AP BIOLOGY

CELL DIVISION

MEIOSIS AND GENETIC VARIATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What are separated during the first meiotic division
A
chromatids
B
chromosomes
C
haploids
D
diploids
Explanation: 

Detailed explanation-1: -In the first meiotic division, the homologs are segregated to separate daughter cells by the spindle apparatus. The cells then proceed to a second division without an intervening round of DNA replication. The sister chromatids are segregated to separate daughter cells to produce a total of four haploid cells.

Detailed explanation-2: -In the first division, homologous chromosomes (e.g., the chromosome 3 pair in the diploid cell) come together and are then separated into different cells. Hence, the first meiotic division separates homologous chromosomes into two daughter cells such that each cell has only one copy of each chromosome.

Detailed explanation-3: -There are two divisions in meiosis; the first division is meiosis I: the number of cells is doubled but the number of chromosomes is not. This results in 1/2 as many chromosomes per cell. The second division is meiosis II: this division is like mitosis; the number of chromosomes does not get reduced.

Detailed explanation-4: -Homologous pairs of cells are present in meiosis I and separate into chromosomes before meiosis II. In meiosis II, these chromosomes are further separated into sister chromatids. Meiosis I includes crossing over or recombination of genetic material between chromosome pairs, while meiosis II does not.

Detailed explanation-5: -Meiosis I, the first meiotic division, begins with prophase I. During prophase I, the complex of DNA and protein known as chromatin condenses to form chromosomes. The pairs of replicated chromosomes are known as sister chromatids, and they remain joined at a central point called the centromere.

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