2.6 cell division, diversity and cellular organisation Flashcards Preview

biology module 2- foundations in biology > 2.6 cell division, diversity and cellular organisation > Flashcards

Flashcards in 2.6 cell division, diversity and cellular organisation Deck (46)
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1

the stages of the cell cycle are

mitosis, cytokinesis, interphase

2

many cells in multicellular tissues don't have the ability to

divide

3

during interphase, cells are

between dividing

4

during mitosis, cells are

dividing and moving to opposite poles of the cell

5

during cytokinesis, cells are

splitting in two

6

the stages of interphase are

G1, S, G2

7

G1 is known as the

growth phase

8

the purpose of G1 is to

prepare the cell for mitosis

9

3 things that happen during G1 are...

1. organelles duplicate
2. cell grows in size
3. proteins needed for mitosis are made

10

S phase is also known as the

synthesis phase

11

the purpose of S phase is to

replicate DNA so that there are 2 sets for the new cells

12

by the end of S phase, all chromosomes

have been replicated

13

during S phase, all - are replicated

DNA strands

14

the purpose of G2 phase is to

check that the cell is ready for mitosis

15

what happens in G2 phase

organelles such as mitochondria and lysosomes divide

16

meiosis is used to create

haploid cells

17

meiosis occurs in

two divisions

18

diploid cells have - pairs of chromosomes

23

19

haploid cells can be called

gametes

20

why do gametes have to be haploid?

so that they have the right number of chromosomes when they grow alongside another gamete in sexual reproduction

21

meiosis occurs

after interphase

22

what happens in meiosis 1?

homologous pairs of chromosomes are separated

23

what happens in meiosis 2?

sister chromatids from each chromosome are separated

24

meiosis creates - - gametes which are - -

4 haploid, genetically different

25

what are the stages in meiosis 1

prophase 1, metaphase 1, anaphase 1, telophase 1

26

prophase 1 is the first...

stage in meiosis overall

27

during prophase 1, chromosomes

supercoil to condense, making them visible

28

during prophase 1, the nuclear envelope

breaks down

29

during prophase 1, spindle fibres

form from centrioles

30

4 things that happen during prophase 1

1. chromosomes supercoil
2. nuclear envelope breaks down
3. spindle fires form from centrioles
4. chromosomes undergo crossing over

31

when does crossing over occur?

during prophase 1

32

crossing over is the...

exchange of DNA between chromatids on homologous chromosomes

33

the stages of crossing over are

1. twisting
2. breaking off
3. swapping

34

crossing over allows

variation in alleles

35

the key purpose of metaphase 1 is to

line up chromosomes at the equator of the cell

36

independent assortment occurs during

metaphase

37

independent assortment is how

homologous chromosomes are arranged

38

independent assortment creates

more genetic variation

39

3 things that happen in metaphase 1 are

1. attachment of chromosomes to spindle fibres at the centromere
2. chromosomes lie with their homologous pair at the equator
3. independent assortment

40

how do chromosomes attach to spindle fibres

at the centromeres

41

spindle fibres are constructed from

centrioles in animals, cytoplasm in plants

42

the purpose of anaphase 1 is

to separate homologous chromosomes to opposite poles of the cell

43

in anaphase 1, chromosomes are pulled to opposite poles by

spindle fibres and motor proteins

44

the purpose of telophase 1 is to

reform two new nuclear envelopes

45

which type of cell undergoes cytokinesis after telophase 1

animal cells

46

do plant cells undergo cytokinesis after telophase 1

no