MOLBIO - MIDTERM Flashcards

1
Q

Which of the following statement is FALSE?

A

The PCR is usually done in a reaction volume of 10 – 200 ml in small tubes in a thermal cycler.

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2
Q

SNPs are detected by Allele-Specific PCR by

A

using Allele-specific primers

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3
Q

Which is INCORRECT about SNPs?

A

They usually affect health and development.

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4
Q

This is added to determine if you have contaminants on your DNA

A

Controls

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5
Q

Principle of separation in Capillary zone electrophoresis

A

C

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6
Q

Statements below describes polyacrylamide gel EXCEPT

A

Mobility does not depend on DNA sequence

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7
Q

Extension time is set for () base pairs of DNA per minute

A

1000

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8
Q

In array-based CGH, what is the sample used?

A

mRNA

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9
Q

In Gel Electrophoresis, how do we make the DNA migrate through the gel?

A

We place a positive electrode away from the wells

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10
Q

This is a type of PRGE in which two fields are arranged in separated straight angle

A

FIELD INVERSION GE ELECTRO

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11
Q

After heating and cooling the mixture, which of the following catalyzes the synthesis of complementary strands of DNA?

A

Taq polymerase

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12
Q

Low annealing temperature leads to some mismatches

A

True

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13
Q

Pfu polymerase is superior over Taq polymerase because:

A

of more accurate amplification

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14
Q

Which is INCORRECT about ASO hybridization?

A

The result is analyzed using gel electrophoresis.

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15
Q

When setting up a Sanger sequencing reaction, each reaction should include template DNA, deoxyribonucleotides, dideoxyribonucleotides, buffer, DNA polymerase, and

A

Forward OR reverse primer

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16
Q

What would be the effect on the PCR reaction if any of the following circumstances arose: 1) there are no primers in the reaction, 2) enough dNTPs in the reaction, 3) there is Taq polymerase in the reaction?

A

Amplicons will not be produced, false negative result.

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17
Q

Nonspecific amplification may be a result of adding:

A

5.5 mM MgCl2+

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18
Q

The PCR technique was developed by

A

Mullis

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19
Q

Among those listed below, which is most common mutation effect that leads to the development on cancer?

A

Increase in the activity of a protein

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20
Q

TRUE for agarose gels

A

High voltage in a high agarose concentration can resolve small DNAs

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21
Q

Why do you need to prepare an extra volume in your Master Mix?

A

To compensate pipetting errors

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22
Q

What will happen if too much enzyme is added to the reaction?

A

Digestion reaction may fail

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23
Q

At what temperature does annealing of primers to the template takes place?

A
  • 47-60˚C
    -10-20˚C below the melting point of primer
    -5˚C below the melting point of primer
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24
Q

LAMP PCR requires this range of temperature:

A

60-65°

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25
Q

What is a palindromic restriction endonuclease?

A

The sequence recognized by the enzyme is the same in the forward and reverse sense.

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26
Q

Example of spontaneously generated mutation:

A

Uncorrected error committed by DNA polymerase

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27
Q

Which of the following is not a practice for autoclaving?

A

All items should have a masking tape

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28
Q

What makes Sanger technique superior over Maxam-Gilbert technique for DNA sequencing?

A

-Uses less hazardous reagents
-Can sequence longer DNA
-It is widly used for sequencing

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29
Q

DNA length is measured in units called

A

base pairs

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30
Q

Sickle cell anemia is caused by a point mutation in the hemoglobin gene, resulting in the substitution of a single amino acid in the mature protein. This mutation could be detected by all of the following methods EXCEPT:

A

Western blot analysis

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31
Q

It uses pressurized steam to kill infectious agents

A

Autoclaving

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32
Q

It is the standard concentration used in staining DNA in gels

A

0.5 – 1 ug/ml

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33
Q

Acts as a cofactor to create the DNA chain

A

Magnesium ions

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34
Q

Match the following chemical reagents of Maxam-Gilbert with their correct use.

A

Piperidine
-After chemical modification of bases, this reagent will generate breaks on the strands

Hydrazine + Salt
-Inhibits the reaction of thymine for the C- only reaction

Hydrazine
-Hydrolyzes pyrimidines Formic acid
-Modifies purine bases in the template

Dimethylsulphate
-Adds methyl group to Guanine

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35
Q

Fidelity in amplification may be decreased in which of the following conditions?

A

Increased concentrations of dNTPs

36
Q

Which of the following IS NOT a biological activity of Reverse transcriptase?

A

DNA ligase activity

37
Q

It is routinely used to stain DNA in agarose and polyacrylamide gels

A

Ethidium bromide

38
Q

Which is INCORRECT regarding Restriction Endonucleases applied in molecular techniques?

A

They have modification activity.

39
Q

It protects the host DNA from being cleaved.

A

Methyltransferase

40
Q

Which of the following is TRUE for optimizing a primer?

A

Optimal G-C content should range between 40-60%.

41
Q

Which stage of a PCR is affected by the primers’ melting temperature?

A

Annealing

42
Q

What is the most widely used sequencing technique principle?

A

Chain termination sequencing

43
Q

Which is the easiest, fastest and most economical method of detecting mutation?

A

DNA sequencing

44
Q

It is a premixed solution that contains most of the components necessary to run a PCR assay

A

Master Mix

45
Q

Which of the following is FALSE?

A

Check if there is a buffer that indicates 25% activity for each enzyme

46
Q

This conformation is the fastest to migrate in an agarose gel

A

Form I

47
Q

What is the volume of dNTPs in a 50ul reaction if the stock concentration = 10mM; Final concentration= 0.2mM?

A

1ul

48
Q

In this type of electrophoresis, the mobility of DNA molecules is highly dependent on the electrical field applied to the gel

A

Pulsed-field electrophoresis

49
Q

PCR variant that requires partitioning of the template:

A

Digital PCR

50
Q

How many types of dDNTPs are used in Sanger technique?

A

4

51
Q

Which of the following is a chemical sequencing method?

A

Maxam-Gilbert

52
Q

What is the difference between a deoxyribonucleotide and a dideoxyribonucleotide?

A

A dideoxynucleotide is missing a 3’- hydroxyl group on its sugar.

53
Q

This is a modification of PCR which is designed to improve sensitivity and specificity of amplification.

A

Nested PCR

54
Q

What will happen if there is a low concentration of MgCl in the reaction?

A

No PCR product will be seen

55
Q

Sickle cell anemia is an example of

A

Missense mutation

56
Q

Which of the following statement is TRUE?

A

Reaction conditions will vary based on the enzyme.

57
Q

PCR Supermix is a ready-to-use mixture of DNA polymerase, salts, magnesium and dNTPs for efficient amplification.

A

TRUE

58
Q

This PCR method is also used to detect different viral, bacterial and other pathogens in a single reaction.

A

Multiplex PCR

59
Q

Which technique uses southern blotting?

A

RFLP

60
Q

Why do the restriction endonucleases NOT cleave the genome of the microorganism they belong to?

A

Because the sequences recognized by the endonuclease are appropriately methylated in the genomic DNA for their protection.

61
Q

Single stranded nucleic acid primer sequences may form hairpin loop due to the presence of:

A

complementary sequences within its length

62
Q

Which of the following is TRUE for EtBr?

A

Bands with DNA of less than 5 ng DNA may not be visible after staining

63
Q

How many DNA duplex is obtained from one DNA duplex after 3 cycles of PCR?

A

8

64
Q

Which statement is a FALSE statement?

A

All mutations have harmful effects on an individual.

65
Q

The restriction enzyme SmaI recognizes a 6- base pair, “palindromic” sequence in double stranded DNA. The first three bases of one strand are given: 5´ C C C ()()() 3´. What are the last three bases of this restriction site?

A

G G G

66
Q

To sequence DNA by Sanger method, the DNA must first be made in single stranded form.

A

True

67
Q

Polymerase used for PCR is extracted from

A

Thermus aquaticus

68
Q

Which is INCORRECT regarding restriction endonucleases?

A

Cleave methylated DNA

69
Q

Which of the following recommended concentrations or volume is a mismatched?

A

MgCl2+ : 1.0-6.0 mM

70
Q

A DNA fragment was cut by HaeIII into three fragments and PstI cuts into two fragments. How many DNA bands do you expect from a double digest in gel electrophoresis?

A

5

71
Q

The recognition site of the restriction endonuclease BalI is 5’ T G G C C A 3’. If it cuts the site between G and C, what type ends will be produced?

A

Blunt ends

72
Q

When a dideoxyribonucleotide is added to the DNA strands being synthesized:

A

replication of the strand stops

73
Q

Which consists of primer molecules that have attached to each other because of strings of complementary bases in the primers?

A

Primer dimers

74
Q

What type of bonds is present during gelation?

A

Hydrogen bond

75
Q

What is the temperature that breaks apart hydrogen bonds during denaturing stage?

A

95°C

76
Q

Which is INCORRECT regarding restriction endonucleases?

A

They degrade DNA completely

77
Q

Agarose gel is matrix

A

Negatively charged

78
Q

Which of the following statements is true about migration of biomolecules?

A

Rate of migration is directly proportional to current

79
Q

Which of the following sequencing techniques requires strands amplification?

A

Chain termination sequencing

80
Q

Which is INCORRECT regarding Allele- Specific PCR?

A

It requires blotting on a nylon membrane

81
Q

Which DOES NOT use restriction endonucleases?

A

DNA microarray

82
Q

Low to no yield of PCR products may be a result of which of the following?

A

Decreased MgCl2+ and decreased dNTPs

83
Q

What are the factors to consider in choosing a DNA polymerase?

A

-Thermostability
-Specificity
-Fidelity

84
Q

If a restriction endonuclease has only one cleavage site in a circular plasmid DNA, how many bands do you expect in gel electrophoresis?

A

one

85
Q

It is the tracking dye to monitor the progress of gel electrophoresis

A

Bromphenol blue

86
Q

To sequence DNA by Maxam-Gilbert method, the DNA must first be made in single stranded form.

A

True

87
Q

Which of the following PCR Techniques is used for mass testing for COVID19 infection?

A

Reverse Transcription Real-Time PCR