Chapter 11: Cell Divison

Interphase

Growth and synthesis (G0,G1,S,and G2)- takes the longest

M phase

Parent cell divides into 2 daughter cells

G1

Name the preparation stage in interphase:

-Growth and regulatory protein expression

S phase

Name the preparation stage in interphase:

-DNA synthesis

G2

Name the preparation stage in interphase:

-Prep for mitosis

G0

Name the preparation stage in interphase:

-Cell is not actively dividing (no prep)

Semiconservative model

Semiconservative model or Conservative model

-After replication, new DNA consist of 1 old strand (parental) and 1 new strand daughter.

Conservative model

Semiconservative model or Conservative model

-After replication, new DNA consist of 2 new daughter strands, leaving parental DNA intact.

Helicase

Name the enzyme:

-Unwinds the parental DNA strand.

Toposiomerase

Name the enzyme:

-Relieves the stress of unwinding.

DNA polymerase

Name the enzyme:

-This complex acts at the site of the growing chain to increase the chain length one DNA subunit at a time.

5' to 3'

In which direction does replication occur?

Primase

Name the enzyme:

-Lays down the RNA primer

DNA ligase

Name the enzyme:

-Joins Okazaki fragments with sugar phosphate backbone

Telomeres

Short repeating sequences on ends of chromosomes

-Prophase

-Prometaphase

-Metaphase

-Anaphase

-Telophase

What are the phases of mitosis?

Prophase

Name the phase of mitosis:

-Chromosomes condense, centrosomes move to opposite poles.

Prometaphase

Name the phase of mitosis:

-Nuclear membrane breaks down

-Microtubules attach to chromosomes at the centromere

Kinetochore

Site of attachment for microtubules to chromosomes

Metaphase

Name the phase of mitosis:

-Chromosomes line up on single plane

Anaphase

Name the phase of mitosis:

-Kinetochore microtubules shorten, pulling chromatids toward centrosome

-Ensures one chromatid from each pair or sister chromatids goes to opposite poles

Telophase

Name the phase of mitosis:

-Chromosomes on opposite poles (microtubules break down and nuclear envelope reforms)

-Chromosomes decondense (end of telophase and mitosis)

Contractile ring

In animals cells, cytokinesis is carried out by what?

Cell plate

In plant cells, cytokinesis is carried out by what?

Cyclins

Proteins that cyclically appear in the cell cycle.

Cyclind-dependent kinases (CDKs)

Cyclins activate what?

Cell division

What do CDKs promote?

- DNA damage checkpoint

-DNA replication checkpoint

-Spindle assembly checkpoint

What are the 3 cell cycle check points?

Apoptosis

Programmed cell death

Growth factors

Released by certain cells and stimulate other cells to divide (like PDGF)

Density-dependent inhibition

Too crowded, cells stop dividing

Anchorage dependence

Must be attached to divide

Density-dependence and anchorage dependence

What checks cell growth at optimal density?