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Biology > Cells > Flashcards

Cells Flashcards

1
Q

gWhat does nucleus have

A

Nuclear envelope
Nucleurnpores
Nuecluoplasm
Chromosomes
Nucleolus

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2
Q

Nuclear ENVELOPE

A
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3
Q

Nuclear pores

A
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4
Q

Nucleoplasm

A
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5
Q

Chromosomes

A
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6
Q

Nucleolus

A
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7
Q

Functions of nucleus

A
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8
Q

Mitochondria structures

A

Inner membrane folds to form Cristae
Holds the protein in place required for aerobic respiration

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9
Q

Double membrane

A
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10
Q

Cristae

A
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11
Q

Matrix

A
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12
Q

What chloroplasts contain

A
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13
Q

Grana

A
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14
Q

Stroma

A
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15
Q

How chloroplast adapted

A
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16
Q

Rough endoplasmid reticulum

A

To hold ribosomes in place
Form vesicles to seperste proteins products from the cytoplasm

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17
Q

Smooth endoplasmid reticulum

A
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18
Q

Function of Golgi apparatus

A
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19
Q

Function of lysosomes esicles

A

Vesicles contsintjng hydrolysis enzymes
Seperste hydroylytic enzymes from the cytoplasm

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20
Q

Ribosomes

A
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21
Q

Cell wall

A
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22
Q

Vacuoles

A
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23
Q

Why is tissue placed in buffer

A

Keeps the ph constant

Enzymes are protein which would be affected by the ph so if ph changes they would denature

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24
Q

Why would specimens be held in vacuum chamber

A

To hold it still

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25
Q

Largest to smallest chloroplast nucleus ribosome mitochondria

A

Nucleus

Chloroplast

Mitochondria

Ribosomes

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26
Q

Why is tissue placed in cold

A

Stop harmful bacteria down

Slow enzymes down

Stops breaking down the organelles for digestion

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27
Q

Why do some parts of a specimen see, bright

A

Allows electrons to pass through

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28
Q

Electron beam characteristics

A

Short wavelength

Resolve objects well

High revolving power

Negatively charged

Beam focused using electromagnets

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29
Q

Cell fractionation

A

Separates organelles according to their density

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30
Q

Centrifuge process

A

1)filtrate placed In centrifuge and spun at low speed

2)heaviest organelle forced to bottom of tube forming thin sediment or pellet

3)fluid at top is supernatant is removed leaving nucleui sediment

4)supernatant transferred to another tube and spun even faster

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31
Q

What are the two stages of cell fractionation

A

1)homogenation

2)ultracentrifugation

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32
Q

What does transmission microscope consider

A

Electron gun that produces a beam of electrons that is focused onto the specimen by a condenser electromagnet

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33
Q

How electron microscopes works

A

1)Use an electron beam of light which is focused using electromagnets as electrons are neg charged

2)Specimen has to be spec prepared and held inside vacuum chamber

3)Beam passes through this section of specimen .heavy metal stain absorbs electrons but electron passes through other parts of specimen

4)These areas appear brighter

5)the image formed as photograph (electron micrograph)or as image on tv

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34
Q

Homogenised

A

Cells are broken up

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35
Q

Resolution definition

A

The minimum distance apart that two objects can be in order for them to appear as separate items

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36
Q

Why tissue in same water potential

A

Isotonic

It would burst

Prevents osmosis so no lysis shrinkage of organelles

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37
Q

Light microscope characteristics

A

Light

Longer wavelengths

Cannot see objects more than 200nm

Glass lens focuses

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38
Q

What actually is ultracentrifugation

A

Process when the drag,ente are filtered and homogenate are separated from in centrifuge sounnng the tubes at high speed

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39
Q

What does resolving power depend on

A

The wavelength or form of radiation used

Greater resolution greater Clarity clearer image and more precise

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40
Q

How has fractionation and ultrafugation has helped

A

Allow detailed study of structure and function of organelles by showing what isolated components do

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41
Q

Tem characteristics

A

Electrons

Very short wavelength

0.1 nm resolving power

Prices by electromagnets

Vacuum needed

Complex staining process

2d image

Extremely thin specimen

Electrons from below

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42
Q

What actually happens in homogenation

A

Cells broken in blender releasing organelles fro, cell. Resultant Fukui (homogenate) filtered to remove complete cells or large pieces of debris

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43
Q

How to obtain large numbers of isolated organelle

A

Cells are broken up and then different organelles separated out

Tissue is placed in cold buffered solution of same water potential

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44
Q

Scanning electron microscope

A

Also beam of electron onto surface pf specimen from above rather than below

Beam passed backcknand forfth

3d

Lower resolving power

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45
Q

How cell fractionation is carried out

A

1)cells in specific solutions

2)tissue placed in isotonic solution

3)tissue placed in a ph buffer

4)placed in ice cold solution /water

5)the cells are then homogenised in a blender

6)removing debris

7)filtered homogenate spun at a low speed

8)increasing speed removing suoernatant at each stage

8)nucleui are the densest organelle form the first pellet

10)mitochondria form the next pellet

11)keep spinnning until you form the fractions that you want eg.depending on what you want to isolate like ribosomes or mitochondria

12)supernatant is spun at even higher speeds to pellet ribosomes

46
Q

Cristae

A

Site of electron transport chain

47
Q

Transmission electron microscope limitations

A

complex staining process required

in a vacuum so living specimens can’t be observed

-extremely thin specimen

-2d

48
Q

Sem chacarteristics

A

Electrons

Short wavelength

20nm resolving power

Focused using electromagnets

Vacuum needed

Dead specimens

Electrons directed from above

49
Q

Why electron microscopes have a higher resolution than an optical

A

Electron beam has shorter wavelength and light rays

50
Q

What have we learnt from electron microscopes

A

Cells contain organelles to carry out different functions

Internal structure of organelles and how they function

Structure of bacteria and viruses

Causes of medical conditions

51
Q

Cell specialisation

A

-cells of multicellular organisms are each specialised in different ways to perform a particular role
-stem cells in embryo are identical but then as it matures they become specialised
-to do this some genes are switched on and off

52
Q

Tissue

A

A collection kf similar cells that preform a specific function

53
Q

Organ

A

A combination of tissues that are coordinated to preform a variety of functions

54
Q

Tissue types

A

Epithelial
Connective
Muscle
Nervous

55
Q

Epithelial

A

Covers the outside of your body as well as your internal organs

56
Q

Muscle tissue

A

Cells that shorten due to the chemical and physical interaction between myofilsmrntd actin and myosin

57
Q

Nervous tissue

A
58
Q

Virus structure - hiv

A

Acellular (not cells)

59
Q

When are chromosomes visible

A

During cell divisions
You would see chromatins

60
Q

What do chromosomes consist of

A

Each chromosome consists of two chrimsrids joined somehweee along its length at the centromere
Genetic info (genes/alleles)carried on each chromatic is identical

61
Q

Two main parts of cell cycle

A

Interphase
Cell division

62
Q

Cell cycle

A

G1)growth if duaghger cells. Rep or organelles
S)replication of dna
G2)cell checks dna and makes any repairs. Cell prepared fir division
3)nuclear division
4)cytoplasmic division

63
Q

G1 stage

A

Variable duration
Eg. Some cells do not divide like nervous cells
Formation of cellular proteins

64
Q

S stage

A

Constant duration
Formation of cellular proteins

65
Q

G2 duration

A

Constant
Formation of cellular proteins

66
Q

Interphase in embryo

A

There is no interphase for the first few division
As the zygote contains materials to form the first 16 cells
Cells decrease in size as cells divide

67
Q

What stage does dna unravel

A

S
Interphase

68
Q

What holds chromatids together

A

Centromere

69
Q

Protein associated with dna in the chromosomes

A

Histone

70
Q

What produces spindle fibres

A

Centriole

71
Q

Prokaryotic characteristics

A

1)no nucleus
2)dna not associated with
3)plasmids
4)no chloroplasts only bacterial chlorophyll
5)smaller ribosomes
6)Muerin cell wall
7)capsule

72
Q

Eukaryotic characteristics

A

1)distinct nucleus
2)dna associated with histone
3)no plasmids
4)membrane bound
5)chloroplast
6)ribosomes cellulose cell wal
7)no capsule

73
Q

Viruses(more)

A

Acellular
Smaller than bacteria
Nucleui acids enclosed in protein coat capsid
dna or rna as genetic material
Multiply inside host cells

74
Q

What mitosis does

A

Produces two daughter cells that have the same number of chromosomes as the parent cells and each other

75
Q

Meiosis does

A

Produces four daughter cells
Each with half number chromosomes

76
Q

Interphase

A

Cell is not dividing
Replication of dna
Then joined at centromere

77
Q

Prophase

A

When chromosomes become visible
Long thin threads
Centrioles opposite poles form spindle fibres
Nuclear envelope breaks down
Chromosomes at equator

78
Q

Metaphase

A

Chromosomes made of two chromatids
Joined by centromere
Chromosomes pulled along the spindle apparatus

79
Q

Anaphase

A

Centromeres divide into two
Fibres pull chromatids
Opposite poles now chromosomes

80
Q

Telophase and cytokinesis

A

Chromosomes thinner again
Spindle fibres disintegrate
Nucleus envelope and nucleolus reform
Cytoplasm divides

81
Q

Replication of viruses

A

Cannot undergo cell division
Replicate attach to host cells with proteins on their surface
Inject nucleuc acid into host cell
Provides instructions for hosts metabolic processes
Stewart producing new viral components
Then assembled into a new virus

82
Q

The role of the cell surface membrane is.

A

To control the movement of substances into and out of the cell / exchange of substances with the cell’s external environment; [1 mark]
Contains molecules on its outer surface that enable cell to cell communication / display hormone receptors / present antigens ; [1 mark]

83
Q

Lysosomes

A

Sacs/compartments surrounded by membrane OR sacs/compartments containing digestive enzymes; [1 mark]

84
Q

stage micrometer is needed in addition to the eyepiece graticule because…

A

The size of the units of the eyepiece graticule change depending on the magnification being used; [1 mark]
The micrometer can be used to calibrate the graticule; [1 mark]

85
Q
A

1)chromosomes shorten due to super coiling
2)chromosomes become identical chromatids

86
Q

causes of cancer

A

occurs when the rate of cell multiplication is faster than the rate of cell death which causes growth of tumour. often in a tissue with a high rate or mitosis such as the lung or bowel.

87
Q

malignant tumour

A

destroy the surrounding tissue and their cells can break away and spread through the food or lymph into other sites where the form secondary tumours

88
Q

benign

A

can compress tissues preventing normal blood flow or nerve function

89
Q

factors to do with cancer

A

infection
gender
occupation
sun and radiation
alcohol
pollution
diet
tobacco

90
Q

preventing cancer with diet

A

-food containing antioxidants fruits and veg that destroy radicals (chemicals from the diet and uv etc that contribute to ageing and dna damage.

91
Q

preventing cancer -viruses

A

they can trigger some cancers
eg.hep trigger liver and cervical cancer
preventing viruses by vaccines may prevent cancer

92
Q

inherited cancer

A

-through genes
-BRCA1 gene synthesis a protein to repair dna
-mutation in the brca1 gene predispose a person to breast cancer later in life if the other allele in great tissue becomes damaged.
-other gene predispose people to other cancers

93
Q

how cancer can be treated

A

-surgery- remove cancerous tissue
-chemotherapy- chemical used to destroy cancer cells
-radiotheraoy- x rays to destroy cancer cells

94
Q

problems with radiotherapy and chemotherapy

A

-damage to healthy ceklls
-infertility
-hair loss

95
Q

binary fission

A

1)circular dna replicates and both copies attach to cell membrane
2)plasmids also replicate
3)cell membrane begins to grow between 2 dna molecules and pinch inwards dividing cytoplasm
4)new cell wall forms between 2 molecules of dna dividing original cell into 2 daughter cells

96
Q

What cell looks like in interphase

A

Growth of daughter cells
Organelles replicate
Dna replicates
Dna repairs

97
Q

How cell looks like during prophase

A

Chromosomes more visible in nucleus
Chromosomes thicken
Spindle fibres form
Nuclear envelope disappear

98
Q

How cell looks like in metaphase

A

Chromosomes line up at the equator
Spindle fibres from centrioles attatch

99
Q

Anaphase how cell looks

A

Chromatids at opposite poles
Spindle fibres contract and pull chromatids opposite poles

100
Q

Telophase how cell looks

A

Uncoiled chromosomes and nucleur envelope
Chromosomes uncoil do spindle fibres disintegrated and envelope reappears

101
Q

fluid mosaic membrane

A
102
Q

phospholipid bilayer

A

the most stable arrangement
fatty acid face inwards

103
Q

liposome

A

water inside the structure and outside.spherical bilayer that forms with hydrophilic heads facing outwards and hydrophobic tails to the inner potion

104
Q

micelle

A

phospholipids in water
hydrophilic head attcrated but tails are hydrophobic

105
Q

bilayer sheets

A

cytoplasm contains lots of holes tissue fluid surrounds the cell because hydrophilic heads are facing outwards so bilayer forms

106
Q

intrinsic

A

span the membrane
channel protein has water filled pores to allow water soluble ions to diffuse across or carrier proteins binds to ion then changes shape to move across membrane

107
Q

extrinsic

A

give mechanical support or act as cell receptor with glycolipids

108
Q

cholesterol

A

reduces lateral movement of the phospholipids and hence reaches membrane fluidity at high temperatures
prevents leakage of water and dissolved ions from the cell
adds strength to membrane

109
Q

the more unsaturated fatty acids …

A

the less tightly packed and more fluid the membrane

110
Q

glycolipid

A

-used for cell attachment
-form receptors

111
Q

glycoprotein

A

-form receptors for hormones and neurotransmitters
-used for cell attachment for tissue formation

112
Q

membrane permeability

A

high temps it becomes more permeability

Biology (48 decks)

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