Combined Flashcards

1
Q

Iodine is an element commonly found in high abundance in which areas?

A

in the sea

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2
Q

What is the RDI for iodine

A

150ug

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3
Q

What is TRH? where is it released from?

A

Thyrotropin releasing hormone - released from the hypothalamus

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4
Q

What is cretinism? what is it caused by?

A

A congenital condition caused by maternal iodine deficiency, worlds most common form of mental retardation and growth retardation

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5
Q

Radiation from I (-131) can be used to what?

A

destroy the thyroid

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6
Q

What kind of receptors do thyroid hormones operate via?

A

membrane receptors and cause direct activation of genes in DNA

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7
Q

What is the atomic number of iodine?

A

53

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8
Q

Where is cholesterol found in the body?

A

free in membranes and as esters in storage

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9
Q

Where are human steroids derived from?

A

dietary steroids or are made from acetyl-coA in the liver

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10
Q

Corticosteroids refers to which two groups of steroids?

A

Glucocorticoids (eg cortisol) and mineralocorticoids (aldosterone)

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11
Q

Where are oestrogen and progesterone made primarily

A

ovary and also placenta during pregnancy

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12
Q

Where is testosterone primarily produced?

A

testes

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13
Q

Tamoxifen blocks what steroid action?

A

blocks oestrogen receptors and is used in the treatment of breast cancer

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14
Q

What is the effect of leuprolide?

A

lowers testosterone - used in treatment of prostate cancers

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15
Q

What are the actions of anabolic steroids?

A

interact with androgen receptors to increase muscle and bone synthesis

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16
Q

Where does the name cholesterol originate from?

A

greek chole- (bile) and stereos (solid)

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17
Q

What is cholesterol?

A

a waxy steroid metabolites

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18
Q

What is cholesterols role in cell membranes?

A

required for proper membrane permeability and fluidity (makes membrane LESS fluid)

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19
Q

What is a lipoprotein? What is their function?

A

biochemical assembly that contains proteins and lipids. Carry cholesterol in the blood

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20
Q

What are some examples of lipoproteins?

A

chylomicrons, low density lipoprotein (LDL), very low density lipoprotein (VLDL) and high density lipoprotein (HDL)

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21
Q

Arteriolosclerosis is promoted by excess levels of which lipoprotein?

A

LDL

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22
Q

What did Goldstein and Brown win a nobel prize for?

A

Identifying the LDL receptor on the liver which carries LDL and VLDL into the liver via receptor mediated endocytosis - this process is essential for feedback inhibition of HMG-CoA Reductase, muatations in this receptor lead to familial hypercholesterolaemia

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23
Q

Apart from its role in cell membranes what other roles (3) does cholesterol have?

A
  1. precursor to steroid hormones such as testosterone, cortisol, aldosterone, 2. component of bile salts 3. Vit D production
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24
Q

how many carbons does cholesterol have?

A

27

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25
Q

How many more times energy does NADPH have compared to ATP

A

7 times more

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26
Q

Where are human steroids derived from?

A

Cholesterol -> dietary or made in the liver from Acetyl-CoA

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27
Q

What is the most abundant steroid in the body?

A

cholesterol

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28
Q

Where is oestrogen and progesterone made?

A

Ovary and placenta

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29
Q

How are steroids eliminated?

A

by CYP3A4 in the liver endoplasmic reticulum which adds a OH group

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30
Q

What is Cyproterone acetate? what is it used for?

A

Inhibitor of the andreogen receptor. Used to treat Hirsuitism in females, male-to female gender change, prostate cancer, benign prostatic hyperplasia, priapism and hypersexuality (chemical castration)

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31
Q

What protein does cortisol bind in the blood?

A

transcortin

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32
Q

Hb makes up what percentage of RBC dry content?

A

97%

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33
Q

carbon dioxide can bind to Hb and form what? what proportion of the total respiratory CO2 is in this form?

A

forms carbaminohaemoglobin15% of total

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34
Q

Hb carries nitric oxide bound to what molecule on globin?

A

thiol group of globin

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35
Q

Why does Hb carry nitric oxide?

A

releases it at the same time as oxygen to relax vascular walls and enhance gas diffusion

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36
Q

Kendrew and Perutz one a nobel price for doing what regarding Hb?

A

solving its protein structure (the first protein structure solved)

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37
Q

What is the structural difference between adult and foetal Hb?

A

Foetal: alpha2-gamma2Adult:alpha2-beta2

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38
Q

Mutations in amino acid sequences cause hundred of whats (in relation to Hb)?

A

haemaglobinopathies

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39
Q

What was Christian Bohrs contributed to our knowledge about Hb?

A

described the sigmoid binding character of Hb-O2

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40
Q

What is the structure of haemaglobin?

A

Tetramer of globin subunits (proteins) with 4 haem groups inserted into each

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41
Q

What colour is Hb-CO?

A

bright red

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42
Q

What colour is De-oxy Hb?

A

dark red

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43
Q

What colour is HbO2?

A

scarlet red

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44
Q

What binds better to Hb O2 of CO?

A

CO binds 200x better than O2

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45
Q

What is Met Hb?

A

Hb with Fe3+ in the haem due to oxidation = found in aged RBCs

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46
Q

Haem inserts into the globin via a locking mechanism involving binding of histidine residues F8 and E7. One is always bound whilst the other can be displaced - which is which?

A

F8 is always locked (think its FATE for globin and haem to be together)E7 can be displaced by O2, CO and cyanide

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47
Q

What is the role of Bisphosphoglycerate (BPG)

A

stabilises Deoxy-Hb via 8 salt bonds which makes this form rigid (tense) and stops Oxygen binding back to Hb in the tissues. It is displaced when O2 levels are high (in the lungs)

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48
Q

Oxygen binding to Hb shows cooperativity - what does this mean?

A

When the first Oxygen binds to Hb it induces a change in the quaternary structure of Hb which changes the affinity of the other Oxygen binding sites - this means with only small increases in the concentration of O2 it is much easier to saturate the rest of the Hb molecule

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49
Q

What happens to the Hb-Oxygen binding curve in the presence of acid (bohr effect)? What functionally is the relevance of this?

A

graph is shifted to the right- meaning Hb has LESS affinity for O2, the relevance of this is that working tissues produce lactic acid and they require more O2 so we want the DeOxy-Hb form to be more stabilized so more oxygen is given up in the tissues - this is achieved via bonding to histidine residues

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50
Q

How does altitude alter the Oxygen-Hb binding curve? how is this achieved?

A

shifts it to the right -> giving more O2 to the tissues compensates for less O2 being picked up in the lungs. At altitude RBCs produce more BPG

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51
Q

Why does foetal Hb have higher affinity for O2 than adult hb?

A

gamma subunits have 6 positive charges (not 8) so BPG is bound less avidly so deoxy-form is stabilised less

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52
Q

What was Archibald Garrods field of study?

A

inborn errors of metabolism

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53
Q

The major burden of pathology in australia from genetic diseases is due to what disease?

A

Cystic Fibrosis

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54
Q

________was the first disease to be routinely tested for at birth and treated as required

A

phenylketonuria (PKU)

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55
Q

Genetic testing is usually carried out using what technique?

A

PCR

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56
Q

What is the most common x-linked recessive disorder? give some other examples

A

red-green colour blindess is the most common, others are haemophilia Am duchenne muscular dystrophy, Lesch-Nyhan syndrome

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57
Q

What happens in children affected by PKU?

A

they lack phenylalanine hydroxylase leading to a build up of Phe which gets converted to phenylpyruvate (a ketone) which damages the brain and affects melanin synthesis

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58
Q

What is the incidence of CF in australia?

A

in in 2500 births

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59
Q

What is the carrier rate of the CF gene in Australia?

A

1 in 25

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60
Q

What is the most common CF mutation?

A

Delta F506 in the CFTR protein (chloride channel)

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61
Q

What is Ehlers Danlos syndrome?

A

Inherited connective tissue disoder - mostly autosomal dominant condition due to mutations in genes that encode the structure, production or processing of COLLAGEN or proteins that interact with collagen -> those affected have hypermobile joints, hyper-elasticity of the skin but also affects arteries.

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62
Q

What is Marfan Syndrome?

A

mutation in fibrillin gene leading to bone overgrowth and joint laxity, with disproportionately long extremities compared to the size of the trunk

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63
Q

What enzyme is important in melanin formation?

A

tyrosinase

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64
Q

Is the inheritance of skin colour mono or polygenetic?

A

polygenetic -> 40 genes influence skin colour

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65
Q

If you lack tyrosinase what colour is your skin?

A

NO melanin = albinism

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66
Q

How do dietary toxins get to the liver?

A

Directly, via the hepatic portal vein

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67
Q

Which molecules are oxidised by P450 system?

A

ALL foreign chemicals with MW < 5,000

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68
Q

Where in the cell are the P450 cytochromes located?

A

Endoplasmic reticulumMitochondria

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69
Q

What are microsomes?

A

Pink spherical vesicles with embedded cytochrome P450. They don’t exist in cells - they’re an artefact of centrifuging.

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70
Q

What sort of enzymes are the P450s?

A

Monoxygenases

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71
Q

What reaction do the P450s typically catalyse?

A

RH + NADPH + H+ + O2 —>ROH + H2O + NADP+(The key point is that RH becomes ROH)

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72
Q

What initiates the P450 cycle of reactions?

A

Binding of a substrate to the P450

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73
Q

What P450 is deficient in people who can’t convert codeine to morphine?

A

CYP 2D6

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74
Q

What’s the structure of bilirubin?

A

It’s a a tetrapyrrole - an open chain of 4 pyrrole rings

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75
Q

Where is bilirubin usually produced?

A

In the spleen

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76
Q

What cells are responsible for the breakdown of senescent RBCs?

A

Macrophages

77
Q

What haem breakdown product do macrophages make?

A

Biliverdin

78
Q

What colour is bilirubin?

A

Yellow

79
Q

What happens to bilirubin when exposed to light?

A

Some of the double-bonds isomerise

80
Q

What isomer of bilirubin is more soluble?

A

The E,E-isomer

81
Q

Which isomer of bilirubin is less soluble

A

The Z,Z-isomer

82
Q

What’s the clinical application of bilirubin isomerisation?

A

Phototherapy for jaundices newborns

83
Q

What are the two chemical forms of bilirubin?

A

Conjugated and unconjugated

84
Q

What’s another name for conjugated bilirubin?

A

Direct

85
Q

What’s another name for unconjugated bilirubin?

A

Indirect

86
Q

In which form is bilirubin excreted in bile?

A

Conjugated - as glucuronide

87
Q

What toxicity does bilirubin have in high levels, and in which population?

A

Neurotoxicity in newborns

88
Q

What’s the name for bilirubin-induced neurotoxicity?

A

Kernicterus

89
Q

What gives rise to jaundice?

A

Hyperbilirubinaemia

90
Q

What things can cause elevated bilirubin?

A

Neonatal hyperbilirubinaemiaBile duct obstructionSevere liver failure w/ cirrhosisCriger-Najjar syndromeDubin-Johnson syndromeCholedocholithiasis

91
Q

What is urobilinogen?

A

The colourless product of bilirubin reduction

92
Q

How & where is urobilinogen formed?

A

In the intestines by bacterial action

93
Q

What constitutes the normal enterohepatic urobilinogen cycle?

A

Some of the urobilinogen is reabsorbed from the gut and then excreted by the kidney

94
Q

How many Australians have health problems related to risky alcohol consumption?

A

2-3 million

95
Q

WHat proportion of Australians exhibit alcohol-induced Wernicke Korsakoff syndrome

A

2%

96
Q

What is the primary organ of alcohol damage?

A

The liver

97
Q

What stages of damage does the liver progress through?

A

Fatty infiltrationAlcoholic hepatitisCirrhosis

98
Q

What is cirrhosis?

A

Irreversible fibrous degradation of the liver

99
Q

What’s the most significant pathway for alcohol breakdown?

A

Alcohol dehydrogenase

100
Q

What’s the inducible system of alcohol breakdown?

A

MEOS - Microsomal ethanol oxidising system

101
Q

What is the enzyme involved in MEOS?

A

CYP2E1

102
Q

What’s the 3rd minor system of alcohol breakdown?

A

Oxidisation via catalase

103
Q

What does aldehyde dehydrogenase do?

A

Converts acetaldehyde to acetate

104
Q

What are the two fates of acetate?

A

Oxidisation for energy via the TCA cycleConverted to fat

105
Q

At what rate do most humans clear alcohol?

A

10g per houror .015% BAC per hour

106
Q

T/F: Addiction to alcohol is always due to inherited predispostition

A

False - there’s multiple causes, but inherited predisposition is one of them

107
Q

What are some ways to treat alcohol addiction?

A

Drugs that make alcohol less pleasurable to drink

108
Q

T/F: Immense economic and social damage is caused by alcohol

A

TRUE

109
Q

T/F: People who abstain from alcohol have better health and longevity

A

False - research suggests moderate drinkers are healthier

110
Q

What two processes are linked by metabolism?

A

Catabolism & anabolism

111
Q

What does catabolism refer to?

A

The breakdown of biomolecules (including food)

112
Q

What does anabolism refer to?

A

The synthesis of biomolecules (including protein)

113
Q

What are the two main “energy carrying” intermediates in metabolism

A

ATP & NADH

114
Q

ATP vs NADH. Which is the low-energy intermediate?

A

ATP

115
Q

ATP vs NADH. Which is the high-energy intermediate?

A

NADH

116
Q

How many kJ/mol is ATP?

A

30.5

117
Q

How many kJ/mol is NADH?

A

220

118
Q

How many ATPs are produced in anaerobic metabolism?

A

2

119
Q

How many ATPs are produced in aerobic metabolism?

A

32

120
Q

In what form is the fasting reserve of glucose stored?

A

Glycogen

121
Q

What are the two main families of sugars?

A

Aldose and ketose

122
Q

What are some examples of aldose sugars (2)

A

GlucoseGalactose

123
Q

What’s an example of a ketose sugar?

A

Fructose

124
Q

What proteins are the transporter of sugar into cells?

A

GLUTs

125
Q

How many members of the GLUT family are there?

A

12

126
Q

Which GLUT is universal?

A

GLUT1

127
Q

Which GLUT is found on cells of the liver and pancreas?

A

GLUT2

128
Q

Which GLUT is found on myocytes and adipocytes?

A

GLUT4

129
Q

Which GLUT’s translocation is dependent on insulin?

A

GLUT4

130
Q

Problems with which GLUT plays a major role in diabetic hyperglycaemia?

A

GLUT4

131
Q

What byproduct comes from anaerobic glycolysis?

A

Lactate

132
Q

Which cells are obliged to perform anaerobic metabolism and why?

A

RBCs as they have no mitochondria

133
Q

What is gluconeogenesis?

A

The generation of glucose from glycerol or AAs

134
Q

Can fat be used for gluconeogenesis?

A

No

135
Q

What sugar in processed food is correlated with increased obesity?

A

Fructose! ;)

136
Q

How many mitochondria does a healthy cell have?

A

200-10,000

137
Q

How many mitochondria do liver cells have?

A

~1,000

138
Q

Define syncytium

A

A multinucleated cell formed by the fusion of many cells

139
Q

What’s are some examples of syncytium?

A

Skeletal muscleGiant cells

140
Q

What’s the evolutionary background of mitochondria?

A

They’re endosymbiotic bacteria

141
Q

How long ago was mitochondrial bacteria incorporated into eukaryotes?

A

2 billion years

142
Q

What processes take place in the mitochondria?

A

Acetyl Coa productionKetone body synthesisTCAOxidative phosphorylation

143
Q

Mitochondria can make Acetyl CoA from which substrates? (2)

A

PyruvateFatty acid oxidation

144
Q

The TCA cycle is aka?

A

Krebs cycle

145
Q

What are ketone bodies synthesised from?

A

Acetyl CoA via HMG-CoA

146
Q

Which cells lack mitochondria?

A

RBCs and the retina

147
Q

What happens when electrons leak from the electron transport chain?

A

They create ROSs

148
Q

What process can explain many of the infirmities of age?

A

ROS damage - including loss of mitochondria

149
Q

What causes mitochondrial diseases?

A

Mutations in mitochondria or nuclear DNA

150
Q

What’s the pathological appearance of many mitochondrial diseases?

A

Ragged red fibres

151
Q

InfectionInherited abnormalities& ______ are major causes of disease?

A

Faulty nutrition (over & under)

152
Q

What is macronutrition?

A

The study of obtaining energy to fuel normal activity

153
Q

How many Joules does the typical adult need per day?

A

10MJ

154
Q

In what form is the 10MJ of energy lost?

A

Heat

155
Q

What is BMR?

A

The minimum energy required to sustain life

156
Q

Can BMR be measured?

A

Yes

157
Q

Exercise is usually less than __% of energy expenditure?

A

40%

158
Q

What anatomical structures do humans have that define us as omnivores?

A

DentalGut

159
Q

Archeological evidence shows healthy homonid skeletons from the hunter-gatherers of 30,000 years ago - what does Graham think this indicates?

A

That “caveman” diets may be our evolutionary optimum

160
Q

Do different populations have different dietary needs?

A

Sort of - lactose intolerance is an example

161
Q

What’s out cheapest and most abundant fuel?

A

CHOs

162
Q

What diseases does fibre protect us from (2)

A

DiverticulosisHaemorrhoids

163
Q

What disease is fibre unlikely to protect us from (despite common belief?)

A

Cancer

164
Q

Why are low GI diets recommended?

A

They avoid high glucose levels that can encourage insulin resistance

165
Q

We need to eat protein for which two reasons?

A

For energyFor biosynthesis of all structural components and enzymes for metabolism

166
Q

What molecule has the most complex digestive process?

A

Protein

167
Q

What are the (basic) steps of protein digestion?

A

DenatureRender to AAsTransport AAs via gut transporters

168
Q

What are the branched chain AAs?

A

ValineLeucineIsoleucine

169
Q

Which AA’s transaminate in muscles?

A

The branched chain ones

170
Q

Is there any evidence that branched-chain AAs improve sports performance?

A

No

171
Q

How many grams of protein do we make & breakdown daily?

A

300

172
Q

What proportion of the protein we break down gets recycled?

A

200g

173
Q

What is the major waste product that removed excess nitrogen?

A

Urea

174
Q

Is there renal ammonia clearance?

A

Yes - some

175
Q

Are proteins stored for fuel?

A

No

176
Q

Can protein be used for fuel?

A

Yes

177
Q

What are the products of protein breakdown? (2)

A

Glucose and ketone bodies

178
Q

Define vitamin

A

An organic compound, not made by the body but with essential biochemical functions

179
Q

Which are the fat soluble vitamins?

A

A, D, E, K

180
Q

What are the water soluble vitamins?

A

Thiamin - B1Riboflavin - B2Niacin - B3Pyridoxine - B6Pantothenic acidBiotinFolateCobalamin (B12)Ascorbic acid (vit C)

181
Q

In what situations should we consider vitamin deficiencies?

A

Unusual dietsPeriods of growthDiseaseDeveloping countries

182
Q

What are the major minerals required by the body? (6)

A

SodiumPotassiumCalciumPhosphorusMagnesiumSulphate

183
Q

What are the trace minerals required by the body? (7)

A

IronZincCopperManganeseFluorideChromiumMolybdenum

184
Q

What things affect the trace mineral content of foods

A

Soil & water composition

185
Q

What’s the most common result of mineral deficiency in children?

A

Failure to grow & thrive

186
Q

How is BMI calculated?

A

kg/m^2

187
Q

What BMI is considered underweight?

A

<18.5

188
Q

What BMI is considered normal weight?

A

18.5-25

189
Q

What BMI is considered overweight?

A

25-30