Bioc 192 2-21 Flashcards
1
Q
Are proteins branching or non-branching polymers??
A
Non-branching
2
Q
What bonds bind amino acids together??
A
Peptide bonds
3
Q
How does the different patterns of the amino acids do??
A
determine the folding and shape of the protein
4
Q
What amino acid forms disulfide bonds?
A
Cystine
5
Q
what 3 processes determine protein shapes?
A
crystallography, cryo-electron microscopy, NMR.
6
Q
what does ‘ase’ mean in the protein name?
A
the protein is an enzyme
7
Q
What is the basic function of hemoglobin?
A
protein that transports oxygen by binding to it from the lungs and carries it in the blood to tissues for use
8
Q
What is the basic function of insulin?
A
protein hormone that binds to insulin receptors signalling cells to take up glucose.
9
Q
what is the basic functions of hexokinase?
A
protein used for metabolism by adding a phosphate to glucose in the cell.
10
Q
What do kinase add to molecules?
A
phosphates
11
Q
what is the basic function of trypsin?
A
protein used for digestion by breaking down proteins
12
Q
what are enzymes called that break down proteins?
A
proteases
13
Q
what is the basic function of HIV protease?
A
essential for HIV replication as viruses and bacteria make proteins too
14
Q
what is the basic function of amylase?
A
protein used in digestion, enzyme that breaks down starch into sugars
15
Q
where is the amylase found in the body?
A
salivary glands and the pancreatic juices
16
Q
what is the basic functions of alcohol dehydrogenase?
A
protein that is used in metabolism and helps to metabolize ethanol
17
Q
what is the basic functions of ATP synthesis?
A
a membrane protein that generates ATP that is used in cellular functions
18
Q
what is the basic functions of antibody?
A
protein used in immune protection by binding to cellular invaders to stop infections
19
Q
what is the basic functions of DNA polymerase?
A
the protein used in replication and maintenance as it binds to one strand and adds a complementary strand.
20
Q
what is the basic functions of RNA polymerase?
A
protein used in replication and maintenance as it creates a single strand of RNA that is complementary to one of the strands of duplex DNA
21
Q
what is the dumb down version of a cell?
A
a bag of proteins, lipids and nucleic acids.
22
Q
what does chiral mean?
A
can form mirror images
23
Q
what is the two mirror images produced in chiral amino acids?
A
L-form dominates
D-form can appear
24
Q
what is a zwitterion?
A
has a negative and positive charge attached to it
25
what are the 4 groups of the amino acids side chains?
polar, non-polar, positive, negative
26
what are non-polar amino side chains?
mostly hydrocarbon side chains
they are hydrophobic
when the side chain loops back around it makes the amino acid very rigid.
27
what are 2 polar amino side chains?
can be charged or uncharged
28
what 2 things can charged amino acid side chains be?
either positive or negative
29
what are uncharged amino side chains?
at pH 7 which are important for hydrogen bonding
they are hydrophillic
30
are negatively charged side chains acidic or basic?
acidic
31
are positively charged side chains acidic or basic?
basic
32
what happens in ionisable amino acids?
we change the pH of the environment of the amino acid.
this changes the protein
the charge can change depending on the pH
33
how do we classify ionisable side chains?
by their pKa value
34
what does a smaller pKa mean?
a stronger acid
35
what is pI (isoelectric point)?
where the pH at which the net charge on an amino acid is zero
36
can non-polar amino acids be ionizable?
nope
37
what does PTM do?
helps modify the protein to behave differently
38
what is a post-translational modification (PTM)?
a chemical group that can be added to an amino acid residue after translation has occured.
this is added via covalent attachment
39
what is phosphorylation?
PTM
often used to control enzyme activity like a chemical on/off switch
40
what is hydroxylation?
PTM
needed to prevent connective tissues diseases and scurvy
41
what is carboxylation?
PTM
needed for blood clotting
42
what is glycosylation?
adds sugar to the haemoglobin and can be used to detect diabetes
43
what are peptides?
short, single amino bonds
a polypeptide is a long chain that it folds up and forms a protein.
44
what are amino acid residues?
amino acids covalently joined together in a peptide or protein.
this is because they are no longer complete, individual amino acids.
45
are proteins more long straight chains or more globular?
globular
46
what are the 4 levels of protein structure?
primary, secondary, tertiary and quanternary
47
what is a primary protein structure?
the linear sequence of amino acids that make up a polypeptide.
48
what is a secondary protein structure?
the 3-D arrangment of a protein chain over a short stretch
49
2 examples of secondary protein strutures?
A-helices and B-sheets
50
what is a tertiary protein structure?
the 3-D structure of a complete protein chain
51
what is a quanternary protein structure?
interchain packing that contains multiple polypeptide chains
52
what is a phi angle?
rotation angle around the N-Ca bond
53
what is a psi angle?
rotation angle around the Ca-C bond
54
what is the rotation angle around the peptide bond called?
omega
55
what is the purpose of the bond angles?
to not have polypeptide colliding and causing a steric hindrance.
56
what do phi rotation lead to?
O-O collision
57
what do psi rotation lead to?
NH-NH collision
58
why are peptide bond usaully trans but can sometimes be cis?
to avoid steric hinderance
59
what leads to its overall 3-D structure?
the combination of all the rotations and twists around all the bonds
this inturn leads to the function of the protein.
60
what are the 2 dominant secondary protein structures?
A-helices, B-sheets
61
what is an alpha helix?
the main chain spirals around the central axis with non-covalent interactions
62
why are there non-covalent interactions in a-helices?
this is because there is a small charge so they form non-covalent interactions themselves.
63
what direction do alpha helices point in a protein?
outwards of the helix
64
what way do the a-helix dipoles run?
in the same direction
65
what does the negativly charged end of the A-helix bind to?
phosphate groups
66
what are B-strands?
stretches of amino acids that extend further than the a-helix
67
what stabilizes B-sheets?
hydrogen bonds which occur between adjacent strands
68
around how many amino acids are in each of the B-strands?
around 6 amino acids
69
what decides if the B-strand is parrallel or antiparallel?
the hydrogen bonding pattern
70
what are the 2 alternative B-strands?
polar, non-polar
71
what does a parallel B-strands look like?
when the strands run in the same direction
72
what does an anti-parallel B-strand look like?
when the strands run in opposite directions
73
what is a B-pleated sheet?
like a paper fan shape with a slight twist to the left
74
what are turns?
turns are an element that links together to change the direction of a polypeptide
75
what are the 2 things that allow turns to happen?
phi and psi angles
76
what are coils?
just longer turns
77
what are supersecondary structures?
a collection of secondary structure but not the entire fold of the protein
78
what is a helix-turn-helix?
2 alpha helices that are connected by a turn
79
what is a B-hairpin?
they are antiparallel sheets that are connected by a small turn
they look like hairpins
80
what is a greek key?
has 4 anti-parallel strands that start in the middle and is connected by small loops to make a B-sheets
81
what is a strand-helix-strand?
a combination of alpha helices and beta structures
the B-strand runs parallel
the B-strand can still form hydrogen bonds as the helix is on a different plane
82
what do super secondary structures form?
domains
83
what are domains?
independantly folded regions of super secondary structures that have a specific function
84
what are the 3 types of domain functions?
a-domain
a-domain family globin
a/b family
85
what are a-domains?
consists of 4 a-helical structures which forms a 4 helix bundle
they have a hydrophobic core and a hydrophillic outside
the helical structures are connected by small loops
86
what are a-domain family globins?
a fold that is an amphipathic helices with side chains packed closely within the hydrophobic core
87
what are a/b family domains?
a mixture of a-helices and b-structures to form a barrel shape with a hydrophobic center and a hydrophillic outside
88
what domains are mostly used to transport molecules?
b-barrel
these are mostly b-structures as the interior is hydrophobic
89
what do domains fold into?
tertiary structures
90
what does nature do with domains?
reuses them and combines them with other domains to make proteins with different functions
91
what is the anfinsen experiment?
breaking of the ribonuclease by breaking the disulfide bonds and making a long chain and watching it fold back to its original shape
92
what forces folding pathways of amino acids?
hydrophobic molecules forming hydrophillic walls
93
what are 2 factors that stabilise protein folding?
non-covalent interactions and disulfide bonds
94
what are chaperone proteins?
able to help polypeptides fold
can put the polypeptide in a bin to apply extra help to fold
95
how does protein unfolding occur?
when the non-covalent bonds break and denature
96
how to denature a protein?
by using heat or changing the pH
97
what can misfolding a protein do?
changes the shape and can aggregate the protein which can lead to brain damage
98
what are misfolded proteins called?
prions
99
what are prions?
a to b transformation and can cause diseases
there is no treatment and can be fatal
100
how much more oxygen can hemoglobin carry compared to saline?
25 times
101
where does haemoglobin reside?
in the muscle
102
how much oxygen can haemoglobin store for?
enough for around a 7 second sprint
103
what is myoglobin?
a 8 a-helices structure that folds to make a hydrophobic pocketto bind the haem molecule which gives the molecule its function
104
what is the structure of haem?
4 pyrrole rings linked together in a plane where they bind an iron atom
this binds to the nitrigen atom of histidine F8 and the other side binds to the O2 groupi
105
is the binding of the O2 group reversible?
yes
106
what do we use to find the concentration of oxygenated haemoglobin?
spectroscopy
107
what does the spectroscopy of haemoglobin find?
2 peaks in the oxygenated state and 1 in the deoxygenated state
108
why do proteins change shape?
to allow oppotunity to change activity
109
what does allosteric control mean?
controlling without overlapping
can be used by any protein to change shape
110
why is myoglobin easier to be saturated than haemoglobin?
Myoglobin binds to oxygen better and tighter
myoglobin does not need as much before it soaks up the molecules
111
why does haemoglobin change shape?
to release the oxygen that is binded to the haemoglobin eaiser
112
what is co-operativity when talking about haemoglobin?
when all 4 structures of the haemoglobin symaltaneouslyget used instead of working one at a time.
113
what are the2 states of haemoglobin?
T state
R state
114
what is the T state?
Tense state
115
what is the R state?
Relaxed state
116
what is the 'KNF' sequential model show?
the first subunits that bind making it harder for the other subunits to bind
MWC model works better
117
what structures make haemoglobin a tertramer?
2 copies of an alpha chain and 2copies of a beta chain
118
what does the tetrameric state allow?
communication between chains as a change of shape
119
what does oxygen binging deform?
the shape of the chain which tells the next shape that is oxygen bound
120
what shape is deoxygenated haem?
a dish shape
121
what shape is oxygenated haem?
a planar shape
122
how does the oxygen binding to the haem change its shape?
the Fe atom is dragged down which pulls the histine F8 and distorts the shape of the protein
123
why does the R state of heme have a high affinity?
because the heme has oxygen bound to it
(oxyhaemoglobin)
124
why does the T state of heme have a low affinity?
because the heme is most likely not binded to an oxygen atom (deoxyhaemoglobin)
125
how do the interactions between the chains lead to the main change of heme?
the subunits get further apart as the oxygen binds which changes the shape and the angle which leads to a change in interactions of subunits.
126
what happens when subunits get further apart?
they form a binding site for biphosphoglycerate invetween all the subuits
127
what is biphosphogylcerate (BPG)?
its highly negatively charged signalling molecule which tells haemoglobin what ti do such as move to the T state
128
where does BPG bind?
to the positive sidechains of the beta chains and the BPG stabilizes the hemoglobin and can move the haemoglobin from the R state to the T state to release the oxygen atoms
129
when is BPG produced?
through respiration and is found where the oxygen is required more
130
what is the bohr effect?
CO2 or low pH pushes haemoglobin to the T state to release the oxygen
131
how do foetuses recieve oxygen?
they catch it as it moves across the placenta so they have a higher affinity than there mothers.
132
why do foetuses use gamma subunits rather than beta subunits?
this is a less positive binding site for the BPG so it a weaker bind so the protein spends more time in the R state
so the foetus can draw what it needs across the placenta
133
what is methaemoglobin?
the oxidation from Fe2+ to Fe3+
this only occurs if we strip the electrons off the heme and we get a non-functioning heme
this decreases the amount of oxygen the protein can carry
134
what can be used to reduce the metgaemoglobin?
an enzyme will make the Fe3+ go to Fe2+
135
what does it mean if the delta G is less than 0?
negative
spontaneous
energy released
136
what does it mean if the delta G is greater than 0?
positive
non-spontaneous
energy required
137
what does it mean if the delta G is equal to 0?
Its at equilibrium and nothing works
138
what do spontaneous reactions pass through?
high-energy transition states
139
what is the activation energy?
the energy difference from reactants to the transitional state
139
how do we get to the transitional state?
we have the achieve the activation energy
140
how do enzymes catalyse the reaction?
by lowering the transitional state
141
what does lowering the transitional state do?
speeds up the rate of reaction
142
what do we call the enzyme that lowers the transitional state?
protein catalyst
143
what do proteins require to help catalyse reactions?
non-protein factors that are called co-factors
144
what are the 2 main classes of co-factors?
metal ions
co-enzymes
145
what are metal ions?
good electron receptors so they help with acid/base catalysis
they also co-ordinate compounds so reactants are positioned well
146
what are co-enzymes?
small organic molecules that come from vitamins
good at donating a proton to a phosphate group that needs it
147
what is pyridoxal phosphate (PLP)?
a co-enzyme of glycogen phosphorylase
148
what are enzyme active sites?
where enzymes bind to substates
they have amino acid side chains projecting into it
binds to substates via several weak interactions
149
why do we want weakish bonds between the enzymes and the substate?
makes it easier for the complex to met the transitional state
150
what are ionic bonds?
these make use of charged side chains
151
what are hydrogen bonds?
side chains or backbone of O and N atoms can often act as hydrogen bond donor and acceptors
152
what are Van der waals interactions?
between any protein and substrate atoms in close proximity
these are the weakiest of the interactions
153
what are covalent bonds?
these are relatively rare and are stronger than the other bonds
154
what happens when the active site becomes substrate bound?
changes shape as the enzyme induced a fit for the substrate
155
what are the 2 factors that decrese the activation energy?
ground state destabilisation
transition state stabilisation
both of these reduce the amount of activation energy for the reaction
156
what are catalytic mechanisms?
preferential binding of the proximity and orientation effects are both common to all entry ways
157
what is preferential binding of the transitional state?
is when an enzyme should bind, the transitional state more tightly than it binds to the substrate
158
what is proximity and orientation effects?
needs 2 molecules that are going to react to be close together and in correct orientation
159
what does acid-base catalysis require?
involves proton transfer which requires side chains that can donate or accept protons
160
what is metal ion catalysis?
its cofactors at active sites
these metals provide substate orientation so will interact as specific co-ordination geometry
they are able to act as a lewis acid (electron acceptor) to polarise functional groups
161
what is covalent catalysis?
less common
these involve the formation of a reactive, short-lived intermediate, which is covalently attached to the enzyme
162
what is spectrophotometry?
gives us a way of measuring compounds in a solution
163
how do we compare enzymes to another?
we measure the progress curve
164
what is the Vmax of a curve?
the top point of the progress curve
this is the maximum possible velocity when we have as much substrate as possible
165
what is the initail velocity of the progres curve?
the linear phase of the progress curve
166
what is it when the curve becomes non-linear?
when the reactants are running out and products are reduced over time
167
what is the Vo proportional to?
the enzyme concentration
168
what is the first order kinetics?
rate depends on substrate concentration
169
what is the zero order kinetics?
rate does not depend on substate concentration
170
what is the Km?
the substrate concentration at half of the Vmax
this is called the Michaelis constant
171
what happens if we have a lower Km?
the less substrate the enzyme needs to hit the Vmax
this means its an efficient enzyme
172
how do we get a lineweaver-burk plot?
if we plot one over the velocity by one over the substrate concentration
173
what are the intercepts on a lineweaver burk plot?
y-intercept is 1 over the Vmax
x-intercept is -1 over Km
174
what does the Km mean?
characterize one enzyme-substrate pair
175
what does the Kcat mean?
the turnover number which is the number of substrate molecules converted into a product
176
why do we want a higher Kcat?
to have the higher ability to turnover a lot of substrate into product per second
177
why do we want a high Km?
to have a low substrate concentration required to get up to speed
178
what do enzyme inhibitors do?
bind to enzymes and reduces its activity when the enzymes isn't necessary
179
examples of inhibitors in nature?
drugs, piosons and toxins
180
what are the 2 classes of enzyme inhibitors?
irreversible and reversible
181
what do irreversible enzyme inhibitors do?
bind to the enzyme and are permanently inactivated the enzyme is no longer working
182
what do reversible enzyme inhibitors do?
bind to the enzyme but then can subsequently be released so the enzyme can continue working
183
what are competitive inhibitors?
competes directly with the substrate for the active site of the enzyme
enzymes cant bind to both at the same time
184
what are transition state analouges?
these are competitive inhibitors
185
what are non-competitive enzyme inhibitors?
they bind at a different site than the substrate
can bind to the substrate and the inhibitor at the same time
186
what happens to Vmax and the Km in the presence of non-competitive present?
the Vmax decreases and the Km does not change
187
how is AMP a mode of enzyme regulation?
AMP binds to an allosteric binding site which allows feedforward activation
188
5 methods of enzyme regulation?
covalent modification
allosteric effects
proteolytic cleavage
turn gene expression on and off
degrades the enzyme
189
what can be activated or inhibited by different substrates?
proteins
190
what is pharmocology?
the study of effects of drugs on b iological systems from a molecular level through to a patient study
191
what is toxicology?
closely related to pharmacology but specializes in the study of the harmful effects of drugs and other chemicals
192
what is the definition of binding or reception?
chemical substance interacts with its target protein
the binding event affects the protein to either activate it or inhibit it and leads to a cellular response
193
what is a receptor?
a chemical protein that control chemical signalling between and within cells
194
at least one third of drugs activate or inhibit what?
receptors
195
what are enzymes?
have one active site that binds to substrates
they change the substrate into a product and can be membrane bound or free in cytosol
196
what are receptors?
have several binding sites that binds to ligands
they release ligands unchanged and can be membrane-bound or free in cytosol
197
what are the 3 receptor classes?
ligand-gated ion channels
G protein-coupled receptor
receptor tyrosine kinase
198
what is a ligand?
a chemical substance that specifically binds to a receptor
They are very diverse in chemical structure
199
what is the first step of reception?
chemical substances
200
what is the second step of reception?
binding to reception protein
201
where are most of the receptors on the cell located?
on the outer cell membrane so the receptors are in the extracellular enviroment
202
what is the third step of reception?
causes activation or inhibition
203
what is the chemical substance (ligand) called that binds to a receptor?
agonist
204
what is the fourth step of reception?
changes cellular response (activation)
205
what is signal transduction?
active receptor starts a chain of events where messages are passed on through the cell
206
what is the name of the ligand that binds to a receptor and prevents activation of an agonist?
its called an antagonist
207
what does the antagonist do?
prevents the agonist from activating so signal transduction does not work
208
what are chemical signals called?
second messengers or through sequential phosphorylation
209
what are second messengers?
they transmit the signals from a receptor to other molecules because they are not attached to the membrane
210
are ligands first or second messengers?
first
211
what is phosphorylation?
a widespread mechanism for regulating protein activity where protein kinase transfer phosphates from ATP to a protein
212
what is dephosphorylation?
the removal of a phosphate group from a protein to control signal transduction
213
what is a phosphorylation cascade?
where multiple protein kinase are being active at once to make a cellular response
214
what is internalisation?
where the receptor is removed from the cell surface through endocytosis so it can no longer respond to a ligand
215
what does GPCR mean?
G protein coupled receptor
216
what happens when the G protein starts transduction?
this activates the G protein which communicates with other proteins in the cell
217
what is Gai?
inhibitory G protein that decreases the activity of adenylate cyclase
218
what is a G protein?
guanine nucleotide-binding protein
it has a heterotrimeric shape which has 3 different sub units (alpha, beta, gamma)
219
what is alpha s?
stimulatory of the adenylate cyclase
220
what is alpha i?
inhibitory of the adenylate cyclase
221
what does an activated adenylate cyclase?
produces our secondary CAMP
222
what does CAMP do?
activates the protein kinase which begins the phosphorylation cascade
223
what is glycogen receptor signal transduction?
when the receptor activation causes G protein activation and further signal tranduction events, leading to the breakdown of glycogen breakdown
224
what does GLP-1 receptor signal tranduction do?
when the receptor activation causes G protein activation and further signal transduction events, leading to insulin secretion
225
what does receptor tyrosine kinase?
phosphorylation of adaptor proteins to start signal transduction
when the ligand binds, the receptor changes conformation and becomes activates.
226
what do adaptor proteins do?
communicate with other proteins within the cell
227
what is ligand gated ion channels?
they don't have relay proteins as ions directly to produce effects so this signal transduction is faster than the other
228
What is DNA?
a double helical structure that encodes proteins within a cell
229
what does the cell do within the enviroment?
break molecules, generates energy, and maintain itself
230
what are the percentages of cells within a human?
50% protein
40% lipids
10% carbohydrates
231
what forms macromolecules?
building block proteins
232
what building blocks make what macromolecules?
carbon chains - lipids
sugars - complex carbohydrates
amino acids - proteins
sugar + base - nucleic acids
233
what do macromolecules make?
supramolecular assemblies and they go on and make our organelles
234
what does our DNA encodes proteins?
puts mechanisms together to make more complex structures
235
what is regulation to do with proteins?
being able to control and regulate within a cell to help make things happen
236
how are proteins made from DNA?
bits of DNA transcribe and translate to form the protein
237
what is transcriptional control?
determines when and in what cell a gene is transcribe to produce the mRNA
238
what are the transcription factors?
they are proteins that bind to a specific DNA sequence and control the rate of transcription (DNA to RNA)
239
what is the promotor region?
the region of the gene that proteins can bind to
240
what is the transcribed region?
the sequence of DNA that are copied into RNA (transcribed)
241
what is RNA polymerase?
an enzyme that is at the beginning of the transcribed region
242
how are mRNA made?
transcription factors interact with eachother and recruits the RNA polymerase to make mRNA
243
what is leptin?
a hormone that binds to a receptor which changes the confirmation of the protein
this can be used to regulate a gene within a cell
244
what are mendels 3 laws?
law of segregation
law of independant assortment
law of dominance
245
where are the 2 genetic instructions from?
one from our mum and one from our dads
246
what is the differences in our genes called?
alleles
247
what is the law of segregation?
The alleles are separated so that the gametes carries only one allele from each gene
248
what is the law of independant assortment?
one gene occurs independantly to that of any other gene
249
what is recombination of a gene?
the reshuffling of the DNA which provides more variation so alleles are assorted more independently
250
what is the law of dominance?
some alleles are dominant while others are recessive
an organism with atleast one dominant allele will display this trait
251
what is a dominant allele?
can mask not having a recessive allele and can compensate for not having the allele
252
what are the consequences of not being able to breakdown pheylalanine?
leads to intellectual disability, seizures, behavioral problems an mental disorders
252
what is phenotype?
is the physical trait that is shown
253
what is translation?
when each tRNA carries an amino acid to be added to the polypeptide chain.
254
what are the codons?
are within the coding region of the mRNA which specify the amino acid sequence of the polypeptide chain
255
what is translation initiation?
starts with a small ribosomal subunit binds to mRNA
256
what is elongation?
when the codon recognises and binds to the 'A site'
the peptide bond formation changes from the 'P site' to the 'A site'
257
what is termination?
when the ribosome reaches a stop codonm on the mRNA
This release factor promotes hydrolysis and clears the other sites and everything dissociates
258
what is PKU?
when your mum and dad have a mutation and cant form phenylalanine hydroxylase and results in phenylalanine
259
what do pancreatic beta cells do?
sense how much glucose is in the blood and releases insulin when glucose is high
260
what is glucokinase?
senses how much glucose is broken down therefore how much insulin is produced
261
what happens if there is a mutation to the glucoskinase?
can lead to hyperglycaemia which is a type of diabetes
262
what does PCR (polymerase chain reaction) do?
amplifies a specific gene sequence and then they detect genetic differences of intrest
it heats up the DNA to 95 degress to sequence the DNA strands then cools to 65 degress to anneal a DNA primer. the DNA is then heated to 72 degress to aloow taq DNA polymerase to copy the DNA
263
what is a primer?
a short sequence that is chemically synthesized
263
what is hindIII?
a restriction enzyme that specifically cuts the sequence AAGCTT
cuts and gives 2 DNA fragments
263
what are the 2 types of mutations?
germline and somatic
264
what are germline mutations?
occurs in a cell that go on to a gamete
264
what are somatic mutations?
mutation that occur in other cells and cannot be passed on and can result in cancer
265
how are our cells regulated?
its balanced by cell division (proliferation) and cell death (apoptosis)
266
what are cancer cells?
cells that cant duplicate or die properly
over time they become resistant to cell regulatory control and divid more rapidly
266
what is cancer?
a collection of related diseases and can start anywhere within the body
cells divide faster and this increases the chances of mutations to occur which is why older people are more prone to cancer
267
what are the 2 classes of genes that are mutated and are related to cancer?
tumor suppressor genes
onco-genes
268
what are tumor suppressor genes?
they encode proteins that normally prevent uncontrolled cell growth such as inhibitors
269
what are onco-genes?
they encode proteins that promote cell growth such as proteins that stimulate cell division
270
what are inactive transcription factors (E2F)?
the transcribed factor that binds to protein when it is not being used
when a signal for cell division occurs a ki9mnase is release to release the E2F then we lose control of when cells should divid
271
what do proto-onco genes do?
release excess proteins which increases the cell growth
272
what do mutations in stem cells lead to?
uncontrolled growth of the cells with the ability to keep dividing
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what is tyrosine kinase?
a normal ABL protein for the phosphorylation of the transcription factor for successful cell division
273
what is radiation therapy?
targeted radiation treatment to kill cancer cells
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what is chemotherapy?
uses drugs to target dividing cells as cancer cells grow and divid rapidly but it also affects normal cells
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what is targeted therapy?
drugs that target changes in cancer cells that allow them to grow and divid
it can do this as BCR-ABL is only found in cancer cells
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whjat are the 2 forms of diabetes?
type 1
type 2
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what is type 1 diabetes?
a self-attacking illness where the host cant produce any insulin by the pancreas so it cant break down glucose
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what is type 2 diabetes?
occurs later in life and can be caused by genetics and environment such as weight
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what is insulin?
an enzyme produced in the pancreatic beta cells that is used to break down glucose in the blood
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what are the 2 chains called in insulin?
alpha and beta chains
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what holds insulin chains together?
intermolecular disulfide bridges
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what are plasmids?
circular pieces of double stranded DNA and replicate independently of the hosts chromosomal DNA
they are common in bacteria and are found in eukaryotes so they can have anti-bacterial resistance
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how do we get plasmids?
we take them from the environment and genetically modify them for our own benefit
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why do we put antibiotic resistant gene in the plasmid?
allows us to select the cells to contain our plasmids
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why do put a promotor in the plasmid?
this is to express a particular gene
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why are there restriction sites in the plasmids?
to allow ourgene to fit in like a cut and paste mechanism
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what are restriction sites in plasmids?
used to degrade foreign DNA such as bacteriaphage DNA by using restriction enzymes
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what is complementary base pairing?
puts 2 strands together and we use DNA ligase to repair phosphodiester bond to make the strands one
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why do we use transformation on our recombinant plasmids?
it transfers our plasmids into bacteria to replicate on plates. the bacteria amplifies the DNA to be purified
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what is the universal genetic code?
used for taking our plasmid and expressing a gene
291
what is UGA?
a stop codon
used to transform a human gene into bacteria and it will still make the same protein
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pros and cons of using mammilian cells?
they are food at being glycosylated and folding yet arent the cheapest option
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pros and cons of using bacterial cells?
they are cheap but arent great at being glycosylated and folding
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what is EPO?
a recombinant human protein that increases the production of RBC from stem cells which increases the transport of oxygen around the body which enhances the host endurance
this is a form of blood dopeing
295
what is CHO?
chinese hamster ovary cells
they are used as they have similar glycosalation as humans
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how is cDNA made?
by reverse translation of mRNA
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what is thrombin?
it is blood clotting
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what is anti-thrombin (AT)?
is produced in goats and taken from goat milk as AT has a milk specific promotor to express human specific proteins
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why do we isolate the gene of intrest?
so we can use PCR and only amplify that gene
300
step 1 of a recombinant protein?
to source the gene expressing protein
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how do we mature cDNA?
we seperate the 2 chains (A and B) with a lac Z gene fused to one of the 2
we transform these chains into bacteria and the promotor binds to lac Z which will express the gene
we then extract the lac Z by breaking the peptide bond and removing the lac Z
when then mix the A chain and the B chain togetherwhich will recombine and form disulfide bridges and will leave you with a mature protein
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what is the first cell to use for post-translational modification of a protein?
mammalian cells as they are cheap
303
what is GFP?
normally found in jellyfish and is an illuminessence gene that illuminates when the host feels threatened
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what is optogenetics?
a light sensitive protein found in algae
when light is detected channels open up and let the photos transfer into the cell
305
what is channelrhedopsin?
a form the algae cDNA
306
how can we control epilepsy?
by inserting an optical light into the brain
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why was protein evolution done?
to improve their uses such as in detergents making the proteins work faster
or we can make GFP change to be a different colour
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how do we use protein evolution?
by using a PCR enzyme that cant proof read so no mistakes can be corrected so its prone to making errors so we will end up with many mutations
we then take the mutation we want and amplify the gene to then be purified
309
what is gene therapy?
takes recombinant DNA and inserts it into a the patients cells and the host is producing the proteins that they need to treat their conditions
this would be a one off treatment
310
why do we use viral vectors in gene therapy?
because viruses are good at getting genetic information into cells
it would have to be a disabled virus that no longer carries any pathogenic material
the gene is expressed under the control of an appropriate promoter
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what is ex-vevo genetherapy?
injects from outside the patient
312
what is en-vevo genetherapy
where we inject into a patient
313
what is crispa technology?
can correct diseases effecting people through gene editing
