Unit 3 - Ch 10 - Eukaryotic Cell Cycle

Question 1

Karyotype

Answer 1

• A picture of a persons chromosomes
• Nuclear content of a cell prepared at metaphase of the cell cycle
• technician arranges chromosomes

Question 2

Chromosomes

Answer 2

• complex of chromatin and protein (histone)

= humans have 46 chromosomes

Question 3

Homologous Chromosomes

Answer 3

have a similar size and shape (due to position of centromere)
- receive one from each parent
- contains genes for the same kind of trait (loci)
= humans have 23 homologous chromosomes

Question 4

Sister Chromatids

Answer 4

• exact copies of chromosomes
• joined at the centromere
  = humans have 92 SC’s

Question 5

Interphase

Answer 5

• First phase of the cell cycle
• once considered the “resting phase”
• G1, S, G2
  OR
• Gap1, Synthesis, Gap 2

Question 6

G1

Answer 6

Gap I - part in Interphase 
- cell growth occurs 
(SA/V decreases, nuclear distance increases) 
- organelles double in the cell 
- some cells become arrested in G0

Question 7

S

Answer 7

Synthesis - part of interphase

• DNA replicates to produce sister chromatids
• histone proteins are synthesized

Question 8

G2

Answer 8

Gap II - part of Interphase

- further synthesis of components needed for cell division

Question 9

Mitosis

Answer 9

Part of the cell cycle
- divide a parent nucleus into two genetically identical daughter nuclei 
- Karyokinesis = nuclear division
- includes 
Prophase
Metaphase
Anaphase 
Telophase

Question 10

Prophase (4)

Answer 10

First part of mitosis

1. Chromatin condenses and chromosomes appear
2. Centriole pairs (if present) move apart (only in animal cells)
3. Spindle apparatus forms. Aster (if present) appears (only in animals)
4. Nucleolus & nuclear membrane disappear (go into solution)

Question 11

Metaphase (2)

Answer 11

Second part of mitosis

1. Chromosomes align on equatorial plate (region)
2. Spindle is attached at kinetochore via kinetochore microtubules

Question 12

Anaphase (2)

Answer 12

Third part of mitosis

1. Sister chromatids separate – occurs via shortening of kinetochore microtubules (pull)
2. Two poles also separate - occurs via polar microtubules (push)

Question 13

Telophase (3)

Answer 13

Fourth part of mitosis

1. Spindle disappears - goes into solution
2. Chromosomes uncoil - back to chromatin
3. Nuclear membrane/nucleolus reform

Question 14

Cytokinesis (animal, plant and multinucleate cells)

Answer 14

Part of the cell cycle. Division of the cytoplasm and organelles - overlaps telophase of mitosis.

1. Furrow forms in animal cells - cell membrane constricts - occurs via microfilaments
2. Cell Plate forms in plant cells - forms a new cell wall between dividing plant cells - vesicles from Golgi fuse together
3. Multinucleate cells -mitosis without cytokinesis

Question 15

Role of Mitotic Cell Division (4)

Answer 15

A. Development
- initiated with fertilization - from conception until birth - basis for identical twins

B. Growth
- birth to adulthood

C. Repair
- mitotic activity is stimulated by injury

D. Asexual Reproduction
– produce a clone of the parent = aspen, spider plants

Question 16

Regulation of Eukaryotic Cell Cycle

Answer 16

Cyclins – regulatory proteins that cycle throughout the cell cycle (synthesized and degraded at different points)

Cyclin-Dependent Kinases – enzymes that associate with specific cyclins - only active when bound to a cyclin - are reused by cells