Write about Leptotene and zygotene
Answers
1) LEPTOTENE:-
The nucleus is increased in size .
The chromosomes appear long,thin and single threads distributed irregularly.
Homologous chromosomes attract towards each other.
2) ZYGOTENE:-
The chromosomes become shorter and thicker.
pairing of homologous chromosomes takes place called synapsis.
A pair of homologous chromosomes held tightly along their entire length called bivalents
The no.of bivalents are equal to the haploid no.of chromosomes.
The leptotene stage, also known as the leptonema, is the first of five substages of prophase I in meiosis.
And Zygotene is the second stage in this process. It comes right after the Leptotene stage (stage 1) in which Chromatin fibres begin to condense. During the Zygotene stage, condensation continues to make distinguishable Chromosomes.