This set of Biology Problems for Schools focuses on “Biotechnology – Processes of Recombinant DNA Technology – 3”.
1. The enzyme which cleaves proteins is ______
Explanation: The enzyme which cleaves proteins is a protease. RNase is the enzyme that cleaves the RNA. Lipases are responsible for the breakdown of lipids while DNase catalyzes the breakdown of DNA.
2. Which protein helps in DNA winding?
Explanation: The DNA is wound around histone proteins. They are alkaline in nature which helps in packaging and condensation of DNA. DNA wound around histone forms a complex called a nucleosome.
3. Which chemical is used to obtain a precipitate of pure DNA?
Explanation: Ethanol is used to obtain the precipitate of pure DNA. It’s used in concentrating and de-salting of nucleic acids. It makes the nucleic acid less hydrophilic thus easing their extraction.
4. DNA is _____ charged.
Explanation: DNA is a negatively charged molecule. This negative charge arises due to the presence of negatively charged oxygen present in phosphate groups of DNA backbone.
5. DNA moves towards ______ during agarose gel electrophoresis.
a) negative terminal
d) does not move
Explanation: During agarose gel electrophoresis the DNA moves towards the anode. Since DNA is negatively charged it moves toward the positively charged terminal. An anode is a positive terminal while the cathode is the negative terminal.
6. Which enzyme helps in joining of DNA?
Explanation: Ligases are the enzyme that helps in the joining of two strands of DNA. Lyase is responsible for the breakdown of molecules. Helicase helps in the unwinding of DNA. Lipases are enzymes that breakdown lipids.
7. What does PCR stand for?
a) Polymerase chain radioactivity
b) Polymerase chitin reaction
c) Phenol carbohydrate reaction
d) Polymerase chain reaction
Explanation: PCR stands for Polymerase chain reaction. It is a technique used for DNA amplification. It was developed by Kary Mullis and is a useful technique in genetic engineering.
8. The three steps involved in PCR are ________
a) annealing, extension, and denaturation
b) extension, denaturation, and annealing
c) denaturation, annealing, and extension
d) denaturation, extension, and annealing
Explanation: Denaturation, annealing, and extension are three steps involved in PCR. In denaturation, the DNA is denatured. The primers are added in annealing and in extension, the primers extend giving rise to new DNA strands.
9. Taq polymerase is obtained from _______
c) Thermus aquaticus
Explanation: Taq polymerase is a type of DNA polymerase obtained from the bacteria Thermus aquaticus. It is a thermophilic bacteria and its polymerase remains active at high temperatures (>80°C).
10. The transformants containing ______ gene will grow on plates containing antibiotics.
b) amino acid
c) selectable marker
Explanation: The transformants which will be successfully transformed and consisting of an antibiotic-resistance gene will grow on plates containing antibiotics. This gene can act as a selectable marker to differentiate between transformants and non-transformants. The non-transformants will not grow on a plate containing antibiotics and will eventually die.
11. Bioreactors can contain volume up to ______ litres.
Explanation: Bioreactor is a device or vessel which helps in carrying out various biological reactions providing them optimum conditions. It helps in the proper growth of organisms giving us the desired product with its high yield.
Sanfoundry Global Education & Learning Series – Biology – Class 12.
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