All Free Biology MCQs with Answers
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19844 questions · page 570 of 1985
5691. A clone can be identical copy of a/an:
- A. Molecule
- B. Organism
- C. Cell
- D. Molecule, cell and organisms
Explanation: Cloning can be carried out at cell, organ and organism levels.
Correct answer: Molecule, cell and organisms5692. Bacterial cells take up _, especially, if they are treated with calcium chloride to make them more permeable.
- A. Recombinant DNA
- B. Plasmid
- C. Recombinant plasmid
- D. Extra chromosomal DNA
Explanation: Aqueous calcium chloride is used in genetic transformation of cells by increasing the cell membrane permeability, inducing competence for DNA uptake (allowing DNA fragments to enter the cell more readily).
Correct answer: Recombinant plasmid5693. Third step in PCR technique is:
- A. Heating DNA for one minute to denature
- B. Cooling for two minutes and adding primer
- C. Addition of DNA polymerase and waiting for 1.5 minutes
- D. Recycling
Explanation: In third step of PCR technique, DNA polymerase is added and then we wait for 1.5 minutes.
Correct answer: Addition of DNA polymerase and waiting for 1.5 minutes5694. PCR can create:
- A. Thousands of copies of a single gene
- B. Millions of copies of a single gene
- C. Hundreds of copies of a single gene
- D. Tens of copies of a single gene
Explanation: As it is less time taking and more efficient method in which a chain reaction is generated.
Correct answer: Millions of copies of a single gene5695. PCR is considered a chain reaction because DNA polymerase will carry out replication over and over again, until there are:
- A. Thousand of copies of desired DNA
- B. Millions of copies of desired DNA
- C. Hundreds of copies of desired DNA
- D. Billions of copies of desired DNA
Explanation: PCR can create millions of copies of a single gene or any specific piece of DNA quickly in test tube.
Correct answer: Millions of copies of desired DNA5696. Before carrying out PCR:
- A. Gene product must be available
- B. Vector must be available
- C. Primers must be available
- D. Bacteriophage must be available
Explanation: As DNA polymerase cannot initiate a polynucleotide chain, rather it can elongate a polynucleotide chain.
Correct answer: Primers must be available5697. DNA polymerase _ the replication process.
- A. Continues
- B. Initiates
- C. Extends
- D. Continues and extends
Explanation: It starts a chain reaction and keep on carrying out replication until test tube is filled.
Correct answer: Continues and extends5698. DNA polymerase copies the target DNA, after the:
- A. Primers bind by complementary base pairing
- B. The target DNA duplex is unwound
- C. The target DNA gets denatured
- D. The primers get separated from target DNA
Explanation: In PCR both strands of DNA act as template for new strands to be synthesized.
Correct answer: Primers bind by complementary base pairing5699. Thermus aquaticus bacterium lives in:
- A. Hot springs
- B. Hot pools
- C. Hot thermal vents
- D. Hot ponds
Explanation: As these are thermal bacteria,they are adapted to survive in high temperature.
Correct answer: Hot springs5700. It is possible to insert a foreign DNA into an animal egg by:
- A. Manual microinjection
- B. Vortex mixing
- C. Manual microinjection or vortex mixing
- D. Using electric current
Explanation: These are two available methods to insert a desired gene into an animal egg.
Correct answer: Manual microinjection or vortex mixing