Cell division (paper 2) Flashcards

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1
Q

.what do most cells in the human body contain

A

a nucleus

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2
Q

what does a nucleus contain

A

the genetic meterial of the cell

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3
Q

what is the genetic chemical in the nucleus called

A

DNA

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4
Q

what is DNA arranged into

A

structures call chromosomes

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5
Q

what is a chromosome

A

a coiled molecule of DNA carrying different genes

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6
Q

what is a the term for a body cell

A

somatic cell

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7
Q

how are chromosomes found in somatic cells

A

in pairs

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8
Q

why are chromosomes found in pairs

A

because each pair is inherited from the person’s mother and one from their father

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9
Q

how many chromosomes do humans contain

A

46 chromosomes in 23 pairs

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10
Q

what is the haploid number and what is it for a human

A

the number of pairs of chromosomes
23 pairs in a human

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11
Q

what is the diploid number and what is it for humans

A

the number of chromosoms in a cell
46 chromosomes

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12
Q

what are gametes

A

sex cells

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13
Q

what is the female sex cell

A

an ovum

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14
Q

what is the male sex cell

A

sperm

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15
Q

what is the word for the picture of chromosomes when removed from a nucleus and arranged in order

A

a karyogram or karyotype

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16
Q

what are karyograms/karyotypes used for

A

to determine the sex of an individual and diagnose genetic disorders

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17
Q

how can you tell if an individual is female

A

they will have 2 x chromosomes

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18
Q

how can you tell if an individual is male

A

they will have one x chromosome and one y chromosome

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19
Q

how are new cells made

A

by the proccess mitosis

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20
Q

define mitosis

A

the growth and repair of tissues

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21
Q

what is the cell cycle

A

the series of stages which somatic cells divide in

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22
Q

what happens in stage one of the cell cycle for mitosis (interphase)

A
  • cell increases in size
  • the DNA is replicated
  • the number of organelles is doubled
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23
Q

what happens in the second stage of the cell cycle for mitosis (prophase)

A
  • the chromosomes condense in the middle of the cell
  • half the chromosomes are pulled to one pole of the cell
  • two nuclei are formed
  • cell is split to form 2 genetically identical daughter cells
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24
Q

what is the longest stage of mitosis

A

when the cell grows and replicated their DNA and increases the sub-cellular structures (the first stage)

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25
Q

what do genes do

A

they carry the instructions to control a characteristic

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26
Q

what is binary fission

A

the method of asexual reproduction which single-cell organisms use to create a copy of themselves

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27
Q

in binary fission are plasmids equally shared between the daughter cells? explain?

A

No - the plasmids are shared randomly, but one loop of DNA goes to one daughter cell and the other to the other daughter cell

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28
Q

what happens in the process of binary fission

A
  • Cell replicates DNA
  • cell grows
  • cell wall forms and cell membrane invaginates
  • daughter cells formed
29
Q

what type of cells conduct binary fission

A

prokaryotic

30
Q

what is meiosis used for

A

the formation of gametes

31
Q

what is similar in the processes mitosis and meiosis

A

DNA is duplicated before cell division in both

32
Q

mitosis? meiosis?
which produces genetically identicel cells and which produces genetically unique cells

A

genetically identicle cells - mitosis
genetically unique cells - meiosis

33
Q

mitosis? meiosis?
results in haploid cells or diploid cells

A

diploid = mitosis
haploid = meiosis

34
Q

mitosis? meiosis?
occurs only at certian times of life cycle or takes place throughout lifetime

A

occurs throughout lifetime = mitosis
occurs at certain times of lifecycle = meiosis

35
Q

mitosis? meiosis?
involved in asexual or sexual reproducution

A

asexulal reproduction = mitosis
sexual reproduction = meiosis

36
Q

what is a stem cell

A

an undifferentiated cell

37
Q

what is the function of a stem cell

A

they can differentiate to become different types of specialised cells

38
Q

what are the three different types of stem cells

A
  • embryonic
  • adult
  • plant
39
Q

what is different for stem cells in animals comapred to plants

A

in animals little to no growth takes place, the same type of cells are made. in plants they are able to differentiate trhoguhtout their lives (known as meristem cells)

40
Q

what is the name given to the stem cells in plants which are undifferentated

A

meristem cells

41
Q

how are embryonic stell cells formed

A

after a sperm cell and egg fuse to form a zygote, that cell divides to form an embryo.
the inner cells of this ball are embryonic stem cells

42
Q

give an example of an adult stem cell

A

bone marrow

43
Q

what are adult stem cells described as

A

multipotent stem cells

44
Q

what are embryonic stem cells described as

A

totipotent stem cells

45
Q

where are the meristem cells found in plants

A

at the tips of roots and shoots

46
Q

what are the ethical againsts and fors in stem cell research

A

+they are treating and curing patients
+wasted embryos from fertilisation are being used
-they think its a potential life
-embryos cannot consent
-think time and money should be used to find an alternative solution

47
Q

what are the two types of reproduction

A
  • asexual
  • sexual
48
Q

evalutate asexual reproduction

A
  • involves mitosis (or buimary fission in bacteria)
  • involves only one patient
  • does not involve fusion of gametes
  • does not result in mixing genetic info
  • produces genetical identical offspring
49
Q

how can plants reproduce asexually

A

using the process vegetative reproduction

50
Q

what type of production is in animalas

A

sexual

51
Q

define sexual reproduction

A

the mixing of genetic information which leads to variety in the offspring - the offspring are genetically different to both parents

52
Q

what are the male gametes called

A

sperm

53
Q

what are the female gametes called

A

ova

54
Q

which cell division process does the formation of the gametes involve

A

meiosis

55
Q

how many chromosomes does each gamete contain

A

the haploid number of chromosomes (half)

56
Q

describe fertilisation

A
  • the ovum and sperm fuse together
  • results in single zygote cell (has full number of chromosmes)
  • zygote develops into the embryo
57
Q

what type of plants does sexual reproduction occur in

A

flowering plants

58
Q

what is the reproductive organ of any flowering plant

A

the flower

59
Q

what is the male gamete in plants

A

the stamen (anther and filament) which contain the pollen

60
Q

what is the female gamete in plants

A

the carple (stigma, style and ovary) which contains the ocules

61
Q

what happens during pollination

A

the pollen is transferred from the anther to the stigma

62
Q

what happens when a cell divides to form gametes

A
  • copies of the genetic info is made
  • cell divides twice to form 4 gametes
  • each have a haploid number of chromosomes
  • all gametes are genetically different from each other
63
Q

whtat are the advantages of sexual reproduction

A
  • genetically varied = survival advantage if change occurs
  • natural selection sped up by selective breeding
64
Q

what are the advantages of asexual reproduction

A
  • only one parent needed
  • more time and energy efficient
65
Q

give some examples of organisms that use BOTH sexual and asexual reproduction

A
  • malaria parasite (protist)
  • fungi
  • strawberry plant
  • daffodils
66
Q

how does the malaria parasite reproduce

A

sexually - when inside the mosquito
asexually - when inside the human

67
Q

how does fungi reproduce

A

sexually - releases spores sexually
asexually - releases spores asexually

68
Q

how does the strawberry plant reproduce

A

sexually - produces gametes in flowers
asexually - produce runners

69
Q

Describe mitosis

A

Cell increases in size and dna replicates
One set of chromosomes get pulled to each pole of the cell
Cell membrane and cytoplasm divide into genetically identical cells