Free Chromosomes MCQs with Answers

• A. Hemophilia
• B. Phenylketonuria
• C. Sickle cell anemia
• D. Down's Syndrome

Explanation: Trisomy 21 i.e. the presence of 3 chromosomes at the 21th pair is the characteristic of Down's syndrome.

• A. Genetic drift
• B. Genotype
• C. Gene pool
• D. Gene mutation

Explanation: The total set of gene copies for all genes in a population is referred to as its gene pool.

• A. Down's syndrome
• B. Turner's syndrome
• C. Jacob's syndrome
• D. Klinefelter's syndrome

Explanation: Klinefelter's syndrome is a genetic condition in which a boy is born with an extra X chromosome.

• A. Isoleucine
• B. Tryptophan
• C. Valine
• D. Arginine

Explanation: Tryptophan is unique because it is the only amino acid specified by a single codon.

• A. Ribosomes
• B. Chloroplasts
• C. Deoxyribonucleic acids
• D. None of them

Explanation: Gene mutations can occur in deoxyribonucleic acids (DNA). DNA is the genetic material present in the nucleus of eukaryotic cells and in…

• A. 22 pairs of autosomes and 1 pair of sex chromosomes
• B. 22 pairs of autosomes and XY chromosomes
• C. 22 pairs of autosomes and XX chromosomes
• D. Haploid somatic cells and diploid germinal cells

Explanation: Diploid set of human chromosomes have 22 pairs of autosomes and 1 pair of sex chromosomes. That is why A is correct.

• A. Is completely inert
• B. Carries few genes
• C. Carries many genes
• D. Contains genes for hemophilia and color blindness

Explanation: The (X / Y) chromosome carries the fewest number of genes. The Y chromosome is one-third the size of the X chromosome and contains about…

• A. Both sperm and egg contain yolk
• B. All genetic information comes from sperm
• C. Sperm contains little cytoplasm
• D. Fertilization commonly occurs in the uterus

Explanation: The head of the sperm contains an extremely compact nucleus with very little cytoplasm.

• A. 100 nm
• B. 130 nm
• C. 170 nm
• D. 150 nm

Explanation: Assuming that each nucleotide is 0.34 nm in length, the length of a DNA strand with 500 nucleotides would be approximately: 500…

• A. Purine
• B. Pyrimidine
• C. H3PO4
• D. HNO3

Explanation: DNA and RNA consist of many nucleotides joined together by special ester linkages called phosphodiester bonds.

• A. 4 chromosomes
• B. 8 chromosomes
• C. 8 pair of chromosomes
• D. 3 chromosomes

Explanation: A sperm cell from the fruit fly Drosophila contains four chromosomes.

• A. 3.4 nm
• B. 0.3 nm
• C. 2 nm
• D. 0.2 nm

Explanation: The diameter of the DNA helix is 2 nm and the vertical rise per base pair is 0.34 nm.

• A. 430
• B. 142
• C. 426
• D. 460

Explanation: Each amino acid is coded by 3 nucleotides, hence to form a protein molecule of 142 amino acids, 142 multiplied by 3 nucleotides would be…

• A. 1
• B. 5
• C. 10
• D. 15

Explanation: The distance between two corresponding base pairs is 0.34 nm and a complete helix measures 3.4 nm in length.

• A. DNA and proteins
• B. Only DNA
• C. Only proteins
• D. RNA

Explanation: Evolutionary relationships among species are reflected in their DNA and proteins, in their genes and gene products.

• A. One
• B. Two
• C. Three
• D. Half

Explanation: Even when a chromosome is replicated, it has two sister chromatids. Each sister chromatid has one DNA molecule.

• A. Nucleosome
• B. Gene pool
• C. Karyotype
• D. Centromere

Explanation: Karyotyping is the process of pairing and ordering all the chromosomes of an organism, thus providing a genome-wide snapshot of an…

• A. Ligase
• B. Invertase
• C. Helicase
• D. Topoisomerase

Explanation: DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule

• A. Conservative
• B. Semi - conservative
• C. Dispersive
• D. New synthesis

Explanation: Each strand of original DNA serves as a template to form a new strand with one original and one replicated strand

• A. Two
• B. Three
• C. Four
• D. Five

Explanation: All eukaryotes have three different RNA polymerases (RNAPs) which transcribe different types of genes