Question

ln human karyotype, 13th chromosome belongs to
A. Metacentric type
B. Submetacentric type
C. Acrocentric type
D. Telocentric type

Answer 1

Hint:- The term "karyotype" is used to refer to a group of properties that identify a specific set of chromosomes. The chromosomes number and the shape of each pair of chromosomes are usually constant and characteristic of a particular species.

Complete Answer:-On the basis of position of centromere chromosome divided into following types:
A. Metacentric type-In metacentric chromosomes the centromere is in the middle so that the two arms of the chromosome are the same.
B. Submetacentric type-In sub-metacentric chromosome centromere is situated on one side of the midpoint, It means the centromere is sub median and divides the centromere into two distinct (unequal) arms.
C. Acrocentric type- In acrocentric type centromere is located almost near one end of the chromosome, It means the centromere has a sub-terminal position and due to it's sub-terminal position it gives two arms - one very short and the other long. The acrocentric chromosomes appear in a J-shaped anaphase.
D. Telocentric type- In telocentric chromosomes, the centromere appears to be at one end of the chromosome. In this type, one arm is approximately the length of the chromosome and the other arm, outside the centromere, is represented only by a dot.
E. One the basis of the position of centromere chromosome number 13th comes under the category of acrocentric chromosome one arm of the chromosome is very short and other is very long.

So the correct option is (C).

Note:- - karyotype research helps pinpoint the origin and evolutionary relationships between different taxa. Depending on the difference between the smallest and largest chromosomes in the set, the karyotype can be symmetrical (difference less) or asymmetric (large difference). Increased karyotype asymmetry is associated with advanced plant groups.
- During anaphase movement, the metacentric chromosomes appear as ‘V’.
- During anaphase movement, the sub-metacentric chromosomes appear as ‘J’.