Chapter 5-Mitotic Cell Cycle

Question 1

name of process through which a cell makes exact copies of itself

Answer 1

mitosis

Question 2

name the parts of chromosomes (4 parts)

Answer 2

chromatids
kinetochore
telomeres
centromeres

Question 3

how many DNA molecules are in one chromosome?

Answer 3

2 molecules, one DNA molecule in each chromatid

Question 4

how do chromosomes divide equally?

Answer 4

one chromatid goes into one daughter cell and the other goes into the other daughter cell

Question 5

DNA+protein=?

and name the protein

Answer 5

chromatin

and the protein is histone

Question 6

what is a nucleosome and describe its structure

Answer 6

1. cylindrical structure made of up of 8 histone molecules

2. DNA is wrapped around the outside of the cylinder.

Question 7

when are chromosomes the most coiled?

Answer 7

interphase

Question 8

describe mitosis

Answer 8

a process by which genetically identical cells are made

Question 9

how can uncontrolled cell division result in cancer?

Answer 9

mutations

Question 10

chromatin exists in what 2 forms

Answer 10

euchromatin and hetrochromatin

Question 11

during interphase, which type of chromatin is the majority of chromatin found as?

Answer 11

euchromatin

Question 12

when is chromatin most condensed or coiled (darker)?

Answer 12

during metaphase

Question 13

which is the first stage of a cell cycle?

Answer 13

interphase

Question 14

what does a cell do during interphase?

Answer 14

carries out normal functions until it gets a signal to divide again

Question 15

what happens after the signal for cell division has been recieved?

Answer 15

DNA replicates itself (so that each chromatid will have one DNA molecule)

Question 16

what is the name of the phase when DNA replicates?

Answer 16

S phase (synthesis of DNA phase)

Question 17

name parts of a cell cycle (3 parts)

Answer 17

1. interphase (consists of G1, S, G2)
2. mitosis
3. cytokinesis

Question 18

what are the 4 stages of mitosis? (in order)

Answer 18

1. prophase
2. anaphase
3. metaphase
4. telophase

Question 19

what does the cell look like during early prophase?

Answer 19

1. nuclear envelope is present
2. nucleolus is present
3. centrosomes (things that make spindles) replicate just before prophase
4. chromosomes start to appear as they become shorter and thicker

Question 20

what does a cell look like during late prophase?

Answer 20

1. nuclear envelope disappears
2. nucleolus disappears
3. chromosomes now consist as 2 identical chromatids
4. centrosomes start to move at the end of poles

Question 21

what does a cell look like during metaphase?

Answer 21

1. centroSOMES reach poles
2. spindles are formed and attached to centroMERES
3. chromosomes line up across the equator of the cell

Question 22

what does a cell look like during anaphase?

Answer 22

1. sister chromatids are pulled apart by spindles
2. chromatids separate at the centroMERES

(2 points)

Question 23

what happens during telophase?

Answer 23

1. nucleolus re-forms
2. nuclear envelope re-forming
3. remains of the spindles breakdown
4. chromatids reach the pole
5. cytokinesis takes place

(5 points)

Question 24

what is the role of the centromere?

Answer 24

1. needed for separation of chromatids

2. spindles attach to the centromere to pull the chromatid to the pole

Question 25

describe what are kinetochores

Answer 25

1. made of proteins molecules which bind to the the DNA in centromere and microtubules 2. bundles of microtubules extend from the kinetochores to the poles during mitosis

Question 26

describe centrosomes

Answer 26

1. found in animal cells that act as a microtubule organizing centre (for the construction of spindle) 2. each centrosome = pair of centrioles = large no. of proteins these proteins control the production of microtubules and not the centrioles

Question 27

4 significances of mitosis

Answer 27

1. growth 2. replacement of damaged cells and tissues 3. asexual reproduction 4. immune response

Question 28

what are telomeres?

Answer 28

they are structures found at the end of chromosomes with extra DNA bases (with no useful information). they prevent important DNA bases from being lost.

Question 29

what are stem cells?

Answer 29

cells that are not specialized and can change themselves to any type of cell i.e. tissue cell, muscle cell, etc.

Question 30

types of stem cells

Answer 30

1. totipotent: stem cells that can change into any type of cell 2. embryonic stem cells are pluripotent because they have to become different types of cells. 3. adult stem cells are multipotent because even though they can specialize to become different cells, they are restricted.

Question 31

what results in cancer?

Answer 31

uncontrolled mitosis

Question 32

what is a tumour and how is it formed?

Answer 32

a tumour is a mass of cells formed bh cancerous cells dividing uncontrollably

Question 33

what type of change in the body causes cancer?

Answer 33

mutation in the gene that controls cell division to become an oncogene (oncogene is a mutated gene)

Question 34

what is a cancer causing agent?

Answer 34

carcinogen

Question 35

not all tumours are cancerous. so what are the cancerous tumours called and why are they cancerous ?

Answer 35

malignant tumours | they are cancerous because they interfere with the normal functioning of the body