Biology
Cell Cycle and Chromosomes
1,348 Questions
Explore a curated list of questions covering the cell cycle, mitosis, and meiosis. Topics include DNA replication, chromosomal structures, and genetic disorders. This material is essential for students preparing for biology and general science competitive exams.
Cell cycle eventsDNA replicationMeiosis processChromosomal structuresGenetic disorders
Cell Cycle and Chromosomes Questions
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Edwards Syndrome
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Trisomy
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Patau Syndrome
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Down’s Syndrome
D
Correct answer
Explanation
Down Syndrome is caused by trisomy 21 - having three copies of chromosome 21 instead of the usual two. Edwards Syndrome is trisomy 18, Patau Syndrome is trisomy 13, and 'Trisomy' alone is too general to be the specific answer.
A,B
Correct answer
Explanation
Human somatic (body) cells contain 46 chromosomes total, organized as 23 pairs - one set inherited from each parent. Both '23 pairs' and '46' correctly describe the same fact.
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44 chromosomes
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48 chromosomes
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46 chromosomes
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23 chromosomes
C
Correct answer
Explanation
Humans have 46 chromosomes (23 pairs) in each somatic cell. Option D (23) refers to the number of chromosome pairs, not total chromosomes.
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Cloning
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Reproduction
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Infinity
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Mitosis
D
Correct answer
Explanation
Mitosis is the process of nuclear division in which a cell's nucleus replicates its DNA and divides into two genetically identical daughter nuclei. This occurs before the actual cell division (cytokinesis). Mitosis ensures that each daughter cell receives an exact copy of the parent cell's genetic material, which is essential for growth, repair, and asexual reproduction.
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24 chromosomes
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48 chromosomes
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46 chromosomes
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23 chromosomes
C
Correct answer
Explanation
Normal human somatic cells contain 46 chromosomes arranged in 23 homologous pairs - one set from each parent. Gametes have 23 chromosomes. Chromosome numbers like 24 or 48 would indicate abnormalities or occur in other species.
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Centrioles
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Chloroplast
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Cytoplasm
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Nucleus
C
Correct answer
Explanation
Cytokinesis is the division of the cytoplasm during cell division, resulting in two daughter cells. Centrioles help organize chromosome movement, chloroplasts are involved in photosynthesis in plant cells, and nucleus division is called karyokinesis (not cytokinesis).
C
Correct answer
Explanation
Human somatic cells contain 46 chromosomes arranged in 23 pairs - one set inherited from each parent. The numbers 44 and 43 are not correct counts for normal human cells, while 48 would indicate a chromosomal abnormality.
C
Correct answer
Explanation
Humans have 23 pairs of chromosomes, for a total of 46 chromosomes. This includes 22 pairs of autosomes and 1 pair of sex chromosomes (XX in females, XY in males). Each pair contains one chromosome from each parent.
B
Correct answer
Explanation
Humans typically have 23 pairs of chromosomes, totaling 46 chromosomes per cell. These pairs include 22 pairs of autosomes and one pair of sex chromosomes (XX or XY). The question specifically asks for pairs, not total chromosomes. 18 and 36 are not standard human chromosome numbers. 46 is the total count, not the number of pairs.
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44 chromosomes
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48 chromosomes
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46 chromosomes
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23 chromosomes
C
Correct answer
Explanation
Human somatic cells contain 46 chromosomes, organized as 23 pairs - one set from each parent. This includes 44 autosomes and 2 sex chromosomes (XX or XY). The 23 chromosome count refers only to the chromosome types in a haploid set (gametes), not the total in body cells.
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300 to 400
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100 to 2000
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3000 to 5000
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30000 to 40000
C
Correct answer
Explanation
Humans have 23 pairs of chromosomes (46 total). 22 pairs are autosomes and 1 pair is sex chromosomes (XX in females, XY in males). Each pair contains one chromosome from each parent. Options 21, 22, and 24 are incorrect.
C
Correct answer
Explanation
Normal human beings possess 23 pairs of chromosomes (46 total chromosomes), comprising 22 pairs of autosomes and one pair of sex chromosomes (XX in females, XY in males). This chromosomal complement is fundamental to human biology and genetics.
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Turner’s syndrome
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Down syndrome
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Klinefelteis syndrome
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Edwards’ syndrome
A
Correct answer
Explanation
Turner syndrome is characterized by 45 chromosomes with a karyotype of 45,X (22 pairs of autosomes + one X chromosome). The notation XO indicates only one sex chromosome (X) is present instead of the usual two (XX or XY). This occurs due to nondisjunction during gamete formation.