What is the purpose of cell division?

to produce additional cells, for growth or to replace ones that are normally lost.

somatic cells produce how many identical daughter cells?

2

What is the half-life of an erythrocyte?

115 days, 10¹¹ are replaced daily

neutrophils have a half-life of about?

10.5 h, 6 x 10¹⁰ are replaced daily

The lifespan for cells that line the stomach is?

3 to 5 days

The lifespan for enterocytes is?

5 to 6 days

The cell cycle is divided into three stages, ______________, _______________, and ________________

interphase, mitosis, cytokinesis

What phases make up interphase?

G1 phase, S phase, and G2 phase

What occurs in interphase?

DNA replication

All cells spend a majority of their life in?

interphase

What is the G phase for?

a growth phase and a preparation time for DNA synthesis of S phase

What else takes place in the G1 phase besides DNA synthesis?

RNA and protein synthesis

What examples are reasons why the G1 phase is the most variable among cells types?

embryonic cells divide rapidly, they spend very little time in the G1 phase.

mature cells that do not actively cycle, permanently stay in G1 phase

What is the G0 phase?

a phase where cells are not committed to DNA synthesis

Where is the restriction point located and why is it important?

located in the G1 phase and if passed, it will commit a cell to continue DNA synthesis in the S phase. It is important for cell cycle regulation

What occurs during the S phase?

synthesis of DNA/DNA replication

Actively cycling cells spend about how many hours in S phase?

6

What is the G2 phase?

a time of preparation for the nuclear division of mitosis, allows for the cell to ensure that DNA synthesis is complete before proceeding to mitosis

What does the checkpoint in the G2 phase do?

assesses the nuclear integrity using intracellular regulatory molecules

The G2 phase lasts for about __ hours?

4

What is the purpose of mitosis?

assures that each daughter cell will have identical complete functional copies of the parent cells genetic material

Mitosis is divided into 5 phases called?

prophase, prometaphase, metaphase, anaphase, telophase

Dividing cells spend about ___ hour in mitosis

1

What occurs in prophase?

the nuclear envelope remains intact while the chromatin that was duplicated in S phase is condensed into chromatids

What occurs in prometaphase?

nuclear envelope begins to break down, chromosomes attach to spindle microtubules via kinetochores

What occurs in metaphase?

chromosomes align at the equator of the spindle, kinetochore microtubules attache sister chromatids to opposite poles

What occurs in anaphase?

sister chromatids migrate toward the opposite poles of the spindle

What occurs in telophase?

kinetochore microtubule disaasembly and mitotic spindle dissociation

What is cytokinesis?

is the separation into two distinct daughter cells (cytoplasm is divided)

gametes are associated with ___________, while somatic is associated with ___________

meiosis, mitosis

cyclin-dependent kinases (CDKs) are-

cell cycle mediators

Cyclin D regulates what phase(s) of the cell cycle

G1

Cyclin E regulates what phase(s) of the cell cycle-

some of G1 and some of S

Cyclin A regulates what phase(s) of the cell cycle

S

Cyclin B regulates what phase(s) of the cell cycle

end of S and G2

cyclin concentrations rise and fall throughout the cell cycle due to?

its synthesis and degradation

Which cyclins are essential for progression through the restriction point?

D-type cyclin D1, D2, D3

cyclin D and kinases ____ and _____ function in what way

CDK4, CDK6, progression past the restriction point at the G1/S boundary

cyclin E and A and kinase ____ function in what way

CDK2, initiation of DNA synthesis in early S phase

Cyclin B and kinase ____ function in what way

CDK1, transtion from G2 to M

What catalyzes the phosphorylation of substrate proteins on serine and threonine amino acid residues?

active cyclin-CDK complex