4:1 cell Division

Question 1

What are the phases of the cell cycle?

Answer 1

G1, S, G2, M phase
S: synthesis of DNA
M: mitosis and cytokinesis
G1+S+G2: interphase

Question 2

What happens in interphase?

Answer 2

G1 phase: cell growth
S Phase: each chromosome is replicated to form a pair of sister chromatids. (DNA replication)
G2: protein synthesis for chromosome sorting and cell division. Some cell growth

Question 3

What happens in mitosis/ meiosis (after interphase1/2)

Answer 3

Nuclear division

Question 4

What happens in cytokinesis? (After interphase and m phase)

Answer 4

Division of cytoplasm

Question 5

What is the semi conservative DNA model?

Answer 5

replication produces DNA molecules with 1 parent strand and 1 newly made daughter strand.

11>12+12>12+11 + 12+11

Question 6

What is the conservative mechanism DNA model?

Answer 6

Produces 1 double helix with both parental strands and 2 new daughter strands

11> 11+ 22 > 11+22 + 11+11

Question 7

Dispersive mechanism DNA model

Answer 7

Produces DNA strands in segments of new DNA mixed with parental DNA

(I can’t model this but it’s like instead of one strand new and one old it’s like old and new mixed for BOTH strands in helix)

Question 8

What are sister chromatids

Answer 8

Two sides of a chromosome that has the same genes and placement

Question 9

What are non sister chromatids

Answer 9

Non identical sides of a chromosome

Question 10

What is a pair of homologous chromosomes

Answer 10

1. Same size
2. Same centromere location
3. Same banding pattern

Question 11

What replication mechanisms do humans have?

Answer 11

Semi conservative

Question 12

Process of DNA double helix condensing into chromosome?

Answer 12

1. Wrapping of DNA around Justine proteins
2. Formation of 3D dimensional zigzag structure via DNA-binding proteins
3. Further compaction of radial loops to form heterochromatin
4. Metaphase chromosome with 2 copies of DNA formed.

Question 13

How to identify cell stages in picture?

Answer 13

Interphase: chromosome replication? 
Prophase: dotty stuff
Metaphase: stringy stuff
Anaphase: stringy stuff on two sides
Telophase; two separate sides

Question 14

The four stages of mitosis?

Answer 14

Interphase
Prophase
Metaphase
Anaphase
Telophase

Question 15

What happens in cytokinesis

Answer 15

In animals:
Formation of cleavage furrow

In plants
Cell plate is formed as vesicles from golgi move along microtubules to separate cells
Cell wall between daughter cells formed

Question 16

Significance of mitotic cell cycle?

Answer 16

• enables growth in multicellular organisms (increase in cells= increase in mass)
• replace old/ worn out cells/ damaged tissue repair (genetically identical)
• allows unicellular organisms to asexually reproduce. (Genetically identical)

Question 17

What happens in interphase?

Answer 17

Chromosomes have already replicated. Cell preparing for division

Question 18

What happens in prophase?

Answer 18

Sister chromatids condense
Mitotic spindle forms
Nuclear envelope dissociates completely
Sister chromatids attach to spindle via kinetochore proteins

Question 19

What happens on metaphase

Answer 19

Sister chromatids align along the metaphase plate

Question 20

What happens in anaphase

Answer 20

Sister chromatids separate, and individual chromosomes move towards poles as kinetochore microtubules shorten.

Question 21

What happens in telophase (and cytokinesis)

Answer 21

Chromosomes FR condense and nuclear envelope reforms

Cleavage furrow forms (in animal cells)

Question 22

What is a Karyotype?

Answer 22

It is a photographic representation of a group of chromosomes

Question 23

What are gametes

Answer 23

Sperm and egg cells