Tag: bio-chemistry

Questions Related to bio-chemistry

Which of the following steps is/are catalysed by Taq polymerase in a PCR?

  1. Denaturation of template DNA

  2. Annealing of primers to template DNA

  3. Extension of primer end on template DNA

  4. All of these


Correct Option: C
Explanation:

PCR is the short form for polymerase chain reaction which is the phenomenon which is used for amplification of the part-specific region of DNA as per our interest. Taq polymerase is the enzyme that attaches nucleotides together and help is the extension of primer end on the template DNA.

So, the correct answer is 'extension of primer end on the template DNA'.

Which among the following is true for protein synthesis in bacteria?

  1. It involves all the three types of RNAs (m-RNA, t-RNA and r-RNA)

  2. It involves $3$ types of RNA polymerase

  3. It involves single type of RNA polymerase

  4. It involves RNA processing


Correct Option: C

Select the wrong pair

  1. RNA polymerase I - Sn RNA 5S rRNA, r-RNA

  2. RNA polymerase I - r-RNA

  3. RNA polymerase II - hnRNA

  4. RNA polymerase III - tRNA


Correct Option: A

Taq polymerase enzyme is used in

  1. Restriction mapping

  2. Gene cloning

  3. PCR

  4. All of the above


Correct Option: C
Explanation:

Taq polymerase is a heat stable enzyme used in the polymerase chain reaction (PCR) to amplify segments of DNA in the lab. 

Thus, the correct answer is option C.

Which of the following would not be a valid reason to use PCR?

  1. Help in analyzing DNA of ancient remains of fossilized woolly mammoth

  2. Help in analyzing the genome of a virus

  3. Help in determining the DNA of a hair sample found at a crime scene

  4. Help in transferring DNA from a plasmid containing GFP into E.coli


Correct Option: D
Explanation:

Majorly the PCR is used in analyzing and determining purposes only not the transferring purposes. For transferring purpose vectors are used. In analyzing and determining purposes, the sample is limited i.e. if the sample gets destroyed no analysis can be carried out which can be a big problem in the investigation cases. So to have extra copies of the sample it is first amplified by PCR.

Thermal cycler is used in one of these reactions.

  1. Radioactivity

  2. Enzyme catalysed reaction

  3. Chemical reaction

  4. Polymerase chain reaction


Correct Option: A

DNA polymerase required for synthesizing copies of DNA at high temperature is obtained from

  1. Thermus aquaticus

  2. Cephalosporium minimum

  3. Bacillus megaterium

  4. Thermoproteus species


Correct Option: A
Explanation:

A. Thermus aquaticus is a thermophilic bacteria which survives at high temperatures. Thus it's DNA polymerase is evolved to synthesize DNA at high temperature. This DNA polymerase is commercially available as "Taq polymerase" and is used in polymerase chain reaction (PCR).

B. Cephalosporium minimum is a plant pathogen and are producers of antibiotic cephalosporin.
C. Bacillus megaterium is a soil bacteria whose DNA polymerase is not thermo resistant. Hence it cannot synthesize DNA at high temperatures.
D. Thermoproteus species are sulphur utilizing hyperthermophiles which grow is acidic hot springs. Such bacteria are difficult to grow in lab conditions. Although its DNA polymerase can synthesize DNA at high temperatures, due to inability to grow in lab conditions, its DNA polymerase cannot be obtained.
Hence the correct answer is 'Thermus aquaticus'

Which of the following techniques is used to make numerous copies of a specific segment of DNA quickly and accurately?

  1. Translation

  2. Transcription

  3. Polymerase chain reaction

  4. Ligase chain reaction


Correct Option: C
Explanation:

For making numerous copies of a specific segment of DNA three steps are required

1.Denaturing
2.Annealing
3.Extending
Which is called a polymerase reaction.
So, the correct option is 'Polymerase chain reaction'.

Read the following statements carefully and select the correct option:
(A) Source of the restriction enzyme Hind III is E.coli
(B) In biolistic method of gene transfer, mircoparticles made up of gold or tungsten are coated with foreign DNA
(C) Micro-injection method for injecting recombinant DNA is used for animal cell
(D) Primers are chemically synthesized oligonucleotides that are complementary to the regions of DNA in PCR.
How many of the above statement are correct?

  1. Four

  2. Three

  3. Two

  4. One


Correct Option: B
Explanation:

A)

Restriction enzymes, also called restriction endonuclease, is a protein that cuts DNA after recognizing a specific sequence of DNA. Hind III is a type  II site-specific deoxyribonuclease restriction enzyme isolated from Haemophilus influenzae that cleaves the DNA via hydrolysis.

B)

In the bolistic method of gene transfer, a gene gun is used to transfer exogenous or foreign DNA  in the cell. A droplet of tungsten powder and genetic material is a bullet. Gold is favored at the place of tungsten as it has better uniformity than tungsten and tungsten can be toxic to cells.

C) 
Micro-injection method for injecting recombinant DNA is used to produce transgenic mice. Harvested oocytes of the mouse are injected with the genetic material and then implanted in the oviduct of a pseudopregnant animal.

D)
A primer is a short strand of RNA or DNA that serves as a starting point for DNA synthesis.In vitro lab techniques that use DNA polymerase, DNA. primers are used. They are usually short, chemically synthesized oligonucleotides, with a length of about twenty bases.
Therefore A, B, and D are correct statements. Answer is B.

Eukaryotic cells have membrane bound organelles.

  1. True

  2. False


Correct Option: A
Explanation:
Organelles are the specialised and organised structures in a living cell. These may be bound by a single or double membrane (Exception is ribosomes which are non-membranous cell organelles present in both prokaryotes and eukaryotes). Membrane-bound cell organelles include nucleus, vacuole, endoplasmic reticulum, chloroplasts, mitochondria, lysosomes, Golgi apparatus and are present only in eukaryotes.
So, the correct answer is 'True'.