ch 2 cell divison and differentiation

Question 1

when do cells divide

Answer 1

when the body needs to
-grow
-replace worn out cells
-repair damaged tissue

Question 2

how many pairs of chromosomes do we have

Answer 2

23 - 46 in total

Question 3

what does homologous mean

Answer 3

identical

Question 4

what are chromosomes

Answer 4

long strands of dna found in nucleus

Question 5

whats the difference between mitosis and meiosis

Answer 5

mitosis produces 2 genetically identical daughter cells while meiosis occurs after mitosis and produces 4 differentiated daughter cells

Question 6

what are the stages of mitosis

Answer 6

1- interphase where dna is replicated
2-chromosome migrates to opposite ends of cell
3- cell divides in 2 with same number of chromosomes
4- end up with 2 identical daughter cells

Question 7

in which cells does mitosis not occur

Answer 7

all cells except gametes (sex cells)

Question 8

what happens when cells divide uncontrollably

Answer 8

causes tumor then cancer

Question 9

what is the cell cycle

Answer 9

the process a cell goes through each time it divides
-chromosome doubles
-cell divides into 2 daughter cells and receives 1 copy of doubled material

Question 10

what are the 3 main phases of the cell cycle

Answer 10

-interphase
-mitosis
-cytokinesis

Question 11

what happens in interphase

Answer 11

organelles double and dna replicates to form 2 coppies

Question 12

what happens in mitosis

Answer 12

the chromosomes move apart and nucleus divides

Question 13

what happens in cytokinesis

Answer 13

the cell membrane splits in 2 to finally give 2 identical daughter cells

Question 14

what happens in meiosis

Answer 14

4 differentiated daughter cells are created (haploids)

Question 15

what happens in the stages of meiosis

Answer 15

-chromosomes are doubled
-mitosis
-cell divides again which forms 4 gametes (sex cells)

Question 16

what are the main features of meiosis

Answer 16

-cell divides twice and forms 4 gametes
-gametes are genetically different

Question 17

what are stem cells

Answer 17

cell that hasnt become differentiated or specialised yet

Question 18

what are the features of stem cells

Answer 18

-can replicate many times by mitosis
-can become different types of cells

Question 19

what happens to stem cells during the development of an embryo

Answer 19

most cells become specialised

Question 20

cell differentiation is a ____ process

Answer 20

irreversable

Question 21

what are plant stem cells called

Answer 21

meristem cells

Question 22

where are meristem cells found

Answer 22

root and shoot tipes

Question 23

what are the 2 functions of stem cells

Answer 23

-growth and development
-repair and replacement

Question 24

what happens to cells over time

Answer 24

they die or get too old to function properly

Question 25

why are adult stem cells needed

Answer 25

for growth eg:bone marrow

Question 26

why are embryonic stem cells needed

Answer 26

to develop- they come from discarded embryos

Question 27

why are adult stem cells resistricted in types of cells they can become

Answer 27

because genes are turned off

Question 28

what are the features of embryonic stem cells

Answer 28

-they can differentiate into any cell -usually removed from human embryos -unspecialised

Question 29

what are the features of adult stem cells

Answer 29

-specialised -can only differentiate into skin or blood cells

Question 30

name 3 organs where adult stem cells can be found

Answer 30

-brain to treat neurological diseases -skin cells repair damaged or worn out cells -intestines to replace worn out cells

Question 31

what is therapeutic cloning

Answer 31

the process of creating stem cells with the same genes as the patient

Question 32

what are the 4 steps of therapeutic cloning

Answer 32

1- nucleus taken out of human egg cell 2- nucleus put into egg cell 3- egg cell stimulated to develop into an embryo 4- stem cells grow

Question 33

what are the advantages of therapeutic cloning

Answer 33

- helps create vital organs -can help prevent or cure diseases -small chance of rejection

Question 34

what are the disadvantages of therapeutic cloning

Answer 34

-stem cells kept in labs show similarities to cancer cells -virus transfer is possible -its very expensive to extract eggs -raises ethical issues

Question 35

whatre the advantages of adult stem cells

Answer 35

-since cells are from the same body they wouldnt get rejected -no embryos envolved so adults give permision

Question 36

whatre the disadvantages of adult stem cells

Answer 36

-cells grown in labs can cause cancer -only a few stem cells remain in the human body -they can only differentiate into specific cells

Question 37

whatre the advantages of embryonic stem cells

Answer 37

-lots of stem cells are avalible -can differentiate into any cell -can be used to replace damaged or destroyed cells

Question 38

what are the disadvantages of embryonic stem cells

Answer 38

-ethical issues -transplants can be rejected by the patients immune system -difficult to obtain and store patatients stem cells -patient can be scammed becaue stem cells are only in their developmental stage

Question 39

a cell that has 2 sets of chromosomes

Answer 39

diploids

Question 40

cells that have only 1 set of chromosomes

Answer 40

haploid

Question 41

mass of abnormal cells caused by mutation that invade and destroy surrounding tissue

Answer 41

tumor

Question 42

what are the features of a benign tumor

Answer 42

grow slowly, harmless but can cause blockage and pressure organs

Question 43

what are the features of malignant tumors

Answer 43

they grow rapidly,invade and destroy tissue,spread in blood

Question 44

what can cause cancer

Answer 44

-carcingogens -raadiation -inhertiance -obestity -age

Question 45

how does chemotherapy treat cancer

Answer 45

chemicals are used to stop cells from dividing or making those cells distruct

Question 46

how does radiotherapy help treat cancer

Answer 46

cancer cells are destroyed by targeted doses of radiation