All Free Biology MCQs with Answers
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19844 questions · page 530 of 1985
5291. In order to obtain virus-free plants through tissue culture, the best method is:
- A. Meristem culture
- B. Protoplast culture
- C. Embryo rescue
- D. Anther culture
Explanation: Meristem culture is a type of tissue culture technique used labs to eliminate vinuses and other parasites while growing plants in vitro. They either use the growing tips of plant shoots or roots-sites containing meristematic cells- for the culturing process.
Correct answer: Meristem culture5292. Mendel's work was rediscovered in:
- A. 1869
- B. 1899
- C. 1920
- D. 1900
Explanation: This is the correct answer. In 1900, scientists independently rediscovered Mendel's work on inheritance, bringing attention to his groundbreaking experiments with pea plants.
Correct answer: 19005293. The work of biotechnology is:
- A. Insulin
- B. Drugs
- C. Pollution
- D. All of the above
Explanation: Modern techniques enable desired substances, for example, insulin. Not very long ago, people with insulin-dependentthey receive human insulin, a product of biotechnology. Since the 1980s, biotechnologyhas produced drugs and vaccines to curb human illnesses.Genetically, engineered bacteria have been used to clean up environmental pollutants,increase the fertility of the soil, and kill insect pests.
Correct answer: All of the above5294. Production of identical copies of gene is:
- A. Replication
- B. Cloning
- C. Reproduction
- D. Multiplication
Explanation: The cloning of a gene produces many identical copies.
Correct answer: Cloning5295. Which of the following techniques produces large number of copies of genes?
- A. PCR
- B. Recombinant DNA technology
- C. RFLP
- D. None of the above
Explanation: Cloning of a gene produces many identical copiesPolymerase chain reaction (PCR) creates a lesser number of copies within a laboratory test tube. Recombinant DNA technology popularly known as genetic engineering aims at synthesizing recombinant DNA which contains DNA from two different sources.Restriction fragment length polymorphism (abbreviated RFLP) refers to differences (or variations) among people in their DNA sequences at sites recognized by restriction enzymes. Such variation results in different-sized (or length) DNA fragments produced by digesting the DNA with a restriction enzyme.
Correct answer: None of the above5296. The technique used to produce copies of genes in laboratory is:
- A. PCR
- B. Recombinant DNA technology
- C. RFLPs
- D. None of the above
Explanation: The use of polymerase chain reaction (PCR) creates a lesser number of copies within a laboratory test tube.
Correct answer: PCR5297. Which of the followings is used to transfer genes?
- A. Molecular scissors
- B. Molecular vector
- C. Expression system
- D. None of the above
Explanation: A vector, as related to molecular biology, is a DNA molecule (often plasmid or virus) that is used as a vehicle to carry a particular DNA segment into a host cell as part of a cloning or recombinant DNA technique.
Correct answer: Molecular vector5298. The system used for the formation of specific product is:
- A. Molecular scissors
- B. Molecular vector
- C. Expression system
- D. Gene of interest
Explanation: The gene of interest along with the vector is then introduced into an expressionsystem, as a result of which a specific product is made.
Correct answer: Expression system5299. Genes are cut by:
- A. Gene of interest
- B. Expression system
- C. Molecular vector
- D. Endonucleases
Explanation: Genes can be isolated from the chromosomes by cutting the chromosomes on theflanking sites of the gene using special enzymes known as restriction endonucleases. Endonucleases can cleave or cut the phosphodiester bond within a polynucleotide chain.
Correct answer: Endonucleases5300. The DNA which is synthesized from mRNA by reverse transcriptase are called:
- A. Endonucleases
- B. Plasmids
- C. cDNA
- D. None of the above
Explanation: This involves converting the RNA back into a DNA copy, known as complementary DNA (cDNA) by reverse transcriptase. Thus, when amplifying eukaryotic genes by PCR the cDNA version is often used (rather than the true chromosomal gene sequence) since this lacks the introns.
Correct answer: cDNA