What is a centromere? How does the position of centromere form the basis of classification of chromosomes. Support your answer with a diagram showing the position of centromere on different types of chromosomes.
Solution and Explanation
Centromere is a constriction present on the chromosomes where the chromatids are held together.
Chromosomes are divided into four types based on the position of the centromere.
(i) Metacentric chromosome
The chromosomes in which the centromere is present in the middle and divides the chromosome into two equal arms is known as a metacentric chromosome.
(ii) Sub-metacentric chromosome
The chromosome in which the centromere is slightly away from the middle region is known as a sub-metacentric chromosome. In this, one arm is slightly longer than the other.
(iii) Acrocentric chromosome
The chromosome in which the centromere is located close to one of the terminal ends is known as an acrocentric chromosome. In this, one arm is extremely long, and the other is extremely short.
(iv) Telocentric chromosome
The chromosome in which the centromere is located at one of the terminal ends is known as a telocentric chromosome.
Top Questions on An Overview Of Cell
- Which is incorrect for chloroplast?
- JIPMER MBBS - 2018
- Biology
- An Overview Of Cell
- What is role of sterol in cell membrane :
- JIPMER MBBS - 2018
- Biology
- An Overview Of Cell
- Match the storage products listed under column I with the organism given under column II, choose the appropriate option from the given options
Column-I Column-II A Glycogen 1 Sargassum B Pyrenoids 2 Nostoc C Laminarin and mannitol 3 Polysiphonia D Floridean 4 Spirogyra 5 Agaricus - JIPMER MBBS - 2017
- Biology
- An Overview Of Cell
- Describe the structure of the following with the help of labelled diagrams.
(i) Nucleus
(ii) Centrosome- CBSE Class XI
- Biology
- An Overview Of Cell
Questions Asked in CBSE Class XI exam
Give reasons for the following.
(i) King Tut’s body has been subjected to repeated scrutiny.
(ii) Howard Carter’s investigation was resented.
(iii) Carter had to chisel away the solidified resins to raise the king’s remains.
(iv) Tut’s body was buried along with gilded treasures.
(v) The boy king changed his name from Tutankhaten to Tutankhamun.- CBSE Class XI
- Discovering Tut: The saga Continues
Draw the Lewis structures for the following molecules and ions: \(H_2S\), \(SiCl_4\), \(BeF_2\), \(CO_3^{2-}\) , \(HCOOH\)
- CBSE Class XI
- Kossel-Lewis Approach to Chemical Bonding
- The following results are observed when sodium metal is irradiated with different wavelengths. Calculate (a) threshold wavelength and, (b) Planck’s constant
λ (nm) 500 450 400 v × 10–5(cm s–1) 2.55 4.35 5.35 - CBSE Class XI
- Atomic Models
- Briefly comment on "The purpose of the author’s journey to Mount Kailash."
- CBSE Class XI
- Silk road
- Prove that. \(2sin^2 \frac{π}{6}+cosec^2 \frac{7π}{6}–cos^2 \frac{π}{3}=\frac{3}{2}\)
- CBSE Class XI
- Trigonometric Functions of Sum and Difference of Two Angles