2.6 cell division, diversity, organisation Flashcards

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1
Q

name the phases of the cell cycle

A

interphase
mitosis
cytokinesis

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2
Q

name the phases and describe what happens in interphase

A

g0= resting phase, cells may die, differentiate
G1= first growth phase, cell increases in size, organelles duplicate, genes transcript, protein synthesis
S= synthesis, DNA replicates
G2= second growth phase, cell checks for errors

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3
Q

what happens at the checkpoints

A

cell cycle halted and checked
g1= DNA damage, cell size etc.
g2=prevents cell replicating if DNA error from replicating

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4
Q

why are there checkpoints in the cell cycle

A

prevent uncontrolled cell division
detect/repair DNA damage
ensure cell cycle cannot be reveresed
DNA is only duplicated once

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5
Q

why do cells undergo mitosis

A

asexual reproduction
tissue growth and repair

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6
Q

name the stages of mitosis

A

prophase
metaphase
anaphase
telephase

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7
Q

what happens in prophase

A

chromosomes condense and become visible
spindle fibres form by centriole splitting and moving to opposite poles
nuclear envelope breaks down

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8
Q

what happens in metaphase

A

pairs of chromatids line up in the middle
spindle fibres attach to centromeres

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9
Q

what happens in anaphase

A

centromere of each pair of chromatids split
spindle fibres pull apart (motor proteins)

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10
Q

what happens in telephase

A

new nuclear membrane forms
cell now contains two nuclei that are genetically identical

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11
Q

what happens in cytokinesis

A

cell splits in two
plasma membrane and cytoplasm spilt
2 daughter cells formed

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12
Q

what is the significance of meiosis

A

sexual reproduction
fertilisation
haploid cells/gametes

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13
Q

what are homologous chromosomes

A

matching chromosome pairs containing the same genes (diff. alleles)

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14
Q

name the stages of meiosis

A

prophase 1
metaphase 1
anaphase 1
telephase 1
p2
m2
a2
t2

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15
Q

what happens at prophase 1

A

p1= chromatin condenses, chromosomes supercoil, nuclear envelope break down, spindle fibres form, chromosomes come together in homologous pairs, crossing over occurs

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16
Q

what happens at metaphase 1

A

bivalents attach along equator, spindle attaches to centromere, independant assortment occurs (random)

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17
Q

what happens at anaphase 1

A

pairs of h.c are pulled apart

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18
Q

what happens at telephase 1

A

spindle fibres break down
two new nuclear membranes form around each set of chromosomes

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19
Q

what happens during cytokinesis after stage 1 of meiosis

A

division of cytoplasm and plasma membrane
produces two haploid cells

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20
Q

what happens at prophase 2

A

the two new nuclear envelopes break down, chromosomes condense and spindle forms

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21
Q

what happens at metaphase 2

A

chromosomes line up at equator attached by centromere

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22
Q

what happens at anaphase 2

A

centromeres divide, chromatids pulled apart and randomly segregated

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23
Q

what happens at telophase 2

A

nuclear envelope form around each of 4 haploid nuclei

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24
Q

how does meiosis produces genetic variation

A

crossing over during prophase
independant assortment

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25
Q

what is independant assortment

A

production of different combinations of alleles in daughter cells due to random allignment of homologous pairs along the equator of the spindle during metaphase 1

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26
Q

what are stem cells

A

unspecialised cells that are pluripotent

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27
Q

what are the sources of stem cells

A

adult stem cells
embryonic stem cells
induced pluripotent stem cells
umbilical cord blood

28
Q

uses of stem cells

A

treatment of Alzheimers, paralysis, parkinsons
research into developmental biology
repair of damaged tissue

29
Q

what is a bivalent

A

pair of homologous chromosomes

30
Q

What is differentiation

A

Process of cells becoming specialised

31
Q

How are embryonic cells differentiated

A

Certain genes are switched on or off/ expressed more so proportions organelles differ, shape of cell, and contents of cell changes

32
Q

What is an erythrocyte

A

Red blood cell

33
Q

What is the function of a erythrocyte

A

Carry oxygen to repairing cells

34
Q

Structure of a erythrocyte and benefits of it

A

Large SA:V
Biconcave shape
Flexible - well developed cytoskeleton to change shape through capillaries
No organelles- more space for haemoglobin

35
Q

What is a neutrophil

A

Type of white blood cell

36
Q

What is the function of neutrophils

A

Attract to and travel towards infected sites by chemotaxis to ingest bacteria/fungi by phagocytosis

37
Q

What is the structure of neutrophils

A

Multilobed nucleus
Flexible - squeeze through capillaries

38
Q

Which are larger - erythrocytes and neutrophils

A

Neutrophils are larger

39
Q

What is the spermatozoa

A

Sperm cell

40
Q

Adaptations of spermatozoa

A

Many mitochondria- carry out aerobic respiration for ATP to tail to mobs
Small, long thin
Enzymes released from acrosome - digest outer layer of egg
Contains haploid male gametes in head

41
Q

What are epithelial cells

A

Cells that make up lining tissue

42
Q

What are squamous epithelium and how are they structured

A

Flattened cells that provide a surface covering/outer layer on organs
Think cross section - short diffusion path
Permeable

43
Q

What are ciliated epithelium and what do they do

A

Cilia - moves substances across surfaces of tissues
Beat in coordinated movement to shift material

44
Q

What do goblet cells secrete

A

Secret mucus to trap, dust , microorganisms

45
Q

How do cilia and goblet cells work together

A

Goblet cells secret the mucus
Cilia waft the mucus out

46
Q

What is a tissue

A

Group of similar cells working together to perform specific function

47
Q

What are the 4 types of animal tissues

A

Nervous
Muscle
Epithelial
Connective

48
Q

What do epithelial tissues do

A

Covers and lines free surfaces (skin, blood vessels, heart chambers, organ walls)

49
Q

What are epithelial tissue specialised for to carry out

A

Projection
Absorbation
Filtration
Excretion
Secretion

50
Q

How are epithelial tissue structured

A

Close together to form continuous sheets
Smooth surfaces with projections

51
Q

What do connective tissues do

A

Holds structures together
Provides support

52
Q

How is connective tissue structured

A

Has non living extracellular matrix containing proteins and polysaccharides and seperates living cells to withstan weight

53
Q

What do cartilage do

A

Strong/ flexible -provides support

54
Q

What are the three types of cartilage

A

Hyaline
Fibrous
Elastic

55
Q

What do muscular tissue do

A

allow movement

56
Q

What are types of muscle tissue

A

Skeletal
Cardiac
Smooth

57
Q

How are muscle cells/fibres specialised

A

Elongated, contain mayofilaments

58
Q

What is nervous tissue made of and what does it conduct

A

Neurones
Electrical impulses

59
Q

Explain palisade cells

A

Within leaves for photosynthesis
Pack together closely
Large vacuole
Cytoskeleton threads/ motors proteins to move chloroplasts nearer to upper surface of leaf

60
Q

explain guard cells

A

found in the lower epidermis
controls opening and closing of stomata so air can enter

61
Q

explain root hair cells

A

found on outer layer of plant roots
hair like projections which increases SA for absorption of mineral ions and water
has special carrier proteins to actively transport ions

62
Q

name tissues found in plants

A

epidermal
vascular
meristematic

63
Q

what is epidermal tissue

A

consists of flattened cells
has waxy cuticle to reduce water loss

64
Q

what is vascular tissue

A

transport tissue made up of phloem and xylem

65
Q

what is meristematic tissue

A

tissue containing stem cells
found at the root/shoots and in cambium of vascular bundles

66
Q

what is an organ system

A

a number of organs working together to carry out an overall life function