Question

In pachytene stage of meiosis, the individual chromosomes appear
A. Single stranded
B. Double stranded
C. Three stranded
D. Four stranded

Answer 1

In the process of cell division parent cells divide into two or more daughter cells. In eukaryotes, this division takes place in two different ways (a) mitosis and (b) meiosis. In mitosis, a single cell will produce two identical daughters. The main purpose of this type of division is the growth and replacement of damaged cells.Meiosis takes place in germ cells of sexually-reproducing organisms to produce eggs and sperm. It involved two rounds of division to obtain 4 daughter cells.

Complete step by step answer:
-Meiosis is divided into two parts meiosis l and meiosis ll. In meiosis l segregation of homologous chromosomes takes place.
-Prophase l is one of the phases of meiosis l. Prophase l is the longest-running phase in cell division. -Pachytene is one of the substages of prophase l.
-In the pachytene tetrad of the chromosome is formed which is known as bivalent. In this stage, homologous recombination occurs which also includes crossing over.
-During the process of pachytene, each chromosome becomes thick and divides into two distinct chromatids. All four chromatids of the homologous chromosome are clearly visible during this stage.
-During pachytene chromosomes appear four-stranded
So, option (D) will be the correct answer.

Note: Any kind of error during the process of meiosis will result in aneuploidy where the abnormal counts of chromosomes are found. This type of error is one of the main causes of miscarriage.
After meiosis l two haploid cells are produced. Meiosis ii is similar to mitosis and it will produce 4 haploid daughter cells which contain a number of chromosomes.