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Biology A Level > Cell Structure :). > Flashcards

Cell Structure :). Flashcards

1
Q

What are eukaryotic cells made of?

A

Eukaryotic cells

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2
Q

What are eukaryotic cells?

A

Complex include all animals and plants

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3
Q

What are prokaryotic cells?

A

Small and simpler e.g bacteria

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4
Q

What is more complicated prokaryotic or eukaryotic?

A

Eukaryotics

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5
Q

Name organelles of animal cells?

A

Plasma membrane, RER, nucleus, SER, ribosome, lysosome, Golgi appartus, cytoplasm, microchrondria

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6
Q

Explain structure of nucleus?

A

Nucleolus wrapped in nucleus wrapped in nuclear envelope

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7
Q

What organelles do plant cells have compared to animals?

A

All the same organelles but with a few extra: the cell wall, vacuole, chloroplasts

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8
Q

What does cell wall have?

A

Plasmodesmata

Channels for exchanging substances with adjacent cells

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9
Q

Description of plasma membrane?

A

Found on surface of animal cells and just inside cell wall of plant cells and prokaryotic cells. Made mainly of lipids and protein.

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10
Q

Function of plasma membrane

A

Regulates movement of substances into and out of cell

Also has receptor molecules which allow it to respond to chemicals like hormones

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11
Q

Description of cell wall?

A

Rigid structure surrounds plant cells. Made mainly of the carbohydrate cellulose.

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12
Q

Function of cell wall?

A

Supports plant cells

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13
Q

Description of nucleus?

A

Large organelle surrounded by a double membrane nuclear envelope containing many pores. Nucleus contains chromatin and the nucleolus

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14
Q

Function of nucleus

A

Controls cell’s activities
Contains DNA to mind proteins
Pores to allow substances to move between nucleus and cytoplasm
Nucleolus makes ribosomes

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15
Q

Lysosome description

A

Round or handle surrounded by a membrane with no clear internal structure

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16
Q

Function lyposome

A

Contains digestive enzymes
Separate from cytoplasm by surrounding membrane and can be used to digest invading cells or break down worn out components of cell

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17
Q

Describe ribosome

A

Very small organelle that either gloats free in cytoplasm or is attached to RER
Made of protein and RNA not surrounded by membrane

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18
Q

Function of ribosomes?

A

Site where proteins made

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19
Q

What are prokaryotic organisms made of?

A

Prokaryotic cells

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20
Q

Rough endoplasmic reticulum describe

A

System of membranes enclosing a fluid filled space. Surface covered with ribosomes

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21
Q

Rough endoplasmic reticulum function

A

Folds and processes protein that have been made at the ribosomes

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22
Q

Smooth endoplasmic reticulum describe

A

Similar to rough endoplasmic reticulum but no ribosomes

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23
Q

Smooth endoplasmic reticulum function

A

Synthesises and processes lipids

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24
Q

Vesicle description

A

Small fluid-filled sac in cytoplasm surrounded by a membrane

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25
Q

Vesicle function

A

Transports substances in and out of cell via plasma membrane and between organelles. Some are formed by Golgi apparatus or endoplasmic reticulum while others are formed at the cell surface

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26
Q

Golgi apparatus describe

A

Group of fluid filler membrane-bound flattened sacs. Vesicles often seen at edges of sacs

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27
Q

Golgi apparatus function

A

Processes and packaged new lipids and proteins. Also makes lysosomes

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28
Q

Mitochondrion describe

A

Usually oval-shaped. Double membrane. Inner one folded into structures (cristae) inside is the matrix which contains enzymes involved in respiration

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29
Q

Mitochondrion function

A

Site of aerobic respiration where ATP is produced.

Found in large numbers in very active cells and cells requiring a lot of energy

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30
Q

Chloroplasts describe

A

Small, flattened structure found in plant cells.
Surrounded by double membrane and membrane inside (thylakoid membrane). These membranes are stacked up in some parts of chloroplasts to form grana. Grana linked together by lamellae

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31
Q

Lamellae are?

A

Thin flat pieces of thylakoid membrane

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32
Q

Chloroplasts function

A

Site of photosynthesis
Some parts of photosynthesis happen in grana
Other parts in the stroma

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33
Q

Stroma is?

A

Thick fluid found in chloroplasts

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34
Q

Centrioles describe?

A

Small, Hollow cylinders made of microtubules (tiny protein cylinders)
Found in animal and some plant cells

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35
Q

Centrioles function

A

Involved with separation of chromosomes during cell division

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36
Q

Cilia describe

A

Small hair like structures found on surface membrane of some animal cells
Cross-section have outer membrane and ring of nine pairs of protein microtubules inside with 2 microtubules in the middle

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37
Q

Cilia function

A

Microtubules allow cilia to move

Movement used by cell to move substances along cell surface

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38
Q

Flagella describe

A

on eukaryotic cells are like cilia but longer
Stick out from cell surface and surrounded by plasma membrane.
Inside like cilia too two microtubules in centre and nine pairs around the side

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39
Q

Flagella function

A

Microtubules contract to make flagellum move

Flagella used like outboard motors to propel cells forwards (sperm cells swims)

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40
Q

Where are proteins made?

A

At the Ribosomes

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41
Q

What do the ribosomes on the rough endoplasmic reticulum do?

A

Make proteins that excreted or attached to cell membrane

Free ribosomes in cytoplasm make proteins stay in cytoplasm

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42
Q

Where are new proteins produced?

A

At the rough endoplasmic reticulum and then they are folded and processed (e.gsugar chains added) in rough endoplasmic reticulum

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43
Q

Where are they transported to from RER?

A

Golgi apparatus in vesicles

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44
Q

What happens at Golgi appartus?

A

Proteins undergo further processing (sugar chains trimmed or more are added)

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45
Q

What do proteins do?

A

Enter more vesicles to be transported around cell e.g. Glycoprotein (found in mucus) move to cell surface and are secreted

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46
Q

What are organelles in cells surrounded by?

A

Cytoplasm

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47
Q

What is cytoplasm?

A

More than just solution of chemicals

Has networks of protein threads running through it

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48
Q

Protein threads are called?

A

Cytoskeleton

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49
Q

What are the protein threads in eukaryotic cells arranged as?

A

Microfilaments (small solid strands) and microtubules (tiny protein cylinders)

50
Q

Cytoskeleton four main functions?

A

Support cell’s organelles, keeping them in position
Help strengthen cell and maintain its shape
Responsible for movement of materials within cell
Cause the cell to move

51
Q

What Support cell’s organelles, keeping them in position

A

Microtubules and microfilaments

52
Q

What Help strengthen cell and maintain its shape?

A

Microtubules and microfilaments

53
Q

Give example of the cytoskeleton being Responsible for movement of materials within cell

A

The movement of chromosomes when separate during cell division depends on contractions of microtubules in spindle

54
Q

Give example of Cause the cell to move?

A

Movement of cilia and flagella is caused by cytoskeletal protein filaments that run through them. So in cause of single cells that have flagellum (sperm) cytoskeleton propels whole cell

55
Q

Why can microtubules and microfilaments be prevented from functioning using respiratory inhibitors?

A

Assembly of microtubules and microfilaments and movement of materials along then requires energy from respiration

56
Q

Prokaryotic size

A

Extremely small cells

Less than 2 nanometers diameter

57
Q

Eukaryotic size

A

Larger cells (about 10-100 nanometers diameter)

58
Q

Prokaryotic DNA

A

Circular

59
Q

Eukaryotic DNA?

A

Linear

60
Q

Prokaryotic nucleus?

A

No nucleus DNA free in cytoplasm

61
Q

Eukaryotic nucleus?

A

Present DNA inside nucleus

62
Q

Prokaryotic cell wall?

A

Made of polysaccharide not cellulose or chitin

63
Q

Eukaryotic cell wall

A

No cell in animals
Cellulose walk in plants
Chitin cell wall in fungi

64
Q

Prokaryotic organelles?

A

Few organelles

No membrane-bound organelles (no Mitochondria)

65
Q

Eukaryotic cells?

A

Many organelles

Microchrondria and other membrane-bound organelles present

66
Q

Prokaryotic flagellum?

A

When present made of protein flagellum arranged in helix

67
Q

Eukaryotic flagellum?

A

When present made of microtubules proteins arranged in “9+2” formation

68
Q

Prokaryotes ribosome?

A

Small

69
Q

Eukaryotic ribosomes?

A

Larger ribosomes

70
Q

Prokaryotic example

A

E.coli bacterium

71
Q

Eukaryotic example

A

Human liver cell

72
Q

Prokaryotes like bacteria rough size?

A

Tenth of the size of eukaryotic cells

73
Q

Can a light microscope really see a prokaryotic bacteria?

A

No

74
Q

Define magnification

A

How much bigger the image is than the specimen you’re looking at

75
Q

Formula to get magnification

A

Magnification= image size /object size

76
Q

Resolution is

A

How detailed the image is

More specially how well a microscope lens can’t separate two objects increasing magnification won’t help

77
Q

Light microscope

A 
Uses light
Lower resolution than electron microscope 
Maximum resolution 0.2 micrometres
Used to look at whole cells/ tissues 
Maximum useful magnification about x1500
78
Q

Laser scanning confocal microscope is?

A

Special type of light microscope

79
Q

Laser scanning confocal microscope uses what

A

Uses laser beams (intense beams of light) to scan specimen which is usually tagged with fluorescent dye

80
Q

What do lasers do Laser scanning confocal microscope

A

Lasers causes dye to fluoresce. Light focused through pinhole onto detector. Detector hooked up to computer which generates image (can be 3D)

81
Q

Pinhole Laser scanning confocal microscope means?

A

Any out-of focus light is blocked so microscopes give clearer image than normal light microscope

82
Q

Laser scanning confocal microscope used to look at?

A

Different depths in thick specimen

83
Q

Electron microscopes?

A

Use electrons to form image
Higher resolution than light microscope to give more detailed images
Two types: TEM, SEM

84
Q

Transmission electron microscope uses?

A

Electromagnets to focus a beam of electrons which is transmitted through specimen

85
Q

TEM denser parts of specimen

A

Absorb more electrons making them look darker on the image you end up with

86
Q

Why are TEM’s good?

A

High resolution image (so can be used to look at range of organelles) but they can only be used on thin specimens.

87
Q

Scanning electron microscopes do what?

A

Scan beam of electrons across specimen knocking off electrons from specimen gathered in cathode ray tube to form an image

88
Q

Images of Scanning electron microscopes

A

Show surface of specimen and can be 3D

Give Lower resolution than TEMs

89
Q

What affects how specimen appear

A

The angle they are cut at

90
Q

Light microscope max resolution

A

0.2 micrometers

91
Q

Light microscopes max magnification

A

x1500

92
Q

TEM max resolution

A

0.0002 micrometers

93
Q

TEM max magnification

A

Can be more than X1,000,000

94
Q

SEM max resolution

A

0.002 micrometers

95
Q

SEM max magnification

A

Usually less than x500,000

96
Q

What happens as a result of light microscope or TEM’s the beam of light or electrons pass through the objects being viewed?

A

An image of produced because some parts of the object absorb more light or electrons than others

97
Q

What happens if the object being viewed is completely transparent?

A

It makes the whole thing look white because light rays or electrons just pass straight through
This has to be stained

98
Q

Staining for light microscopes how

A

Means using some type of dye

Stain taken up by some parts of object more than others- contrast makes different parts show up

99
Q

Common stains for light microscopes

A

Methylene blue and eosin

100
Q

What are different stains used for?

A

To make different parts show up
E.g. Eosin used to stain cell cytoplasm
Methylene blue stains DNA

101
Q

How many stains can be used at once

A

More than one

102
Q

Staining samples for electron microscopes

A

For electron microscopes, objects dipped in solution of heavy metal like lead
Metal ions scatter electron creating contrast- some parts of object show up darker than others

103
Q

Colourful electron microscope images??

A

Black and white even with stain. Artificial colour added after image has been made

104
Q

What’s a slide used for?

A

If you want to look at specimen under light microscope you need to stick it on a slide first

105
Q

Slide is

A

Strip of clear glass or plastic. Slides usually flat but some of them have small dip or well in centre useful if specimens particularly big or a liquid.

106
Q

Dry mount preparation of slide

A

Specimen needs to let light through to see it clearly under microscope do if you have a thick specimen take a thin slice to use for slide
Use tweezers to pick up specimen and put in middle of clean slide
Pop on cover slip on top

107
Q

Wet mount preparation of slide

A

Start pipetting small drop of water onto slide. Use tweezers to place specimen on top of water drop. Put cover slip on, stand slip upright on slide next to water droplet. Carefully tilt and lower it so covers specimen. Try not to get any air bubbles under there. Once cover slip in position add stain.

108
Q

How to add stain in wet mount

A

Put drop of stain next one edge of cover slip then put bit of paper towel next to opposite edge. Stain will get under slip across specimen

109
Q

Why is it bad to get air bubbles in wet mount?

A

Will obstruct your view of specimen

110
Q

What are wet mounts good for?

A

Looking at tiny organisms that live in water

111
Q

How to use microscope 1

A

Start clipping slide containing specimen you want onto stage

112
Q

How to use microscope 2

A

Select lowest- powered objective lens (one producing the lowest magnification)

113
Q

How to use microscope 3

A

Use coarse adjustment knob to move objective lens down to above slide

114
Q

How to use microscope 4

A

Look down eyepiece (containing ocular lens) adjust the focus with fine adjustment knob, until you get a clear image of whatever’s on the slide

115
Q

How to use microscope 5

A

If you need to see the slide with greater magnification swap to higher-powered objective lens and refocus

116
Q

What to remember if draw what’s seen under microscope?

A

Make sure you write down magnification under which specimen was viewed. You’ll need to laced your drawing

117
Q

When you would you use eyepiece graticule and stage micrometer?

A

You might want to know the size of your specimen

They are a bit like a rulers

118
Q

Explain eyepiece graticule?

A

Fitted onto eyepiece

Like transparent ruler with numbers but no units

119
Q

Stage micrometer?

A

Placed on stage
Microscope slide with accurate scale (has units) and used to work out value of division on eyepiece graticule at particular magnification

120
Q

How can you measure the size of the specimen

A

Take stage micrometer away and replace with slide containing specimen

121
Q

Example of eyepiece graticule

A

Line up eyepiece graticule and stage micrometer
Each division on stage microscope 0.1mm long
At magnification 1 division on stage microscope same as 4.5 divisions on eyepiece graticule
Work out size of 1 division on eyepiece graticule divide 0.1 by 4.5
0.22mm
So look at object under microscope at magnification and 20 eyepiece division long

122
Q

At different what will divisions will be different at?

A

Magnifications so eyepiece graticule so eyepiece graticule needs to be recalibrate do

Biology A Level (26 decks)

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