lecture 8- mitosis

Question 1

what is cell division

Answer 1

organisms ability to reproduce
continuity of life through reproduction

Question 2

roles of cell division

Answer 2

reproduction
growth and development
tissue renewal/repair

Question 3

what is a chromatin

Answer 3

dna when the cell is not dividing

Question 4

what is a chromosome

Answer 4

dna during cell division
(chromatin tightly coiled around histones)

Question 5

what is a genome

Answer 5

all the genetic material in a cell

Question 6

what does each chromosome contain

Answer 6

huge molecule of dna and proteins

Question 7

what is the gene locus

Answer 7

the specific place where a gene is located on a specific chromosome

Question 8

how many chromosomes are there in the human genome

Answer 8

46 (number of chromosomes doesn’t mean how advanced a species is)

Question 9

what is a karyotype

Answer 9

organized profile of a person’s chromosomes

Question 10

how is a karyotype arranged

Answer 10

stained
arranged by size (largest to smallest)
photographed

Question 11

what are the 23 pairs of chromosomes

Answer 11

22 autosomes
1 sex chromosomes

Question 12

what is the use of karyotypes

Answer 12

to check irregularities in the number or structure of chromosomes

Question 13

why do you need an x sex chromosome

Answer 13

it has important genes for blood clotting and eyesight

Question 14

what does having an extra chromosome lead to

Answer 14

potentially down syndrome

Question 15

what is a haploid cell and examples

Answer 15

cell that has 23 chromosomes
egg and sperm
N

Question 16

what are diploid cells and examples

Answer 16

23 pairs of chromosomes
all somatic cells
2N

Question 17

what is a somatic cell

Answer 17

cell that isn’t gametic

Question 18

what happens when the sperm and egg cell unite

Answer 18

the nuclei fuse together to form a single nucleus

Question 19

when does the cell cycle happen

Answer 19

between the time a cell is formed and when it divides into two daughter cells

Question 20

what are the characteristics of mitosis

Answer 20

results in two identical cells
occurs during growth and repair
in somatic cells

Question 21

what are the stages in the cell cycle

Answer 21

interphase (G1, S, G2)
mitotic phase (mitosis, cytokinesis)

Question 22

how long does interphase happen compared to the mitotic phase

Answer 22

interphase is most of the cells lifespan (95%)

Question 23

what are the phases of interphase

Answer 23

growth 1
dna synthesis
growth 2

Question 24

characteristics of growth 1

Answer 24

period of active growth (increases in size until it reaches mature size for cell type)
synthesis of new organelles
dna is in chromatin form

Question 25

what happens during dna synthesis

Answer 25

the chromatins are copied

Question 26

what are the copied chromatins referred to as

Answer 26

sister chromatids

Question 27

what are the characteristics of the sister chromatids

Answer 27

contain the same genetic information attached at the centre with a centromere

Question 28

how many chromatins are there after dna replication

Answer 28

92 (46 double sister chromatids)

Question 29

what happens during growth 2

Answer 29

cell increases slightly begins preparing for mitotic phase - duplication of centrosomes - spindle fibers form dna is still in chromatin form

Question 30

what are the two parts of the mitotic phase

Answer 30

mitosis cytokinesis

Question 31

what are the steps of mitosis

Answer 31

prophase (early) prometaphase (late) metaphase anaphase telophase

Question 32

what happens in prophase

Answer 32

dna condenses (still called sister chromatids) nuclear envelope breaks centrosomes separate and move to opposing sides microtubules fibers extend between the centrosomes to form the mitotic spindle (some attach to chromosomes)

Question 33

what happens during prometaphase

Answer 33

nuclear membrane is broken down centrosomes are at opposing sides some microtubules attach to centromere region nucleoli disappears

Question 34

what is the centromere region called

Answer 34

kinetochores

Question 35

what happens in metaphase

Answer 35

chromosomes align in the middle of the cell (single file)

Question 36

what happens in anaphase

Answer 36

centromeres breaks and the sister chromatids separate (now called chromosomes) chromosomes are pulled to opposite ends of the cell cell elongates

Question 37

what happens during telophase

Answer 37

spindle fibers disappear nuclear membrane forms around the chromosomes nucleolus reappears chromosomes unwind and become less compact

Question 38

what is cytokinesis

Answer 38

separation of cells and cytoplasm

Question 39

what happens during cytokinesis

Answer 39

cell pinches along the middle and ends with two identical daughter cells

Question 40

how is mitosis different in plant cells

Answer 40

they don't have centrioles but they have microtubule organizing centers cell can't pinch in half

Question 41

how do the new cells separate in plant cell mitosis

Answer 41

separated by cell plate

Question 42

what are the steps in cytokinesis in plant cells

Answer 42

vesicles from the golgi carry cell wall components to the middle cell plate forms at the center and becomes a cell membrane

Question 43

how do prokaryotic cells divide

Answer 43

binary fission (asexual cloning)

Question 44

most bacteria have how many chromosomes

Answer 44

one

Question 45

how does binary fission work

Answer 45

chromosomes replicate move to opposite sides cell elongates to make room plasma membrane grows inwards split

Question 46

what happens if the cell doesn't pass a checkpoint

Answer 46

the cell tries to correct it if it can't it undergoes apoptosis (cell suicide)

Question 47

what are the checkpoints during mitosis

Answer 47

G1 checkpoint G2 checkpoint (between G2 and M) M checkpoint (between metaphase and anaphase)

Question 48

what's does the G1 checkpoint check

Answer 48

growth factor proteins nutrients cell size dna damage

Question 49

what does the G2 checkpoint check

Answer 49

cell size dna damage dna replication

Question 50

what does the M checkpoint check

Answer 50

chromosome attachment to spindle

Question 51

what is the purpose of the checkpoints

Answer 51

cancer prevention and mutation prevention

Question 52

what is cancer

Answer 52

disease of the cell excessive cell growth and division that is not controlled

Question 53

mutagens can be caused by

Answer 53

various agent that changes the dna of an organism (radiation, light, chemicals)

Question 54

when do mutations occur

Answer 54

during dna replication

Question 55

what are benign tumours

Answer 55

mass of cells that don't invade neighbouring tissue not considered cancer can be removed

Question 56

what are malignant tumours

Answer 56

mass of cells that invade neighbouring tissues can impair functioning of one or more organs considered cancerous can spread to the whole body

Question 57

what is it called when a cancer spreads to parts away from original site

Answer 57

metastasis

Question 58

how does metastasis work

Answer 58

cancer cells get into the bloodstream and move throughout the body

Question 59

what are the treatments for cancer

Answer 59

surgery high energy radiation chemotherapy

Question 60

what is the process of high energy radiation and what is it used for

Answer 60

non specific damage to the dna because cancer cells have lost their ability to repair dna used for localized tumors

Question 61

what is chemotherapy used to treat and how does it work

Answer 61

used for metastatic tumors damage actively dividing cells taxol freezes the mitotic spindles by preventing microtubule formation

Question 62

side effects of chemo

Answer 62

nausea immune suppression hair loss

Question 63

why doesn't your immune system attack cancer cells

Answer 63

because it's your own cells so the immune response doesn't recognize them as dangerous