cells Flashcards
(199 cards)
1
Q
eukaryotic cells: what is the nucleus
A
the spherical nucleus contains hereditary material & regulates cell activities
2
Q
eukaryotic cells: what is the nuclear envelope
A
double membrane
associated w/ er
surrounds nucleus that controls movement of genetic material
3
Q
eukaryotic cells: what are nuclear pores
A
allows passage of large molecules (around 3000 pores)
4
Q
eukaryotic cells: what is the nucleoplasm
A
granular jelly like matieral that suspends nucleus bound structures e.g chromatin
5
Q
eukaryotic cells: what are chromosomes
A
protein bound, linear dna
6
Q
what are bound in chromosomes
A
histones
7
Q
what are histones
A
proteins
8
Q
eukaryotic cells: what is the nucleolus
A
makes ribosomal rna & assembles the ribosomes
may be more than one
9
Q
eukaryotic cells: what is mitochondria
A
produces atp through aerobic respiration
10
Q
how is atp produced in the mitochondria
A
krebs cycle and oxidative phosphorylation
11
Q
eukaryotic cells: what type of membrane does mitochondria have, and name them
A
double membrane
inner and outer
12
Q
eukaryotic cells: what does the outer membrane do in mitochondria
A
controls entry and exit of material
13
Q
eukaryotic cells: what does the inner membrane do in mitochondria
A
it folds to form cristae
14
Q
eukaryotic cells: what does the cristae do in mitochondria
A
increases surface are for enzymes and proteins
15
Q
eukaryotic cells: what is the matrix in mitochondria
A
remainder of mitochondrian
containing proteins, ribosomes, lipids and dna
16
Q
eukaryotic cells: what are chloroplasts
A
disc shaped organelles that carry out photosynthesis
17
Q
eukaryotic cells: what is the envelope in chloroplasts
A
selectively permeable double membrane
18
Q
eukaryotic cells: what is a thylakoid in chloroplasts
A
contains chlorophyll
19
Q
where does the first stage of photosynthesis occur
A
in the thylakoid
20
Q
eukaryotic cells: what is the grana in chloroplasts
A
stacks of thylakoids
21
Q
eukaryotic cells: what is the stroma in chloroplasts
A
fluid filled matrix
22
Q
where does the second stage of photosynthesis take place
A
in the stroma
23
Q
what is the cell membrane made out of
A
phospholipid bilayer
24
Q
eukaryotic cells: what is the structure of endoplasmic reticulum
A
flattened sacs called cisternae
25
eukaryotic cells: what is the rough er
rough due to ribosomes on it
large sa for ribosomal synthesis
proteins and glycoproteins synthesised and packaged into vesicles
26
eukaryotic cells: what is the smooth er
lacks ribosomes
synthesis storage & transport of lipids and carbohydrates
27
eukaryotic cells: what is the golgi apparatus
stack of flattened membrane sacs (cisternae) w/ vesicles
modifies proteins & lipids produced by er
28
eukaryotic cells: what are vesicles
small fluid filled sacs that transport substances around the cell
29
what does the golgi apparatus do
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
30
eukaryotic cells: what are lysosomes
formed when golgi vesicles contain lysozymes that hydrolyse cell walls of bacteria
31
what do lysomsomes do
contain hydrolytic enzymes to break down pathogens
32
eukaryotic cells: what are ribosomes
80s
carry out protein synthesis
33
eukaryotic cells: what are cell walls made up of
cellulose
34
eukaryotic cells: what are cell walls
rigid walls w/ microfibrils provide strength and support
stops cell from bursting
turgidity
35
eukaryotic cells: what is the middle lamella in cell walls
boundary between adjacent cells & cements them together
36
eukaryotic cells: what are algaes cell wall made of
cellulose and/or glycoproteins
37
eukaryotic cells: what are fungi's cell wall made of
polysaccharide chitin & glycoproteins
38
eukaryotic cells: what are vacuoles
cell sap stores sugars, amino acids, wastes and pigments
maintains turgidity to herbaceous plants
food store
attraction for pollination
39
what type of organelles does eukaryotic cells have
membrane bound organelles
40
what is the definition of eukaryotic
true nucleus
41
what is the definition of prokaryotic
before nucleus
42
notes on prokaryotic cells
unicellular
less than 2 micrometres (smaller)
3.5 billion years ago
only 1 chromosome
43
what features are always present in prokaryotic cells
plasma membrane
circular dna
cytoplasm
ribosome
cell wall
44
what ribosomes do prokaryotic cells have
70s (smaller)
45
prokaryotic cells: what is the cell wall made of
peptidoglycan (murein)
46
prokaryotic cells: what type of grams are found at the cell wall
gram positive & negative at structure of cell wall
47
prokaryotic cells: what is a capsule
waxy mucus layer, protective
48
prokaryotic cells: what is the flagellum
for movement
49
prokaryotic cells: what is cillia/pili
small hair like structures that can attach to other cells
50
prokaryotic cells: what is a plasmid
small loop of dna
51
prokaryotic cells: what is a nucleoid
where circular dna is
52
is fungi prokaryotic or eukaryotic
eukaryotic
53
what is magnification
how many times bigger the image is when compared to the actual object
54
what is resolution
the minimum distance apart that two objects can be distinguished as separate items in an image
55
what does resolving power depend on
wavelength or form of radiation used
56
what is the definition of cell fractionation
cells are broken up & organelles separated out
57
what are the 3 things required of the solution for cell fractionation
must be cold
have same water potential as tissue
be buffered
58
why does the solution need to be cold for cell fractionation
to reduce enzyme activity that might break down the organelles
59
why does the cell need to have the same water potential for cell fractionation
to prevent organelles bursting or shrinking due to osmotic gain/ loss of water
60
why does the cell need to be buffered for cell fractionation
so that ph doesn't fluctuate
changes in ph can alter the structure of organelles or affect the enzyme function
61
what are the 2 stages of cell fractionation
homogenation
ultracentrifugation
62
cell fractionation process
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
63
adavantages of the electron microscope
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
64
why does electron microscopes have higher resolution
shorter wavelength
65
what are the 2 types of electron microscopes
transmission electron microscope (tem)
scanning electron microscope (sem)
66
how does tem work
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
67
what resolving power does tem have and why can't it always be achieved
0.1nm h/e can't always reach due to difficulties preparing specimen or high energy electrons may destroy specimen
68
4 limitations of tem
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
69
why does tem need thin specimens
the specimen is in the middle t/f electrons need to pass through
70
how does sem work
directs beam of electrons back & forth across specimen
electrons are scattered depending on contours of specimen t/f causing 3d image
71
what resolving power does sem have
20nm, lower than tem, better than light microscope
72
what are the limitations of sem
expensive
require skills
same limitations as tem apart from thin specimen
73
what magnification does sem and tem have
tem - 500000
sem -100000
74
what is the eyepiece called on a light microscope that can measure sizes
graticule
75
what is the microscope calibration method
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
76
how many daughter cells are made from mitosis and meiosis
2 - mitosis
4 - meiosis
77
what is the definition of mitosis
cell division that produces 2 daughter cells, each w/ identical copies of dna from parent cell
78
what are the stages of mitosis
prophase
metaphase
anaphase
telophase
79
when does dna replication occur
interphase
80
notes on interphase
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
what is chromatid
has a centromere
essentially half of the chromosome shape but still considered a whole chromosome
82
what is a centrosome
area in nucleus where centrioles are found
83
what is a centriole
smaller version of centrosomes
84
what is a centromere
special structure on chromosome which holds the chromatids together
85
what is depolymerisation
converting polymers to monomers
86
notes on prophase
chromosomes condense
centrosomes move to opposite poles & form microtuble spindle fibres
spindle fibre attach to centromeres
nuclear membrane breaks down
87
notes on metapase
spindle fibres fully connect to centromere of each chromosome
depolymerisation causes spindle fibres to shorten
chromosomes line up at cells equator
88
notes on anaphase
depolymerisation causes sister chromatids to separate
move to opposite poles of the cell
89
notes on telophase
spindle fibres dissolve
chromosomes decondense to form chromtin
nuclear envelope reforms around chromosomes
90
notes on cytokinesis
cytoplasm divies
2 daughter cells
91
process of binary fission
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
process of virus replication
attach to proteins on a cell surface
inject nucleic acid
93
where is viral dna found
protein coat called capsid
94
what type of cells are viruses
acellular as they're non living
95
what envelope do some viruses have
lipid envelope containing attachment proteins for recognition
96
what are the 3 stages of the cell cycle
g1 (growth)
s (synthesis)
g2 (growth)
97
cell cycle: what happens in g1
cell grows physically larger
organelles divide
98
cell cycle: what happens in s
dna & centrosomes are duplicated
99
cell cycle: what happens in g2
more growth
proteins & organelles are made
100
cell cycle: interphase
occupies most of the cell cycle, no division takes place
101
cell cycle: nuclear divison
nucleus divides into 2 (mitosis) or 4 (meiosis)
102
cell cycle: cytokinesis
cytoplasm divides to produce 2 (mitosis) or 4 (meiosis)
103
what is cancer the result of
damage to genes that regulate mitosis & the cell cycle
leading to uncontollable growth & division causing a tumour to develop
104
what type of tumours are there
malignant and benign
105
what happens to most mutated cells
the die
h/e some divide and form clones
106
how does chemotherapy treat cancer
disrupts the cell cycle by:
preventing dna from replicating (s)
inhibiting metaphase by interfering w/ spindle formation
107
what is the fluid mosaic model
arrangement of various molecules in a cell surface membrane
108
what does the fluid part of fluid mosaic model mean
individual phospholipids can move relative to one another
109
what does the mosaic part of fluid mosaic model mean
proteins embedded vary in shape, size & pattern
110
fluid mosaic model: what are extrinsic/peripheral proteins
for mechanical support,
or act as receptors
only on one layer
111
fluid mosaic model: what are glycoproteins
cell recognition,
or cell signaling receptors
112
fluid mosaic model: what is cholesterol
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
fluid mosaic model: what can diffuse through the phospholipid bilayer
small lipid soluble molecules
o2
co2
h20
114
fluid mosaic model: what can't diffuse through the phospholipid bilayer
large molecules
charged ions
water soluble molecules
115
fluid mosaic model: what are channel & carrier proteins
transport proteins
integral (go through both layers of phospholipid bilayer)
116
fluid mosaic model: what are channel proteins
allow water soluble ions to diffuse through
117
fluid mosaic model: what are carrier proteins
they chemically bind to the protein, protein changes it's shape
amino acids, ions, glucose
118
what is the definition of diffusion
net movement of molecules or ions from a region of higher concentration to lower concentration until equilibrium is reached
119
what are all the different movement across membranes
simple diffusion
facilitated diffusion
osmosis
active transport
co transport
120
what is the definition of osmosis
movement of water particles from a region of higher water potential to lower water potential through a selectively permeable membrane
121
what is the defintion of water potential
the pressure created by water molecules
122
what is the greek letter psi
represents water potential (trident looking thing)
measued in kilopascals kPa
123
what is the water potential of pure water
0
124
what happends when a solute is added to pure water
lowers the water potential
125
what are the different types of water potential
isotonic solutions
hypotonic solutions
hypertonic solutions
126
what is an isotonic solution
normal
127
what is a hypotonic soluion
cells swell, b/c there's a lot of water molecules outside the cell so the cell gains the water
128
what is a hypertonic solution
cells shrink
more soluts, lower water potential t/f cell loses water
129
what is the definition of active transport
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
what is the process of active transport
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
what's an example of active transport
sodium potassium pump
132
what is the definition of co transport
two substances are simultaneously transported across a membrane in the same direction facilitated by symporters/ carrier proteins
133
what is the definition of simple diffusion
small non polar molecules down a concentration gradient (high to low)
134
what is the definition of facilitated diffusion
large charged molecules down a concentration gradient by transport proteins
135
what is the function of atp hydrolyse
releases energy
allows active transport of ions
136
what are antigens
molecules present on the surface of cells which trigger a immune response
137
what things can the immune system identify
pathogens
non self
toxins
cancerous cells
138
are specific lymphocytes produced
no they already exist
139
what is clonal selection
when the complimentary lymphocyte is stimulated to divide
140
when surface barriers fail what's the next line of defence
phagocytes and lymphocytes
141
what is chemotaxis
chemical sign from pathogens, phagocytes move towards it
142
process of phagocytosis
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
when inflammation occurs what is released
histamines
144
what do histamines do
cause blood vessels to dilate
more blood & heat in the area
leaky capillary walls
145
what happens when body temperature rises from being ill
reduces pathogen production rate
increases immune cell activity
146
what do bacterial infections do to body temperature
steady rise in temperature
147
what do viral infections do to body temperature
sudden spikes in temperature when cells burst
148
what 2 lymphocytes are there
b lymphocytes
t lymphocytes
149
where are b lymphocytes found
bone marrow
150
what immunity are b lymphocytes associated with
humoral immunity
151
where are t lymphocytes found
thymus
152
what immunity are t lymphocytes associated with
mediated immunity
153
what are antigen presenting cells
cells that activate t cells using the antigen from the pathogen
154
name the antigen presenting cells
phagocytes
infected body cells
foreign cells
cancer cells
155
how are phagocytes antigen presenting cells
present engulfed pathogen's antigens on it's membrane
156
how are infected body cells antigen presenting cells
present viral antigens on a membrane
157
how are foreign cells antigen presenting cells
transplanted cells from same species have different on the membrane
158
how are cancer cells antigen presenting cells
present abnormal antigens on membrane
159
what do t lymphocytes respond to
specific antigens presented on cell surface membrane
160
explain the role of t lymphocytes in cell mediated immunity
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
what do cloned t helper cells do
develop into memory cells
stimulate phagocytes to engulf pathogens
stimulate b cells to divide and secrete the antibody
activate cytotoxic cells ( t killer)
162
what do cytotoxic cells do
kill abnormal cells by making holes in the membrane w/ protein called perforin
t/f membrane more permeable and will die
163
what are antibodies
proteins produced in immune system in response to an infection
bind to antigens
neutralise toxins & pathogens
164
explain the role of b cells in humoral immunity
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
what happens to the other clones of b cells
develop into memory cells, respond to future infections, can produce plasma cells and antibodies more rapidly
166
how long can plasma cells last for
a couple days
167
draw an antibody
search up
168
how many polypeptide chains are antibodies made of
4
169
what are the short polypeptide chains called in antibodies
light chain
170
what are the long chains called in antibodies
heavy chain
171
what is it called when an antigen and antibody bind
antigen antibody complex
172
what is the antigen binding site called on an antibody and why
variable region
b/c it's different n different antibodies
173
what is the rest of the antibody called
constant region an binds to receptors
174
how do antibodies prepare antigens for destruction
agglutination
175
what is agglutination
clumps of the pathogen are formed
176
what is clonal selection
the process of matching the antigens on an antigen presenting cell w/ the antigen receptors on b & t lymphocytes
177
what is clonal expansion
the process of rapid cell division resulting in multiplication of genetically identical cell clones from a single parent cell
178
what is a vaccine
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
what are the types of vaccines
live attenuated
inactivated
180
what are live attenuated vaccines
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
what is an example of live attenuated vaccines
mmr
182
what is an inactivated vaccine
whole killed pathogen
can't cause disease
shorter immune response t/f repeated doses are required
183
what is an example of an inactivated vaccine
polio vaccine
184
what are the different types of immunity
active
passive
185
what is active immunity
antibodies produced by body
1-2 weeks for antibody production
have memory cells
186
how can active immunity be induced
naturally by exposure to pathogen when ill
artificially by vaccination
187
what is passive immunity
antibodies not produced by body
immediate
no memory cells
188
how can passive immunity be induced
naturally from antibodies received from another organism (placenta)
artificially from manufactured antibodies & injected/transfused into organisms (blood transfusions)
189
what is herd immunity
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
name the features of a hiv cell
lipid envelope
attachment proteins
capsid
matrix
rna strands
reverse transcriptase
191
what is on the outside of a hiv cell
lipid envelope embedded with attachment proteins
192
what is inside the envelope of hiv
capsid enclosing 2 strands of rna and some enzymes
193
what is a capsid
protein layer
194
what is a retrovirus
virus that uses rna as genetic material
195
what is the enzyme within the capsid of hiv
reverse transcriptase
196
how does hiv replicate
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
how does hiv interfere with the immune system
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
what is the test for hiv
elisa test
199
describe the elisa test
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
