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

Which one is present on chromosome?

  1. Centromere

  2. Centrosome

  3. Nucleus

  4. Golgi body
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The centromere is the lighter staining region present on the chromosome of a cell which appears as a constriction.
  • They are also known as a primary constriction or kinetochore.
  • It is a specialized DNA sequence that links a pair of sister chromatids where the spindle fibres are attached during cell division.
  • So, the correct answer is 'Centromere'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Sister chromatids are joined at

  1. Chromocentre

  2. Metacentre

  3. Centromere

  4. Telomere
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • The specialized DNA sequence that links a pair of sister chromatids where the spindle fibres are attached during cell division is known as a centromere.
  • It is the lighter staining region on the chromosome of a cell which appears as a constriction.
  • They are also known as a primary constriction or kinetochore.
  • So, the correct answer is 'Centromere'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Kinetochore is

  1. Granule within centromere

  2. Surface of centromere

  3. Constriction near chromosome end

  4. End of chromosome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The centromere is the lighter staining region on the chromosome of a cell which appears as a constriction.
  • They are also known as a primary constriction or kinetochore.
  • The kinetochore is a proteinaceous structure that assembles at the surface of the centromere which forms the site for binding of spindle fibres during cell division.
  • So, the correct answer is 'Surface of centromere'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

More than $200$ chromosomes occur in

  1. Chicken

  2. Dog

  3. Amoeba

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

1) Chicken has a diploid number of 78 (2n = 78).

2) Dog has a diploid number of 78 (2n=78).
3) The genome for Amoeba proteus is very large containing over 290 billion base pairs in its genome. The Amoeba proteus has more than 500 chromosomes in a single nucleus.
4) Gorilla has a diploid number of 48 (2n=48).
So, the correct answer is 'Amoeba'.

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

Kinetochore is?

  1. Surface of centromere

  2. Trilaminar plate over centromere

  3. End of chromosome

  4. Constriction near chromosome end
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The centromere is the lighter staining region on the chromosome of a cell which appears as a constriction.
They are also known as a primary constriction or kinetochore.
The kinetochore is a proteinaceous structure that assembles at the surface of the centromere which forms the site for binding of spindle fibres during cell division.
So, the correct answer is 'Surface of centromere'.
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

Somatic chromosome number is 40.What shall be chromosome number in the cells seminiferous tubule ?

  1. 40

  2. 20

  3. 10

  4. 40 and 20
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Somatic cell is diploid (2n) in nature. It is given that the number of somatic chromosomes is 40. Seminiferous tubules contain haploid (n) spermatozoa. These spermatozoa are haploid in nature.
Hence, the number of chromosomes in the cells of seminiferous tubules will be 20.
Thus, the correct answer is '20.'
Multiple choice botany the mitotic cell cycle chromosome and its structure chromosome nucleus and chromosome

A pericentric inversion in chromosome involves _______________.

  1. One arm of a chromosome

  2. Both the arms of a chromosome

  3. Two different chromosomes

  4. More than two chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A pericentric inversion involves a chromosome segment that undergoes a 180-degree reversal and includes the centromere, thus affecting both arms of the chromosome. In contrast, paracentric inversions occur entirely within a single arm and exclude the centromere.

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

Lamp brush chromosomes found in certain organisms are directly related to metamorphosis. Which one of the following statements in this regard is incorrect?

  1. These are very large chromosomes

  2. These are actively engaged in RNA and protein synthesis and accumulation

  3. Lamp brush loops recede and these become normal looking chromosomal parts looking chromosomal parts

  4. They are compactly packed and have very high DNA content
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lampbrush chromosomes are giant chromosomes found in the oocytes of certain vertebrates. They are characterized by extensive loops that are sites of very high transcriptional activity (RNA and protein synthesis), meaning they are not compactly packed with high inactive DNA content as claimed by the incorrect statement.

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

$6$p $23$ in chromosome nomenclature indicates band number.

  1. $6$ in short arm of chromosome $23$
  2. $3$ in region $2$ of short arm of chromosome $6$
  3. $3$ in region $2$ of long arm of chromosome $6$
  4. $6$ in long arm of chromosome $23$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In standard cytogenetic chromosome nomenclature, a band designation such as 6p23 is read as chromosome 6, short arm (p), region 2, band 3. Thus, the digit 3 represents the band number in region 2 of the short arm.