Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A-level Biology > Chapter 3 - Cell Structure > Flashcards

Chapter 3 - Cell Structure Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

what is an object

A

the material placed under the microscope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is an image

A

the appearance of the material viewed under the microscope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why is the resolution of an electron microscope greater than that of an optical microscope

A

electrons have a very small wavelength compared to light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

equation for magnification

A

magnification = size of image/size of real object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is magnification

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is resolution

A

how well a microscope can distinguish between two points that are close together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what do optical microscopes use to form an image

A

light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what do electron microscopes use to form an image

A

electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

maximum resolution of a light microscope

A

0.2 micrometres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

maximum resolution of light microscopes

A

1500 x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

maximum resolution of electron microscopes

A

0.0002 micrometres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

maximum magnification of electron microscopes

A

1,500,000 x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the two types of electron microscopes

A

transmission electron microscopes TEM

scanning electron microscopes SEM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

hoe do transmission electron microscopes work

A

a beam of electrons is focussed onto a specimen using electromagnets
the electrons are transmitted through the specimen
denser parts of the specimen absorb more electrons so they appear darker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the main limitations of TEM 3

A

they can only be used on thin specimens
the whole system must be observed in vacuum- living specimens can’t be viewed
a complex preparation process mans artefacts are common

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are artefacts

A

things that you can see on the microscope but aren’t part of your specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how many micrometers are in a millimetre

A

1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how many nanometers in a micrometre

A

1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how do scanning electron microscopes work

A

a beam of electrons is scanned onto the surface of a specimen
this knocks electrons off of the specimen which are gathered in a cathode ray tube to form an image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

advantages of TEM

A

high resolution images mean you can see internal structures like chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

advantages of SEM

A

they can be used on thick and living specimens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

disadvantages of SEM

A

the resolution is lower than TEM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is an eyepiece graticule

A

a transparent rule with number but no units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how to calibrate a microscope

A

1) divide total length of stage micrometer by how many intervals to find one micrometer unit
2) find a point where the two lines are equal
3) work out how many micrometers units equal how many eyepiece units
4) convert the stage micrometre units to micrometers
5) divide stage units by eyepiece units to find the value of one eyepiece unit
6) this can be used in calculations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is cell fractionation

A

the process where cells are broken up and different organelles they contain are separated out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

during homogenisation why is the solution

a) cold
b) same water potential as the tissue
c) buffered

A

a) to reduce enzyme activity that could break down organelles
b) to prevent organelles bursting or shrivelling due to osmosis
c) any change in pH could affect the organelles or enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens during homogenisation

A

cells are broken up in a blender to release organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what happens during filtration

A

the homogenate is filtered to remove any large sections of cell and debris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what happens during ultracentrifugation

A

the filtrate is poured into a test tube place in the centrifuge and spun slowly
the heaviest organelles sink to the bottom forming the pellet whilst the rest of the organelles stay suspended in a fluid called the supernatant
the supernatant is drained off, poured into another test tube and spun at an even higher speed
the next heaviest organelles form the pellet and are remove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

description of the nucleus

A

nuclear envelope surrounding chromatin and nucleoplatism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

function of the nucleus

A

stores genetic info DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

decription of mitochondria

A

double membrane. inner highly folded-cristae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

function of mitochondria

A

makes energy ATP rich molecules during aerobic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

description of cell surface membrane

A

free in cytoplasm attached to RER smaller in prokaryotic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

function of cell surface membrane

A

makes proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

rough size of mitochondria

A

between 2 and 10 um

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is the chloroplast envelope

A

a double membrane surrounding the organelle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are grana

A

stacks of thylakoid membranes inside chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is stroma

A

a matrix where the sugar are synthesised during photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

function of chloroplasts

A

site of photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

how are chloroplasts adapted for photosynthesis

A

the grana provide a large surface area for the first stage of photosynthesis
chloroplasts contain ribosomes and DNA so they can quickly make proteins required for photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what are the two types of endoplasmic reticulum

A

smooth endoplasmic reticulum SER

rough endoplasmic reticulum RER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what is the RER

A

a system of membranes covered in ribosomes

network of interlined sheets with ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

functions of RER

A

ribosomes make protein and channel transport these proteins

45
Q

what are cistern

A

a stack of membranes that make flattened sacks

46
Q

functions of Golgi apparatus

A

processes and packages new lipids and proteins

47
Q

description of Golgi apparatus

A

contains vesicles for export

48
Q

what are Golgi vesicles

A

fluid filled sacks produced by the Golgi apparatus

49
Q

function of Golgi vesicles

A

stores lipids and proteins made by the Golgi apparatus and transports them out of the cell

50
Q

when are lysosomes formed

A

when vesicles contain enzymes like lipase and proteases

51
Q

description of lysosomes

A

vesicles contain hydralytic enzymes

52
Q

functions of lysosomes

A

modify proteins or lipids. package them is vesicles for export

53
Q

description of ribosomes

A

free in cytoplasm
attached to RER
smaller in prokaryotic cells

54
Q

function of ribosomes

A

makes proteins

protein synthesis

55
Q

function of microvilli

A

increase surface area for absorption and diffusion

56
Q

what is a cell wall

A

a rigid structure surrounding cells in plants algae and fungi
it consists of cellulose embedded in a matrix

57
Q

functions of the cell wall

A

to prevent the cell bursting form the movement of water

gives mechanical support to the cell

58
Q

what are cell walls made from in fungi

A

chitin

59
Q

what is tonoplast

A

the membrane surrounding the vacuole

60
Q

what is a vacuole

A

a fluid filled sack surrounded by the tonoplast

61
Q

function of a vacuole

A

stores water to keep the cell rigid and the plant turgid

helps to isolate unwanted chemicals

62
Q

why do cells become specialised

A

to carry out specific functions

63
Q

how do cells become specialised

A

certain genes can be turned on and off

64
Q

what is a tissue

A

a group of cells working together to perform a specific function

65
Q

function of the epithelial tissue

A

covers the inside and outside of organs

66
Q

function of xylem

A

transports water and mineral ions throughout the cell and also gives mechanical support

67
Q

what is an organ

A

a variety of tissues coordinated to perform a variety of functions

68
Q

what do muscular tissues do in the stomach

A

churns content

69
Q

what does epithelial tissues do in the stomach

A

protects stomach lining

70
Q

which of the blood vessels are organs and which are tissues

A

organs arteries and veins

tissue capillaries

71
Q

function of phloem

A

moves food away from the leaves in a plant

72
Q

function of the epidermis in a plant

A

to protect the leaf

73
Q

function of the spongy mesophyll in a plant

A

gaseous diffusion

74
Q

function of the palisade mesophyll in a plant

A

photosynthesis

75
Q

what does the digestive system do

A

digests and processes food

76
Q

what does the respiratory system do

A

breathing and gas exchange

77
Q

what does the circulatory system do

A

pumps and circulates blood

78
Q

what are cell walls made from in bacteria

A

the glycoprotein murine

79
Q

function of slime capsule

A

protects bacterium from other cells and helps them group together

80
Q

function of circular DNA

A

contains informations needed for bacteria cells to replicate

81
Q

function of plasmid

A

contains genes that may help the bacteria survive in adverse conditions

82
Q

is the DNA of bacteria cells associated with proteins

A

no

83
Q

why are viruses described as acellular

A

they are nucleic acids surrounded by a protein called the cashed they aren’t alive

84
Q

what is the function of attachment proteins an where are they found

A

they are found sticking out from around the cased and help virus cling to a host cell

85
Q

how do viruses replicate

A

they use proteins to attach to host cells

they inject their DNA into the host cell

86
Q

why can viruses only infect one type of cell

A

their attachment proteins are complementary to just one receptor cell

87
Q

process of binary fission

A

the DNA and plasmids in the cell replicate
the cell gets bigger and the DNA moves to the opposite end of the cell where it attaches to the membrane
the cytoplasm begins to divide and new cell walls begin to form
a new cell wall forms between the the two molecules of DNA creating two identical daughter cells

88
Q

what is mitosis

A

a parent cell divides to produce two genetically identical daughter cells

89
Q

3 uses of mitosis

A

growth repair and reproduction

90
Q

what are the three stages in the cell cycle

A

interphase
nuclear division
cytokinesis

91
Q

which stage isn’t part of mitosis

A

interphase

92
Q

what happens during interphase 2

A

the cells DNA unravels and replicates

the organelles and ATP are replicated

93
Q

what happens during prophase 3

A

the chromosomes condense and become visible
centrioles move to opposite ends of the cell forming the spindle apparatus
the nuclear envelope breaks down

94
Q

what happens in metaphase 2

A

the chromosomes line up along the cells equate

the spindle fibres attach to the centimetre

95
Q

what happens in anaphase 2

A

the centromeres divide separating the chromatids

the spindles contract and pull chromatids to the cells pores

96
Q

what happens during telophase 2

A

the chromosomes reach the poles and unravel

the cytoplasm divides and two nuclear envelopes form leaving two identical daughter cells

97
Q

what is cytokinesis

A

the process by which the cytoplasm divides

98
Q

what is cancer

A

a group od diseases characterised by a growing disorder of cells

99
Q

characteristics of benign tumours

A

grow slowly are more compact and less life threatening

100
Q

characteristics of malignant tumours

A

grow quickly less compact and are more life threatening

101
Q

how do cancer drugs work

A

they disrupt the cell cycle to stop the tumour diving and growing

102
Q

how does chemotherapy work

A

chemicals prevent the synthesis of enzymes needed for DNA replication

103
Q

how does radiotherapy work

A

radiation damages DNA so the cell kills itself

104
Q

formula for mitotic index

A

number of cells with visible chromosomes / total number of cells observed

105
Q

why are hair cells often affected by the cancer drugs

A

the drugs target cells that divide rapidly such as hair cells

106
Q

why do specimens have to be kept in a vacuum before using an electron microscope

A

the air would otherwise absorb the elctorns and prevent them from reaching the specimen

107
Q

what chromosomes do women have

A

XX

108
Q

what chromosomes do men have

A

XY

A-level Biology (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions