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 the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Diagrammatic representations of a chromosome is known as ____________.

  1. Homotype

  2. Idiotype

  3. Merotype

  4. Karyotype
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
An ideogram is a diagrammatic representation of the karyotype that shows all of the pairs of homologous chromosomes in the nucleus. The pairs of chromosomes are lined up in order of size, so that the centromeres are aligned and the short arm is uppermost. An ideogram is a useful point of reference for analyzing mutations.
So the correct option is 'Idiotype'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

How are chromatin, chromatid and chromosomes related to each other?

  1. Chromosomes are made up of chromatin

  2. Chromatin is made up of chromosomes

  3. Chromatin is made up of chromatids

  4. Chromosomes are made up of chromatids and chromatids are made up of chromatin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chromatin fibers are made from coiling of a long polynucleotide strand of a DNA to fit into the cell. Chromatids are made up of chromatin. The two sister chromatids are present in a chromosome.

So, the correct answer is option D. 

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Choose the correct answers from the alternatives given :
The thread like structures that begin to radiate from each centromere by the end of prophase are

  1. aster microtubules

  2. spindle microtubules

  3. kinetochore microtubules

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

  • Prophase is the third stage of the mitosis where the chromosomes which were lined up at the metaphase plate in the metaphase are to be pulled towards the pole of the dividing cells.
  • The centrioles which are present at the pole of the dividing cells produce spindle fibers which are will help pull the chromosomes towards the pole .
  • These spindle fiber will attach to the kinetochore which is present with the centromere in the middle of the chromosome,
  • The kinetochore also produces microtubles which will attach will the incoming spindle fibers forming a bond so that they can be pulled towards the pole.
  • After reaching the pole the fibers will distangle from the kinetochore and disappear leaving the chromosomes to decondense and formation of the nuclear membrane around them .
  • Therefore the answer option 'kinetochore microtubules' is correct.

















Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Choose the correct answers from the alternatives given :
The centromere or primary constriction of the chromosome contains rings of protein that are intimately associated with a spindle fibre. These rings are called

  1. asters

  2. secondary constrictions

  3. centrioles

  4. kinetochores
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The kinetochore is the region which is present in the center of the chromosome near the centromere or the primary constriction.
  • The spindle fibers which are formed from the centrioles are required to pulled the chromosome towards the poles of the dividing daughter cells.
  • The spindle fiber of the centrioles are attached to the kinetochore which is a protein ring or made up of protein which forms bonds with tubulin protein of the spindle fiber, so that the chromosomes can be pulled apart towards the poles. 
  • Therefore the answer option 'kinetochores' is correct.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome
According to most recent studies, each chromosome consists of

  1. Single double helical DNA which is highly coiled and folded

  2. Variable number of DNA helices, depending upon the length of chromosome

  3. Many small DNA helices, which are joined by peptide linkages

  4. Small DNA helices, wrapped around each other like a rope
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

There is a single, long, double-stranded, linear DNA molecule in a chromosome. The DNA contains biological and genetic information. It is highly coiled and folded, however this packing varies during the cell cycle.

So, the correct answer is 'Single double-helical DNA which is highly coiled and folded'.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

which of the following is typically not found in normal somatic cells of human male?

  1. the entire genetic information possesed by the original zygote

  2. an inactivated X chromosome

  3. forty four autosomes

  4. a diploid nucleus

  5. A Y chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An inactivated X-chromosomes : female have XX chromosomes and male have XY chromosomes ,for balance Xlinked gene between male and female,one X chromosome undergo inactivated during the female embryo development this is termed as X chromosomes inactivation

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Which of the following dyes is best suited for staining chromosomes ?

  1. Basic Fuchsin

  2. Safranin

  3. Methylene blue

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

(a) Basic Fuchsin-  It is a green crystalline dye. It includes staining of tissues sections.

(b) Safranin- It is used to stain gram-negative bacteria, mucin, etc.
(c) Methylene blue- It is used to examine DNA or RNA under the microscope.
(d) Carmine -  It is a type of stain used to stain chromosomes, nuclei etc.
So, the correct option is 'Carmine'.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Which of the following does not occur during condensation of chromosomes?

  1. Unfolding of protein molecules

  2. Coiling of DNA

  3. Dehydration

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

Chromosome condensation is the dramatic re-organization of the long thin chromatin strands into the compact short chromosomes that occur in mitosis and meiosis. Here, the unfolding of proteins takes place, the DNA coils, dehydration takes place. However, there is no addition of water molecule or hydration that takes place during condensation.

So, the correct answer is option D.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Structure which provide shape to chromosome is called as

  1. Telomere

  2. Satellite

  3. Centromere

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

Centromere provides structure to the cell. The sister chromatids are linked together at the centromere. During mitosis, spindle fibers attach to the centromere via kinetochore. Their physical role is to act as the site of assembly of the kinetochore, a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation, i.e., binding microtubules and send signals to the cell cycle machinery.

So, the correct answer is option C.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Part of chromosome after secondary constriction is called as

  1. Chromomere

  2. Telomere

  3. Satellite

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

Chromosomes are the carrier of genetic information in form of DNA. The secondary constrictions are used as a point of identification of chromosomes. These are always constant in their positions and hence, can be used as markers that identify particular chromosomes. A satellite chromosome or SAT chromosome has a chromosome segment that is separated from the main body of the chromosome by such a secondary constriction.

So, the correct answer is option C.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

General length of chromosome is

  1. 5$\mu$m - 10$\mu$m
  2. 0.2$\mu$m - 2$\mu$m
  3. 0.1$\mu$m - 30$\mu$m
  4. 0.1$\mu$m - 4$\mu$m
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chromosomes are the genetic material present in the nucleus of a cell. It is composed of DNA and protein. The functional segment of DNA is known as a gene. The size of chromosomes varies from as small as 0.1$\mu$m to as big as 15$\mu$m in length.

So, the correct answer is option C.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

The chromosome that lacks a centromere is called as

  1. Telocentric

  2. Acentric

  3. Metacentric

  4. Acrocentric
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
In acrocentric chromosome, the centromere is present close to the end of the chromosome. Due to this one arm is very short and another arm is longer. 
In metacentric, the centromere is in the middle of the chromosome and the two arms are of equal length. 
In telocentric, the centromere is present at the end of a chromosome.
In acentric the chromosome that lacks a centromere. So, the correct answer is option C.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

The largest normal metaphasic chromosome has a size of

  1. $1\mu m$
  2. $10\mu m$
  3. $20\mu m$
  4. $30\mu m$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The largest normal metaphasic chromosome has the size of 30nm with the base of the nucleosome core particle consists of the 146 base pairs of DNA. During metaphasic state, when a chromosome in its most condensed state can range in size between 130,000 base pairs in the endosymbiotic bacteria, then the chromatin can be further condensed by coiling into 30nm in fibres.
So, the correct answer is option D.

Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

During staining, chromosomes get stained with

  1. Eosine

  2. Borax carmine

  3. Acetocarmine

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

  • Stains are used in the microscopic studies of different components and organelles within a cell.
A. Eosine is stain used to stain the cytoplasm of the cell because these acidic dyes bind to basic proteins in the cytoplasm of the cell.
B. Borax carmine consists of borax, carmine and water which produces a permanent red nuclear stain which stains the nucleus and the cytoplasm.
C. Acetocarmine is a saturated solution of carmine in 45% of acetic acid which is used for staining the unfixed chromosomes within the nucleus of a cell that is used to study different stages of the chromosomes in cell division.
D. Safranin is a basic counterstain dye used in histology and cytology.

So, the correct answer is 'Acetocarmine'.