Q1. Which molecule is the primary carrier of genetic information in humans?
a) RNA
b) DNA
c) Protein
d) Lipids
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Correct Answer: b) DNA
Explanation: DNA (Deoxyribonucleic Acid) is the primary carrier of genetic information in humans. It is composed of two strands that coil around each other to form a double helix, carrying the genetic instructions used in growth, development, functioning, and reproduction of all known living organisms and many viruses.
Q2. What is a gene?
a) A segment of DNA that encodes a protein
b) A type of chromosome
c) A cell organelle
d) A type of virus
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Correct Answer: a) A segment of DNA that encodes a protein
Explanation: A gene is a segment of DNA that is responsible for the physical and inheritable characteristics or phenotype of an organism. It functions in the encoding of proteins or RNA molecules that have various roles in the body.
Q3. How many chromosomes are found in a normal human cell?
a) 23
b) 46
c) 92
d) 44
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Correct Answer: b) 46
Explanation: A normal human cell contains 46 chromosomes, arranged in 23 pairs, with one set of 23 chromosomes inherited from each parent. This includes 22 pairs of autosomes and one pair of sex chromosomes (XX in females and XY in males).
Q4. What is the term for a change in the DNA sequence?
a) Mutation
b) Replication
c) Translation
d) Transcription
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Correct Answer: a) Mutation
Explanation: A mutation is a change in the DNA sequence. Mutations can be caused by various factors including environmental insults and errors in DNA replication. They can lead to changes in the protein sequence, potentially causing phenotypic changes.
Q5. Which type of genetic inheritance requires two copies of a mutated gene for the disease to develop?
a) Autosomal Dominant
b) Autosomal Recessive
c) X-linked Dominant
d) X-linked Recessive
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Correct Answer: b) Autosomal Recessive
Explanation: In autosomal recessive inheritance, an individual must inherit two copies of the mutated gene, one from each parent, for the disease or trait to develop. If only one mutated copy of the gene is inherited, the individual is typically a carrier without the symptoms of the disease.
Q6. What is a genome?
a) A single gene
b) The complete set of genes or genetic material present in a cell or organism
c) A type of chromosome abnormality
d) The study of genes and inheritance
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Correct Answer: b) The complete set of genes or genetic material present in a cell or organism
Explanation: The genome is the complete set of genes or genetic material present in a cell or organism. It includes both the genes and the non-coding sequences of the DNA/RNA.
Q7. Which genetic disorder is caused by the presence of an extra chromosome 21?
a) Turner Syndrome
b) Klinefelter Syndrome
c) Down Syndrome
d) Cystic Fibrosis
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Correct Answer: c) Down Syndrome
Explanation: Down Syndrome is caused by the presence of an extra chromosome 21. This genetic disorder is characterized by a combination of major and minor anomalies, intellectual disability, and developmental delays.
Q8. In humans, which chromosome determines the sex of the child?
a) Chromosome 1
b) Chromosome 21
c) The X chromosome
d) The Y chromosome
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Correct Answer: d) The Y chromosome
Explanation: The sex of a child is determined by the Y chromosome. The presence of a Y chromosome leads to male development, while its absence (XX chromosomes) results in female development.
Q9. What is a karyotype?
a) A type of gene therapy
b) A genetic mutation
c) The full chromosomal complement of an organism as seen under a microscope
d) A model of a DNA molecule
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Correct Answer: c) The full chromosomal complement of an organism as seen under a microscope
Explanation: A karyotype is the full chromosomal complement of an organism, visible under a microscope. It involves the number, size, and shape of chromosomes in an individual’s cells, and is used in genetic diagnosis and research.
Q10. Which genetic disorder is characterized by the body’s inability to process phenylalanine?
a) Tay-Sachs disease
b) Phenylketonuria (PKU)
c) Sickle cell anemia
d) Huntington’s disease
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Correct Answer: b) Phenylketonuria (PKU)
Explanation: Phenylketonuria (PKU) is a genetic disorder in which the body cannot process the amino acid phenylalanine due to a lack of or deficiency in the enzyme phenylalanine hydroxylase. Accumulation of phenylalanine can lead to intellectual disabilities and other serious health problems.