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 bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

Which characteristics are shared by chromosomes and ribosomes of eukaryotic cell?

  1. <p>They consist of nucleic acid.</p>

  2. <p>They consist of protein.</p>

  3. <p>They are in the nucleus.</p>

  4. A and B

  5. A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The chromosomes are composed of DNA and histone proteins. The ribosomes are composed of RNA and proteins. Both the structures contain the nucleic acid as well as proteins in them. The chromosomes are found in the nucleus but the ribosomes are present in the cytoplasm and on the surface of RER. 

Thus, the correct answer is option 'A and B'.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

Which of the following represents the correct sequence of relative sizes in descending order?

  1. Cell, nucleus, chromosome, water molecule, oxygen atom

  2. Cell, nucleus, water molecule, oxygen atom, chromosome

  3. Chromosome, cell, nucleus, water molecule, oxygen atom

  4. Cell, nucleus, water molecule, chromosome, oxygen atom
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cells are the largest units listed, followed by the nucleus within the cell, then chromosomes within the nucleus, followed by molecules, and finally atoms.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

The structure of the nuclear membrane facilitates

  1. Organization of spindle

  2. Nucleo-cytoplasmic exchange of materials

  3. Anaphasic separation of daughter chromosomes

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

In eukaryotic cells, the nucleus is bound by a double membrane or nuclear envelope. It possesses openings at certain intervals called as 'nuclear pore'. Nuclear pores are large protein complexes regulates the exchange of material between nucleus and cytoplasm, i.e., nucleo-cytoplasmic exchange of materials. 

Multiple choice biology life processes in living organism movements in plants coordination in plants tropic and nastic movements in plants

Centromere is a part of chromosome which helps in the 

  1. Division of centrosomes

  2. Formation of spindle fibres

  3. Movement of chromosomes

  4. Formation of nuclear spindle
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Centromere joins the microtubules of 'Chromosomal spindle fibres and helps in the movement of chromosome during cell division. Centromere also plays an important role in the polymerization of tubulin protein used in the formation of microtubules. Hence it is helpful in attaching the chromosome with spindle fibres.

Multiple choice biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

Cytokinesis refers to ................

  1. Division of chromosomes

  2. Division of cytoplasm

  3. Division of nucleus

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

Cytokinin is a plant hormone which is vital for the mitotic divisions taking place in plants. It thus enables cytokinesis and karyokinesis in the cells. This makes cytokinin an important constituent in callus culture.

Multiple choice classification of pteridophytes kingdom plantae plant kingdom biology

The cell of Dryopteris, prothallus contain nucleus with

  1. 4 n chromosomes

  2. 3 n chromosomes

  3. 2 n chromosomes

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

Prothallus is the self supporting haploid plant of the gametophytic generation and is concerned with sexual reproduction. Prothallus is generally monoecious and bears sex organs on the ventral side.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Cause of chromosome laggards in meiosis is?

  1. Inversion

  2. Dicentric chromosome

  3. Acentric chromosome

  4. Duplication of a gene
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A laggard is defined as a chromosome that does not overlap along the long axis of the spindle with any of the properly segregating chromosomes. A dicentric chromosome is an abnormal chromosome with two centromeres. It is formed through the fusion of two chromosome segments, each with a centromere, resulting in the loss of acentric fragments (lacking a centromere) and the formation of dicentric fragments.

So, the correct answer is 'Dicentric chromosome'.
Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

What are the spindle fibres that connect the centromere of chromosome to the respective poles called?

  1. Astral rays

  2. Interpolar fibres

  3. Chromosomal fibres

  4. Inter chromosomal fibres
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The central region of the chromosome where the two arms of chromatid are attached is called as the centromere. It is the region where the spindle fibers attach at the time of the cell division and are called as chromosomal fibers. 
Thus the correct answer is option C. 
Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Spindle chromosomes have

  1. Centriole

  2. Kinetochore

  3. Chromocentre

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

Chromosomes when attached to spindle fibres are called as spindle chromosomes. These Chromosomes have narrow very lightly coloured centromere or primary constriction. The centromere has a proteinaceous covering called as kinetochore on the two free surface of the centromere complex. The kinetochore has centromere binding proteins.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Centromere is required for -

  1. Movement of chromosomes towards poles

  2. Cytoplasmic cleavage

  3. Crossing over

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

Centromere is present in every cell. It is a specific DNA sequence in a chromosome. It is specifically useful in the process of cell division. During mitosis, the spindle fibres attach to the centromeres via kinetochore and all the chromosomes are arranged in an equatoral plane. After this, the chromosomes move towards their respective poles and cell division takes place.

So, option A is the correct answer.

Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Which chromosome does not provide attachment site for spindle fibers?

  1. Acrocentric

  2. Metacentric

  3. Submeta centric

  4. Acentric
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A chromosome in which the centromere is located quite near one end of the chromosome is called the acrocentric chromosome. Humans normally have five pairs of acrocentric chromosomes. Down syndrome is caused by an extra acrocentric chromosome (chromosome21). The acrocentric chromosome does not provide the attachment site for spindle fibers because centromere is located quite near one end of the chromosome.
So, the correct answer is 'Acrocentric'.
Multiple choice botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

Centromere is required for 

  1. Transcription

  2. Crossing over

  3. Cytoplasmic cleavage

  4. Movement of chromosomes towards poles
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The late prophase or metaphase chromosome has two similar threads or chromatids attached to each other by a narrow non stainable area called as centromere. The two parts of the chromatids on either side of centromere are called as arms. Centromeres bind to spindle fibres and help in movement of chromosomes to opposite poles.