Q11. What does ‘homozygous’ mean in genetics?
a) Having two different alleles at a gene locus
b) Having two identical alleles at a gene locus
c) The presence of only one chromosome in a pair
d) A mutation that affects a gene
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Correct Answer: b) Having two identical alleles at a gene locus
Explanation: In genetics, ‘homozygous’ refers to having two identical alleles for a single trait. Alleles are different forms of a gene, and when an organism has two identical alleles, it is considered homozygous for that particular gene or trait.
Q12. Which condition is an example of a chromosomal disorder?
a) Hemophilia
b) Alzheimer’s disease
c) Cystic Fibrosis
d) Turner Syndrome
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Correct Answer: d) Turner Syndrome
Explanation: Turner Syndrome is a chromosomal disorder that affects females, typically characterized by the partial or complete absence of one of the two X chromosomes. This leads to various developmental and physical issues, such as short stature and infertility.
Q13. Which term describes the physical expression of a gene?
a) Genotype
b) Phenotype
c) Karyotype
d) Allele
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Correct Answer: b) Phenotype
Explanation: The phenotype of an organism refers to the physical expression of its genes, including traits like eye color, height, and other characteristics. It results from the interaction of the genotype (the organism’s genetic makeup) with the environment.
Q14. What is genetic engineering?
a) Studying genes under a microscope
b) Modifying the genetic material of an organism
c) The natural process of mutation
d) Creating new genes in a laboratory
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Correct Answer: b) Modifying the genetic material of an organism
Explanation: Genetic engineering involves the deliberate modification of the genetic material of an organism. It often involves the manipulation of genes to achieve desired traits or the addition of foreign genes to enhance certain characteristics or produce new ones.
Q15. Which process involves the copying of DNA?
a) Translation
b) Replication
c) Transcription
d) Mutation
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Correct Answer: b) Replication
Explanation: DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. Replication is an essential process because it ensures that each cell has a complete set of identical genetic information.
Q16. In genetics, what does ‘dominant’ mean?
a) An allele that is always expressed, even if only one copy is present
b) An allele that is only expressed if two copies are present
c) The allele that is not expressed in the phenotype
d) A trait that is superior to others
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Correct Answer: a) An allele that is always expressed, even if only one copy is present
Explanation: In genetics, a dominant allele is one that is expressed in the phenotype, even if only one copy is present. This means that if an individual has one dominant and one recessive allele for a trait, the dominant allele will determine the phenotype.
Q17. What is the function of ribosomes in the cell?
a) DNA replication
b) Protein synthesis
c) Lipid metabolism
d) Storing genetic information
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Correct Answer: b) Protein synthesis
Explanation: Ribosomes are cellular structures responsible for protein synthesis. They read the RNA produced by transcription and assemble the amino acids into a polypeptide chain, forming proteins based on the genetic information conveyed by the RNA.
Q18. What is a pedigree chart used for in genetics?
a) Mapping gene locations on chromosomes
b) Tracking the inheritance of traits through generations
c) Predicting the outcomes of genetic crosses
d) Analyzing the structure of DNA
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Correct Answer: b) Tracking the inheritance of traits through generations
Explanation: A pedigree chart is a diagram that shows the occurrence and appearance or phenotypes of a particular gene or organism and its ancestors from one generation to the next, most commonly for tracking the inheritance of a specific trait.
Q19. Which of the following is not a component of a DNA nucleotide?
a) Phosphate group
b) Ribose sugar
c) Nitrogenous base
d) Deoxyribose sugar
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Correct Answer: b) Ribose sugar
Explanation: A DNA nucleotide is composed of three components: a phosphate group, a deoxyribose sugar, and a nitrogenous base. Ribose sugar, instead, is a component of RNA nucleotides, not DNA.
Q20. What is a mutation that involves the addition or deletion of a single base pair in DNA?
a) Point mutation
b) Frameshift mutation
c) Missense mutation
d) Nonsense mutation
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Correct Answer: b) Frameshift mutation
Explanation: A frameshift mutation involves the insertion or deletion of a nucleotide in the DNA sequence that is not in multiples of three. This alters the frame in which the sequence is read, leading to significant changes in the amino acid sequence from the mutation point forward, potentially disrupting the entire structure and function of the resulting protein.