Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

biology 30 > Cell division > Flashcards

Cell division Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What three things do we need cell division for

A
  1. growth (need more cells)
  2. repair (cells need to be replaced)
  3. reproduction (unicellular organisms use mitosis to reproduce asexually)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the SA vs V ratio of growing cells

A

when a cell grows, the volume of the CYTOPLASM grows at a faster rate than the sa of the PLASMA MEMBRANE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

somatic cells

A

body cells. any cell in the body other than reproductive cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how many chromosomes do humans have and how many from each parent

A

46 chromosomes, 23 from each parent

every cell has the same 46 chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

difference between the splitting of organelles vs chromosomes

A

organelles can be randomly separated into daughter cells

chromosomes must split even;y so each daughter cell gets exactly same DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

homogolous chromosomes

A

chromosome pairs containing maternal and paternal chromatid similar in length, position, and joined together at the centromere (belt)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

autosomes. how many are there

A

22 pairs of chromosomes all ppl share.

the last one would be sex chromosome (XX female or XY male)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

diploid, haploid, polyploidy

A

diploid (2n)- all pairs of chromosomes (humans-46)
haploid (n)- in gametes (humans-23)
polyploidy (3n,4n,5n…) sets of more than 2 homogolous chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are benefits of polyploidy 4

A
  • more vigorous and healthy than diploid parents
  • offspring shielded from negative effects off recessive mutations cus it has twice as many copies of genes.
  • gene redundancy gives organism ability to diversify gene function over time. extra gene copies that arent used normally are used in new ways leading to new opportunities in evolutionary selection
  • self fertilization, favoring asexual reproduction. may improve fitness in stable environments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is critical in oganisms with more chromosomes

A

the ability of homologs to find one another, pair, and stay together during the first meiotic division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

spindle fibres

A

protein strands that attach to the centromere and pull chromatids to opposite ends of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

centriole

A

found only in animal cells and provide attachment for spindle fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the 2 different states chromosomes are in before and after they REPLICATE their dna

A

before:
one chromatid

after:
2 sister chromatid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the support protein that holds together the chromatid’s DNA called

A

histones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

chromatin

A

the things that make up chromosomes. they are strands of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

karyotype

A

each chromosome has specific length and banding pattern, so they are matched up in a karyotype

look at sex chromosomes first and then check all pairs of autosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

cell cycle phases

A

I PMAT
interphase
prophase
metaphase
anaphase
telophase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

3 phases of interphase

A

g1- rapid growth
s- duplication of chromosomes (doubling DNA)
g2- grows and prepares to divide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

interphase use

A

spend the most time here.
grow, divide, and undergo metabolic processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

prophase

A

chromosomes condense, proteins (histones) attach to the dna to shorten it to a chromosome

  • nuclear envelope disappears
  • centrioles move to opposite ends of cell
  • spindle fibres made of microtubules start to form, growing out of centrioles toward chromosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

metaphase

A

short resting period where chromosomes line up on equator of cell and spindle fibers attach to centromeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

anaphase

A

centromeres divide. individuals go from
1 chromosome 2 chromatid
2 chromasome 1 chromatid EACH

spindle fibers contract, chromosomes pulled to positive poles, toward centrioles

each end of pole has one set of chromosomes (1 pair)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

telophase

A

chromosomes at poles of spindle
chromosomes unwind
spindle disintegrates
nuclear envelope reforms around two sets of chromosomes and
cytoplasm divided into 2 separate cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

cytokinesis

A

organelles other than chromosomes divide into 2 daughter cells passively. they go w whichever cell they find themselves in

plant and animal cells divide cytoplasm differently

interphase again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are two differences between animal and plant cells in mitosis

A

animal: cleavage furrow. cytokinesis occurs by CONSTRICTION of microtubules
plant: cytokinesis occurs by growth of cell plate of cellulose

animal: has centrioles and involves spindle formation
plant: lack centrioles

26
Q

what happens in cytokinesis specifically in animal cells

A

ring of ACTIN FIBERS (microfilaments are composed of actin) forms around cell equator and contacts, pinching the cell in half

27
Q

what happens in cytokinesis specifically in plant cells

A

new cell wall made of cellulose forms between two nuclei

28
Q

max amount of cell divisions before cells die

A

50

29
Q

cell division is stopped by cell what?

A

cell specialization

30
Q

only what two kinds of cells casn divide endlessly

A

cancer and spermatogonia cells

31
Q

meisosis

A

cell division to form gametes, sperm and egg

32
Q

are gametes diploid, haploid, or polyploid

A

haploid. one copy of every gene. need to choose 1 copy of each gene randomly

33
Q

what happens to good and bad combinations of alleles between parents and offspring in gametes?

A

bad combinations die without reproducing and good combinations survive to reproduce more

34
Q

alleles

A

one of two or more alternative forms of a gene that are created by MUTATION and are found at the same place on a chromosome

35
Q

gene

A

section of the chromosome that codes for a protein

36
Q

meiosis overview

A

starts with homologues
XX

separate homologues
X X

separate chromatids
II II

37
Q

key outcomes of meiosis 2

A
  1. reduction division, daughter cells have fewer chromosomes
  2. recombination, daughter cells have diff comb of genes
38
Q

what are two important events that cause variations in MEIOSIS 1

A

crossing over in prophase //// \\&raquo_space; ///\ \\/

random pairing of homologues in metaphase
1st possibility: // // \
2nd: /\ /\ \/ \/

39
Q

crossing over

A

replicated homologous pair of chromosomes come together (in synapsis) and sections of chromosomes are exchanged. creates new combinations of alleles on each chromosome

chromosomes neither entirely paternal or maternal but contains genes from both parents

occurs randomly several times on every chromosome

results in mixing of genes inherited from parents

40
Q

how does crossing over contribute to genetic diversity

A

crates new combinations of genes in gametes that are not found in either parent (blue x blue = brown eyes)

41
Q

independent assortment

A

alleles of 2 diff genes get assorted into gametes independent of each other

// // \ \ or /\ /\ \/ \/

42
Q

prophase 1

A

each pair of homologous chromosomes align side by side (synapsis/crossing over)

43
Q

what is a tetrad in prophase 1

A

2 chromasomes next to each other (or 4 chromatids) that have crossed over, created in prophase 1. chromosomes have different alleles.

44
Q

homologous chromosomes

A

chromosomes that have same genes but diff order. after crossing over

45
Q

metaphase 1

A

pairs of homologous chromosomes line up side by side

independent assortment occurs here.

46
Q

anaphase 1

A

instead of the centromeres breaking apart, the chromatids stay together. spindle fibers shorten and separate homologous chromosomes from one another.

47
Q

results of meiosis 1

A

go from 1 to 2 cells. each daughter cell contains 1 copy of EACH CHROMOSOME

humans: 2 cells containing 23 chromosomes

as a result of crossing over ,each chromosome is the mixture of original homologues.

48
Q

interkinesis

A

in some species. cells enter a brief interphase, or interkinesis, before entering meiosis 2

lacks S phase, so chromosomes are not duplicated. (replicates DNA to make two sister CHROMATIDS)

49
Q

difference and similarities between meiosis II and mitosis

A

meiosis is jusst like mitosis except there is no dna replication before it begins

each cell is a haploid in meiosis II

50
Q

prophase Ii

A

if the chromosomes decondensed in telophase I, they will condense again

centrioles that were duplicated during interkinesis move away from each other toward opoositte poles and new spindles are formed.

51
Q

metaphse I and Ii comparison

A

I- homologous chromosomes PAIR at equator
II- chromosomes line up and chromatids split

I: -XX- -xx-
II: -X- -x-

52
Q

anaphase I and II comparison

A

I- homologous chromasomes seperate
II- chromatids seperate

53
Q

telophase ii

A

chromosomes arrive at opposite poles and decondense

nuclear envelopes form around chromosomes

cytokinesis separates two cells into four unique haploids

newly formed nuclei are both haploid (one chromatid per chromosome) (diploid: XX (pair) haploid: II(different chromosomes))

54
Q

telophase I and II comparison

A

I- haploid cell, chromatids still attached
II- haploid cells, 4 unique cells produced (chromatids no longer attached)

55
Q

summary of meiosis

A
  • 2 cell divisions
  • start w 2 copies of each chromosome (homologues), each w 2 chromatids
  • meiosois 1: crossing over in prophase and mixing alleles between homologues
  • ends with 4 cells, each having a copy of each chromosome with 1 chromatid each
56
Q

in male animals, what do all 4 products of meiosis develop into

A

sperm cells

57
Q

each sperm is a diploid/haploid/polyploid with _____ number of chromosomes

A

each sperm is haploid with 23 chromosomes

58
Q

oogenesis

A

formation of female gametes

cell division of meiosis are asymmetric in female cells, most of cytoplasm goes into 1 out of the 4 meiotic products, which becomes the egg.

other 3 are small “polar bodies” which degenerate

59
Q

nondisjunction

A

failure of homologous chromosomes or sister chromatids to separate during meiosis

produces gametes that have too many or too few chromosomes (n+1 or n-1)

60
Q

disorders due to nondisjunction

A

zygote w 45 chromosomes has only one copy of particular chromosome: MONOSOMY

zygote w 47 chromosomes has three copies of particular chromosome: TRISOMY

*only humans

61
Q
A

biology 30 (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions