Lecture 15 Flashcards
1
Q
What is happening during G2 of interphase?
A
- nuclear envelope intact
- nucleolus visible
- 2 centrosomes formed
- chromosomes are duplicated but not condensed
2
Q
What happens during prophase I?
A
- nuclear envelope breaks down, chromosomes condense + spindle forms
- crossing-over between non-sister chromatids at chiasmata
- each chromatid is now mix of each homologous chromosome
3
Q
What happens during metaphase I?
A
- chromosomes are attached to kinetochore microtubules at each centromere
- each pair lines up independently
-paired homologous chromosomes have moved to metaphase plate - chiasmata line up on plate
4
Q
What happens during Anaphase I?
A
- homologous chromosomes disjoin
- sister chromatids remain attached
- cell starts to elongate and duplicated chromosomes move to opposite ends of cell
5
Q
What happens during telophase I?
A
- duplicated chromosomes reach poles
- spindles disappear + nuclear envelope forms
- is a haploid cell
6
Q
What happens during prophase II?
A
- spindle forms as centrosomes duplicate + move to opposite ends
- kinetochore microtubules join at centromere
7
Q
What happens during metaphase II?
A
- duplicated chromosomes line up on metaphase plate
- centromeres line on metaphase plate
8
Q
What happens during anaphase II?
A
- sister chromatids disjoin at centromeres, resulting in independent daughter chromosomes
- go to opposite poles
- cell elongates
9
Q
What happens during telophase II?
A
- 2 daughter nuclei w/nuclear envelope form
- results in 4 genetically distinct daughter cells
10
Q
What is the benefit to sexual reproduction?
A
- diversity
- allows responses to spatially variable environments, changing environments, sib-sib competition
11
Q
What is the difference between a haploid and diploid cell?
A
Haploid = one set of chromosomes
Diploid = 2 sets of chromosomes
