Tag: botany

Questions Related to botany

Swellings present over the chromosomes are

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

  1. Centromeres

  2. Centrosome

  3. Puffs

  4. Chromomeres

Show answer
Correct Option: A
Explanation:
The centromere is the specialized DNA sequence of a chromosome that links a pair of sister chromatids
During mitosis, spindle fibers attach to the centromere via the kinetochore.
Centromeres were first thought to be genetic loci that directs the behavior of chromosomes
So, the correct answer is 'Centromeres'

Kinetochore is 

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

  1. Granule within centromere

  2. Surface of centromere

  3. Constriction near chromosome end

  4. End of chromosome

Show answer
Correct Option: A
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'.

Telomeres

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

  1. Initiate RNA synthesis

  2. Help chromatids to move towards poles

  3. Seal ends of chromosomes

  4. Identify correct members of homologous pairs of chromosomes.

Show answer
Correct Option: C
Explanation:
  • A telocentric chromosome is a chromosome in which the centromere is located at the terminal end of the chromosome and their shape is similar to the letter i.
  • These chromosomes have a repetitive nucleotide sequence at each end of chromosomes. 
  • It seals and protects each end of the chromosomes from deterioration or fusion with the neighbouring chromosomes during cell division.
  • So, the correct answer is 'Seal ends of chromosomes'.

A constriction on the chromosome is

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

  1. Centromere

  2. Centrosome

  3. Centriole

  4. Chromomere.

Show answer
Correct Option: A
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.
  • It is a specialized DNA sequence that links a pair of sister chromatids where the spindle fibres are attached during cell division.
  • It is responsible for the transfer of replicated chromosomes into the two daughter cells during the cell division.
  • So, the correct answer is 'Centromere'

Satellite means

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

  1. Terminal part of the chromosome beyond secondary constriction

  2. Terminal part of the chromosome beyond primary constriction

  3. Terminal part of chromosome beyond tertiary constriction

  4. None of the above

Show answer
Correct Option: A
Explanation:
  • Satellite chromosomes or SAT chromosomes are those chromosomes which have secondary constrictions other than a centromere.
  • The terminal end of the chromosome present beyond the secondary constriction is called satellite which is attached to the chromosome by a thin thread called chromatin.
  • So, the correct answer is 'Terminal part of the chromosome beyond the secondary constriction'.

Which one is present on chromosome?

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

  1. Centromere

  2. Centrosome

  3. Nucleus

  4. Golgi body

Show answer
Correct Option: A
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'.

Sister chromatids are joined at

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

  1. Chromocentre

  2. Metacentre

  3. Centromere

  4. Telomere

Show answer
Correct Option: C
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'.

A duplicated chromosome has how many chromatids

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

  1. One

  2. Two

  3. Three

  4. Four

Show answer
Correct Option: B

Kinetochore is

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

  1. Granule within centromere

  2. Surface of centromere

  3. Constriction near chromosome end

  4. End of chromosome

Show answer
Correct Option: B
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'.

Which statement is not correct

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

  1. Histones rich in arginine are $H _3$ and $H _4$

  2. Nucleolar organiser is found in the secondary constriction of a chromosome

  3. Polytene chromosomes are found in Chironomus

  4. B-chromosomes are genetically active.

Show answer
Correct Option: B