MolBio

Question 1

Which mutation could result from alteration due to transition or transversion of a single nitrogenous base?

Answer 1

Point Mutation

Question 2

A type of recombination where viruses infecting a bacterium
transfer the genetic code between bacteria by growing the phage on one strain and then infecting a second strain.

Answer 2

Transduction

Question 3

Which of the following degrades RNA?

Answer 3

Ribonuclease

Question 4

Which is a type of helicase that relaxes or prevent super twisted DNA?

Answer 4

Topoisomerase

Question 5

Which results in local folding of polypeptide backbone into helical, pleated sheets or random conformations?

Answer 5

Secondary Protein Structure

Question 6

The first mRNA codon specifies this amino acid which serves as the initiation complex in protein translation.

Answer 6

Methionine

Question 7

Which structure is attached to the 3’ end of the mRNA during RNA processing as preparation for protein translation?

Answer 7

200 adenines forming a poly A tail

Question 8

What is the type of RNA with a cloverleaf conformation where its three loops contain three bases forming an anticodon?

Answer 8

tRNA

Question 9

During DNA replication, the new bases are added starting from
which structure in the replication fork?

Answer 9

RNA Primer

Question 10

Which significant process involves the addition of the RNA
nucleotides by RNA polymerase depending on the sequence the DNA specifies?

Answer 10

Transcription

Question 11

Which part of the nucleotide carries the genetic information?

Answer 11

Nitrogenous Base

Question 12

What is the type of chemical attraction responsible for holding the DNA base pairs together?

Answer 12

Hydrogen bonds

Question 13

This is a protein where DNA coils around forming structures that resemble beads on a string.

Answer 13

Histones

Question 14

How does the DNA double helix form become symmetrical?

Answer 14

When nucleotides A pair with 1 and subsequently G pair with C

Question 15

Which represents the anti-parallel alignment of the double stranded DNA?

Answer 15

One strand run based on number 5 carbon af the top to the
number 3 carbon and the other strand runs from the number 3
to the numbers carbon

Question 16

Which is true about RNA?

Answer 16

RNA fold and loop upon themselves to take on a
double-stranded character

Question 17

Why is the process of RNA transcription selective and efficient?

Answer 17

Transcription factors regulate which specific genes needed to
be transcribed

Question 18

In Griffith’s experiment, how does the non-virulent strain of the
bacteria transform into a virulent strain?

Answer 18

DNA is passed from Type S bacteria into Type R bacteria to
encase itself in smooth coat

Question 19

How does mRNA form from the template DNA strand?

Answer 19

• Enzymes unwind the DNA double helix
• Transcription factors and necessary enzymes are attracted to
  a promoter
• Recognition of the end of the gene
• Enzymes add the RNA nucleotides depending on the sequence
  the DNA specifies

Question 20

Which type of mutation is capable of adding a genetic material?
1-Deletion mutation
2- Expanding repeats
3-Frameshift mutation
4-Insertion mutation
5-Transposons
6-Tandem Duplication

Answer 20

2, 4 and 6

Question 21

What type of nucleic acid isolation method is referred to as a
salting-out procedure?

Answer 21

Inorganic DNA isolation method

Question 22

What is a cation-chelating resin that can be used for simple
extraction of DNA?

Answer 22

Chelex

Question 23

What is the first step of DNA isolation methods?

Answer 23

Cell disruption

Question 24

To inactivate RNAses, how are tissues prepared for RNA isolation?

Answer 24

Dissociated while frozen in liquid nitrogen

Question 25

How does cell lysis step of organic RNA isolation occur?

Answer 25

Done in phenol:chloroform:isoamyl alcohol solution with the ratio 25:24:1

Question 26

What is the most abundant RNA fraction and how much of the total RNA does it comprise?

Answer 26

Messenger RNA (75-85%)

Question 27

Using electrophoresis, how would a laboratory scientist know that the genomic DNA extracted is of good quality?

Answer 27

Presence of bright band with low mobility

Question 28

Using a spectrophotometer, nucleic acids absorb light at through the adenine

Answer 28

260nm

Question 29

Fluorescent spectroscopy measures fluorescence related to DNA concentration in association with DNA-specific fluorescent dyes. What dye is currently used by modern Fluorometry procedures that combines with adenine-thymine base pairs in the minor groove of the DNA double helix and is thus specific for intact double. stranded DNA?

Answer 29

Hoechst 33258

Question 30

There are three techniques utilized to assess the quality of yielded DNA or RNA. Which of these methods rely on the Beer-Lambert Law?

Answer 30

Spectrophotometry

Question 31

Which of the following is an enzyme product utilized to breakdown bacterial or fungal tough cell walls?

Answer 31

lysozyme

Question 32

Which of the following precautionary measures would help one achieve an RNAse-free working area?

Answer 32

Allocation of a separate RNAse-free area of the laboratory for storage of materials and specimen handling

Question 33

Which of these steps DOES NOT guarantee isolation of mitochondrial DNA through centrifugation?

Answer 33

Mitochondrial DNA can then be precipitated with warm ethanol with DNAse and resuspended in appropriate buffers for analysis.

Question 34

Extraction of DNA with chelating resin is most commonly used in which of the following laboratory/study?

Answer 34

forensic analysis

Question 35

Why is it that protocols employing oligomers of thymine or uracil immobilized on a matrix resin column are often used to enrich the yields of mRNA?

Answer 35

The polyT or polyU oligomers will bind the polyA tail found exclusively on mRNA

Question 36

Which is not a requirement in order for the mRNA to be translated?

Answer 36

The genetic code overlaps

Question 37

Which scenario doesn’t happen during DNA replication?

Answer 37

New bonds between complementary bases and incorporated nucleotides form into a strong chain.

Question 38

Which is a relevant application of recombination?

Answer 38

- It results to a genetic combination of the child similar to the parents - The manipulation of a specific gene has implications in the potential prevention of diseases - The diversity in recombination cannot predict traits after reproduction

Question 39

Which does not lead to the deduction of the overall structure of DNA molecule

Answer 39

A suggestion that the DNA has a triple helix structure

Question 40

From a one mL sample of blood, what is the expected yield of RNA?

Answer 40

1-10 ug

Question 41

Which of the following steps DOES NOT belong to the DNA organic isolation methods?

Answer 41

After the cell lysis step, DNAse is added to remove contaminating DNA.

Question 42

Which of the following steps does not belong to the DNA inorganic isolation methods?

Answer 42

Further purification of DNA sample requires removal of contaminating proteins, lipids, carbohydrates, and debris and it is accomplished through an organic mixture of phenol and chloroform.

Question 43

Which of these situations would indicate that we had extracted a good quality of nucleic acid material?

Answer 43

A DNA sample exposed to 260nm and 280nm wavelengths of a spectrophotometer. The 260 nm/280 nm ratio is 1.5

Question 44

If the Ficoll solution is not available for differential density gradient centrifugation of whole blood, which of these techniques will help in preparing nucleic acids for isolation from WBCs?

Answer 44

Incubation of whole blood in the hypotonic buffer will result in lysis of the RBCs before the WBCs. The WBCs are then pelleted by centrifugation, leaving the empty RBC membranes in suspension.