Replication of Eukaryotic Cells

Question 1

What is the cell cycle and it’s phases?

Answer 1

G1 phase: occurs after mitosis and cytokinesis.
phase where the majority of cellular activity for the functions of the cell occurs.
S phase: the DNA composing the chromosomes is duplicated. at the end of the S phase each chromosome consists of an identical pair of chromosomal DNA strands called sister chromatids, attached at a centromere.
G2 phase: molecules and structures necessary for mitosis are synthesized
M phase (Mitosis): IPPmMATc
1. Interphase- chromosomes have already replicated during interphase.
2. Prophase-sister chromatids condense and spindle starts to form. Nuclear membrane begins to dissociate into vesicles
3. Prometaphase-nuclear membrane has completely dissociated into vesicles and the spindle is fully formed. sister chromatids attach to spindle via kinetochore microtubules
4. Metaphase- Sister chromatids align along the metaphase plate.
5. Anaphase-sister chromatids separate and individual chromosomes move toward poles as kinetochore microtubules shorten. polar microtubules lengthen and push poles apart.
6. Telophase and cytokinesis- chromosomes decondense and nuclear membranes re-form. cleavage furrow separates the 2 cells

Question 2

What is the differences in plant and animal cell mitosis?

Answer 2

animal cells have the formation of asters with centrioles at the center, as well as cytokinesis. cytokinesis includes formation of a cleavage furrow.

Plant cells have no centrioles, and during cytokinesis a formation of a partition called a cell plate perpendicular to the axis of the spindle apparatus forms.

Question 3

what is a haploid?

Answer 3

A nucleus such as that in a gamete, with only one chromosome of each homologous pair

Question 4

what is a diploid?

Answer 4

chromosomes in eukaryotic nuclei occur in pairs

Question 5

what are homologous chromosomes?

Answer 5

two chromosomes of a pair

Question 6

Mitosis and Meiosis

Answer 6

Purpose of process: Mit-Growth and replication
Mei-Growth and replication of sex cell (gametes)

Number of cells produced: Mit-two cells
Mei- four cells

Number of nuclear divisions: Mit- 1 division
Mei- 2 divisions

Haploidy or diploidy of resulting cells: Mit-diploid
Mei-haploid

Genetically identical cells: Mit-yes
Mei-no

Pairing of homologues: Mit-No
Mei-yes

Occurrence of crossing over: Mit-no
Mei-yes