Topic 10.1: Meiosis

Question 1

When do chromosomes replicate?

Answer 1

DNA is replicated during the S phase of interphase, resulting in sister chromatids that contain identical DNA strands

Question 2

Divisions of Meiosis

Answer 2

a) Homologous pairs are separated during meiosis I

b) Sister chromatids are separated during meiosis II

Question 3

Independent Assortment

Answer 3

a) During Metaphase I, homologous pairs of chromosomes line up in a random orientation along the equator
b) There is an equal chance of a gamete containing either the maternal or paternal copy of a given chromosome
c) The orientation of each homologous pair is independent to the orientation of any other homologous pair

Question 4

Crossing over

Answer 4

a) During Prophase I, homologous pairs of chromosomes form points of connection between non-sister chromatids
b) The connection points form via a process known as synapsis and the resulting complex is called a bivalent
c) While in synapsis, non-sister chromatids may break and recombine with their homologous partner
d) The non-sister chromatids remain physically connected at points of exchange (chiasmata) until separated by anaphase

Question 5

What may result from crossing over?

Answer 5

In the exchange of alleles

Question 6

Recombinants

Answer 6

The non-sister chromatids that have had genetic material exchanged