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

Multiple choice

An unfertilised egg has __________________.

  1. Y chromosome

  2. X chromosome

  3. a pair of X and Y chromosomes

  4. no chromosomes

  5. a pair of X and X chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An unfertilised egg always has an X chromosome.

Multiple choice

What are the structural abnormalities of chromosomes associated with Patau and Down syndrome?

  1. Deletions

  2. Duplications

  3. Robertsonian translocation

  4. Isochromosome

  5. Inversions
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A Robertsonian translocation in balanced form results in no excess or deficit of genetic material and causes no health difficulties. In unbalanced forms, Robertsonian translocations cause chromosomal deletions or addition and result in syndromes of multiple malformations, including trisomy 13 (Patau syndrome) and trisomy 21 (Down syndrome).

Multiple choice

Polysomy of sex chromosomes in an individual is induced by successive nondisjunctions in meiosis I and II. The squamous cell carcinoma is associated with _____________________.

  1. Trisomy 21

  2. Chromosome 7

  3. Tetrasomy 9p

  4. Tetrasomy 18p

  5. Chromosome 17
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In squamous cell carcinoma, a protein from the epidermal growth factor receptor (EGFR) gene is often overexpressed in conjunction with polysomy of chromosome 7, so chromosome 7 can be used to predict the presence of EGFR in squamous cell carcinoma.

Multiple choice

The absence of an entire sex chromosome is observed in _______________________.

  1. 47, XXY

  2. 47, XYY

  3. XX male syndrome

  4. mixed gonadal dysgenesis

  5. 45, X Turner syndrome
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Turner syndrome 45, X encompasses several conditions in human females, of which monosomy X (absence of an entire sex chromosome, the Barr body) is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent or has other abnormalities.

Multiple choice

__________ of the sex chromosomes leads to the Turner syndrome.

  1. Monosomy

  2. Disomy

  3. Trisomy

  4. Tetrasomy
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Monosomy refers to lack of one chromosome of the normal complement. Partial monosomy can occur in unbalanced translocations or deletions, in which only a portion of the chromosome is present in a single copy. Monosomy of the sex chromosomes (45X) causes Turner syndrome.

Multiple choice

Which of the following processes is common in cancer?

  1. Loss of heterozygosity

  2. Inversion

  3. Interstitial deletions

  4. Chromosome translocation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In genetics, a chromosome translocation is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. A gene fusion may be created when the translocation joins two otherwise separated genes, the occurrence of which is common in cancer.

Multiple choice

The unit of heredity is

  1. locus

  2. chromosome

  3. allele

  4. gene
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A gene is a unit of heredity in a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living things depend on genes, as they specify all proteins and functional RNA chains.

Multiple choice

_____ chromosome decides the sex of the person.

  1. A

  2. B

  3. Y

  4. Z
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Y chromosome is the sex-determining chromosome in humans. Females have XX chromosomes while males have XY chromosomes. Presence of the Y chromosome determines male sexual characteristics during development.

Multiple choice

In human (male) there is/are ______ X chromosome(s).

  1. only one

  2. two

  3. three

  4. many
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Males have one X chromosome and one Y chromosome (XY sex determination). The X chromosome comes from the mother and the Y chromosome from the father. Females have two X chromosomes (XX).