Meiosis

Question 1

Describe Prophase 1

Answer 1

-Development of spindle fibres
-crossing over is taking place
-disappearing membrane

Question 2

Describe Anaphase 1

Answer 2

-Spindle fibres shorten
-Chromosome pairs separate
-and move to the opposite poles

Question 3

Describe how crossing over may lead to down syndrome

Answer 3

-When chromo pair 21 fails to separate
-during Anaphase
-the daughter cells will have an extra chromosome
-when this gamete is fertilised by a normal gamete
-the zygote will have 47 chromosome

Question 4

Describe how Crossing Over contributes to genetic variation

Answer 4

-During crossing over
-in Prophase 1
-segment of chromatids of homologous chromosomes
-are exchanged
-leading to each gamete having a mix of genetic form both parents

Question 5

A way in which meiosis contributes to genetic variation

Answer 5

During Metaphase 1/2
-each pair of homologous chromosomes
-may line up in different ways
-on the equator of the spindle
-Allowing the gamete to have different combinations of maternal and paternal chromosome