Lecture 16: cell division Flashcards
Which cells use binary fission?
prokaryotes and protozoa
What are the two phases of eukaryotic cell cycle
M phase and interphase
What three phases are in interphase
G1, S, G2
What is in the M phase?
Mitosis and cytokinesis
What do histones do?
package DNA into linear chromosomes
Define dipliod
having 2 copies of each chromosome
What happens in prophase
- chromosomes condense
- centrosomes migrate and start forming microtubules
What happens in prometaphase
microtubules attach to chromosomes and nuclear envelope starts to break down
What are kinetochore
protein complex that help microtubule attachment
What are centromeres
where microtubules attach
What happens during metaphase
chromosomes line up in the center of the cell
What happens during anaphase?
sister. chromatids separate and move to opposite ends
What happens during telophase?
Nuclear envelope reforms and chromosomes decondence
What actually pinches and divides. the cells in cytokinesis
a contractile ring of actin
How do plants divide the cell
cell plate forms
What type of cells go through meiosis
gametes
How much of the genetic material do the daughter cells of meiosis contain?
half
What happens in prophase 1
crossing over
chromosomes condense
nuclear envelope breaks down
Where does crossing over occur
prophase 1
recombinant chromatids
chromatids with two recombinant DNA
chiasma
crossing over point for homologous chromosomes
What happens in metaphase 1
pairs of homologous chromosomes move to the equator of the cell
What happens in anaphase 1
homologus chromosomes move to opposite poles of the cell
What happens in telophase 1 and cytokinesis
chromosomes gather at poles and cytoplasm divides
What happens in meiosis 2
cell divides again without replicating DNA
How many viable gametes do females produce after meiosis 2
1-oocyte
How many viable gametes do males produce after meiosis 2
all 4 sperms
where does independent assortment occur?
metaphase of meiosis
