Tag: nucleus and chromosome

Questions Related to nucleus and chromosome

The chromosome in which centromere lies slightly away from the middle of the chromosome resulting into one shorter arm and one longer arm, is called as
botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

  1. Metacentric

  2. Submetacentric

  3. Acrocentric

  4. Telocentric

Show answer
Correct Option: B
Explanation:

In submetacentric type of chromosome, the centromere lies at some distance away from the midpoint, dividing the chromosomes into two unequal arms.

So, the correct answer is 'Submetacentric'

Nucleoprotein structures found at the end of chromosome are

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

  1. Centromere

  2. Telomeres

  3. Satellites

  4. Centrosomes

Show answer
Correct Option: B
Explanation:
  • Telomeres are essential nucleoprotein structures at the ends of eukaryotic chromosomes. They play several essential roles preserving genome stability and function, including distinguishing chromosome ends from DNA double-stranded breaks (DSBs) and maintenance of chromosome length.
  • The centromere is the point of attachment of the kinetochore, a structure to which the microtubules of the mitotic spindle become anchored.
  •  Satellite DNA consists of very large arrays of tandemly repeating, non-coding DNA. Satellite DNA is the main component of functional centromeres, and form the main structural constituent of heterochromatin.

So, the correct answer is 'Telomeres'.
Read the given statements.

(i) Centromere is present in the middle of the chromosome and forms two equal arms.
(ii) Chromosome has a terminal centromere.
(iii) Centromere lies close to the end of the chromosomes forming one extremely short and one very long arm.
(iv) Centromere lies slightly away from the middle of the longer arm.

Select the correct option as per the codes given above.
botany nucleus and chromosome membrane bound organelles cell: size and differentiation microscopy

  1. $Metacentric - (i), Submetacentric - (iv), Acrocentric - (iii), Telocentric - (ii)$

  2. $Metacentric - (i), Submetacentric - (ii), Acrocentric - (iii), Telocentric - (iv)$

  3. $Metacentric - (iv), Submetacentric - (i), Acrocentric - (iii), Telocentric - (ii)$

  4. $Metacentric - (iv), Submetacentric - (ii), Acrocentric - (iii), Telocentric - (i)$

Show answer
Correct Option: A
Explanation:

metacentric chromosome - has centromere in the center with arms of identical length on either sides (p=q) telocentric chromosome: has centromere at terminal end, one single arm, not distinguished as p and q sub metacentric chromosome: centromere slightly away from the centre, forming two unequal arms - p -shorter and q-longer acrocentric chromosome : centromere farther away from the center, closer to the terminal end. forms unequal arms, p-much shorter, q- quite longer. So, the correct answer is 'Metacentric−(i),Submetacentric−(iv),Acrocentric−(iii),Telocentric−(ii)'

The chromosome in which centromere lies slightly away from the middle of the chromosome resulting into one shorter arm and one longer arm, is called as _____________.

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

  1. Metacentric

  2. Submetacentric

  3. Acrocentric

  4. Telocentric

Show answer
Correct Option: B
Explanation:
In submetacentric type of chromosome, the centromere lies at some distance away from the midpoint, dividing the chromosomes into two unequal arms.
So, the correct answer is 'Submetacentric'

Select the incorrect match : 

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

  1. Submetacentric - L-shaped chromosomes chromosomes

  2. Allosomes - Sex chromosomes

  3. Lampbrush - Diplotene bivalents chromosomes

  4. Polytene - Oocytes of chromosomes amphibians

Show answer
Correct Option: D
Explanation:

Polytene chromosomes are large chromosomes which have thousands of DNA strands. They provide a high level of function in certain tissues such as salivary glands of Drosophila.

Lampbrush chromosomes are a special form of chromosome found in the growing oocytes of most animals, except mammals. Lampbrush chromosomes of amphibians, birds and insects are described best of all. Chromosomes transform into the lampbrush form during the diplotene stage of meiotic prophase I. They are bivalent.
So, the correct option is 'Polytene - Oocytes of chromosomes amphibians'.

Maximum arm ratio is found in

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

  1. Metacentric chromosome

  2. Acrocentric chromosome

  3. Telocentric chromosome

  4. Submetacentric chromosome

Show answer
Correct Option: B
Explanation:

The chromosomes were named according to the position of the centromeres. This is expressed in the ratio “long arm to short arm”. Here the following terms are used: metacentric (arm ratio 1.0–1.7), submetacentric (ratio 1.7–3.0), subtelocentric (ratio 3.0–7.0), acrocentric (ratio more than 7.0), and telocentric (chromosome with only one arm).

So, the correct answer is option B.

In which chromosome the centromere is located at the terminal end of the chromosome

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

  1. Acrocentric

  2. Sub meta centric

  3. Meta centric

  4. Telocentric

Show answer
Correct Option: D
Explanation:
  • A telocentric chromosome, the centromere is located at the terminal end of the chromosome. 
  • A telocentric chromosome has therefore only one arm.
  • Telomeres may extend from both ends of the chromosome, their shape is similar to letter I during anaphase. 
  • Hence, In the chromosome in which the centromere is located at the terminal end of the chromosome is Telocentric.
  • So, the correct answer is 'Telocentric'.

Select the incorrect match from the following

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

  1. Submatacentric chromosomes - L shaped chromosomes

  2. Allosomes - sex chromosomes

  3. Lampbrush - Diplotene bivalents

  4. Polytene chromosomes- oocytes of amphibians

Show answer
Correct Option: A
Explanation:
Metacentric Chromosomes
Metacentric chromosomes have the centromere in the center, such that both sections are of equal length. Human chromosome 1 and 3 are metacentric.

Submetacentric Chromosomes
Submetacentric chromosomes have the centromere slightly offset from the center leading to a slight asymmetry in the length of the two sections. Human chromosomes 4 through 12 are submetacentric.

Acrocentric Chromosomes
Acrocentric chromosomes have a centromere which is severely offset from the center leading to one very long and one very short section. Human chromosomes 13,15, 21, and 22 are acrocentric.

Telocentric Chromosomes
Telocentric chromosomes have the centromere at the very end of the chromosome. Humans do not possess telocentric chromosomes but they are found in other species such as mice.

So, the correct answer is 'Submetacentric chromosomes-L shaped chromosomes.'

Which chromosome may be lost during cell division?

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

  1. Giant chromosome

  2. Acentric chromosome

  3. Polycentric chromosome

  4. Telocentric chromosome

Show answer
Correct Option: B
Explanation:

Acentric chromosome may lost during cell division as centromere is absent in them. During metaphase and anaphase spindle fibres are not attached with them and so they are not able to reach to the poles.