Test 3: Ch. 13 Meiosis Flashcards
Test Friday 11/8/13 (37 cards)
Meiosis makes two types of gametes, what are they?
Sperm, Ova
What is half of chromosome number?
Haploid (1N)
Combined gametes to get full chromosome set?
Diploid (2N)
chromosome numbers need to be…
constant
what is a single celled embryo?
zygote (2n)
How many divisions of meiosis are there?
two
What happens in Meiosis I?
1) Homologs separate (one from dad & mom, same size & shape)
2) start with one 2N cell and end up with two 1N cells (2N–>1N)
3) “Reduction” Division which is reducing chromosome number by 1/2
What happens in Meiosis II?
1) Chromatids Separate
2) get the same chromosome number
3) similar to mitosis
4) 1N (two)–> 1N (four) cells
5) “Equation” Division
Spermatogenesis occurs where?
In the testes
KNOW THE SPERMATOGENESIS PROCESS
BE ABLE TO DRAW IT OUT
When does Random Assortment Occur?
at Anaphase I
What happens during Random assortment?
chromosomes randomly end up in carious combinations in 2 degree gametes
KNOW THE OOGENESIS PROCESS
BE ABLE TO DRAW OUT A DIAGRAM
Phases of Meiosis…
Prophase, Metaphase, Anaphase, Telophase… all go around the phase twice.
What happens in Prophase I?
crossing over
Detailed happening in Prophase I?
Homologs line up side-by-side (synapsis)
What is it called when homologs line up side-by-side in Prophase I?
synapsis
Why is it a good think to have synapsis occur during prophase I?
1) generic variability
2) may have a stronger/ healthier person
What about Metaphase I?
Chromosome homologs are equal distance from equator, also most condensed chromosomes do so
What happens in Anaphase I?
homologs separate
Telophase I (Meiosis) –>
Interkinesis (rather fast phase between MI and MII —> Prophase I (Meiosis)
What does Prophase II look like?
Mitosis
What happens in Metaphase II?
lining up at equator (recombined earlier)
What happens in Anaphase II?
chromatids separate
