Metabolism Flashcards
0
Q
Describe the relationship between catabolism and anabolism
A
Catabolism produces reducing agents and energy for anabolism to take place.
1
Q
Define metabolism
A
The processes which derive energy and raw materials from food stuffs and use them to support repair, growth and activity of tissues of the body.
2
Q
Define homeostasis and what is its importance?
A
The control of the internal environment within set limits and it is a dynamic equilibrium. Failure of homeostasis leads to disease.
3
Q
What is BMI? How is it calculated?
A
A simple way to estimate desirable weight. It stands for Body Mass Index. Calculated by weight (kg)/(height(m))^2
4
Q
How do you interpret BMI results
A
Underweight=18.5 or lower Desirable= 18.5-24.9 Overweight= 25-29.9 Obese= 30-34.9 Severely obese= 35 or over
5
Q
Define daily energy expenditure
A
Energy required for:
- BMR
- Voluntary physical activity
- Energy required to process food (diet-induced thermogenesis)
6
Q
Define basal metabolic rate (BMR)
A
Measure of basal energy required to maintain life and functioning of tissues at physical, emotional and digestive rest.
7
Q
What are the percentages associated with BMR?
A
Skeletal muscle= 30%
Central nervous system= 20%
Liver= 20%
Heart= 10%
8
Q
How do you get a rough estimate for BMR?
A
A very rough estimate for BMR is the weight (kg) X 100
So 70kg man= about 7000kJ
And 58kJ woman= about 5800kJ
9
Q
What are approximate value of daily energy requirement?
A
A 70 kg man at normal activity level will need about 12000kJ (2800kcal) to support BMR, voluntary physical activity and processing of food.
10
Q
What does voluntary physical activity encompass?
A
Reflects the energy demands of skeletal muscles, heart muscle and respiratory muscles.
The energy required will vary dependant on intensity and duration of activity.
11
Q
What are rough values of energy required at different energy levels in voluntary physical activity?
A
Sedentary person- 30kJ/Kg/day
Moderate activity- 65KJ/Kg/day
Very active- 100kJ/Kg/day
12
Q
What are the energy levels available from different foods?
A
Carbohydrate- 17000kJ/kg
Protein- 17000kJ/kg
Lipid- 37000kJ/kg
Alcohol- 29000kJ/day
13
Q
What are the essential components of the diet?
A
Carbohydrates Protein Fat Vitamins and minerals Water Fibre
14
Q
What do the essential components of the diet provide us with?
A
Carbohydrate- mostly energy Protein- energy and amino acids Fat- energy and essential fatty acids Vitamins and minerals- essential for life Water- maintains hydration Fibre- necessary for normal GI function
15
Q
How is energy intake linked to body weight?
A
- If energy intake is equal to expenditure then body weight will be stable
- if energy intake exceeds expenditure then energy stores will increase (body weight increase)
- if expenditure is greater than intake first energy will deplete then other body components (protein) will be utilised to provide energy (body weight decreases)
16
Q
What is energy needed for?
A
1-Biosynthetic work (synthesis of cellular components (anabolism))
2-Transport work (membranes a- maintenance of ion gradients
b- nutrient uptake)
3-Specialised functions:
-mechanical work- muscle contraction
-electrical work- nervous impulse conduction
-osmotic work- kidney
17
Q
Give examples of major carrier molecules
A
Nicotinamide adenine dinucleotide (oxidised form:NAD+, reduced form:NADH + H+)
Nicotinamide adenine dinucleotide phosphate. (oxidised form:NADP+, NADPH + H+)
Flavin adenine dinucleotide (oxidised form:FAD, reduced form:FADH2)
18
Q
What are high and low energy signals and how do they regulate pathways?
A
When ATP is HIGH, anabolic pathways are activated
When ATP is LOW, and ATP and AMP are HIGH, catabolic pathways are activated
19
Q
What is creatine phosphate used for?
A
Can provide a short time boost to ATP levels when levels fall. This is because the creatine is converted to creatine phosphate when ATP levels are high and this reaction is reversed to release a phosphate group on the ADP when needed.
20
Q
What enzyme is associated with creatine phosphate?
A
Creatine kinase
21
Q
What is the presence of a particular isoform of creatine kinase in the blood used to diagnose?
A
MI, the isoform is released from cardiac myocytes (cells) when damaged, in a myocardial infarction. It appears in the blood after few hours.
22
Q
What is creatinine?
A
Produced by a spontaneous reaction at a constant rate unless the muscle is wasting. It is a breakdown product of creatine (and creatine phosphate)
23
Q
What does creatinine excretion over 24h show?
A
It is proportional to muscle mass of the individual
24
What does creatinine concentration in urine show?
It is a marker of urine dilution so can be used as a benchmark for measuring other concentrations in the urine
25
How is reducing power converted to ATP?
Oxidative phosphorylation
26
Give an overview of stage 1 catabolism
```
Breakdown of large molecules to building block molecules
Extra cellular (GI tract)
No energy produced
```
27
Give an overview of stage 2 catabolism
Intercellular (cyotosolic and mitochondrial)
Building block molecules (many) to simple molecules (few)
Oxidative (coenzymes are reduced e.g. NAD+ to NADH)
Some energy produced
28
Give an overview of stage 3 catabolism
```
Mitochondrial
Single pathway- tricarbxylic acid cycle (TCA or Krebs cycle)
Oxidative requires NAD+ and FAD
Some energy produced directly
Acetyl converted to 2 CO2
```
29
Give an overview of stage 4 catabolism
```
Mitochondrial
Electron transport and ATP synthesis
NAD and FAD2H re-oxidised
O2 required (reduced to H2O)
Large amounts of ATP produced
```
30
What are carbohydrates?
```
General formula (CH2O)n
Contain aldehyde (-CHO) or keto (-C=O) group
Multiple -OH groups
```
31
What is a polymer of glucose and where is it found in animals?
Glycogen
Major store of energy in mammals
Highly branched 1-4 and 1-6 bonds
32
What is a polymer of glucose (plants)?
Starch
Less branched than glycogen
GI tract enzymes release glucose and maltose
33
Describe details of cellulose
Structural polymer of glucose found in plants
Beta 1-4 linkages
No GI enzymes to digest linkages
Dietary fibre important for GI function
34
Give a example of a stage 1catabolism enzyme
Amylase
Found in saliva and pancreas
Breaks down glucose polymers
35
What is the stage 2 catabolism called?
Glycolysis
36
What are the key feature of glycolysis?
Exergontic, oxidative
C6 to C3 (no loss of CO2)
With only one more enzyme, glycolysis is the only pathway that can operate anaerbically (no oxygen)
37
What charge is glucose given during stage 1 of glycolysis?
Negative (anionic)
| This prevents passage back across the plasma membrane
38
How many moles of ATP are require to convert glucose to fructose 1,6 bis phosphate?
2 moles of ATP per mole of glucose
39
What is the first committing step that commits glucose to metabolism via glycolysis?
The conversion of fructose 6 phosphate to fructose 1,6 bis phosphate with a molecule of ATP
40
What happens to glucose during the first step of glycolysis?
It is phosphorylated to fructose 1,6 bis phosphate with the addition of 2 ATP
41
How many units is the fructose 1,6 bis phosphate cleaved into?
2
3 carbon units
The units are inter convertible
42
How many molecules of NADH are produced during glycolysis?
2 molecules
43
What are the end products of glycolysis?
```
2 molecules of pyruvate
2 molecules of ATP
2 molecules of NADH
2 H+
2 H2O
```
44
What is another name associated with glycolysis?
Substrate level phosphorylation
45
Name an important intermediate in glycolysis
- DHAP which is converted to glycerol phosphate in the adipose tissue and the liver
- 1,3 bis phosphate glycerate which is converted to 2,3 bis phosphate glycerate in RBC
46
What does 2,3- bis phosphate glycerate regulate?
It is a regulator of O2 affinity of haemoglobin (tense form)
Found in RBC at same molar concentration as haemoglobin (about 5mM)
47
Why is glycerol phosphate important?
It is important to triglyceride and phospholipid biosynthesis
48
Where are potential sites of control of glycolysis?
Enzymes catalysing irreversible steps are potential sites of control
49
Name a type of regulation
Allosteric (activator/inhibitor binds at a site other than the active site on the enzyme)
50
What happens when there is no more NAD+ for glycolysis?
NAD+ is regenerated by:
NADH + H+ + pyruvate NAD+ + lactate
So lactate and NAD+ are produced from NADH and pyruvate
51
Where is lactate produced?
Lactate is produced by RBC and skeletal muscles (skin, brain, GI)
Released into blood and metabolised by liver and heart
52
What is the enzyme responsible for the production (and conversion) of lactate?
Lactate dehydrogenase (LDH)
53
What 2 enzymes are required to metabolise fructose?
Fructokinase- if missing fructose is present in urine (essential fructosuria) no clinical signs
Aldolase- if missing fructose 1-P accumulates in liver resulting in damage (fructose intolerance) treatment is to remove fructose from diet
54
Where is galactose metabolised?
In the liver
55
What enzymes are required to metabolise galactose?
Galactokinease
Galactose-1-P uridyl transferase
UDP-galactose 4'-epimerase
56
What is galactose converted to so it can enter glycolysis?
Glucose-1-P which is then converted to glucose 6-P
57
What is galactosaemia?
The inability to utilise galactose
58
What different types of galactosaemia are there?
- Galactokinease deficiency (rare) galactose accumulates
| - transferase deficiency (common) galactose and galactose 1-P accumulate
59
What problems does galactosaemia cause?
Galactose enters other pathways
Is converted to galactitol. This also converts NADPH to NADP+
The depletion in levels of NADPH leads to damage to structures in places such as the eye so cataracts form (disulphide bridges)
Accumalation of galactose 1-P affects liver, kidney and brain
60
What is the treatment of galactosaemia?
No lactose in diet (lactose is consists of galactose and glucose)
61
What is the function of the pentose phosphate pathway?
1-to produce NADPH (used as a Biosynthetic reducing power and also to maintain free -SH (cysteine) groups on certain proteins (prevents cataracts))
2-produce C5 sugars for nucleotides for nucleic acid synthesis
62
What are the effects if the pentose phosphate pathway cannot take place? Lack of the enzyme glucose 6-phosphate dehydrogenase (G6PDH)
There will be a lack of NADPH so disulphide bridges will form between cysteine groups on some proteins and this will lead to cataracts in the eyes and heniz bodies in RBC
63
In general are lipids soluble in water?
No,con general they are insoluble (hydrophobic)
64
Where are triacylglycerols stored?
In the adipose tissues which is specialised for this purpose.
They can be used in prolonged exercise or starvation
65
What are triglycerides converted to?
Glycerol and fatty acids in the GI tract
66
What is type of enzyme responsible for the hydrolysis of lipids?
Lipase
67
Name some fat soluble vitamins
A
D
E
K
68
Where is glycerol metabolised?
In the liver
69
What enzymes are used in glycerol metabolism?
Glycerol kinase
70
What molecules are used in glycerol metabolism?
ATP
| NAD+
71
What molecules are produced in glycerol metabolism?
ADP
glycerol phosphate (intermediate)
NADH
Dihydroxyacetone phosphate (enters glycolysis)
72
What is the name of the process that releases energy from fatty acids?
Beta oxidation
| Occurs in mitochondria
73
Where does beta oxidation not occur?
In red blood cells (do not possess mitochondria)
| Cells of the CNS (fatty acids do not readily cross the blood-brain barrier)
74
Outline fatty acid metabolism
1-FA is activated by linking to coenzyme A outside the mitochondrion
2-transported across membrane using carnitine shuttle
3-FA cycles through series of oxidative reactions with C2 removed each cycle
75
What is used in fatty acid metabolism?
FAD
H2O
NAD+
76
Does beta oxidation produce ATP?
No
77
What does beta oxidation stop in the absence of?
Oxygen
78
What is the main convergence point for catabolic pathways?
Acetyl CoA
79
How many ketone bodies are produced in the body and what are they?
3
Acetoacetate
Acetone
Beta-hydroxybutyrate
80
Where are acetoacetate and beta-hydroxybutyrate synthesised?
In the liver from Acetyl CoA
81
Where does acetone arise from?
The spontaneous (non-enzymatic) decarboxylation of acetoacetate
82
What are the concentrations of ketone bodies in the blood like and how and why do they vary?
```
Normally low (less than 1 mMol/L)
Increases in starvation (2-10mmol/L) (physiological ketosis)
Increases in untreated type 1 diabetes (over 10 mMol/L) (pathological ketosis)
```
83
Why does the breath of untreated diabetes type 1 patients smell of nail polish remover?
Acetone is sometimes excreted via the lungs and acetone is nail polish remover
84
What happens to ketone body synthesis when insulin/glucagon ratio is high? (Fed state)
The enzyme lease is inhibited, reductase is activated so cholesterol is synthesised
85
What happens to ketone body synthesis when insulin/glucagon ratio is low? (Starvation)
Lease is activated, reductase inhibited, ketone body synthesis
86
What are ketone bodies used for?
They are important fuel molecules that can be used by all tissues contains mitochondria including the CNS
87
How are ketone bodies used as fuel?
They are converted to Acetyl CoA and this is subsequently oxidised via stage 3 of catabolism
88
Why is Acetyl CoA important?
It is the main convergence point for catabolic pathways
| It is an important intermediate in both catabolic and anabolic pathways
89
Where is pyruvate dehydrogenase found?
In the mitochondrial matrix
90
Describe pyruvate dehydrogenase
Large multi enzyme complex
| Converts pyruvate to Acetyl CoA irreversibly
91
What inhibits pyruvate dehydrogenase?
Acetyl CoA
NADH
ATP
92
What activates pyruvate dehydrogenase?
```
Pyruvate
CoASH
NAD+
ADP
Insulin
```
93
Why is the conversion of pyruvate to Acetyl CoA considered irreversible?
It involves the irreversible lose of CO2
94
Per glucose molecule how many turns of the Krebs cycle take place?
2
| As there are 2 C3 compounds produced from 1 glucose molecule
95
Where does the Krebs cycle take place?
Inside the mitochondria
96
What happens to Acetyl CoA during the Krebs cycle?
The C-C bonds are broken
| The carbons oxidise to CO2
97
Does Krebs cycle run in absence of O2?
No
98
What is another name for Acetyl CoA?
Acetate
99
How many molecules of NADH are produced per turn of the Krebs cycle?
3
| So 6 for the 2 turns per glucose molecule
100
How many molecules of FAD2H are produced per turn of the Krebs cycle?
1
| So 2 for the 2 turns for each molecule of glucose
101
How many molecules of GTP (similar to ATP) are produced per turn of the Krebs cycle?
1
| So 2 for the 2 turns for each molecule of glucose
102
How is the Krebs cycle regulated?
ATP/ADP ratio
NADH/NAD+ ratio
Both of these feed back into the Krebs cycle about the rate of ATP use
103
Name an enzyme that is responsible for an early irreversible step in the Krebs cycle and can be allosterically controlled
Isocitrate dehydrogenase
Allosterically inhibited by high energy signal NADH
Allosterically activated by the low energy signal ADP
104
What happens to the NADH and FAD2H after the Krebs cycle?
They are reoxidised
| Requires O2
105
What happens to the H+ and electron lost from NADH and FAD2H?
Electrons transferred through series of carrier molecules to O2 with release of energy
H+ moved across membrane into the inter membrane space of the mitochondrion (H+ gradient across membrane is the protein motive force or pmf)
106
What is the pmf used to drive?
ATP synthesis from ADP and a phosphate
107
How much energy is required to bind a phosphate onto ADP?
+31 kJ/mol
108
How many moles of ATP can be produced from 2 moles of NADH?
5
109
How many moles of ATP can be produced from 2 ,olds of FAD2H?
3
110
How is energy released from ATP?
The hydrolysis of the phosphate bond to form ADP and a phosphate group
111
How is ATP synthesised?
ATP synthase allows the return of H+ across the membrane which is favoured energetically by the electrochemical gradient.
This drives ATP synthesis
112
What is the final stage of catabolism called?
Oxidative phosphorylation
113
What are the 2 processes involved in oxidative phosphorylation?
Electron transport
| ATP synthesis
114
How is oxidative phosphorylation regulated?
When ATP is high, ADP is low so no substrate for ATP synthase
Therefore inward flow of H+ stops
So concentration of H+ goes up
This prevents further H+ pumping
115
How do inhibitors of oxidative phosphorylation work?
They block electron transport (e.g. Cyanide) by preventing acceptance of electrons by O2
116
How do uncouplers of oxidative phosphorylation work?
They increase the permeability of the mitochondrial inner membrane to H+ so pmf is reduced so less drive for ATP synthesis
117
What is the purpose of brown adipose tissue?
Contains a naturally occurring uncoupling protein
Electron transport is uncoupled from ATP synthesis
The energy of pmf is captured as extra heat
118
How many moles of ATP are produced from one mole of glucose?
32
119
Name some tissues that have an absolute requirement for glucose
Erythrocytes
Leukocytes
Kidney medulla
Lens of eye
120
What type of fuel does CNS prefer?
Glucose
121
What is about a normal blood glucose level?
5mM
122
Why is glucose stored as glycogen?
It is efficient
Large molecule
Minimal osmotic effect
123
Where is glycogen stored?
As granules in:
Liver (up to about 100g)
Skeletal muscle (up to about 300g)
124
What is another name for glycogen synthesis?
Glycogenesis
125
What enzyme are involved in glycogenesis?
Hexokinase (muscles) /glucokinase (liver)
Phosphoglucomutase
Glycogen synthase
126
What is the first step in glycogenesis?
Glucose is phosphorylated
Requires ATP
produces ADP and glucose 6 phosphate
127
What does phosphoglucomutase do?
Move the position of the phosphate group on glucose 6-P to make glucose 1-P
128
What does glucose 1-P combine with before it can bind to glycogen?
UTP (similar to ATP but a different base)
129
When is glycogen degraded in the skeletal muscles and liver?
Skeletal muscles- in response to exercise
| Liver- in response to fasting or stress
130
What is the break down of glycogen called?
Glycogenolysis
131
Name the enzymes involved in glycogenolysis
Glycogen phosphorylase
Phosphoglucomutase
Glucose 6-phosphatase (liver only)
132
What is glycogen from skeletal muscles broken down to?
Glucose 6-phosphate (which then enters glycolysis)
133
What is glycogen from the liver broken down into?
Glucose (which is then released into the blood)
134
What is the regulatory enzyme in glycogen synthesis?
Glycogen synthase
135
What is the regulatory enzyme in glycogen degradation?
Glycogen phosphorylase
136
What affect does glucagon and adrenaline have on glycogen synthesis and degradation?
Decreased synthesis
| Increased degradation
137
What affect does insulin have on glycogen synthesis and degradation?
Synthesis increases
| Degradation decreased
138
How do glycogen storage diseases arise?
Through inherited conditions- inborn errors of metabolism
| Deficiency or dysfunction of enzyme involved in glycogen metabolism
139
Give an example of a glycogen storage disease
von Gierke's disease
| Deficiency of the enzyme glucose 6-phosphate
140
What does gluconeogenesis mean?
The production of new glucose
| Occurs in liver and kidney cortex
141
Name some precursors for gluconeogenesis
```
Galactose
Fructose
Glycerol (from TAG)
Lactate
Glucogenic amino acids
```
142
Name some enzymes involved in gluconeogenesis
```
Fructose 1,6-bisphosphatase
Phosphoenolpyruvate carboxykinase (PEPCK)
```
143
What is gluconeogenesis regulated in response to?
Starvation/fasting
Prolonged exercise
Stress
144
What affect on gluconeogenesis does glucagon and cortisol have?
They stimulate it
145
What affect on gluconeogenesis does insulin have?
Inhibits gluconeogenesis
146
Approximately how long after feeding does glycogenolysis take place?
Up to 8-10 hours
147
Approximately how long after feeding does gluconeogenesis take place?
8-10 hours onwards
148
When are triacylglycerols used as a source of energy?
Prolonged exercise
Stress
Starvation
During pregnancy
149
Where are triacylglycerols stored?
Adipose tissue
150
What is fatty acid synthesis known as?
Lipogenesis
151
What are fatty acids synthesised from?
Acetyl CoA
| Requires ATP and NADPH
152
Where does lipogenesis occur?
In the cytoplasm of liver cells
153
Where does the Acetyl CoA for the lipogenesis come from?
Mitochondria
154
What does Acetyl CoA bind to to be transported out of the mitochondria?
Oxaloacetate to form citrate
155
What is the first step of fatty acid synthesis?
Acetyl-CoA is converted to malonyl-CoA
156
What enzyme converts Acetyl-CoA to Malonyl-CoA?
Acetyl carboxylase
157
What is added each time to the fatty acid chain kn fatty acid synthesis?
C2 (as malonyl-CoA)
158
What enzyme is involved in fatty acid synthesis?
fatty acid synthase
| multi-enzyme complex
159
What inhibits fatty acid oxidation?
insulin
160
What inhibits fatty acid synthesis?
Glucagon
| Adrenaline
161
What stimulates fatty acid oxidation?
Glucagon
| Adrenaline
162
What stimulates fatty acid synthesis?
Insulin
163
What are fuel stores in the body?
Triacylglycerol
Glycogen
Muscle Protein
164
What is the triacylglycerol fuel store used for?
It is thee largest energy store
165
What is the glycogen fuel store used for?
Vital for glucose requiring tissues
166
What is the muscle protein fuel store used for?
Important in prolonged starvation
167
Name some classes of lipids?
```
triacyl gylcerol
fatty acids
cholesterol
cholesterol esters
phospholipids
```
168
Name some functions of cholesterol
```
Major component of membranes
Precursor of steroid hormones
Precursor of bile acids
Some from diet, but mostly synthesised in liver
Can be esterified with a fatty acid
-Eliminates the only polar part
```
169
Describe some features of phospholipids
Diacylglycerol with phosphate group
Major component of membranes
Phosphate is polar
170
Approximately what percentage of lipids are carried in the blood?
2%
| carried bound to albumin
171
Of the lipids that are in the blood, what are they mainly composed of?
fatty acids
172
How are the rest of the lipids transported in the blood?
As lipoprotein particles (small assemblies of lipid molecules surrounded by polar molecules (micelles))
173
Where are lipoprotein particles constructed?
In liver
174
What 2 properties of lipoprotein particles mean they can be separated by electrophoresis?
They vary in:
Density
Surface
175
What are singular apolipoproteins known as?
Apoproteins
176
What is a apolipoprotein composed of?
Lipids
| Proteins
177
What are lipoproteins particles made of?
Apolipoproteins
178
Name some apoproteins
```
apoA
apoB
apoC
apoD
apoE
apoH
```
179
What functional roles do apoproteins have?
activation of enzymes
| recognition of cell surface receptors
180
What are some differenrt classes of lipoprotein particles in order of increasing density?
Choylomicrons
Very low density lipoproteins (VLDL)
Low density lipoproteins (LDL)
High density lipoproteins (HDL)
181
Where are chylomicrons fromed?
enterocytes (intestinal absorbing cells0 lining the intestine
182
What are chylomicrons formed from?
combining triacylglycerols (from food) with specific apoproteins
183
How long after a meal are chylomicrons normally present in the blood?
4-6 hrs
184
Where are VLDLs formed?
in the liver
185
What are VLDLs formed from?
Triacylglycerols (synthesised in liver) with specific apoproteins
186
Where are LDLs formed?
In the liver
187
What are LDLs formed from?
cholesterol (synthesised in liver) with specific apoproteins (Apo B100 is important)
188
What does an increase in the levels of LDLs give rise to?
A higher risk of atherosclerosis
189
Where are HDLs formed?
in the tissues
190
What are HDLs fromed from?
Cholesterol (from tissues) combined with specific apoproteins
191
How are triacylglycerols from chylomicrons and VLDLs transferred?
```
Endothelial cells of capillaries have lipase on outside of membrane
Bind chylomicrons and VLDLs
Cleaves triacylglycerols into:
-Glycerol
-fatty acids
```
192
What is the fate of glycerol from tracylglycerols when they are transferred from chylomicrons and VLDLs?
it remains in the circulation
193
What is the fate of fatty acids from tracylglycerols when they are transferred from chylomicrons and VLDLs?
enter tissues for metabolism
194
What is the fate of VLDLs remnants from tracylglycerols when they are transferred from chylomicrons and VLDLs?
usually removed by liver or converted to other types of lipoprotein particles
195
How is cholesterol transferred from LDL?
cells have LDL receptor
complex proteins bind to LDL to create receptor/LDL complex which enters cell by endocytosis
cholesterol ester released and cleaved into cholesterol and fatty acid
197
What controls LDL receptor expression?
cholesterol concentration in cell
| -uptake stimulated by need
198
What is hyperlipoproteinaemias?
Raised levels of one or more lipoprotein classes
199
What causes hyperlipoproteinaemias?
```
Over-production
Under-removal
Defective
-Enzymes
-Receptors
-Apoproteins
```
200
Outline the stages of atheroma formation
```
Oxidised LDL
Macrophages
Foam cells
Accumulate in intima of blood vessle walls
Fatty streak
Atheroma
```
201
How is hyperlipoproteinaemias treated?
```
Diet
-Reduce cholesterol, saturated lipids
Lifestyle
-Increase exercise
-Stop smoking to reduce cardiovascular risk
Drugs
-Statins
```
202
How do statins work to treat hyperlipoproteinaemias?
Reduce cholesterol synthesis by inhibition of HMG CoA reductase enzyme
Increase expression of LDL receptors in hepatocytes
Anti-inflammatory?
203
Name some major nitrogen containing compounds
Proteins (amino acids)
| Purines and pyramidines (DNA/RNA)
204
How does most nitrogen enter the body?
Protein from the diet (amino acids)
205
How is most nitrogen excreted from the body?
Urea in the urine
206
Give an example of when the body is in positive nitrogen balance
Growth
| Pregnancy
207
Give an example of when the body is in negative nitrogen balance
Starvation
| Tissue wasting diseases
208
What is meant by an essential amino acid?
An amino acid that is needed in the diet
209
Name some essential amino acids
```
Lysine
Isoleucine
Leucine
Threonine
Valine
Tryptophan
Phenylalanine
Methionine
```
210
What amino acids may become essential under certain conditions?
Histidine
Arginine
Tyrosine
Cysteine
211
Name 2 methods of removing toxic amine NO2 groups from the blood
Transamination
| Deamination
212
What is transamination?
The transfer of the amino group
213
What is deamination?
The disposal of the amine group
214
During transamination an amino acid+ alpha-ketoglutarate forms what?
Glutamate and a keto acid
215
During transamination an amino acid+ oxaloacetate forms what?
Aspartate and a keto acid
