Biology

Cell Cycle and Chromosomes

1,219 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 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 bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Lifecycle of Saccharomyces cerevisiae is 

  1. haplontic type

  2. diplontic type

  3. haplo diplobiontic type

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
This type of life cycle is represented by haploid and diploid phases, of more or less equal duration, found in Saccharomyces cerevisiae. The haploid cells of opposite mating type normally multiply by budding. Two such cells of opposite mating behave as gametangia and undergo fusion initially only plasmogamy takes place, wherein the nuclei exist separately also called the dikaryotic phase. Later on the nuclei undergo fusion in specialized sac like structures called the ascus to form a diploid zygote, which undergoes meiosis to release the haploid ascospores.
So, the correct answer is 'haplodiplobiontic type'
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.

Multiple choice biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

Centrosome includes a pair of centrioles that help in cell division by spindle formation. The non-dividing cells in human are

  1. Chondrocytes

  2. Epithelial cells

  3. Neurons

  4. Neuroglial cells
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
A. Chondrocytes are the cells that are found in cartilage. These cells can divide forming a nest of 2-4 cells.
B. Epithelial cells are the cells lining the surfaces of the body. These cells can also divide by mitosis.
C. Neurons or the nerve cells are the largest cells in the body and found in the nervous system. These cells do not have centrioles and hence, do not undergo cell division.
D. Neuroglial cells are the cells in the central nervous system, other than neurons. These cells are meant for the protection of neurons and can divide by mitosis.
Hence, non-dividing cells in humans are neurons.

So, the correct answer is 'Neurons'.
Multiple choice zoology inherited changes compatibility of blood groups blood group blood groups and compatibility advance

Multiple alleles are situated at 

  1. Homologous chromosme at same locus

  2. Homologous chromosome at different locus

  3. Non-homologous chromosome at different locus

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alleles are alternative forms of a gene. They are responsible for differences in phenotypic expression of a given trait. When a gene exists in three or more allelic forms it is called multiple allele. Homologous chromosomes are chromosome pairs, one from each parent. They are similar in length, gene position and centromere location. Multiple alleles are situated in homologous chromosome at the same locus. Thus the correct answer is option A.

Multiple choice botany kingdom plantae uses of bryophytes introduction to bryophytes cryptogams

If the leaf of Funaria has 5 chromosomes, the primary protonema will have ____________.

  1. 10 chromosomes

  2. 5 chromosomes

  3. 15 chromosomes

  4. 20 chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The leaf of Funaria belongs to the haploid gametophytic generation, meaning the leaf cells are haploid (n = 5). The primary protonema develops directly from the germination of a haploid spore, so its cells are also haploid and will contain the same number of chromosomes, which is 5.