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Biochem sem1 Flashcards

1
Q

What does the:
atomic number
atomic mass
Represent

A

Number: protons
Mass: protons and neutrons

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2
Q

what is the most common chemical formula for a monosaccharide?

A

(CH2o)n
n=3,5,6

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3
Q

What is the name of:
1 sacharide
2 sacharides
3-10 sacharides
10+ sacharides

A

1 = monosaccharide
2 = disaccharide
3 = ogliosaccharide
10+ = polysaccharide

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4
Q

How do multiple saccharides bond?

A

Through condensation reaction
glycosidic bond (type of ether bond)

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5
Q

what makes up
sucrose
lactose
maltose

A

sucrose = glucose + fructose
lactose = glucose + galactose
maltose = 2 alpha glucose

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6
Q

What is Van Der Waals?

A

cloud of - charge around atom, can congregate in one section to attract other atoms

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7
Q

What are 5 roles of lipids?

A
  • cell membranes
  • protection/insulation
  • neurone myelination
  • hormone production
  • absorb fat soluble vitamins
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8
Q

what are the 3 classifications of lipids?

A
  • triglycerides
  • phospholipids
  • sterols
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9
Q

Describe triglycerides?

A

TRIGLYCERIDES:
- glycerol backbone 3FA condensation reaction, sat (c-c) bonds or unsat (at least 1 c=c)
- double bond can be cis or trans

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10
Q

Describe phospholipids?

A

arranged in bilayers
hydrophilic tails
hydrophobic head

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11
Q

Describe sterols?

A
  • cyclic organic compound
  • found in most eukaryotic cells
  • e.g: cholesterol
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12
Q

what are proteinogenic amino acids?
What do they consist of?

A
  • only 20 genetically coded amino acids in DNA
  • amine group, carboxyl group, hydrogen atom, organic side chain (R group)
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13
Q

How and what is a protein formed of?

A

Peptide chains = amino acids joined by condensation reaction, peptide bond between carboxyl and amine groups

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14
Q

What is the primary structure?

A

amino acid sequence from N- terminus to C- terminus?

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15
Q

what is the secondary structure?

A

alpha helix =
- c=o forms H bond with amine hydrogen between carboxyl and amine group
- turns right handed

beta sheet =
- parallel or antiparallel structure
- zig zag peptide chain
- backbone forms H bonds between segments

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16
Q

what is the tertiary and quaternary structure?

A

Tertiary =
- a helix or b sheet folds itself, 3D, intermolecular forces change shape

Quaternary =
- multiple subunits
- intermolecular forces change behaviour

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17
Q

What is avogadros constant?

A

6.02 X 10^23

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18
Q

how do you calculate molarity?

A

mass of substance (g)

molecular| number of
weight | moles

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19
Q

what is a heterocyle?

A

ring that has another element in it

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20
Q

what are 3 regular classes of functional groups?

(draw them ideally)

A

hydroxyl
amine
carbonyl

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21
Q

what are the 2 laws of thermodynamics?

A

1 = energy cant be created or destroyed only interconverted between forms

2 = total entropy of a system always increases

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22
Q

what is entropy and enthalpy?

A

entropy = level of disorder
enthalpy = energy

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23
Q

what is the definition of Gibbs free energy?

A

the amount of available energy to do work

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24
Q

what is the equation for Gibbs free energy?

A

△G = △H-T △S

G= Gibbs free energy
H = enthalpy
T= temperature
S= entropy

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25
Q

When △G is more than zero reaction is?
When △G is less than zero reaction is?

A

More than 0 = not spontaneous (requires addition of energy to occur)

Less than 0 = spontaneous (happens on its own)

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26
Q

Explain what a coupled reaction is?

A

when an exergonic reaction drives an endergonic reaction

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27
Q

What is an:
anabolic reaction
catabolic reaction

A

anabolic = smaller — bigger

catabolic = bigger — smaller

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28
Q

What is energy stored as by activated carrier molecules?

A

transferable chemical group or electrons

instead of being lost as heat

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29
Q

when △S (entropy):
bigger than zero
less than zero
Entropy is ordered or disordered
?

A

bigger than zero = disordered

less than zero = ordered

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30
Q

how do cells get energy? where is the energy stored?

A

energy from oxidising organic molecules by metabolism

store in covalent bonds

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31
Q

explain REDOX?

A

Oxidation is loss of electrons

reduction is gain of electrons

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32
Q

Describe haemoglobins structure

A

2 alpha subunits, 2 beta subunits
globular, compact
tetrameric protein
o2 binds to haem groups

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33
Q

what are enzymes?

A
  • biological catalysts
  • regenerated at end of reaction so not used up
  • globular
  • powerful
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34
Q

Name 5 biological functions enzymes are used in?

A
  • metabolism
  • movement
  • digestion
  • cell signalling
  • gene expression
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35
Q

describe the structure of an enzyme?

A
  • globular protein
  • AA sequence decides catalytic activity
  • active site has different AA, some for binding substrate, some for catalysing reaction
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36
Q

What are the two theories of enzyme binding?

A

LOCK AND KEY: rigid and fixed, complementary geometry

INDUCED FIT: conformational change in binding

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37
Q

Describe the allosteric site?

A
  • can induce conformational change e.g: change in active site/ROR
  • regulatory molecule binds and inhibits/activate enzyme
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38
Q

what is a:
- cofactor
- coenzyme
- prosthetic group

A

cofactor: inorganic, required for enzyme/protein to work

coenzyme: organic, directly involved in enzyme reaction, transiently bond, required for optimal

prothetic group: non protein molecule covalently bonds for enzyme function

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39
Q

What is an enzyme called when It needs a cofactor/enzyme when:
- cofactor hasn’t bound?
- cofactor has bound?

A

Hasn’t bound: APOENZYME
Has bound: HOLOENZYME

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40
Q

What enzyme? pt1
1. transfer H or O2 or E- from one substrate to another
2. transfer functional groups from one substrate to another
3. hydrolysis of a substrate

A
  1. oxidoreductases
  2. transferases
  3. hydrolases
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41
Q

What enzyme? pt2
4. add or remove a group to form a double bond
5. transfer groups within a molecule
6. bond formation coupled with ATP hydrolysis

A
  1. lyases
  2. isomerases
  3. ligases
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42
Q

what is:
1.activation energy
2. transition state

A
  1. energy barrier required to be overcome for reaction
  2. not substrate not product, transient molecular state
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43
Q

9 ways which enzymes reduce activation energy?

A
  1. exclusion of water
  2. induced fit
  3. close proximity of substrate and enzyme
  4. metal ion cataylses
  5. covalent catalyses
  6. acid base catalyses
  7. chemical complementarity
  8. transition state stabilisation
  9. substrate binding and orientation
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44
Q

describe the 4 main catalytic mechanisms

A
  1. metal ion catalyses: use metal ion to help with catalyses
  2. covalent catalyses: briefly substrate binds with covalent bond until substrate fully bonds
  3. enzyme transfers H to catalyses can occur
  4. approximation = further away is harder
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45
Q

What is enzyme velocity?
When must it be measured

A
  1. initial ROR, amount of substrate covered to product per unit of time

Must be measured before 10% of substrate is converted

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46
Q

What is VMax?
What is Km? How do you calculate it

A

Vmax = max enzyme ror
Km = measure of affinity for substrate to enzyme

also conc of substrate when 1/2 Vmax
1. Calc vmax, calc 1/2 vmax, draw line down to substrate conc

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47
Q

what does…. indicate?
1. high Km
2. Low Km

A
  1. weak binding , need high substrate conc to reach Vmax
  2. strong bonding, need low substrate conc to reach vmax
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48
Q

how to regulatory mechanism control enzyme activity?

A
  • allosteric inhibition/activation
  • confine enzymes into compartments
  • cell controls quantities of enzymes so is controlled
  • covalently modify to control activity
  • rate of protein destruction by targeted proteolyses
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49
Q

describe 4 types of reversible inhibition?

how is Vmax effected for each?

A
  1. end product inhibition: end product inhibits earlier pathways
  2. competitive: inhibitor blocks actual substrate. Vmax = same, longer to get there
  3. non competitive: inhibitor binds to allosteric site, conformational change, Vmax lower
  4. uncompetitive: substrate already bound, inhibitor binds and stop catalysis. Vmax lower
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50
Q

what is metabolism?

A

series of anabolic and catabolic reactions that happen in living cells

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51
Q

Name 4 examples of catabolic reactions

A
  1. protein breakdown
  2. lipid oxidation
  3. carbohydrate oxidation
  4. nucleotide hydrolysis
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52
Q

Name 4 examples of anabolic reactions

A
  1. protein synthesis
  2. lipid synthesis
  3. carbohydrate synthesis
  4. nucleotide synthesis
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53
Q

if deltaG is large is ATP more or less willing to give up its phosphates?

A

more

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54
Q

Where does lactate come from?

A

When no o2 present, anaerobic respiration uses glycolysis to produce ATP

NADH passes electrons to pyruvate to form lactate

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55
Q

give 5 examples of membrane function

A
  1. chemical/physical barrier
  2. cell/cell communication
  3. energy conversion
  4. recognition
  5. allow cellular processes
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56
Q

what is the word for: hydrophillic+hydrophobic parts?

A

amphipathic

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57
Q

how can mutation in enzyme lead to disease?

A

over/under production , deletion leads to wrong enzymes created, regulate cell cycle = lead to cancers

58
Q

how is an enzymes structure specific to substrate?

A

amino acid sequence specifies 3D conformation
active site has different AA sequence
Cleft on surface of active site

59
Q

Describe the allosteric site

A

can induce conformational change
activate or inhibit reactions

60
Q

what is the standard unit of enzyme activity?

A

U

61
Q

how does temp effect enzyme activity?

A

rise = overcome activation energy, increase ror
too high = breaks bonds, alter active site, denature protein

62
Q

spontaneous or not?

1) △S﹥0 and △H < 0
2) △S﹥0 and △H﹥0
3) △S < 0 and △H < 0
4) △S < 0 and △H﹥0

A

1) spontaneous
2) spontaneous at high temp
3) spontaneous at low temps
4) not spontaneous

63
Q

what is the most important activated carrier molecule?

what reactions does it drive?

A

ATP

endergonic

64
Q

what is △G°

A

standard conditions, 25°c, 298K

65
Q

what is △G°’ (delta G nought prime)

A

standard biological conditions, 37°, 310K

66
Q

what do the different parts of this equation mean?
△G=△G° + RT ln Q

A

△G = change in gfe
△G° = delta g in standard conditions
R = 8.314J mol-1, K-1
T = temp
ln = log
Q = [products] / [reactants]

67
Q

with this reaction: △G=△G° + RT ln Q,
what do you do when calculating Q if there’s e.g: 2 reactants and e.g: 2O^2

A

[C][O2]^2
instead of times by 2, you square, if 3 lots you will cube

68
Q

METABOLISM
what reactions occur in stages 1-3 of glycolysis? what enzymes do this?

A

1) phosphorylation - HEXOKINASE
2) isomerisation - PHOSPHOGLUCOSE ISOMERASE
3) phosphorylation - PHOSPHOFRUCTOKINASE

69
Q

METABOLISM
what is the importance of glucose being isomerised to fructose in step 2?

A

2 G3P molecules can be created in step 5 , if didn’t happen 2 isomers (2 and 4c molecules would be created instead

70
Q

METABOLISM
summarise steps 1-5 of glycolysis

A

1) Glucose — glucose 6phosphate by HEXOKINASE, uses ATP

2) Glucose6phosphate — fructose6phosphate by PHOSPHOGLUCOSE ISOMERASE

3) fructose6phosphate — fructose1-6bisphosphate by PHOSPHOFRUCTOKINASE , uses ATP

4) fructose1-6bisphosphate — DHAP + 1XG3P by ADOLASE

5) DHAP — G3P so = 2xG3P instead

71
Q

what do kinases do?

A

add a phosphate, phosphorylated

72
Q

METABOLISM
Summarise stages 6-10 of glycolysis

A

6) 2xG3P — 2x1.3 bisphosphoglycerate by G3P DEHYDROGENASE , 2 NAD – 2 NADH (activated carrier molecule)

7) 2x1,3 bispho…. — 2x3phosphoglycerate by PHOSPHOGLYCERATE KINASE, 2 ADP –
2 ATP couple reaction with NAD-NADH prev

8) 2x 3 phosphoglycerate — 2x 2 phosphoglycerate by PHOSPHOGLYCEROMUTASE

9) 2x 2phosphoglycerate – 2x phosphoenolpyruvate by ENOLASE , loose 2H20

10) 2x phosphoenolpyruvate — 2xPyruvate by PYRUVATE KINASE , 2 ADP – 2ATP

73
Q

metabolism

what are the products of glycolysis?

A

net 2 ATP
2 NADH
2 pyruvate

74
Q

what is the rate limiting enzyme of glycolysis?
what is it activated and inhibited by?

A

PFK phosphofructokinase

activated by: AMP, F2,6 BP
inhibited by: ATP, as already high energy so don’t need more, low pH

75
Q

GLUCONEOGENESIS
1. what is it
2. where does it happen
3. what does it use

A
  1. reversal of glycolysis, forms glucose
  2. liver
  3. non carbohydrate precursors: lactate, glycerol,
76
Q

GLUCONEOGENESIS
why is gluconeogenesis not a direct reversal of glycolysis?

A

If it was, deltaG would be +84Kj/mol = energetically unfavourable

77
Q

GLUCONEOGENSIS
1. what does pyruvate carboxylase do?
2. what does it have attached to it?
3. what has to be present for biotin to be carboxylated? what type of regulation is this?

A
  1. adds co2 to a molecule
  2. biotin prosthetic group
  3. Acetyl CoA, allosteric regulation
78
Q

GLUCONEOGENISIS
what molecule can’t exit the mitochondria?
what does it need to be converted to?

A

oxaloacetate
malate

79
Q

When lactate is produced by heavy exercise, it can be:
1.
2.

A
  1. converted to pyruvate by tissues and used for energy (TCA cycle)
  2. transported to liver and converted to glucose (Cori Cycle)
80
Q
  1. What is the proper name for the link reaction?
  2. what happens in this?
A
  1. pyruvate dehydrogenase reaction
  2. pyruvate —- acetyl coA, large enzyme does this, reduces NAD— NADH
81
Q

structure of triacylglycerols?

A

3 FA bound to glycerol molecule

82
Q

FATTY ACID OXIDATION
1) summarise stage 1

A

ACTIVATION
- FA react with atp
- atp hydrolysed — AMP + pyrophosphate
- pyrophosphate — 2 inorganic pi , releases energy
- AMP is on acyl adenylate
- acyl adenylate attacked by sulfhydryl on CoA
- AMP removed = Acyl CoA formed

83
Q

FATTY ACID OXIDATION
summarise stage 2

A

CARNITINE
carnitine — acyl carnitine using CPT 1, so can get inside mitochondria

once in mitochondria

acyl carnitine —- carnitine using CPT II

84
Q

FATTY ACID OXIDATION
summarise stage 3
what does it produce?
what is the aim of it?
when does it stop?

A

B OXIDATION
produces|: acetyl coA, NADH, FADH2
aim|: reduces carbons
will stop when|: FA fully degraded

  1. FA Acyl CoA oxidised by FAD
  2. +h20
  3. oxidation by NAD+
  4. thiolysis by coA
  5. = acetyl CoA , Fatty Acyl CoA (2C less than start)
85
Q

FATTY ACID OXIDATION
what happens when a fatty acid is unsaturated in B oxidation?

what does cis and trans double bonds look like?

A

isomerase convert cis – trans , cis not substate of B oxidation

cis = on same side, trans = on both sides

86
Q

KETOGENESIS
what does acetyl coA usually enter|?
why would it not?
where would it go instead?

A

tca cycle

lack of oxaloacetate, diabetes or starvation

ketogenesis, in liver, use ketones over glucose

87
Q

FATTY ACID SYNTHESIS
summarise the steps

A

1) acetyl ACP + malonyl ACP = 3 ketoacyl ACP
release co2
2) 3 ketoacyl acp — butyrylACP
reduced + dehydrated v
3) butyryl acp + malonyl ACP
4) cycle continues until C16 Palmitate formed

88
Q

FATTY ACID SYNTHESIS
what enzymes regulate this process?

A

AMPK: detects energy charge/ATP , if atp low , AMPK phosphorylate ACC so FA synthase doesn’t happen

89
Q

METABOLISM 2: ACETYL CoA TRANSFER
summarise the cycle, where each bit happens, why it happens and how much product is formed

A

acetyl coA in mitochondria
converted to citrate via tca cycle to get into cytosol
citrate — oxaloacetate — malate — pyruvate
malate – pyruvate produces NADPH (used in FA synthesis)
pyruvate driven to continue cycle

1 NADPH produced per cycle

90
Q

METABOLISM 2: ACETYL CoA TRANSFER
how many acetyl coA needed to form palmitate (16c fa from fa synthesis?)

how many NADPH are formed?

how many are needed?

A

8

so 8 NADPH formed, need 14 for fa synthesis so PPP

91
Q

PENTOSE PHOSPHATE PATHWAY
what are the 2 phases called

A
  1. oxidative phase
  2. non oxidative phase
92
Q

PENTOSE PHOSPHATE PATHWAY
summarise the 2 phases

A

1) OXIDATIVE : produces NADPH
glucose 6 phosphate — ribulose 5 phosphate , produces 2NADPH

2) NON OXIDATIVE : interconvert sugars
ribulose 5 phosphate —
2x fructose6phosphate
1x glyceraldehyde 3 phosphate

these can then produce glucose via glycolysis

93
Q

PENTOSE PHOSPHATE PATHWAY
When would the different two phases be used

A

1) OXIDATIVE : the cell needs NADPH and Ribulose 5 phosphate (for eg. dna, rna)

2)BOTH OXIDATIVE + NON OXIDATIVE: cell needs NADPH and ATP

94
Q

PENTOSE PHOSPHATE PATHWAY
what is this pathway regulated by?

A

1) NADP+ levels
higher = more NADPH needed for biosynthesis
2) cell requirement for ATP and ribulose 5 phosphate

95
Q

AMINO ACID METABOLISM
TRANSAMINATION
what happens in this?
what enzyme is used?
what is an example of it?

A

transfer amine group from AA to keto acid
enzyme: aminotransferase

e.g: oxalocacetate accept amine group –ASPARTATE, can be transaminate to form: GLUTAMATE

96
Q

AMINO ACID METABOLISM
DEAMINATION
what happens here?
what enzyme is used?
continue example?
where does it go next?

A

amine group removed to leave carbon skeleton

e.g: GLUTAMATE has amine group to be removed
enzyme: GLUTAMATE DEHYDROGENASE
UREA CYCLE

97
Q

AMINO ACID METABOLISM
UREA CYCLE
what happens here?

A

remove ammonia as toxic via urea
excreted on toilet
e.g: aspartate bring NH2 to go into urea

98
Q

AMINO ACID METABOLISM
what happens to the carbon skeletons?
what are they degraded to?
what are the 3 different types?

A

amino acid degraded to 1 of 7 metabolic intermediates

metabolic intermediate either considered:
ketogenic
keto + glucogenic
glucogenic

99
Q

MITOCHONDRIA
What care the 2 complexes that allow things in?
What is needed for proteins to be recognised?

A

TOM COMPLEX: translocase outer membrane
TIM COMPLEX: translocase inner membrane
SIGNAL SEQUENCE: @ N terminus, certain aa sequence to cell knows where to send it

100
Q

MITOCHONDRIA
How does pyruvate enter mitochondria?

what’s needed for them to function

A

Outer membrane: Porin
Inner membrane: mitochondrial pyruvate carriers

needs change in ph to function

101
Q

MITOCHONDRIA
How does NADH enter?
hint: 1st way

A

MALATE ASPARTATE SHUTTLE
1. NADH reduce oxaloacetate – malate
2. malate into matrix, back into oxaloacetate
3. NAD+ regenerated , NADH regen.

malate carried electrons
alpha ketoglutarate needed to be transported other way

102
Q

MITOCHONDRIA
How does NADH enter?
hint: 2nd way

A

GLYCEROL 3 PHOSPHATE SHUTTLE
1. NADH reduce DHAP — glycerol 3 phosphate
2. G3P into mitochondria. oxidised back to DHAP
3. generate FADH2
4. G3P transfer electrons from NADH – FADH2

103
Q

MITOCHONDRIA
How does fatty acids enter mitochondria?

A

CARNITINE — ACYL CARNITINE, using cpt1

once in

ACYL CARNITINE — CARNITINE , using cpt2

104
Q

MITOCHONDRIA
what is the quantity of mitochondrial DNA controlled by?

A

fission + fission

105
Q

MITOHCHONDRIA
how many genes are there?

A

37

2rRNA
22tRNA
13 protein

106
Q

MITOCHONDRIA
RESPIRATORY CHAIN
Why are different molecules better at accepting/transferring electrons?

A

redox potential
more negative = donate e-
more positive = accept e-

107
Q

MITOCHONDRIA
RESPIRATORY CHAIN
what happens are complex 1?

A

NADH goes to FMN on complex1
donate 2e- = nadh
2e- pass to iron sulphur clusters
2e- to coenzyme Q
4h+ matrix to inter membrane space

108
Q

MITOCHONDRIA
RESPIRATORY CHAIN
what happens on complex 2?

A

succinate dehydrogenase (in C2) couples with FADH2
transfers 2e- to iron sulphur clusters
e- + 2h+ to CoQ = QH2

109
Q

MITOCHONDRIA
RESPIRATORY CHAIN
what happens at complex 3?
explain the Q cycle

A

QH2 passes 2e- to C3
C3 has cytochromes, can only carry 1e-

Q CYCLE
1) QH2 arrives, 1e- pass up to cyt. c, 1e- pass down to Qi site

2) 2nd QH2 arrives, 1e- up to cyt. c, 1e- down so Qi fully reduced to QH2, can go back into pool and passed back in

110
Q

MITOCHONDRIA
RESPIRATORY CHAIN
what happens at complex 4?

A

1) 2 cyt. c arrive so 2e- arrive
2) 1e- reduce iron, 1e- reduce copper
3) O2 arrives, final electron acceptor
4) O2 accept 2e- so reduced + 2 hydroxyl = 2H20

111
Q

RESPIRATORY CHAIN
how many molecules of cytochrome c are needed to generate h20 at complex 4?

A

4 molecules

112
Q

RESPIRATORY CHAIN
explain what proton motive force is

A

electrochemical proton gradient generated through proton pumping in respiratory chain , can generate ATP

113
Q

ATP SYNTHASE
what’s the relation between the proton motive force and atp generation by atp synthase?

A

protons along conc gradient from IM space – matrix
cause c-subunits in F0 to rotate, causes y-unit to rotate
alpha + beta subunits in F1 remain fixed so position changes with each rotation
B subunits = atp synthetic centre of atp synthase so drive atp synthesis and release

114
Q

CELL MEMBRANE
membrane functions (5)

A
  1. facilitate diffusion (physical/chemical barrier)
  2. cell to cell communication/recognition
  3. energy conversion
  4. platform for cellular processes
  5. recognition
115
Q

CELL MEMBRANE
describe the structure of the membrane

A

lipid bilayer
non covalent interactions hold lipids and proteins togryhrt
impermeable barrier to polar molecules
proteins in bilayer
lipids = amphiatic

116
Q

CELL MEMBRANE
what is it composed of?

A

LIPIDS:
PROTEINS
CARBOHYDRATES

117
Q

CELL MEMBRANE
what are 2 factors that effect membrane fluidity?

A
  • cholesterol
  • cis double bond in FA
118
Q

CELL MEMBRANE
what are the 2 types of phospholipids?
what are the other 2 types of lipids?

A

PHOSPHOLIPIDS:
- glycerophospholipids
- sphingolipids

STEROLS:
- cholesterol

GLYCOLIPIDS

119
Q

CELL MEMBRANE - PROTEINS
describe the 2 different types of proteins

A

INTEGRAL:
single pass or multi pass

PERIPHERAL:
embedded
covalently bonded to lipids
non covalently bonded to other proteins

120
Q

CELL MEMBRANE
what’s the name of the carbohydrate coating on the cell?

A

glycocalyx

121
Q

CELL MEMBRANE
5 membrane functions

A

facilitate diffusion
cell - cell recognition
recognition
cellular process platform
energy conversion

122
Q

CELL MEMBRANE
describe a lipid raft

A

reduces fluidity
lots of sphingolipids
more cholesterol = rigid
more proteins

123
Q

CELL MEMBRANE
what type of molecule will:
1) dissolve easily
2) dissolve slowly
3) need a form of transporter
4) need special transport mechanism

A

1) small non polar
2) small polar
3) large uncharged polar
4) charged ions

124
Q

CELL MEMBRANE: TRANSPORT PROTEINS
1) what do they need to be?
2) what are the 2 types and what do they do?
3) what type of transport do they allow?

A

1) transmembrane, multipass
2) CARRIER PROTEINS: bind to solute, conformational change, release

CHANNEL PROTEINS: weak interact with solute, continuous pore, selective filter

3) passive transport

125
Q

CELL MEMBRANE: ACTIVE TRANSPORT
1) what are the 2 types of coupled carriers?

A

1) SYMPORTER: two solutes in same direction, 1 up conc grad. 1 down conc. grad
2) ANTIPORTER: two solutes in diff directions, energy from atp hydrolysis to push against gradient

126
Q

CELL MEMBRANE: CHANNELS
what type of diffusion do they allow?

3 types of gated channels?

A

passive transport/facilitated diffusion
voltage, ligand, mechanical

127
Q

NUCLEUS what’s inside?
define:
CHROMOSOME
HISTONES
NUCLEOSOME
SISTER CHROMATIDS
CHROMATIN

A

CHROMOSOME: specific set of genes, chromatin region

HISTONES: protein bind to dna, form eukaryotic chromosome

NUCLEOSOME: protein dna complex, 8 histones

SISTER CHROMATIDS: identical copies of same chromosome

CHROMATIN: repeating nucleosome structure

128
Q

NUCLEUS/NUCLEOLUS
what is this the site of?
what enzyme is required?

A

RNA synthesis (transcription)
RNA polymerases

129
Q

NUCLEUS/NUCLEOLUS
describe the nucleus and nucleolus membranes

A

NUCLEUS: double membrane, phospholipid bilayer

NUCLEOLUS: doesn’t have membrane

130
Q

NUCLEUS
describe sections of the nuclear envelope

A

ribosomes: protein synthesis
nuclear pore complex:
nuclear lamina: part of cytoskeleton
nucleolus: dark stain region
chromatin: beads on a string
rer: continuous with envelope

131
Q

NUCLEUS
it is the __________ organelle In eukaryotic cells
what does it contain?
what is this packaged into?

A

biggest organelle
contains DNA genetic material
chromatin

132
Q

NUCLEUS
describe the structure of the nuclear pore complex

A
  • large quaternary protein
  • ordered 8 fold symmetry
  • aqueous channel, nucleoplasm - cytosol
  • made of nucleoporins (30 types)
  • nuclear basket, cytosillic fibres
  • disordered inside
133
Q

NUCLEUS
what can diffuse through nuclear pore complex?
freely diffuse:
diffuse but take longer:
need special mechanism:

A

less than 5000KDa
up to 60kDa
more than 60KDa

134
Q

NUCLEUS
what does a protein have so it can go into the nucleus?
what are these recognised by?

A

nuclear localisation signal
specific nuclear import receptors/ Importins

135
Q

NUCLEUS
what is the name of the signal proteins have

A

protein with nuclear localisation signal

136
Q

NUCLEAR IMPORT
describe the process

A

1) protein has nls, nuclear import receptor bind
2) goes through nuclear pore complex , bind and unbind to FG repeats
3) in nucleus, RAN GTP bind, protein releases
4) receptor + GTP back to cytosol
5) Ran binding protein bind, receptor recycled, Ran binding protein+ ran gtp left
6) ran gap hydrolyse gtp — gdp
7) gdp back to nucleus
8) GDP — GTP by ran gef

137
Q

NUCLEAR EXPORT
describe the process

A

1) GTP + nuclear export receptor bind with protein with nuclear export signal
2) complex goes through nuc pore complex by FG repeats
3) Ran binding protein + Ran GAP bind, protein released
4) GTP — GDP by ran GAP
5) GDP goes back to nucleus
6) GDP – GTP by Ran GEF

138
Q

NUCLEAR BIOGENESIS
what rna is in the nucleolus?
what are its subunits?
what enzyme is used?
what is joined to it?
what does it form?

A

45s pre rRNA
18s, 5.8s, 28s
rna polymerase I
ribosomal proteins from cytosol
90s pre ribosome

139
Q

NUCLEAR BIOGENESIS
what rRNA is in the nucleoplasm?
what enzyme is used?

A

5s rRNA
POL III

140
Q

NUCLEAR BIOGENESIS
what is 90s pre ribosome modified by?
what are the 3 ways in which they modify?

A

snoRNPs
methylation, isomerisation, separate 3 groups of 45s

141
Q
A

Sport Science sem 1 (3 decks)

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