Q41. What is a genotype?
a) The physical appearance of an organism
b) The genetic makeup of an organism
c) The combination of proteins in a cell
d) The environmental influence on a gene
Show Answer
Correct Answer: b) The genetic makeup of an organism
Explanation: The genotype refers to the genetic makeup of an organism; it’s the complete set of genes that an organism carries. This genetic constitution influences, but does not solely determine, many of the organism’s traits (phenotypes).
Q42. In which genetic phenomenon do neither of two alleles mask the other, resulting in a third phenotype?
a) Incomplete dominance
b) Codominance
c) Complete dominance
d) Recessive inheritance
Show Answer
Correct Answer: a) Incomplete dominance
Explanation: Incomplete dominance is a genetic situation in which neither allele in a gene pair completely masks the other. This leads to a third phenotype, where the expressed physical trait is a combination or intermediate of the phenotypes of both alleles.
Q43. What is the ‘central dogma’ of molecular biology?
a) DNA replicates itself, then converts to RNA, which then makes protein
b) Protein converts to RNA, which then makes DNA
c) RNA replicates itself, which then makes protein
d) RNA converts to DNA, which then makes protein
Show Answer
Correct Answer: a) DNA replicates itself, then converts to RNA, which then makes protein
Explanation: The central dogma of molecular biology describes the two-step process, transcription and translation, by which the information in genes flows into proteins: DNA → RNA → Protein. It signifies that DNA contains the information necessary to make all of our proteins, and that RNA is a messenger that carries this information to the ribosomes.
Q44. What is an allele?
a) A form of a gene
b) A type of chromosome
c) A cellular protein
d) A DNA mutation
Show Answer
Correct Answer: a) A form of a gene
Explanation: An allele is one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent. Alleles can vary slightly in their sequence of DNA bases, leading to different traits or characteristics in the organism.
Q45. Which process allows for the exchange of genetic material between homologous chromosomes?
a) Mitosis
b) Binary fission
c) Genetic engineering
d) Crossing over
Show Answer
Correct Answer: d) Crossing over
Explanation: Crossing over is a process that allows for the exchange of genetic material between homologous chromosomes. Occurring during meiosis, it contributes to the genetic variation in sexually reproducing organisms by combining the DNA of each parent into unique recombinant chromosomes.
Q46. What genetic principle did Gregor Mendel discover?
a) The structure of DNA
b) The principles of heredity
c) The process of genetic mutation
d) The function of chromosomes
Show Answer
Correct Answer: b) The principles of heredity
Explanation: Gregor Mendel is known for discovering the fundamental principles of heredity through his experiments with pea plants. His work laid the foundation for modern genetics and led to the discovery of genes and the understanding of how they work.
Q47. Which condition is the result of nondisjunction, a failure of chromosome pairs to separate properly?
a) Cystic Fibrosis
b) Down Syndrome
c) Sickle cell anemia
d) Hemophilia
Show Answer
Correct Answer: b) Down Syndrome
Explanation: Down Syndrome is often caused by nondisjunction, which is a failure of chromosome 21 pairs to separate properly during meiosis. This results in the presence of an extra chromosome 21 (trisomy 21), leading to the developmental changes and physical features of Down Syndrome.
Q48. What is the purpose of the Human Genome Project?
a) To create genetically modified organisms
b) To discover new types of chromosomes
c) To map the entire human genome
d) To change human genetic material
Show Answer
Correct Answer: c) To map the entire human genome
Explanation: The purpose of the Human Genome Project was to map the entire human genome, including identifying all the genes in human DNA and determining the sequences of the chemical base pairs that make up human DNA. This project has provided crucial information for understanding human biology, disease, and evolution.