the sun

A

b) Transcription errors by RNA polymerase

58
Q

A mutated eukaryotic cell contains a mutation in the middle of an exon in gene Q. What will be the most likely result of this mutation?
a) The amount of transcription of gene Q would be greater than normal
b) The mRNA produced from gene Q would be longer than normal
c) The enzyme produced from gene Q would have less activity than normal
d) The breakdown of the mRNA from gene Q would be slower than normal

A

c) The enzyme produced from gene Q would have less activity than normal

59
Q

The sentence that describe back mutation is:
a) Mutation that lead to the death of organism
b) Mutation that restores the original sequence and hence the original phenotype
c) Mutation that change the gene product such that it gains a new and abnormal function
d) Mutation that suppresses the effect of other mutation

A

b) Mutation that restores the original sequence and hence the original phenotype

60
Q

Chromosomes differ by:
a) Length
b) Banding patterns
c) Centromere location
d) Colour
e) Type of nucleic acid

A

a) Length
b) Banding patterns
c) Centromere location

61
Q

Which two statements below are correct?
a) During transcription, the template strand is read in a 3’ to 5’ direction
b) During transcription, the template strand is read in a 5’ to 3’ direction
c) During transcription, an RNA is transcribed in the 3’ to 5’ direction
d) During transcription, an RNA is transcribed in the 5’ to 3’ direction

A

a) During transcription, the template strand is read in a 3’ to 5’ direction
d) During transcription, an RNA is transcribed in the 5’ to 3’ direction

Biochemistry 2 (5 decks)

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