Cell Cycle

Question 1

cell continuity

Answer 1

cells arise from pre-existing cells

Question 2

chromosomes

Answer 2

threads made up of DNA and protein found in the nucleus that carry genetic information in the form of genes

Question 3

gene

Answer 3

a section of DNA that codes for the production of a protein

Question 4

haploid

Answer 4

one set of chromosomes in the nucleus

Question 5

diploid

Answer 5

two sets of chromosomes in the nucleus

Question 6

homologous pair

Answer 6

two chromosomes of equal length with the same sequence of genes

Question 7

interphase

Answer 7

when a cell is not dividing

Question 8

mitosis

Answer 8

a form of nuclear division in which one nucleus divides to form two nuclei, each containing identical sets of chromosomes

Question 9

cancer

Answer 9

a group of disorders in which certain cells lose their ability to control both the rate of mitosis and the number of time mitosis occurs

Question 10

meiosis

Answer 10

a form of nuclear division in which the daughter nuclei contain half the chromosome number of the parent nucleus

Question 11

describe interphase

Answer 11

cellular processes occur: respiration, protein synthesis
chromosomes are elongated and thin- known as chromatin during this phase
cells spend 90% of its cycle in this phase

Question 12

mitosis includes

Answer 12

prophase
metaphase
anaphase 
telophase
10% of the cycle

Question 13

prophase

Answer 13

chromosomes duplicate and are double stranded chromatid pairs
nuclear membrane breaks down
spindle forms
nucleolus disappears

Question 14

metaphase

Answer 14

chromatid pairs line up along the equator of the cell

spindle fibres attach the the centromeres

Question 15

anaphase

Answer 15

spindle fibres contract and pull the centromeres until they split
sister chromatids separate and move to opposite poles of the cell
identical genes are now at opposite poles

Question 16

telophase

Answer 16

spindle fibres break down
chromosomes at each end elongate and become chromatin threads
nuclear membrane forms around chromatin at both poles
nucleolus reappears
two identical nuclei have been formed

Question 17

cell wall prevents

Answer 17

furrow formation

Question 18

cell division in plant cells

Answer 18

vesicles containing cellulose gather along the centre of the cell; forms the cell plate
two cell walls form

Question 19

cell division in animal cells

Answer 19

cleavage furrow (shallow groove) forms along cell equator
gets deeper until it splits into two cells

Question 20

mitosis functions in unicellular organisms

Answer 20

asexual reproduction

Question 21

mitosis functions in multicellular organisms

Answer 21

produces new cells, not new individuals

responsible for growth, renewal and repair of cells

Question 22

meiosis functions

Answer 22

sexual reproduction (produces sex cells)
variation as a result of different gene combinations

Question 23

cancer types

Answer 23

benign tumours - non life threatening and do not invade other tissues eg warts

malignant tumours - uncontrolled multiplication of abnormal cells
invades other cells and move around the body (metastasis)
cancer cells divide indefinitely

Question 24

causes of cancer

Answer 24

carcinogens

• exposure to UV radiation
• exposure to asbestos fibres
• cigarette smoke from inhaling/second hand smoke

Question 25

cancer treatment

Answer 25

``` surgery chemotherapy (slows down the rate of mitosis) ```

Question 26

meiosis vs mitosis

Answer 26

meiosis: 4 daughter cells daughter cells not identical to each other/parent sexual reproduction: allows variation mitosis: 2 daughter cells daughter cells identical to each other/parent asexual reproduction: growth + repair of cells