Free Chromosomes MCQs with Answers
633 Chromosomes MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Chromosomes are DNA-protein structures that carry genes and become visible during cell division. Coverage includes chromatin, centromeres, sister chromatids, homologous chromosomes, chromosome number, and the distinction between diploid and haploid cells, with links to DNA replication, mitosis and meiosis.
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633 questions · page 2 of 32
- A. DNA
- B. Histones
- C. Chromocentres
- D. RNA
Explanation: DNA is the hereditary material in chromosomes because its nucleotide sequence stores the instructions transmitted from parents to…
Correct answer: DNA- A. RNA
- B. DNA
- C. Histones
- D. Calcium
Explanation: DNA performs the information-carrying role of chromosomes because its replicated sequences can be passed to daughter cells during cell…
Correct answer: DNA- A. Mendel
- B. Strasburger
- C. Darwin
- D. Levitzky
Explanation: Strasburger was among the early scientists who described chromosomes as thread-like structures in the nucleus during cell division.
Correct answer: Strasburger- A. Salvary glands of Drosophila
- B. Salvary gland of silk moth
- C. Oocytes of frog
- D. Nucleus of man
Explanation: Lampbrush chromosomes occur in the oocytes of frogs and other vertebrates, where their extended loops support intense RNA production…
Correct answer: Oocytes of frog- A. Metacentric
- B. Sub-metacentric
- C. Acrocentric
- D. Telocentric
Explanation: A chromosome with a centromere in the middle has two approximately equal arms and is called metacentric.
Correct answer: Metacentric- A. Johannsen
- B. Mendel
- C. Lemark
- D. Cuvier
Explanation: Wilhelm Johannsen introduced the term gene in 1909 for the hereditary unit responsible for a trait.
Correct answer: Johannsen- A. Kinetochore
- B. Kinochore
- C. Centromere region
- D. all of these
Explanation: The kinetochore is a protein-containing structure assembled at the centromere, and spindle-fibre microtubules attach to it during cell…
Correct answer: Kinetochore- A. Karyokinesis
- B. Cytokinesis
- C. Anaphase
- D. Meiosis
Explanation: Karyokinesis is the division of the nucleus, during which duplicated chromosomes are separated into daughter nuclei.
Correct answer: Karyokinesis- A. Hay fever
- B. Scurvy
- C. Parkinson Disease
- D. Downs syndrome
Explanation: A zygote with three copies of chromosome 21 has trisomy 21, which causes Down syndrome and is associated with characteristic developmental…
Correct answer: Downs syndrome- A. 15 to 19
- B. 20 to 34
- C. 35 to 39
- D. 40 to 45
Explanation: The risk of nondisjunction and therefore trisomy 21 rises markedly with maternal age, with the highest risk among the listed groups at 40…
Correct answer: 40 to 45- A. spores
- B. gametes
- C. both a & b
- D. all the above
Explanation: In animals, meiosis occurs in reproductive organs and produces haploid gametes, such as sperm or ova, from diploid precursor cells.
Correct answer: gametes- A. meiosis
- B. mitosis
- C. both a & b
- D. none of these
Explanation: Mitosis involves one nuclear division and produces two genetically similar daughter cells with the same chromosome number as the parent…
Correct answer: mitosis- A. meiosis
- B. mitosis
- C. cell division
- D. none of these
Explanation: Meiosis has two successive divisions, meiosis I and meiosis II, and therefore produces four haploid daughter cells from one starting cell.
Correct answer: meiosis- A. 48
- B. 44
- C. 46
- D. 26
Explanation: A normal human somatic cell contains 46 chromosomes arranged in 23 pairs, including 22 pairs of autosomes and one pair of sex chromosomes.
Correct answer: 46- A. Muscle cell of worm
- B. Uterine cells of dog
- C. Sperm cells of frog
- D. Guard cells of leaf
Explanation: A sperm cell is haploid, so it contains one chromosome from each homologous pair rather than genes in pairs.
Correct answer: Sperm cells of frog- A. G1 phase
- B. S phase
- C. G2 phase
- D. M phase
Explanation: The G2 phase directly precedes the M phase in the cell cycle and allows the cell to prepare for mitosis after DNA replication has occurred…
Correct answer: G2 phase- A. Klinefelters syndrome
- B. Turners syndrome
- C. Downs syndrome
- D. All of these
Explanation: Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate during meiosis, producing gametes with abnormal…
Correct answer: All of these- A. Diakinesis diplotene pachytene leptotene zygotene
- B. Zygotene leptotene pachytene diplotene diakinesis
- C. Leptotene zygotene pachytene diplotene diakinesis
- D. Pachytene leptotene diplotene zygotene diakinesis
Explanation: The five substages of prophase I occur in the order leptotene, zygotene, pachytene, diplotene and diakinesis.
Correct answer: Leptotene zygotene pachytene diplotene diakinesis- A. 23
- B. 46
- C. 0
- D. 4
Explanation: A tetrad is formed during prophase I of meiosis when homologous chromosomes pair, with each homolog consisting of two chromatids.
Correct answer: 0- A. The centromere
- B. Nuceleosome
- C. Telomere
- D. Histone
Explanation: A nucleosome is the basic structural unit of chromatin, formed when DNA winds around a core of histone proteins, helping package DNA into…
Correct answer: Nuceleosome