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YEAR 12- biology a-level > cells > Flashcards

cells Flashcards

1
Q

name all the organelles in an animal cell

A

cell membrane
cytoplasm
nucleus
nucleolus
nuclear envelope + pores
lysosome + lysozymes
ribosomes
mitochondria
golgi apparatus + vesicles
rough endoplasmic reticulum
smooth endoplasmic reticulum

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2
Q

name all the organelles in a plant cell

A

cell membrane
cytoplasm
nucleus
nucleolus
nuclear envelope + pores
lysosome + lysozymes
ribosomes
mitochondria
golgi apparatus + vesicles
rough endoplasmic reticulum
smooth endoplasmic reticulum
chloroplasts
vacuole
cell wall

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3
Q

what is the function of the rough endoplasmic reticulum

A

folds and processes proteins that have been made by ribosomes

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4
Q

what is the function of the SER

A

synthesises and processes lipids

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5
Q

what is the function of the vacuole

A

maintains cell pressure and keeps the cell rigid, isolates unwanted chemicals in the cell

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6
Q

what is the function of the golgi apparatus

A

processes and packages lipids and proteins and make lysosomes

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7
Q

what is the function of the golgi vescicle

A

stores lipids and proteins made by G.A and transports them out of the cell

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8
Q

what is the function of the lysosomes

A

type of golgi vescicle which contains digestive enzymes called lysozymes and digest invading cells

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9
Q

features of algal cells

A

similar to plant cells
can be unicellular
have chloroplasts and cellulose cell walls
chloroplasts differ in size and shape

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10
Q

features of fungal cells

A

uni or multicellular
chitin cell walls
no chloroplasts

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11
Q

role of organelles in production, transport and release of proteins

A

nucleolus makes ribosomes
ribosomes make proteins
RER- folds and processes proteins
golgi A processes + packages
golgi V stores and transports out of cell

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12
Q

which type of cells don’t have chloroplasts

A

animal cell
fungal cell

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13
Q

which cells don’t have a cell wall

A

animal

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14
Q

which cells don’t have a vacuole

A

animal

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15
Q

what is the cell wall of a fungal cell made of

A

chitin

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16
Q

what are the folds of the inner mitochondrial membrane called

A

cristae

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17
Q

what are the 3 substructures of mitochondria

A

outer membrane
inner membrane
matrix

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18
Q

what are the 4 substructures found in chloroplasts

A

outer membrane
inner membrane
grana/ stacked thylakoids
stroma

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19
Q

what are the similarities and differences between mitochondria and chloroplasts

A

both have a double membrane
starch grains vs none
pigments vs no pigments
stroma vs matrix
grana vs cristae

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20
Q

why are viruses acellular and non living

A

they have no cell membrane and no mitochondria

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21
Q

what is the cell wall of a prokaryote made from

A

murein ( a glycoprotein )

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22
Q

what is cell fractionation

A

separating cell components

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23
Q

what is the process of homogenisation

A

cells are broken up and release organelles

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24
Q

what is the process of filtration

A

filtering the homogenate using a gauze to remove large debris

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25
Q

what is the process of ultracentrifugation

A

homogenate fragments separated by centrifugal force in a centrifuge, heaviest organelles forma pellet at the bottom with the lowest speed, the rest form a supernatent and process is repeated

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26
Q

what are the conditions needed for homogenisation

A

ice cold- prevent enzymes from working
isotonic- no osmosis for the same water potential
pH buffer-stops pH from fluctuating

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27
Q

what happens during prophase

A

chromosomes condense
nuclear membrane and nucleolus break down
centrioles move to poles
spindle fibres develop

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28
Q

what happens during metaphase

A

chromatids line up in middle of cell
spindle fibres attach to chromatids at the centromere

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29
Q

what happens during G1 of the cell cycle

A

cell grows larger as new proteins and organelles are duplicated

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30
Q

what happens during S in the cell cycle

A

DNA replicates to divide by mitosis
chromosomes are copied

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31
Q

what happens during G2 of the cell cycle

A

cell continues to grow and synthesise enzymes
spindle proteins for mitosis

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32
Q

what are the organelles in a bacterial cell

A

plasmid dna
slime capsule
cell membrane
ribosomes
cytoplasm
chromosome dna
cell wall (murein)

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33
Q

what is the function of plasmid dna

A

carry genes to transfer between bacteria

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34
Q

function of the slime capsule

A

protection

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35
Q

what is murein an example of

A

a glycoprotein

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36
Q

what is the function of chromosome dna

A

contain genes to allow replication of bacteria

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37
Q

what is the structure of a virus- organelles

A

capsid
enzymes
attachment proteins
genetic material
lips envelope
matrix

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38
Q

what is the function of attachment proteins

A

bind to receptors on host cells

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39
Q

what is the function of capsid

A

protect genetic material

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40
Q

what is chitin

A

the polysaccharide found in fungus cell walls

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41
Q

how do viruses work

A

attach to a host and reproduce by inserting genetic material

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42
Q

characteristics of TEMs

A

use electromagnets
high resolution to see internal structures
only in 2D
only thin specimens
electrons have a short wavelength

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43
Q

characteristics of SEMs

A

scan a beam of electrons
gathered in cathode ray tube
images show surfaces
can be 3D
thick specimens allowed
low resolution

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44
Q

magnification equasion

A

magnification = image size / actual size

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45
Q

definition of magnification

A

how much bigger the image is than the specimen

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46
Q

definition of resolution

A

how detailed the image is/ how well a microscope distinguishes between 2 close points

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47
Q

features of optical microscopes

A

use light
maximum resolution of around 0.2 um (can’t view organelles smaller than 0.2um)
maximum magnification is around x 1500

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48
Q

what happens during anaphase

A

centrioles divide and seperate chromosomes
spindle fibres contract and pull them to opposite poles

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49
Q

what happens during telophase

A

chromatids reach opposite poles, uncoil and extend back into chromosomes
new nuclear envelope forms 2 nuclei
cytoplasm divides, spindle fibres disappear

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50
Q

what happens during cytokinesis

A

cell divides into 2 genetically identical daughter cells

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51
Q

what is a prokaryote

A

unicellular with no membrane bound organelles

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52
Q

what organelles can only be found in SOME bacterial cells

A

flagellum
slime capsule
plasmids

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53
Q

how are bacterial ribosomes different to eukaryotic ribosomes

A

bacterial ribosomes are smaller - 70S

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54
Q

name 3 components of ALL viruses

A

capsid
attachment proteins
genetic material

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55
Q

what is the approximate size of a virus

A

0.1um

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56
Q

what is binary fission

A

process of bacterial cell division

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57
Q

describe the binary fission process

A

-circular dna and plasmids replicate
-cell lengthens, circular dna is pulled to poles
-new cell membrane grows between 2 dna molecules and pinches in
-new cell wall forms
-cytoplasm splits
2 daughter cells with a copy of circular dna

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58
Q

mitotic index

A

number of cells in mitosis / total cells

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59
Q

what are cell membranes needed for

A

keep conditions inside cell separate from conditions outside

act as a barrier between organelles and cytoplasm

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60
Q

what is the phospholipid bilayer

A

fluid- constantly moving

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61
Q

what is the function of the glycoprotein

A

found on the outside of the cell membrane
made of protein attached to a carbohydrate
help hormone signalling

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62
Q

what is the function of cholesterol in the fluid mosaic

A

fits between phospholipids and help them pack tightly
makes membranes more rigid
maintain animal cell shape

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63
Q

what is the function of the extrinsic proteins

A

only found on the outside of membrane
mechanical support
receptors for hormones
allows cell to recognise other cells

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64
Q

name the 2 integral proteins

A

channel and carrier

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65
Q

what is the function of the channel protein

A

form proves to facilitate movement of chargers particles

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66
Q

what is the function of carrier proteins

A

facilitate diffusion of different molecules that are larger to enter the intracellular space

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67
Q

how do carrier proteins allow molecules to pass through

A

a large molecule attaches to the binding side of the carrier protein
carrier protein changes shape
releases molecule to the intracellular space

68
Q

what is the function of aquaporins

A

water can flow more rapidly in or out of cells compared to simple diffusion across plasma membrane

69
Q

what is the definition of diffusion

A

net movement of particles from an area of higher concentration to lower concentration down a concentration gradient

70
Q

what is simple diffusion

A

small simple molecules diffuse directly through a cell membrane (non polar molecules)

71
Q

how does temperature affect the rate of simple diffusion

A

higher temperature= more kinetic energy to move faster through the membrane, increasing rate of reaction

72
Q

how does size of concentration gradient affect rate of simple diffusion

A

steeper concentration gradient increases the rate of reaction

73
Q

how does surface area affect the rate of reaction of simple diffusion

A

increased surface area= increased rate of reaction as there is more area for diffusion to occur across

74
Q

how does having a thin membrane affect the rate of simple diffusion

A

short diffusion distance= pass through membrane earlier and faster= increased rate of reaction

75
Q

applicable to an experiment- how does stirring affect rate of simple diffusion

A

more kinetic energy= increased rate of diffusion

76
Q

why can’t large molecules pass through simple diffusion

A

larger molecules such as amino acids or glucose would diffuse slowly through the phospholipid bilayer as they are too large

77
Q

what are the factors that affect facilitated diffusion

A

simple diffusion factors
amount of channel proteins or carrier proteins

78
Q

how does amount of channel/ carrier proteins affect rate of facilitated diffusion

A

faster rate of diffusion as more charged particles can diffuse

79
Q

what is the definition of osmosis

A

the net movement of water molecules form an area to higher to lower water potential through a partially permeable membrane until equilibrium

80
Q

what is the definition of water potential

A

likelihood of water molecules diffusing out of/ into a solution

81
Q

what is water potential measured in

A

kilopascals- negative scale

82
Q

isotonic

A

2 solutions with the same water potential, no net movement of water

83
Q

hypertonic

A

lower water potential than inside the cell, water moves out of the cell and shrivels up/ becomes flaccid

84
Q

hypotonic

A

higher water potential than inside the cell, water moves into the cell and bursts/ becomes turgid

85
Q

why won’t plant cells burst in hypertonic solutions

A

has a cellulose cell wall which is strong and rigid

86
Q

factors that affect osmosis

A

temperature
surface area
water potential gradient
humidity
more aquaporins
thin membrane

87
Q

how does surface area affect osmosis

A

larger exchange surface, more aquaporins and faster rate of osmosis

88
Q

how does water potential gradient affect osmosis

A

steep= faster osmosis as there is a bigger difference in water potential

89
Q

features found in a cell specialised for absorption

A

aquaporins/ integral proteins
surface area
active transport

90
Q

how does a large number of aquaporins affect rate of absorption

A

larger number means a faster rate of osmosis/ facilitated diffusion and faster absorption of substances

91
Q

how does surface area affect the rate of absorption

A

folded membrane leads to larger SA and faster rate of absorption

92
Q

how does integral proteins affect rate of absorption

A

large number allows a faster rate of diffusion and absorption of large molecules via facilitated diffusion, increasing absorption

93
Q

how does active transport affect the rate of absorption

A

more mitochondria in cells to release ATP for active transport so rate of absorption increases

94
Q

definition of active transport

A

movement of molecules/ ions in or out of a cell from an area of lower to higher concentration against a concentration gradient using proteins and atp

95
Q

differences between AT and simple diffusion

A

AT lower-higher. SD higher-lower
AT against conc gradient. SD passive
AT uses energy. SD doesn’t use energy
AT carrier proteins. SD no integral proteins

96
Q

process of active transport including integral protein

A

molecule being transported binds to carrier protein
atp binds to protein and is hydrolysed into adp and pi, energy changes shape
molecule travels through newly opened channel
phosphate ion is released and recombines with atp
carrier protein returns to original shape

97
Q

factors affecting rate of active transport

A

number of mitochondria- atp production +respiration

98
Q

when is active transport used

A

digestion
phloem loading
absorb mineral ions from soil
reabsorbtion of useful molecules

99
Q

what is co transport

A

cells can transport 2 substances at the same time through the same carrier protein

100
Q

what is a pathogen

A

a microorganism which can cause infectious diseases

101
Q

how are pathogens detected

A

foreign entigens on pathogen surface

102
Q

what is an antigen

A

protein on the cell surface that generates an immune system response when detected by the body

103
Q

chemical barriers the body defends itself by

A

tears- lysozymes
mucus
stomach acid

104
Q

physical barriers

A

skin
hair- nose
cilia- trachea
scabs- made by platelets to prevent pathogens from entering through wounds

105
Q

what are the 2 types of immune response

A

specific
non specific

106
Q

what is a specific immune response

A

a slower response which directly targets pathogen, immune system recognises pathogen and coordinates response

107
Q

what is a non specific immune response

A

immediate response which happens regardless of pathogen type e.g phagocytosis

108
Q

what is a phagocyte

A

macrofage/ white blood cell which digests and engulfs a pathogen

109
Q

what is phagocytosis

A

process which phagocyte engulfs and digests a pathogen

110
Q

what are the steps of phagocytosis

A

antigens on surface of pathogen are recognised by phagocyte

cytoplasm engulfs pathogen

pathogen > phagosome

phagosome fuses with lysosome > phagolysosome

lysozymes hydrolise/ digests pathogen

phagocyte presents antigen on its surface >antigen presenting cell , to activate other cells

111
Q

what do the role of antibodies in stimulating phagocytosis

A

bind to a complimentary antigen on the pathogen
agglutinate pathogens to engulf many at the same time with many phagocytes

112
Q

why do phagocytes become antigen presenting cells

A

present antigens on surface to activate t- cells for a cell mediated response

113
Q

what are the 2 cells involved in a cell mediated response

A

T- helper cells
cytotoxic T-cells

114
Q

when are t cells activated

A

when an antigen binds to receptor proteins on surface

115
Q

what is the role of T-helper cells

A

release chemical signals that activate and stimulate phagocytes + CT cells

116
Q

what is the role of cytotoxic T-cells

A

kill abnormal and foreign cells as they produce perforan to create a hole in the cell membrane of the infected cell and granzymes enter to digest contents

117
Q

what are the cells involved in humoral response

A

B-cells

118
Q

when are B-cells produced

A

final stage of immune response

119
Q

what is the role of a B-cell

A

covered in antibodies that bind to antigens
activated by cells divide into plasma cells via clonal selection

120
Q

which cells can produce memory cells

A

B + T cells

121
Q

what are plasma cells

A

identical to their B-cells
rapidly reproduce antibodies specific to antigen

122
Q

where are lymphocytes produced

A

bonemarrow

123
Q

where do b cells mature

A

thymus gland

124
Q

what are the 2 types of white blood cell

A

phagocyte
lymphocyte

125
Q

where are antigens found

A

cell surface

126
Q

what is a memory lymphocyte

A

stay in blood after primary infection and produce more antibodies at a faster rate

127
Q

which type of white blood cell makes antitoxins

A

lymphocytes

128
Q

what is found in a vaccine

A

dead/ inactive/ weakened form of pathogens

129
Q

what are anti toxins

A

neutralise a toxin by bacteria

130
Q

why are antibodies specific to one antigen

A

complimentary shape

131
Q

what is the structure of an hiv virus

A

capsid
reverse transcriptase enzyme
attachment proteins
lipid envelope
matrix
genetic material/ RNA

132
Q

how is hiv different to regular virus cells

A

has a-
matrix
enzyme - reverse transcriptase
rna

133
Q

how is hiv different to regular virus cells

A

has a-
matrix
enzyme - reverse transcriptase
rna

134
Q

what does hiv destroy

A

CD4+ T cells/ t helper cells

135
Q

what do t helper cells do

A

activate b cells which produce plasma cells to make antibodies

136
Q

what do antibodies do

A

destroy pathogens

137
Q

why are you more likely to develop secondary infection with hiv virus

A

antibodies can’t be created to produce antibodies to immobilise and destroy pathogens

138
Q

what sit eh process of hiv replication in easy steps

A

hiv binds to t cell
rna is injected
rna converted into dna
viral dna enters nucleus and joins dna
cell produces viral proteins
new virus leaves cell

139
Q

what do cytotoxic t cells do

A

destroy abnormal cells by releasing perforin to put a hole in the cell membrane of the infected cell and granzymes enter cell and digest contents

140
Q

what do suppressor t cells do

A

prevent innume system from being over active, slows down CT and helper T cells

141
Q

what are the steps of cellular response

A

•pathogen destroyed by phagocytosis
•phagocyte displays pathogen antigens and becomes an APC
•t helper cell binds to antigen with a complimentary receptor and is activated
•t helper cells divide by mitosis to form genetically identical clones

142
Q

what are the clones that a t cell turns into when going through mitosis

A

t memory cell
stimulate b cells
stimulate phagocytosis
activate CT cells

143
Q

process of phagocytosis

A

phagocyte detects foreign antigen on pathogen surface
phagocytes cytoplasm engulfs pathogen
pathogen in a phagosome
lysosome fuses with phagosome and forms a phagolysosome
lysozymes hydrolise pathogen
phagocyte displays pathogen on outside of cell and becomes an APC
T cells activated

144
Q

antibody structure

A

2 light chain polypeptides
2 heavy chain polypeptides
binding sites which are complimentary
veritable region
constant region

145
Q

humoral response

A

antigens taken up by b cells
antigens displayed on b cell surface
activated t helper cell attached to antigens and activates b cells
activated b cell clones by mitosis- plasma cells or b memory cells

146
Q

what are vaccinations contain

A

dead, attenuated, purified pathogens

147
Q

what is the primary infection process

A

antigens enter body for 1st time
slow reaction due to lack of b cells
symptoms show
t and b cells produce memory cells

148
Q

what is the secondary infection process

A

same pathogen enters body
faster immune response
memory b cells activated and divide into plasma cells

149
Q

immunity definition

A

capacity to recognise the intrusion. of foreign antigens

150
Q

what are the 2 types of immunity

A

passive and active

151
Q

what is passive immunity

A

antibodies given to a person
don’t make their own antibodies

152
Q

what is active immunity

A

makes their own antibodies after exposure to pathogen
longer lasting

153
Q

what are the 2 factors of immunity

A

artificial
natural

154
Q

what does attenuated and purified mean

A

weakened
inactive

155
Q

what is the process of vaccination

A

vaccine- with dead/ purified/ attenuated pathogens- given to a person
makes complimentary antibodies
plasma b cells create memory b cells
small response
secondary infection of antigen- rapid production of antibodies

156
Q

what is antigenic variability

A

pathogen may mutate frequently, immune system won’t have antibodies to destroy pathogen

157
Q

what is the role of a suppressor t cell

A

prevent immune system from being over active, slows down t and ct cells

158
Q

what is the role of a suppressor t cell

A

prevent immune system from being over active, slows down t and ct cells

159
Q

what are b cells

A

cells activated by chemical signals and differentiate into plasma cells to produce antibodies

160
Q

what is the special adaptation of plasma cells

A

have. a large nucleus to code for proteins and RER

161
Q

process of producing monoclonal antibodies

A

mouse is exposed to pathogen
b cells in mouse produce antibodies- exctranced from spleen
b cells are mixed with cells that divide outside of body (cancer cells)
detergent added to cells to break down cell membrane of both cell types
cells fuse together- hybridoma cells
hybridoma cells separated + cultured to form clones
clones tested for antibody required
any clone porduciny antibody is grown on large scale
antibodies extracted - monoclonal antibodies

162
Q

what is a monoclonal antibody

A

collection of antibodies that are specific to one antibody- come from a clone of a single b cell

163
Q

what are the 2 types of t cell

A

t helper cell
cytotoxic t cell

164
Q

what happens during clonal selection

A

t cells release a chemical signal to activate b cells and they divide into plasma cells

165
Q

what is an antibody

A

protein found in body that bind to antigens and stimulate immune response

166
Q

what are the uses of the eliza test

A

medical diagnosis- pregnancy tests
targeting drugs to specific cells

YEAR 12- biology a-level (6 decks)

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