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biology > cells > Flashcards

cells Flashcards

1
Q

eukaryotic cells: what is the nucleus

A

the spherical nucleus contains hereditary material & regulates cell activities

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2
Q

eukaryotic cells: what is the nuclear envelope

A

double membrane
associated w/ er
surrounds nucleus that controls movement of genetic material

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3
Q

eukaryotic cells: what are nuclear pores

A

allows passage of large molecules (around 3000 pores)

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4
Q

eukaryotic cells: what is the nucleoplasm

A

granular jelly like matieral that suspends nucleus bound structures e.g chromatin

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5
Q

eukaryotic cells: what are chromosomes

A

protein bound, linear dna

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6
Q

what are bound in chromosomes

A

histones

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7
Q

what are histones

A

proteins

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8
Q

eukaryotic cells: what is the nucleolus

A

makes ribosomal rna & assembles the ribosomes
may be more than one

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9
Q

eukaryotic cells: what is mitochondria

A

produces atp through aerobic respiration

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10
Q

how is atp produced in the mitochondria

A

krebs cycle and oxidative phosphorylation

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11
Q

eukaryotic cells: what type of membrane does mitochondria have, and name them

A

double membrane
inner and outer

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12
Q

eukaryotic cells: what does the outer membrane do in mitochondria

A

controls entry and exit of material

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13
Q

eukaryotic cells: what does the inner membrane do in mitochondria

A

it folds to form cristae

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14
Q

eukaryotic cells: what does the cristae do in mitochondria

A

increases surface are for enzymes and proteins

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15
Q

eukaryotic cells: what is the matrix in mitochondria

A

remainder of mitochondrian
containing proteins, ribosomes, lipids and dna

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16
Q

eukaryotic cells: what are chloroplasts

A

disc shaped organelles that carry out photosynthesis

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17
Q

eukaryotic cells: what is the envelope in chloroplasts

A

selectively permeable double membrane

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18
Q

eukaryotic cells: what is a thylakoid in chloroplasts

A

contains chlorophyll

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19
Q

where does the first stage of photosynthesis occur

A

in the thylakoid

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20
Q

eukaryotic cells: what is the grana in chloroplasts

A

stacks of thylakoids

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21
Q

eukaryotic cells: what is the stroma in chloroplasts

A

fluid filled matrix

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22
Q

where does the second stage of photosynthesis take place

A

in the stroma

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23
Q

what is the cell membrane made out of

A

phospholipid bilayer

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24
Q

eukaryotic cells: what is the structure of endoplasmic reticulum

A

flattened sacs called cisternae

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25
Q

eukaryotic cells: what is the rough er

A

rough due to ribosomes on it
large sa for ribosomal synthesis
proteins and glycoproteins synthesised and packaged into vesicles

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26
Q

eukaryotic cells: what is the smooth er

A

lacks ribosomes
synthesis storage & transport of lipids and carbohydrates

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27
Q

eukaryotic cells: what is the golgi apparatus

A

stack of flattened membrane sacs (cisternae) w/ vesicles
modifies proteins & lipids produced by er

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28
Q

eukaryotic cells: what are vesicles

A

small fluid filled sacs that transport substances around the cell

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29
Q

what does the golgi apparatus do

A

labels added to sort & transport glycoproteins to correct destination
produces lysosomes
modified proteins transported in vesicles
pinched off from ends of cisternae
there’s endocytosis and exocytosis

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30
Q

eukaryotic cells: what are lysosomes

A

formed when golgi vesicles contain lysozymes that hydrolyse cell walls of bacteria

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31
Q

what do lysomsomes do

A

contain hydrolytic enzymes to break down pathogens

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32
Q

eukaryotic cells: what are ribosomes

A

80s
carry out protein synthesis

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33
Q

eukaryotic cells: what are cell walls made up of

A

cellulose

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34
Q

eukaryotic cells: what are cell walls

A

rigid walls w/ microfibrils provide strength and support
stops cell from bursting
turgidity

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35
Q

eukaryotic cells: what is the middle lamella in cell walls

A

boundary between adjacent cells & cements them together

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36
Q

eukaryotic cells: what are algaes cell wall made of

A

cellulose and/or glycoproteins

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37
Q

eukaryotic cells: what are fungi’s cell wall made of

A

polysaccharide chitin & glycoproteins

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38
Q

eukaryotic cells: what are vacuoles

A

cell sap stores sugars, amino acids, wastes and pigments
maintains turgidity to herbaceous plants
food store
attraction for pollination

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39
Q

what type of organelles does eukaryotic cells have

A

membrane bound organelles

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40
Q

what is the definition of eukaryotic

A

true nucleus

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41
Q

what is the definition of prokaryotic

A

before nucleus

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42
Q

notes on prokaryotic cells

A

unicellular
less than 2 micrometres (smaller)
3.5 billion years ago
only 1 chromosome

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43
Q

what features are always present in prokaryotic cells

A

plasma membrane
circular dna
cytoplasm
ribosome
cell wall

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44
Q

what ribosomes do prokaryotic cells have

A

70s (smaller)

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45
Q

prokaryotic cells: what is the cell wall made of

A

peptidoglycan (murein)

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46
Q

prokaryotic cells: what type of grams are found at the cell wall

A

gram positive & negative at structure of cell wall

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47
Q

prokaryotic cells: what is a capsule

A

waxy mucus layer, protective

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48
Q

prokaryotic cells: what is the flagellum

A

for movement

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49
Q

prokaryotic cells: what is cillia/pili

A

small hair like structures that can attach to other cells

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50
Q

prokaryotic cells: what is a plasmid

A

small loop of dna

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51
Q

prokaryotic cells: what is a nucleoid

A

where circular dna is

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52
Q

is fungi prokaryotic or eukaryotic

A

eukaryotic

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53
Q

what is magnification

A

how many times bigger the image is when compared to the actual object

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54
Q

what is resolution

A

the minimum distance apart that two objects can be distinguished as separate items in an image

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55
Q

what does resolving power depend on

A

wavelength or form of radiation used

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56
Q

what is the definition of cell fractionation

A

cells are broken up & organelles separated out

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57
Q

what are the 3 things required of the solution for cell fractionation

A

must be cold
have same water potential as tissue
be buffered

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58
Q

why does the solution need to be cold for cell fractionation

A

to reduce enzyme activity that might break down the organelles

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59
Q

why does the cell need to have the same water potential for cell fractionation

A

to prevent organelles bursting or shrinking due to osmotic gain/ loss of water

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60
Q

why does the cell need to be buffered for cell fractionation

A

so that ph doesn’t fluctuate
changes in ph can alter the structure of organelles or affect the enzyme function

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61
Q

what are the 2 stages of cell fractionation

A

homogenation
ultracentrifugation

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62
Q

cell fractionation process

A

cells undergo homogenation in homogeniser
resultant homogenate filtered to remove complete cells & large debris
centrifugation spins homogenate in centrifuge
heaviest organelles (nuclei) are forced to the bottom where pellet/ sediment formed
fluid at the top (supernatant) is transferred & centrifuged at faster speed, next heaviest forms at bottom
process repeated until all organelles are sedimented and separated out

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63
Q

adavantages of the electron microscope

A

high resolving power
focused using magnets as they are charged
electrons can be deflected or absorbed by molecules in the air t/f a near vacuum has to be created

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64
Q

why does electron microscopes have higher resolution

A

shorter wavelength

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65
Q

what are the 2 types of electron microscopes

A

transmission electron microscope (tem)
scanning electron microscope (sem)

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66
Q

how does tem work

A

beam of electrons passes through a thin section of specimen
focused through magnets within vacuums
areas that absorb electrons appear darker on electron micrograph that is produced

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67
Q

what resolving power does tem have and why can’t it always be achieved

A

0.1nm h/e can’t always reach due to difficulties preparing specimen or high energy electrons may destroy specimen

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68
Q

4 limitations of tem

A

vacuum means living organisms can’t be observed –> no air
staining still doesn’t produce coloured images
specimen needs to be extremely thin
image may contain artefacts

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69
Q

why does tem need thin specimens

A

the specimen is in the middle t/f electrons need to pass through

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70
Q

how does sem work

A

directs beam of electrons back & forth across specimen
electrons are scattered depending on contours of specimen t/f causing 3d image

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71
Q

what resolving power does sem have

A

20nm, lower than tem, better than light microscope

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72
Q

what are the limitations of sem

A

expensive
require skills
same limitations as tem apart from thin specimen

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73
Q

what magnification does sem and tem have

A

tem - 500000
sem -100000

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74
Q

what is the eyepiece called on a light microscope that can measure sizes

A

graticule

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75
Q

what is the microscope calibration method

A

align stage micrometer w/ graticule
work out how many stage units is 10 graticules
convert stage units into micrometre –> this is equal to 10 graticules
divide stage units by 10 to find out 1 graticule unit

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76
Q

how many daughter cells are made from mitosis and meiosis

A

2 - mitosis
4 - meiosis

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77
Q

what is the definition of mitosis

A

cell division that produces 2 daughter cells, each w/ identical copies of dna from parent cell

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78
Q

what are the stages of mitosis

A

prophase
metaphase
anaphase
telophase

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79
Q

when does dna replication occur

A

interphase

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80
Q

notes on interphase

A

dna replication
two copies of dna after replication remain joined at centomere
dna present as uncondensed chromatin, contained in nucleus
centrosomes & organelles replicated
cell enlarged ready for duplication

81
Q

what is chromatid

A

has a centromere
essentially half of the chromosome shape but still considered a whole chromosome

82
Q

what is a centrosome

A

area in nucleus where centrioles are found

83
Q

what is a centriole

A

smaller version of centrosomes

84
Q

what is a centromere

A

special structure on chromosome which holds the chromatids together

85
Q

what is depolymerisation

A

converting polymers to monomers

86
Q

notes on prophase

A

chromosomes condense
centrosomes move to opposite poles & form microtuble spindle fibres
spindle fibre attach to centromeres
nuclear membrane breaks down

87
Q

notes on metapase

A

spindle fibres fully connect to centromere of each chromosome
depolymerisation causes spindle fibres to shorten
chromosomes line up at cells equator

88
Q

notes on anaphase

A

depolymerisation causes sister chromatids to separate
move to opposite poles of the cell

89
Q

notes on telophase

A

spindle fibres dissolve
chromosomes decondense to form chromtin
nuclear envelope reforms around chromosomes

90
Q

notes on cytokinesis

A

cytoplasm divies
2 daughter cells

91
Q

process of binary fission

A

circular dna & plasmids replicate
both copies attach to cell membrane
cell membrane begins togrow round 2 molecules of dna dividing cell in 2
new cell wall forms dividing cell into 2 genetically identical daughter cells

92
Q

process of virus replication

A

attach to proteins on a cell surface
inject nucleic acid

93
Q

where is viral dna found

A

protein coat called capsid

94
Q

what type of cells are viruses

A

acellular as they’re non living

95
Q

what envelope do some viruses have

A

lipid envelope containing attachment proteins for recognition

96
Q

what are the 3 stages of the cell cycle

A

g1 (growth)
s (synthesis)
g2 (growth)

97
Q

cell cycle: what happens in g1

A

cell grows physically larger
organelles divide

98
Q

cell cycle: what happens in s

A

dna & centrosomes are duplicated

99
Q

cell cycle: what happens in g2

A

more growth
proteins & organelles are made

100
Q

cell cycle: interphase

A

occupies most of the cell cycle, no division takes place

101
Q

cell cycle: nuclear divison

A

nucleus divides into 2 (mitosis) or 4 (meiosis)

102
Q

cell cycle: cytokinesis

A

cytoplasm divides to produce 2 (mitosis) or 4 (meiosis)

103
Q

what is cancer the result of

A

damage to genes that regulate mitosis & the cell cycle
leading to uncontollable growth & division causing a tumour to develop

104
Q

what type of tumours are there

A

malignant and benign

105
Q

what happens to most mutated cells

A

the die
h/e some divide and form clones

106
Q

how does chemotherapy treat cancer

A

disrupts the cell cycle by:
preventing dna from replicating (s)
inhibiting metaphase by interfering w/ spindle formation

107
Q

what is the fluid mosaic model

A

arrangement of various molecules in a cell surface membrane

108
Q

what does the fluid part of fluid mosaic model mean

A

individual phospholipids can move relative to one another

109
Q

what does the mosaic part of fluid mosaic model mean

A

proteins embedded vary in shape, size & pattern

110
Q

fluid mosaic model: what are extrinsic/peripheral proteins

A

for mechanical support,
or act as receptors
only on one layer

111
Q

fluid mosaic model: what are glycoproteins

A

cell recognition,
or cell signaling receptors

112
Q

fluid mosaic model: what is cholesterol

A

reduces fluidity
adds strength and rigidity
helps anchor peripheral/extrinsic proteins
less permeable to small water soluble molecules
separates tails so prevents crystallisation
prevents leakage at high temperatures

113
Q

fluid mosaic model: what can diffuse through the phospholipid bilayer

A

small lipid soluble molecules
o2
co2
h20

114
Q

fluid mosaic model: what can’t diffuse through the phospholipid bilayer

A

large molecules
charged ions
water soluble molecules

115
Q

fluid mosaic model: what are channel & carrier proteins

A

transport proteins
integral (go through both layers of phospholipid bilayer)

116
Q

fluid mosaic model: what are channel proteins

A

allow water soluble ions to diffuse through

117
Q

fluid mosaic model: what are carrier proteins

A

they chemically bind to the protein, protein changes it’s shape
amino acids, ions, glucose

118
Q

what is the definition of diffusion

A

net movement of molecules or ions from a region of higher concentration to lower concentration until equilibrium is reached

119
Q

what are all the different movement across membranes

A

simple diffusion
facilitated diffusion
osmosis
active transport
co transport

120
Q

what is the definition of osmosis

A

movement of water particles from a region of higher water potential to lower water potential through a selectively permeable membrane

121
Q

what is the defintion of water potential

A

the pressure created by water molecules

122
Q

what is the greek letter psi

A

represents water potential (trident looking thing)
measued in kilopascals kPa

123
Q

what is the water potential of pure water

124
Q

what happends when a solute is added to pure water

A

lowers the water potential

125
Q

what are the different types of water potential

A

isotonic solutions
hypotonic solutions
hypertonic solutions

126
Q

what is an isotonic solution

127
Q

what is a hypotonic soluion

A

cells swell, b/c there’s a lot of water molecules outside the cell so the cell gains the water

128
Q

what is a hypertonic solution

A

cells shrink
more soluts, lower water potential t/f cell loses water

129
Q

what is the definition of active transport

A

movement of molecules or ions into or out of a cell from a region of lower concentration to higher using atp and carrier proteins

130
Q

what is the process of active transport

A

molecules bind to receptor on carrier protein
atp binds to carrier protein on inside of cell
carrier protein changes in shape and opens
molecule or ion is released to other side of membrane
when phosphate ion is released carrier protein returns to original shape

131
Q

what’s an example of active transport

A

sodium potassium pump

132
Q

what is the definition of co transport

A

two substances are simultaneously transported across a membrane in the same direction facilitated by symporters/ carrier proteins

133
Q

what is the definition of simple diffusion

A

small non polar molecules down a concentration gradient (high to low)

134
Q

what is the definition of facilitated diffusion

A

large charged molecules down a concentration gradient by transport proteins

135
Q

what is the function of atp hydrolyse

A

releases energy
allows active transport of ions

136
Q

what are antigens

A

molecules present on the surface of cells which trigger a immune response

137
Q

what things can the immune system identify

A

pathogens
non self
toxins
cancerous cells

138
Q

are specific lymphocytes produced

A

no they already exist

139
Q

what is clonal selection

A

when the complimentary lymphocyte is stimulated to divide

140
Q

when surface barriers fail what’s the next line of defence

A

phagocytes and lymphocytes

141
Q

what is chemotaxis

A

chemical sign from pathogens, phagocytes move towards it

142
Q

process of phagocytosis

A

pathogens release chemicals
receptors on phagocyte cell membrane surface attach to pathogen
engulfs pathogen in vesicle, called phagosome
lysosomes move towards phagosome, fuse w/ it
lyzozymes hydrolyse pathogen cell wall
small soluble products from pathogen are released or absorbed

143
Q

when inflammation occurs what is released

A

histamines

144
Q

what do histamines do

A

cause blood vessels to dilate
more blood & heat in the area
leaky capillary walls

145
Q

what happens when body temperature rises from being ill

A

reduces pathogen production rate
increases immune cell activity

146
Q

what do bacterial infections do to body temperature

A

steady rise in temperature

147
Q

what do viral infections do to body temperature

A

sudden spikes in temperature when cells burst

148
Q

what 2 lymphocytes are there

A

b lymphocytes
t lymphocytes

149
Q

where are b lymphocytes found

A

bone marrow

150
Q

what immunity are b lymphocytes associated with

A

humoral immunity

151
Q

where are t lymphocytes found

152
Q

what immunity are t lymphocytes associated with

A

mediated immunity

153
Q

what are antigen presenting cells

A

cells that activate t cells using the antigen from the pathogen

154
Q

name the antigen presenting cells

A

phagocytes
infected body cells
foreign cells
cancer cells

155
Q

how are phagocytes antigen presenting cells

A

present engulfed pathogen’s antigens on it’s membrane

156
Q

how are infected body cells antigen presenting cells

A

present viral antigens on a membrane

157
Q

how are foreign cells antigen presenting cells

A

transplanted cells from same species have different on the membrane

158
Q

how are cancer cells antigen presenting cells

A

present abnormal antigens on membrane

159
Q

what do t lymphocytes respond to

A

specific antigens presented on cell surface membrane

160
Q

explain the role of t lymphocytes in cell mediated immunity

A

phagocytosis occurs
phagocytes present antigens from pathogens on its cell surface membrane
receptors on specific helper t cells bind to antigens
this activates helper t cells to divide rapidly by mitosis to form clones

161
Q

what do cloned t helper cells do

A

develop into memory cells
stimulate phagocytes to engulf pathogens
stimulate b cells to divide and secrete the antibody
activate cytotoxic cells ( t killer)

162
Q

what do cytotoxic cells do

A

kill abnormal cells by making holes in the membrane w/ protein called perforin
t/f membrane more permeable and will die

163
Q

what are antibodies

A

proteins produced in immune system in response to an infection
bind to antigens
neutralise toxins & pathogens

164
Q

explain the role of b cells in humoral immunity

A

surface antigens of pathogen are taken by b cell
b cell process and present the antigens on it’s cell surface membrane
helper t cell attaches to processed antigen on b cell activating it
b cell divides by mitosis to form clones that produce the same antibody
a clone known as plasma cells secrete the specific antibody on pathogens surface
antibody attaches to antigen, destroying the pathogen
the other b cell clones turn into memory cells

165
Q

what happens to the other clones of b cells

A

develop into memory cells, respond to future infections, can produce plasma cells and antibodies more rapidly

166
Q

how long can plasma cells last for

A

a couple days

167
Q

draw an antibody

168
Q

how many polypeptide chains are antibodies made of

169
Q

what are the short polypeptide chains called in antibodies

A

light chain

170
Q

what are the long chains called in antibodies

A

heavy chain

171
Q

what is it called when an antigen and antibody bind

A

antigen antibody complex

172
Q

what is the antigen binding site called on an antibody and why

A

variable region
b/c it’s different n different antibodies

173
Q

what is the rest of the antibody called

A

constant region an binds to receptors

174
Q

how do antibodies prepare antigens for destruction

A

agglutination

175
Q

what is agglutination

A

clumps of the pathogen are formed

176
Q

what is clonal selection

A

the process of matching the antigens on an antigen presenting cell w/ the antigen receptors on b & t lymphocytes

177
Q

what is clonal expansion

A

the process of rapid cell division resulting in multiplication of genetically identical cell clones from a single parent cell

178
Q

what is a vaccine

A

suspension of antigens intentionally put in our body to induce artificial active immunity, specific immune response where antibodies are released by plasma cells (orally or injection)

179
Q

what are the types of vaccines

A

live attenuated
inactivated

180
Q

what are live attenuated vaccines

A

whole weakened pathogens
pathogens multiply slowly –> allows body to recognise the antigens
stronger & longer immune response
people w/ weak immune/allergies systems are affected

181
Q

what is an example of live attenuated vaccines

182
Q

what is an inactivated vaccine

A

whole killed pathogen
can’t cause disease
shorter immune response t/f repeated doses are required

183
Q

what is an example of an inactivated vaccine

A

polio vaccine

184
Q

what are the different types of immunity

A

active
passive

185
Q

what is active immunity

A

antibodies produced by body
1-2 weeks for antibody production
have memory cells

186
Q

how can active immunity be induced

A

naturally by exposure to pathogen when ill
artificially by vaccination

187
Q

what is passive immunity

A

antibodies not produced by body
immediate
no memory cells

188
Q

how can passive immunity be induced

A

naturally from antibodies received from another organism (placenta)
artificially from manufactured antibodies & injected/transfused into organisms (blood transfusions)

189
Q

what is herd immunity

A

large proportion of population is vaccinated t/f are immune making difficult for the pathogen to spread
people who aren’t vaccinated (babies & elderly) are protected / less likely to get the pathogen

190
Q

name the features of a hiv cell

A

lipid envelope
attachment proteins
capsid
matrix
rna strands
reverse transcriptase

191
Q

what is on the outside of a hiv cell

A

lipid envelope embedded with attachment proteins

192
Q

what is inside the envelope of hiv

A

capsid enclosing 2 strands of rna and some enzymes

193
Q

what is a capsid

A

protein layer

194
Q

what is a retrovirus

A

virus that uses rna as genetic material

195
Q

what is the enzyme within the capsid of hiv

A

reverse transcriptase

196
Q

how does hiv replicate

A

1) surface protein on hiv binds to cd4, found on helper t cells
2) capsid fuses w/ cell surface membrane, rna & enzymes enter helper t cell
3) reverse transcriptase converts viral rna to dna
4) new hiv dna is integrated into helper t cell nucleus where is it integrated into the genome
5) inserted hiv dna is transcribed into mrna which will be translated into hiv proteins
6) hiv proteins assembled into new hiv particles
7) hiv particles break away from helper t cell w/ piece of its cell surface membrane which forms its new lipid envelope

197
Q

how does hiv interfere with the immune system

A

hiv causes aids by killing or interfering with the normal function of helper t cells
w/o t cells, b cells won’t be stimulated to produce antibodies or cytotoxic t cells
t/f body becomes more susceptible to infections and cancer

198
Q

what is the test for hiv

A

elisa test

199
Q

describe the elisa test

A

1) hiv antigens attached to surface (glass slide)
2) blood sample added
if they are hiv + there will be specific antibodies in the blood plasma
3) antibodies bind to specific hiv antigens
4) slide is washed to remove unbound antibodies so there’s no false +
5) add 2nd antibody, this is specific to hiv antibody, has an enzyme attached to it
second antibody binds to first antibody if present
6) slide is washed
7) add substrate to slide, enzyme changes substrates colour from yellow to blue

biology (5 decks)

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