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cell structure Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

magnification defintion

A

the number of times larger an image appears compared to its actual size

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2
Q

resolution definition

A

the ability to distinguish between 2 separate points in an image
measure of clarity

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3
Q

microscopes allow us to ______ objects and therefore study organisms at a ______ level

A

magnify
cellular

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4
Q

magnification equation?

A
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5
Q

what is the total magnification?

A

eyepiece magnification x objective magnification

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6
Q

which type of microscope was the first to be developed?

A

light microscope

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7
Q

light microscope magnification range

A

4x to 2000x

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8
Q

light microscope resolution

A

200nm

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9
Q

3 advantages of using light microscopes

A

easy to section and stain specimen
easy to use
both dead and living samples can be viewed
chepa

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10
Q

path of light in a microscope

A

light from source travel through the specimen, through the objective lens, through the eyepiece lens, to your eye

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11
Q

eyepiece lens magnification and what does it contain?

A

x10
contains eyepiece graticule

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12
Q

turret function

A

rotates to bring the objective lenses into place

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13
Q

objective lenses powers/magnifications

A

low=x4
medium=x10
high=x40

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14
Q

stage function

A

where the microscopic slide is placed

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15
Q

condenser function

A

used to vary intensity of light reaching the object

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16
Q

fine focus function

A

used to focus high-power objective lens

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17
Q

coarse focus function

A

used to focus low and medium-power objective lenses

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18
Q

3 advantages of staining specimens to be viewed under a microscope

A

increases contrast in the slide
easier to distinguish between different organelles
stains bind to particular molecules e.g. toluidine blue binds to chromosomes, iodine solution binds to cellulose

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19
Q

what is Gram’s stain used for?

A

classifying bacterial species into 2 large groups: gram-positive and gram-negative
this helps doctors prescribe correct medicine

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20
Q

Gram’s stain steps

A

stain bacteria
fix colour
decolourise cells
apply counterstain

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21
Q

Gram’s stain colour

A

pink and purple

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22
Q

wet mounting meaning and steps

A

involves water/ stain
1)put a drop of water/stain onto specimen
2)lower a cover slip onto the specimen

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23
Q

dry mounting meaning and steps

A

does not involve any water/ stain
1)observe specimen on a slide
assume specimen is cut very thinly so light can pass through

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24
Q

a lot of biological tissue is transparent ; why is this a problem when using microscopy to view it and how can it be overcome?

A

would not show up clearly
stain specimen to increase contrast between cells/organelles and increase ability to distinguish between them

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25
Q

why must specimens be thin on a slide

A

light must be able to pass through the specimen
for clarity you want to be able to only see a single layer of cells

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26
Q

why should the refractive index of media when wet mounting be about equal to glass

A

if light is refracted too much or too little, the image is distorted

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27
Q

describe how a slide to show onion cells could be prepared

A

a layer of onion cells removed from epidermis using mounted needle/forceps
placed onto slide, ensuring it does not fold
stained with 1 drop of iodine solution
cover slip placed on at angle so no air bubbles form
ready to be viewed

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28
Q

why should a cover slip be placed onto a wet mount at an angle

A

it prevents air bubbles forming, which can distort the image

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29
Q

what is laser scanning confocal microscopy

A

a light microscope that sues lasers and fluorescence to create a 3D image of a sample

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30
Q

what type of image does laser scanning confocal microscopy form

A

a 3D image with depth selectivity

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31
Q

how does laser scanning microscopy differ from conventional light microscopy?

A

uses lasers instead of visible light
higher magnification
builds up image thorough computer which is 3D
higher resolution

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32
Q

how is an image formed in laser scanning confocal microscopy

A

laser beam is focussed onto a sample by mirrors. the sample, stained by fluorescent dyes, reflects the laser back through a pinhole to a detector. This is attached to a computer which builds up the image one pixel at a time.

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33
Q

what is laser scanning confocal microscopy used to observe and why

A

living organisms/species because it is non-invasive
you can watch a process taking place

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34
Q

what are the 2 types of electron scanning microscopy?

A

scanning electron microscopy (SEM)
transmission electron microscopy (TEM)

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35
Q

how does a scanning electron microscope work

A

electrons are fired at a specimen and bounce off the surface
these are detected by a compute and an image is built up

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36
Q

scanning electron microscopy magnification range

A

100x-100,000x

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37
Q

scanning electron microscopy resolution range

A

3-10nm

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38
Q

advantages of scanning electron microscopy

A

3D image formed
surface detail

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39
Q

how does a transmission electron microscope work

A

electrons are fired through a specimen
these are detected by a computer and an image is built up

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40
Q

transmission electron microscopy magnification range

A

100x-2,000,000x

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41
Q

transmission electron microscopy resolution range

A

0.2-1.0nm

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42
Q

disadvantages of electron microscopy

A

highly specialist training is required for use
complex slide preparation means artefacts can be produced so the image is distorted
electron beam can damage the specimen
specimens must be dead because the images are viewed under a vacuum so you cannot observe live processes
TEM is 2D

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43
Q

advantages of electron microscopy

A

3D for SEM
surface detail
high magnification and resolution, but TEM>SEM

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44
Q

advantages of laser scanning confocal microscopy

A

depth selectivity
3D image
observe living organisms and processes taking place

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45
Q

disadvantages of laser scanning confocal microscopy

A

limited magnification and resolution (not as high as electron microscopy)

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46
Q

success criteria for biological sketches

A

plain paper; use over half
single, clear, continuous line with a sharp pencil
no shading or colour
correct proportions
label lines in pencil with a ruler; start at structure, do not cross and are horizontal
horizontal labels
no arrowheads
title at top
scale bar in pencil with ruler at the bottom

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47
Q

what makes up a nucleus?

A

nucleolus
chromatin
nuclear envelope
nuclear pores

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48
Q

where is the nucleolus located?

A

in the centre of the nucleus

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49
Q

where is the chromatin located?

A

surrounds the nucleus

50
Q

where is the nuclear envelope located?

A

surrounds the chromatin

51
Q

what are the nuclear pores?

A

they are holes in the nuclear envelope

52
Q

nucleolus structure and function

A

contains ribosomal RNA
ribosome and RNA synthesis

53
Q

chromatin structure and function

A

loosely packed DNA
contains chromosomes

54
Q

nuclear envelope structure and function

A

double membrane
compartmentalises the nucleus
regulates exchange between the nucleus and cytoplasm
some protein synthesis

55
Q

nuclear pore structure and function

A

at regular intervals around the nuclear envelope
allow the mRNA, tRNA and rRNA out of the nucleus

56
Q

nucleus structure and function

A

major cell containing chromatin (DNA and histones)
regulates cell activities
carries hereditary information
site of transcription

57
Q

smooth ER structure and function

A

no ribosomes
tubular
intracellular single-membrane system
lipid, steroid hormone and phospholipid synthesis
lipid transport

58
Q

rough ER structure and function

A

covered with ribosomes
cisternae
continuous with nuclear envelope
intracellular single membrane
transport and folding of proteins
protein synthesis at ribosomes
intracellular transport

59
Q

mitochondrion structure and function

A

double membrane
inner membrane is folded into cristae
carries enzymes for respiration
matrix at centre
site of aerobic respiration to produce energy as ATP

60
Q

Golgi apparatus structure and function

A

specialised smooth ER forming a stack of disc-shaped cavities (cisternae)
glycoprotein, polysaccharide and hormone synthesis
lysosome production
packaging and modification of proteins into vesicles (for storage in cell/ export)

61
Q

microvilli structure and function

A

outfoldings of the plasma membrane
increase surface area for movement of molecules

62
Q

plasma membrane structure and function

A

phospholipid bilayer
single membrane
selective barrier
retains cell contents
compartmentalises cell
controls what enters and leaves the cell

63
Q

lysosome structure and function

A

single membrane-bound same of enzymes
spherical vesicles
intracellular digestion by hydrolytic enzymes

64
Q

where are lysosomes abundant

A

phagocytes

65
Q

centriole structure and function

A

rod-like structures containing microtubules
cell division in animal cells
produces spindle fibres in meiosis and mitosis

66
Q

middle lamella structure and function

A

contains pectin
sandwiched between cellulose in cell wall
increases the rigidity of the cellulose cell wall

67
Q

plasmodesma structure and function

A

pores linking plant cells
allow exchange of water and minerals between cells

68
Q

starch grain structure and function

A

contain strach (polysaccharide of amylose and amylopectin)
compact
insoluble
storage of carbohydrate

69
Q

cellulose cell wall structure and function

A

cellulose is composed of alternate beta glucose monomers (every other is rotated 180 degrees) to produce a straight chain, layered structure of cellulose microfibrils
freely permeable
maintains mechanical strength (holds shape of cell)
protection

70
Q

ribosomes structure and function

A

small particles with complex structure. found on RER/in cytoplasm
2 subunits
protein synthesis (translation)

71
Q

chloroplast structure and function

A

stoma
double membrane
grana (stacks of thylakoids)
contains chlorophyll and enzymes for photosynthesis
absorb light (photons) for photosynthesis
production of carbohydrates from simple raw materials (CO^2 & H2O)

72
Q

cilia and flagella structure and function

A

fine hairs projecting from cell surface
9+2 arrangement of microtubules (2 central surrounded by 9 pairs)
cell locomotion
transport of extracellular materials

73
Q

tonoplast structure and function

A

single membrane
surrounds the vacuole
exerts turgor pressure on the cellulose cell wall

74
Q

cell sap structure and function

A

contains sugars and water
acts a store of food and waste materials

75
Q

what do the tonoplast and cell sap make up together?

A

the vacuole

76
Q

microfilaments structure and diameter

A

long, thin, flexible threads
5nm

77
Q

microfilaments protein

A

actin

78
Q

microfilaments functions

A

cell movement
cell division, because allows formation of plasma membranes around new daughter cells
contractile protein, so is used in muscle contraction

79
Q

3 types of cytoskeleton

A

microfilaments
microtubules
intermediate fibres

80
Q

microtubules structure and diameter

A

thick, cylindrical tubes which form tracks
25nm

81
Q

microtubules protein

A

tubulin

82
Q

microtubules functions

A

movement of organelles and/or vesicles around cell-> this requires motor proteins and ATP
9+3 arrangement in the centrioles -> spindle fibre formation in cell division

83
Q

intermediate fibres structure and diameter

A

rope-like proteins that span the cell
variable diameter

84
Q

intermediate fibres proteins

A

elastin
collagen

85
Q

intermediate fibres functions

A

cell scaffolding
mechanical strength
therefore prevents cell from collapsing and hold organelles in place

86
Q

centrioles structure
found where

A

9+3 microtubule structure
in animal cells
found in pairs near nucleus

87
Q

centrioles function

A

produce mitotic spindle that separates chromosomes in cell division

88
Q

what are centrioles found in? details…

A

pairs
1 member of each pair moves to opposite poles in cell division

89
Q

are centrioles membrane-bound?

A

NO

90
Q

flagella and cilia structure

A

9+2 arrangement (9 pairs with a central pair)

91
Q

flagella location and function

A

attached to some bacteria and sperm cells
provide motility to cell, which requires ATP

92
Q

cilia location, structure and function

A

found in airway lining
hair-like structures
work with GOBLET CELLS (produce mucus) to trap and waft bacteria/dust to the back of the throat

93
Q

division of labour step by step with insulin as an example

A

insulin gene is transcribed in the nucleus
mRNA moves out of the nucleus through a nuclear pore and attaches to a ribosome
translation of mRNA produces a polypeptide chain
as polypeptide moves through the cisternae of the RER, it is folded into a 3D shape
polypeptide buds off the RER in a vesicle and moves towards the cis face of the Golgi apparatus via the microtubules (uses motor proteins and ATP)
as insulin moves through Golgi apparatus, it is modified and packaged into another vesicle, leaving the trans face
insulin moves to the plasma membrane in a vesicle and fuses with it
insulin is released by exocytosis

94
Q

what is a polypeptide chain

A

a chain of amino acids joined by peptide bonds

95
Q

what is exocytosis

A

the process of moving materials from within a cell to the exterior of the cell.

96
Q

example of prokaryotic cell

A

bacteria

97
Q

reproduction of prokaryotic cell

A

asexual

98
Q

do prokaryotic cells have membrane bound organelles?

A

no

99
Q

DNA of prokaryotic cells

A

circular chromosome and plasmids

100
Q

cytoskeleton of prokaryotic cells

A

simple

101
Q

size of ribosomes of prokaryotic cells

A

70s (smaller than eukaryotes)

102
Q

do prokaryotic cells have cilia/flagella

A

some have flagella

103
Q

what is a prokaryotic cell wall made of

A

murein

104
Q

examples of eukaryotic cells

A

animal
plant
fungi
protoctists

105
Q

do eukaryotic cells have membrane bound organelles?

A

yes e.g. nucleus, mitochondria

106
Q

eukaryotic cells DNA

A

nucleus

107
Q

eukaryotic cells cytoskeleton

A

complex cytoskeleton

108
Q

eukaryotic cells ribosome size

A

80s (bigger than prokaryotes)

109
Q

do eukaryotic cells have cilia/flagella

A

yes; both

110
Q

eukaryotic cells cell walls?

A

plants have cellulose cell wall
fungi have chitin cell wall

111
Q

eukaryotic cells reproduction?

A

sexual and asexual

112
Q

5 differences between prokaryotic and eukaryotic cells

A

nucleus
membrane bound organelles
murrain cw/no,cellulose or chitin CW
70s ribosomes/80s ribosomes
looped,circular DNA/linear DNA

113
Q

out of animal, plant and bacterial cells, which contain centrioles?

A

animal cells only

114
Q

can plants and animal cells make glucose?

A

ONLY PLANT CELLS

115
Q

how could a scientist use a light microscope to view cells on a prepared slide containing a blood sample?

A

firstly use the lower powered objective lens
use the coarse adjustment knob to bring the stage up
rotate the mirror so the light shines through the sample
look down the eyepiece and use the knob to focus the image
adjust the focus with the fine adjustment to get a clear image
greater magnification with a higher power so use turret to bring lens with a greater magnification into place if needed

116
Q

why can cytoskeleton degradation lead to a lack of muscle control?

A

proteins may not be successfully carried to the muscle cells because a vesicle cannot be transported
nerve cells may lose strength and stability so break down

117
Q

what does indirect stain do?
examples

A

only stains the background
carbol fuschin, india ink, picric acid

118
Q

what does selective stain stain?
examples

A

stains particular part of specimen
malachite green, congo red, crystal viotel

119
Q

what does direct stain stain
examples

A

only stains the specimen
methylene blue, safranin

120
Q

what does differential stain stain
examples

A

stains the cell wall
grams stain, ziehl nelson stain

biology (27 decks)

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