All Free Biology MCQs with Answers
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19844 questions · page 547 of 1985
5461. DNA made by joining pieces from two or more different sources:
- A. Probes
- B. Restriction endonuclease
- C. Mutated DNA
- D. Recombinant DNA
Explanation: Recombinant DNA (or rDNA) is made by combining DNA from two or more sources. DNA probes are stretches of single-stranded DNA used to detect the presence of complementary nucleic acid sequences (target sequences) by hybridization. A restriction enzyme, restriction endonuclease, or restrictase is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.
Correct answer: Recombinant DNA5462. In the commercial manufacture of insulin, a human gene is inserted into which one of the following?
- A. A chromosome of a human cell
- B. A protein molecule in a yeast cell
- C. The DNA of a bacterium
- D. The nucleic acid in a virus
Explanation: In the commercial manufacture of a human cell, a human gene is inserted into the DNA of a bacterium which then nurtures itself in an environment of its liking producing insulin which is utilized by humans.
Correct answer: The DNA of a bacterium5463. Which kind of therapy was given in 1990 to a four year girl with adenosine deaminase (ADA) deficiency?
- A. Gene therapy
- B. Chemotherapy
- C. Immunotherapy
- D. Radiation therapy
Explanation: Gene therapy is a technique of genetic engineering which involves the replacement of a faulty/disease-causing gene by a normal healthy functional gene. The first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency. This enzyme is very important for the immune system to function and the deficiency of this enzyme can lead to severe combined immune deficiency (SCID).
Correct answer: Gene therapy5464. The 1st human hormone produced by recombinant DNA technology was:
- A. Estrogen
- B. Testosterone
- C. Cortisone
- D. Insulin
Explanation: Insulin is a hormone that regulates blood sugar levels and is essential for the metabolism of carbohydrates. Recombinant DNA technology was first successfully used to produce human insulin, making it the correct option (d). This was done in 1978.
Correct answer: Insulin5465. Treatment of hereditary disorders by gene manipulations is called:
- A. Biotechnology
- B. Genetic engineering
- C. Gene therapy
- D. None of these
Explanation: With gene therapy, the treatment or elimination of inherited diseases or physical conditions due to these mutations could become a reality. Gene therapy involves the manipulation of genes to fight or prevent diseases.
Correct answer: Gene therapy5466. The process of replacing or supplementing the defective allele with a functional, normal allele is known as _.
- A. Allele transplant
- B. Physiotherapy
- C. Gene therapy
- D. Mutation
- E. Cloning
Explanation: Gene therapy is an experimental technique that uses an allele to treat or prevent disease,by replacing the defective allele. In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient's cells instead of using drugs or surgery.
Correct answer: Gene therapy5467. The technique use of identification of criminals is called:
- A. Cloning
- B. DNA fingerprinting
- C. Restriction Analysis
- D. Polymorphism
- E. Gene sequencing
Explanation: DNA fingerprinting is a laboratory technique used to establish a link between biological evidence and a suspect in a criminal investigation. A DNA sample taken from a crime scene is compared with a DNA sample from a suspect. DNA fingerprinting is also used to establish paternity. The figure below shows a DNA fingerprint:
Correct answer: DNA fingerprinting5468. In recombinant DNA technology, the copies of recombinant DNA are increased by:
- A. Restriction enzyme
- B. Ligase
- C. Selection of host with rDNA
- D. Multiplication of host with rDNA
Explanation: The copies of recombinatn DNA can be increased by allowing the DNA to replication with host DNA.
Correct answer: Multiplication of host with rDNA5469. The DNA that has been altered and which now contains the length of nucleotides from two different organisms is called a:
- A. Plasmid
- B. Combined DNA
- C. Vector
- D. Recombinant DNA
Explanation: Recombinant DNA technology involves the joining of DNA molecules from two different species. The Recombinant DNA molecule is inserted into a host organism to produce new genetic combinations that are of value to science, medicine, agriculture, and industry. Vector is the in-between to transfer anything from one organism to another. Combined DNA is not even a word. A plasmid is a small DNA extra found in some bacterium.
Correct answer: Recombinant DNA5470. It is a method for rapid production of a very large number of copies of a particular fragment of DNA:
- A. Gel electrophoresis
- B. Polymerase chain reaction
- C. DNA extraction
- D. Recombination
Explanation: Polymerase chain reaction (PCR) is a technique used to rapidly increase the number of copies of specific regions of DNA for further analyses. The complete process of which is shown below:Image credits:
Correct answer: Polymerase chain reaction