chapter 6 Flashcards

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1
Q

what are the two parts of the cell cycle

A

interphase and mitotic phase

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2
Q

what are the three stages to interphase

A

G1 - proteins are made, cell gets bigger and organelles replicate
S - DNA is replicated (in nucleus)
G2 - cell gets bigger, energy stores increase and DNA is checked for errors

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3
Q

what is the mitotic phase and its two stages

A

its where the cell divides
mitosis - division of the nucleus
cytokinesis - cytoplasm divides and cells divide

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4
Q

what is the G0 stage

A

ite where cells leave the cell cycle and go into a resting state

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5
Q

what are the reasons for cells leaving the cell cycle

A

differentation - they carry out their own jobs and are no longer able to divide
damage - the DNA may be damaged so no longer can be used

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6
Q

what are checkpoints in the cell cycle

A

they moniter and verify that the cells have gone through the stages correctly without fault

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7
Q

where are the different checkpoint in the cell cycle

A

G1 - G1 checkpoint makes sure the cell has grown, got its nutrients and has no DNA damage
G2 - G2 checkpoint makes sure the cell has grown, has no DNA damage and has replicated its DNA
spindle - the spindle fibre checkpoint checks whether the chromasomes has attached to the spindle fibres

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8
Q

what happens if the checpoint picks up something wrong about the cell

A

it goes into the resting state G0

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9
Q

what phase does cell replication happen in

A

interphase

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10
Q

whatsa a chromatid

A

during replication each DNA molecule is converted into two identical DNA molecules called chromatids

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11
Q

what are the four stages to mitosis

A

PMAT
prophase
metaphase
anaphase
telephase

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12
Q

what happens in prophase

A

nuclear membrane starts to break down
chromatid condence making chromasomes
centrioles go to opposite poles
chromosomes are slowly moved to center of the cell

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13
Q

what happens in metaphase

A

where the chromosomes line up along the equator
its called the metaphase plate

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14
Q

what happens in anaphase

A

the pairs of chromatids divide
make V across the spindle fibres

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15
Q

what happens in telephase

A

chromatids have reached poles
nuclear envelope start to form around them
nucleus forms

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16
Q

cytokenisis in animals

A

pulls the membrane in
creates a cleavage furrow down the middle
two daughter cells made

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17
Q

cytokenisis in plants

A

no membrane so no furrow
vesicles from golgi appuratus line up down the middle where the metaphase plate was
cell wall starts to form
two daughter cells made

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18
Q

What does mitosis produce?

A

The nuclear division, producing two, genetically identical daughter cells = exact copy of the parents DNA and same number of chromosomes.

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19
Q

4 stages of meiosis 1

A

prophase 1
metaphase 1
anaphase 1
telophase 1

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20
Q

what happens in prophase one

A

chromosomes condense
nuclear envelope dissolves
nucleolus dissapears
spindle fibres form
homologous chromosomes pairs up
th chromatids could entangle in the transportation

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21
Q

what happens in metaphase 1

A

homologous chromosomes line up on the metabolic plate
orientation of the pairs are random
different assortment of chromosomes create genetic variation

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22
Q

what’s anaphase 1

A

homologous chromosomes are pulled to opposite poles
some DNA sister chromatids which entangle with each other break off and rejoin
this means an exchange in DNA
which could result in genetic variation

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23
Q

what’s telophase 1

A

same as mitosis telophase
nuclear membrane forms around the chromosomes
cell undergoes cytokenisis

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24
Q

what’s prophase 2

A

spindle fibres form
chromosomes condense
nuclear envelope breaks down

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25
Q

what’s metaphase 2

A

individual chromosomes line up on the metaphase plate

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26
Q

what’s anaphase 2

A

chromatids get pulled by spindle fibres attached to centromeres

27
Q

what’s telephase 2

A

chromatids assemble at poles and turn in to chromatins
nuclear envelope forms
then cytokinesis leads to the separation in 4 separate haploid cells

28
Q

what’s an erythrocyte (red blood cell)

A

biconcave disc to increase surface area
transports oxygen in the body
has haemoglobin
flexible to squeeze through capillaries
no nucleus so more room for haemoglobin

29
Q

what’s neutrophil

A

a white blood cell
has a multi lobed nucleus to squeeze though small gaps to get to infections
has a granular cytoplasm containing lysosomes that contain enzymes to attack pathogens

30
Q

what’s sperm cell

A

male gametes
flagella help it to propel towards the female gamete
digestive enzymes on the head help to break down the eggs layers
has lots of mitochondria for energy

31
Q

what’s root hair cell

A

good SA:V ratio
uptakes minerals and water from the soil

32
Q

what’s palisade cell

A

contains chloroplasts
rectangle to pack together
thin cell wall to increase rate of diffusion of carbon dioxide
large vacuole to maintain turgor pressure

33
Q

what’s a guard cell

A

on surface of leaves
CO2 enters through this
no water they are flaccid and closed
water they are turgid

34
Q

what’s squamous epithelium

A

flat and thin
one cell thick
rapid diffusion so is used in lining of the lungs which allows for rapid diffusion of O2 toblood

35
Q

what’s ciliated epithelium

A

cilia on surface
lines trachea

36
Q

what’s cartilage

A

connective tissue
elastin and collegan
cartilage is firm and flexible so is perfect to prevent rubbing at end of the bones

37
Q

what’s muscle

A

it contacts so you can move
heart cant beat

38
Q

what’s epidermis

A

single layer closely packed
on the surface of plants
covered by a waxy cuticle to reduce water loss
stomata are in the epidermis which alows for CO2, water and oxgygen in and out

39
Q

Chromosomes

A

Structures of condensed and coiled DNA in the form of chromatin.

40
Q

Chromatids

A

Two identical copies of DNA held together at the centromere

41
Q

Chromatin

A

Uncondensed DNA in a complex with histones

42
Q

Meiosis

A

A form of cell division where the nucleus divides twice, resulting in half the number of chromosomes and producing 4 haploid cells from one diploid cell.

43
Q

Gametes

A

Haploid sex cells produced by meiosis in organisms that reproduce sexually

44
Q

Zygote

A

The initial diploid cell formed when 2 gametes are joined by the means of sexual reproduction

45
Q

Haploid

A

Half the number of normal chromosome number; one chromosome of each type

46
Q

Homologous chromosomes

A

Matching pair of chromosomes, one from each parent

47
Q

Alleles

A

Different versions of the same gene

48
Q

Genetic variation

A

A variety of different combinations of alleles in a population.

49
Q

Crossing over

A

Sections of DNA which become entangled, breaks and re-joins during prophase 1 of meiosis = genetic variation

50
Q

Independent assortment

A

The arrangement of each homologous chromosome pair in metaphase 1 and 2 of meiosis is independent of each other and results in genetic variation

51
Q

Stem cell

A

Undifferentiated cells with the potential to differentiate into any of the specialised cell types of the organism

52
Q

Potency

A

The ability to differentiate into different cell types

53
Q

Totipotent

A

These can differentiate into any type of cell

54
Q

Pluripotent

A

These can form all tissue types but not whole organisms

55
Q

Multipotent

A

Only form a range of cells within a certain type of tissue

56
Q

Sources of animal stem cells

A

Embryonic stem cells, tissue stem cells

57
Q

Embryonic stem cells

A

Present at the very early stages of embryo development and are totipotent

58
Q

Tissue stem cells

A

Present throughout life, from birth to death. Found in specific areas e.g. bone marrow. Multipotent. Can be harvested from the umbilical cord of new babies

59
Q

Sources of plant stem cells

A

In meristematic tissue

60
Q

Meristematic tissue

A

Found wherever the plant is growing e.g. root tips. Also between xylem and phloem.

61
Q

Potential usage of stem cells in treatment for:

A

Heart disease, type 1 diabetes, Parkinson’s disease, Alzheimer’s disease, muscular degeneration, birth defects, spinal injury

62
Q

Current usage of stem cells in areas such as:

A

Burn treatment, drug trial, developmental biology

63
Q

Ethics

A

Embryos - religious and moral judgement. murder.