Genetics - Stages of Mitosis

Karyokinesis

genetic material (chromosomes) is partitioned to daughter cells during nuclear division in mitosis

cytokinesis

cytoplasmic division occurring after karyokinesis

Cell cycle is composed of _________ and _________ (2 words)

interphase, mitosis

Interphase includes:

1. S-phase: during which DNA is synthesized
2. Two gap phases (G1 and G2)

G0

point in the G1 phase where cells withdraw from cell cycle and are non-dividing but still metabolically active.

Mitosis has discrete stages:

1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase

Prophase

centrioles divide and move apart
nuclear envelop breaks down
chromosomes condense and become visible

sister chromatids are connected at the ____________

centromere

prometaphase

chromosomes move to equatorial plane of the cell

metaphase

centromeres/chromosomes align at the equatorial plane

_______________ responsible for chromosome movement

spindle fibers bound to kinetochores associated with centromeres

Anaphase

Sister chromatids separate from each other and migrate to opposite poles
the separated sister chromatids are called daughter chromosomes

separated sister chromatids in anaphase are called _________________

daughter chromosomes

Telophase

cytokinesis
uncoiling (relaxation) of chromosomes
re-formation of the nuclear envelope
spindles disappear

Cell cycle Check points

1. G1/S
2. G2/M
3. M check-point
cyclin-dependent kinases

1. G1/S (why is the "/S" here?)*****

monitors cell size
evaluates condition of the DNA
cells enlarge in size
make proteins/enzymes to prepare for S-phase

S

DNA synthesis/replication

2. G2/M

DNA checked for completion of replication/presence of DNA damage

3. M check-point

formation of spindle fibers
attachment of spindles to kinetochores
after pro-metaphase, before metaphase

mitosis is a __ hr process

16hr. 1 hour in mitosis. 15 in interphase

cytokinesis

occurs in telophase
no guarantee cell is divided equally. one cell gets more cytoplasm/organelles
cell plate forms and divides 2 daughter cells

CDK

controls MPF (mitosis promoting factor) at G2/M check point
needs to be enough MPF for Mitosis to begin

___________ is defective in B cell lymphoma

Cycline D