NEET BIOLOGY

CELL STRUCTURES AND FUNCTION

CELL DIVISION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
as mitosis begins, a condensed chromosome consists of two ____
A
centromeres
B
centrioles
C
chromatins
D
chromatids
Explanation: 

Detailed explanation-1: -Mitosis begins with prophase, during which chromosomes recruit condensin and begin to undergo a condensation process that will continue until metaphase. In most species, cohesin is largely removed from the arms of the sister chromatids during prophase, allowing the individual sister chromatids to be resolved.

Detailed explanation-2: -The DNA begins to condense into chromosomes. Because all the DNA has been replicated already, each chromosome is made up of two sister chromatids which have identical DNA. The two sister chromatids of a chromosome are connected in the center of the chromosome, called the centromere.

Detailed explanation-3: -Chromosomes and cell division After DNA replication, each chromosome now consists of two physically attached sister chromatids. After chromosome condensation, the chromosomes condense to form compact structures (still made up of two chromatids).

Detailed explanation-4: -The sister chromatids are pairs of identical copies of DNA joined at a point called the centromere. During anaphase, each pair of chromosomes is separated into two identical, independent chromosomes.

Detailed explanation-5: -In the S phase (synthesis phase), DNA replication results in the formation of two identical copies of each chromosome-sister chromatids-that are firmly attached at the centromere region. At this stage, each chromosome is made of two sister chromatids and is a duplicated chromosome.

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