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 biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

Select the correct option:

Synthesis of histone proteins occurs in 

  1. $G _1$ phase

  2. Interphase

  3. Anaphase
  4. $G _0$ phase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The cell cycle is a sequence of event which occurs during cell growth and cell division. It has two phases; interphase and the M phase. Interphase is the period between the end of 1 division and the beginning of next cell division. It is also known as resting phase or the non-dividing stage.

It has three phases G₁ phase which is the post-mitotic phase, the synthetic phase which is the S phase and the G₂ phase. During the S phase, DNA replication takes place and the amount becomes double. Here the synthesis of histone protein and non-histone chromosomal proteins also takes place.
So, the correct option is 'Interphase'

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health
Human cells in culture show a cell cycle to be completed in approximately 

  1. 42 hours

  2. 24 hours

  3. 24 minutes

  4. 24 seconds
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cell division is the process by which a cell divides to form to nearly equal daughter cell which resembles the parent. The cell cycle is the sequence of events which occur during the cell growth and cell division. It is completed into two steps interphase and M-phase.

In the cell cycle interphase is the period between the end of one division to the beginning of next cell division. It is known as the resting phase. In the case of human beings it is around 24 hours then the M phase takes place.

So, the correct option is '24 hours'

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health
________ is characterised by all the chromosomes coming to lie at the equator, with one chromatid connected by its kinetochore to spindle fibres from one pole and its sister chromatid connected by its kinetochore to spindle fibres from the opposite pole.

  1. Prophase

  2. Metaphase

  3. Anaphase

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

During the cellular division phase, metaphase is a stage where all the chromosome arranges themselves on the metaphase plate.

On this equatorial plate, these are aligned and appear as two threaded chromosomes. These are attached to the pole by spindle fibre.
So, the correct option is 'Metaphase'

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

Select the correct option:

Read the following statements about cell division and select the correct ones.
(i) M phase represents the phase when actual cell division occurs and I phase represents the phase between two successive M phases.
(ii) In the 24 hours average duration of cell cycle of a human cell, cell division proper lasts for only about an hour.
(iii) M phase constitutes more than 95% of the duration of cell cycle.

  1. (i) and (ii)

  2. (ii) and (iii)

  3. (i) and (iii)

  4. (i), (ii) and (iii)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cell cycle consists of two basic phases, long nondividing I phase and a short dividing M phase . In the average duration of 24 hours in the cell cycle of dividing human cell , M phase lasts for one hour (less than $5\%$ of total) while I phase or interphase occupies $75-95\%$ of total generation time.

So, the correct answer is '(i) and (ii)'.

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health
Before cell division, copying of DNA is not essential.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • DNA replication must occur before cell division. So, that all newly produced cells have all the DNA of the original cell (except gametes of course). If DNA did not replicate (make exact copies), then new cells would not receive all the chromosomes and genes necessary for life processes.
  •  Each new cell would only have half the needed chromosome. If it could survive each successive generation of cells would have fewer chromosomes and of course after a few divisions cells would receive none at all.
Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

Which of the following is the most direct cuse of polyteny in somatic cells of certain organisms?

  1. RNA transcription

  2. supercoiling of chromatin

  3. chromosome replication without cell division

  4. chromosome recombination

  5. amphification of sex chromosomes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The most direct cause of polyteny in somatic cells of certain organisms is chromosomes replication without cell division
In polyteny homologns chromosomes perform somatic pairing and product remain attached to another ,they produce  several copies of same chromosomes

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

Which one of the following events is incorrect for cell cycle?

  1. All events are under genetic control

  2. Maximum cell growth occurs in M-phase

  3. DNA synthesis occurs only during one specific

  4. Centriole duplication occurs in S-phase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All the different cells of our body usually live, grow and divide in harmony. Our body has many different signals that control how much, and how often our cells divide. If any of these signals are faulty or missing, the result can be cancer, where too many cells are produced.

So, the correct option is 'All events are under genetic control'.

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

The most dramatic period of the cell cycle is?

  1. Metaphase
  2. $G _1$ phase

  3. S phase

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

The major events that take place in mitosis are the alignment of chromosomes at the center of the cell and the subsequent separation of sister chromatids to opposite mitotic spindle poles. Those occur in metaphase and anaphase respectively.

So, the correct option is 'Metaphase'.

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

Intermitosis is

  1. Stage between meiosis I and meiosis II

  2. Stage between two mitotic divisions

  3. Interphase

  4. Both B and C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Interkinesis (often misspelled as intermitosis) is the short resting phase between meiosis I and meiosis II. It is distinct from the interphase that occurs before the start of meiosis I.

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

How many chromosomes will the cell have at GI, after S and after M-phase respectively if it has 14 chromosomes at interphase

  1. 7, 14, 14

  2. 14, 14, 14

  3. 14, 14, 7

  4. 7, 7, 7
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At G1 phase, there will be 14 chromosomes as no DNA replication has taken place. After S Phase, the DNA content doubles but chromosome number still remains same here 14. After completion of M phase, the number of chromosomes will be 28 with each daughter cell having same number of chromosomes as that of parent i.e 14

Therefore B is the correct option. 

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

Match the lists and choose the correct option:

a. $G _1$ phase i. Replication of DNA
b. S-phase ii. Quiescent stage
c. $G _2$-phase iii. Condensation chromatin
d. $G _0$-phase iv. Protein synthesis
v. Interval between mitosis and initiate of DNA replication

  1. a-iii, b-ii, c-i, d-ii

  2. a-v, b-iv, c-i, d-iii

  3. a - v, b -i, c - iv, d-ii

  4. a v, b -ii, c-iii, d - iv
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Interphase generally lasts at least 12 to 24 hours in mammalian tissue. During this period, the cell is constantly synthesizing RNA, producing protein and growing in size. Interphase can be divided into 4 steps: Gap 0 (G0), Gap 1 (G1), S (synthesis) phase, Gap 2 (G2).
Gap 0 (G0): There are times when a cell will leave the cycle and quit dividing
Gap 1 (G1): Cells increase in size in Gap 1, produce RNA and synthesize protein.
S Phase: To produce two similar daughter cells, DNA replication occurs during this S (synthesis) phase.
Gap 2 (G2): During the gap between DNA synthesis and mitosis, the cell will continue to grow and produce new proteins.
Hence answer is 'a - v, b -i, c - iv, d-ii'
Multiple choice biology cell division cell division in embryo development division for growth and reproduction structure of chromosome, cell cycle and cell division mitosis

Which stage of cell cycle occurs immediately prior to mitosis 

  1. $M$
  2. $G _1$
  3. $S$
  4. $G _2$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$G _2$ phase is the phase of cell cycle occurs immediately prior to mitosis.
sequence of cell cycle is -- $G _1$ to $S$ to $G _2$ to $M$ to cytokinesis.

So, the correct answer is '$G _2$

Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

Total number of meiotic division required for forming $100$ zygotes/ $100$ grains of wheat is?

  1. $100$
  2. $75$
  3. $125$
  4. $50$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In angiosperms, one meiotic division produces 4 microspores, but only one functional megaspore is formed from one megaspore mother cell. For 100 grains, 100 meiotic divisions are needed for the male side (pollen) and 100 for the female side (ovule), totaling 200. However, if the question implies the standard formula (n + n/4), it is 125.

Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

.......... is responsible for hybridization.

  1. Haploidy

  2. Polyploidy

  3. Seggregation

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

Presence of three or more sets of chromosomes in an organism is called polyploidy. It is often seen in plants and very rare in animals. It is caused due to the non disjunction of the sister chromatids during the recombination (at meiosis). It can be induced in plants and cell cultures with the help of some chemicals like colchicine. Polyploidy causes variation, as it adds new genomes into a species. It has been widely used in producing hybrids of wheat. Ploidy level also effects some characteristics of plants. For example, higher ploidy leads to the larger cell size. So, the correct answer is B.