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 expression of gene inherited changes biology

Telomere of eucaryotic chromosome possesses short segments of

  1. Guanine rich repeats

  2. Thymine rich repeats

  3. Cytosine rich repeats

  4. Adenine rich repeats
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Telomeres, the ends of eukaryotic chromosomes, consist of repetitive DNA sequences that are typically rich in guanine.

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

MHC genes in humans are located on 

  1. Chromosome 1.

  2. Chromosome 2.

  3. Chromosome 4.

  4. Chromosome 6.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Major histocompatibility complex (MHC) are the proteins on the surface of cell membrane. These proteins play an important role in the recognition of the foreign antigens. There are two MHC complexes called as MHC-I and MHC-II complex. These complexes play a different role in different processes. The genes for MHC complex are located on the chromosome 6 in the case of humans. In the case of mice, these genes are on chromosome 17. 

Thus, the correct answer is option D. 

Multiple choice botany asexual and sexual reproduction in plants introduction to flower pre fertilization - plants modes of reproduction

Meiotic division occurring just at the time of gametogenesis is 

  1. Sporic

  2. Initial

  3. Intermediate

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

  • In plants, meiosis is occurring as in diploid sporophyte to produce haploid spores. 
  • The haploid spores are germinating to produce structures called gametophytes. The gametophytes then produce gametes. 
  • Gametic or the terminal meiosis occurs in all multicellular animals. It takes place in the gonads and hence as results in the formation of gametes. 
  • It is responsible for gametogenesis and does not give rise to gametophytes.
  • The correct option is D.

Multiple choice botany asexual and sexual reproduction in plants introduction to flower pre fertilization - plants modes of reproduction

$32$ chromosomes are present in the green leaf of Onion. When meiosis takes place to produce gametes after fertilization how many chromosomes will be there in triploid nucleus.

  1. $32$
  2. $16$
  3. $48$
  4. $9$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If the leaf (diploid) has 32 chromosomes, the gametes (haploid) have 16. Fertilization of an egg (16) by a sperm (16) produces a zygote (32). The triploid nucleus (endosperm) is formed by the fusion of two polar nuclei (16+16) and one male gamete (16), resulting in 48 chromosomes.

Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

The eukaryotic chromosome contains nucleosome spools.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A nucleosome is a basic unit of DNA packaging in eukaryotes, consisting of a segment of a DNA wound in sequence around eight histone protein octamer cores. This structure is often compared to thread wrapped around a spool. Nucleosome constitutes the repeating unit of a structure in nucleus called chromatin, thread-like stained (colored) seen in the nucleus. The negatively charged DNA is wrapped around the positively charged histone octamer to form a structure called DNA helix.
So, the statement is 'True'.
Multiple choice biology reproduction in animals fertilization in human being fertilization in humans human fertilization

If an organism is a diploid (or 2n) with 16 chromosomes, then how many chromosomes its sperm cells or egg cells will contain?

  1. 8

  2. 16

  3. 32

  4. 64
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An organism consists of two types of cells in their body, somatic cells and germs cells/ gametes. During the process of meiosis, a diploid number of chromosome is cut down to haploid. This division is an important event since after fertilisation haploid chromosomes from each gamete (male and female) fuse to retain the diploid state in the zygote. Diploid means two sets of chromosome and haploid is one set. Since here the diploid set is 16 thus one set will be half it, i.e, 8. Thus the answer A is correct.

Multiple choice biology the reproductive system menstruation male reproductive system in humans male reproductive system reproduction in plants and animals

The immature male germ cell undergo division to produce sperms by the process of spermatogenesis. Choose the correct one with reference to above.

  1. Spermatogonia have 46 chromosomes and always undergo meiotic cell division.

  2. Primary spermatocytes divide by mitotic cell division.

  3. Secondary spermatocytes have 23 chromosomes and undergo second meiotic division.

  4. Spermatozoa are transformed into spermatids.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Spermatogonia are diploid cells on the inside wall of seminiferous tubules that multiply by mitotic divisions. Some of the spermatogonia called primary spermatocyte undergo meiosis-I to give rise to secondary spermatocytes (haploid). Each secondary spermatocyte undergoes melosis-II to give rise to two haploid spermatids which are transferred to spermatozoa by spermiogenesis.

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Which of the following microtubule arrangement is absent in the kinetosome of eukaryotic flagella?

  1. 9+0

  2. 9+2

  3. Both of the above

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Eukaryotic cilia and flagella have similar organization-
  • They possess a central bundle of microtubules called the axoneme which contain nine outer doublet microtubules surrounded by a central pair of singlet microtubules.
  • This characteristic 9 + 2 arrangement of microtubules is seen when the axoneme of eukaryotic flagella.
  • The correct answer is OPTION B.
Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

In Amoeba, the cell division takes place ____

  1. Involving changes in the chromatin reticulum

  2. Without involving changes in the chromatin reticulum

  3. Leading to reduction in the number of chromosomes

  4. Without dividing the nucleus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Through the cell division process one cell splits into two identical cells. There can be two kind of cell divisions- Mitosis and Meiosis. Cell division mitosis takes place in Amoeba for replicating genetic material (chromatin network) into the daughter cells. It is a form of asexual reproduction in unicellular organisms like Amoeba. The process is known as binary fission.
So, the correct answer is 'Involving changes in the chromatin reticulum'
Multiple choice zoology animal diversity - ii (phylum: chordata) aves and mammalia classifications of chordata aves

If the number of chromosomes in most body cells of a marnmal is 40, the cells in the seminiferous tubule will have

  1. 40 chromosomes

  2. 20 chromosomes

  3. 10 chromosomes

  4. While some other will have 20
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reduction division takes place during spermatogenesis. Spermatids and sperms will have haploid number of chromosomes.