meiosis

Question 1

How are male gametes formed

Answer 1

Spermatogenesis

Question 2

what is meiosis

Answer 2

is the cell division where we create sex cells (the gametes)

Question 3

How are female gametes formed

Answer 3

Oogenesis

Question 4

What process are haploid gametes produced through?

Answer 4

meiosis

Question 5

how many division cycles does meiosis consist of?

Answer 5

2

meiosis 1& 2

Question 6

B4 meiosis:

Answer 6

• Before the cell enters meiosis 1 it goes through interphase. It goes through G1 phase, S phase, G2 phase
• This is where double it’s genetic material, the DNA and cellular organelles are doubled e.g. mitochondria, centrioles.
• We start of with a cell that has diploid (full compliment of DNA material). Same interphase process as the beginning of mitosis

Question 7

Non-disjunction meaning

Answer 7

Non- disjunction results in the one daughter cell having an extra chromosome and another daughter cell having less

Question 8

What happens during non-disjunction

Answer 8

• This pair of chromosomes does not separate, this means that when the spindle fibres are contracting, each chromosome doesn’t go to opposite poles of the cell
• They instead remain in this tetrad and remain paired together and are drawn to the same end of the pole
• This means when cytokinesis takes place and nuclear envelope is reforming, one daughter cell will have an extra chromosome and the other daughter cell will have one less chromosome.
• This will result in the gametes being expressed exactly the same
• Fertilisation using a gamete with an extra chromosome will result in a zygote with 3 copies of that chromosome (trisomy)

Question 9

what is Interkinesis

Answer 9

Interkinesis:

• The cells go through a stage called interkinesis, period between meiosis 1 and 2
• During this period no DNA replication occurs, we still have double DNA in each cell. Each cell has the genetic info amounting to halopid cells -haploid daughter cells