NEET BIOLOGY

CELL STRUCTURES AND FUNCTION

CELL DIVISION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A chromosome has two homologous parts held together by a centromere. What are those two parts?
A
sister chromatids
B
sister cells
C
daughter cells
D
daughter chromatids
Explanation: 

Detailed explanation-1: -A chromatid is one of the two identical halves of a chromosome that has been replicated in preparation for cell division. The two “sister” chromatids are joined at a constricted region of the chromosome called the centromere.

Detailed explanation-2: -After DNA is replicated each chromosome consists of paired sister chromatids held together by cohesin.

Detailed explanation-3: -A sister chromatid refers to the identical copies (chromatids) formed by the DNA replication of a chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said to be ‘one-half’ of the duplicated chromosome. A pair of sister chromatids is called a dyad.

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. The chromosomes are separated by a structure called the mitotic spindle.

Detailed explanation-5: -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). As a cell prepares to divide, it must make a copy of each of its chromosomes.

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