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Metabolism - Alex's Cards (ESA2) > Session 1 Lecture Notes > Flashcards

Session 1 Lecture Notes Flashcards

1
Q

What do catabolic processes do?

A

Break down molecules to release energy in the form of reducing power
Energy from catabolic processes drives anabolic processes

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2
Q

What do anabolic processes do?

A

Use energy and raw materials to make larger molecules for growth and maintenance

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3
Q

What is biosynthetic work?

A

Synthesis of cellular components

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4
Q

What percentage of the brains’ energy is used for transport work and give an example

A

50%

NA, K ATPase

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5
Q

What form of energy is used in our bodies to drive every biological reaction?

A

Chemical bond energy

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6
Q

What are the 3 components of ATP?

A

Adenine ring
Ribose sugar
3 phosphate groups (alpha beta and gamma)

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7
Q

Where is the energy source obtained from in ATP?

A

In the last phosphodiester bond - the energy is released when the bond is broken

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8
Q

Using oxidation give three examples of where energy can be obtained?

A

Carbohydrates
Lipids
Protein - in times of need
Alcohol - but dangerous

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9
Q

What is the official unit of food energy?

A

Kilojoules (kJ)

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10
Q

What does calorie actually refer to? How many calories in a kilojoule?

A

Calorie (kcal) = kilocalorie
So 1 calorie is actually 1000 calories
1 calorie = 4.2 kilojoules

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11
Q

What is fibre necessary for?

A

Maintaining normal GI function

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12
Q

What is the formula for carbohydrate?

What does carbohydrate contain?

A

(CH20)n
Aldehyde or keto groups
Multiple OH groups

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13
Q

What is a monosaccharide?

A

A single sugar unit e.g. glucose

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14
Q

How many carbons do the following monosaccharides contain?
Triose sugar
Pentose sugar
Hexose sugar

What is glucose classified as?

A

Triose = 3 carbons
Pentose = 5 carbons
Hexose = 6 carbons
Glucose contains 6 carbons so is a hexose sugar

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15
Q

What are disaccharides?

A

2 simple sugar units linked together (2 monosaccharides)

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16
Q

What are oligosaccharides?

A

3-12 simple sugar units linked together

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17
Q

What are polysaccharides? Give 3 examples

A

More than 10 simple sugar units linked together - up to thousands
e.g. cellulose, starch and glycogen

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18
Q

What 2 sugars make up the disaccharide sucrose (table sugar)?
What 2 sugars make up the disaccharide lactose (milk sugar)?

A 
Sucrose = glucose-fructose
Lactose = galactose-glucose
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19
Q

What is fructose and what form of sugar is it?

A

Fruit sugar

Monosaccharide

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20
Q

Maltose is a disaccharide. What sugars compose it?

A

Glucose-glucose

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21
Q

What does digestion break protein down into?

A

Amino acids which enter the bloodstream

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22
Q

What are essential amino acids and how many are there?

A

They are AAs that we cannot synthesise (can only be obtained from our diet)
9 out of 20 AAs in our body are essential

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23
Q

Try and name as many of the essential AAs as you can

Clue = If learned this huge list may prove truly valuable

A 
Isoleucine
Lysine
Threonine
Histidine
Leucine
Methionine
Phenylalanine
Tryptophan
Valine
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24
Q

What does conditionally essential mean when referring to AAs?

A

They are essential at periods of rapid growth

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25
Q

What 3 AAs may pregnant women and children also require?

A

Arginine
Tyrosine
Cysteine
As they cannot be synthesised at the required rate

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26
Q

Give an example of a high quality and low quality source of protein. Why are they classified in this way?

A

High = animal origin
Low = plant origin
High contain all essential AAs
Low are deficient in one or more essential AAs

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27
Q

What are triacylglycerols?

A

3 fatty acids esterified to one glycerol (compose lipids)

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28
Q

What are the fat soluble vitamins?

A

A D E and K

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29
Q

Give 2 examples of essential fatty acids

A

Linoleic

Linolenic

30
Q

What are the 3 major electrolytes?

A

Sodium
Potassium
Chloride

31
Q

What is the routine maintenance (IV fluids) for

1) the key electrolytes
2) water

A

1) 1 mmol per kg per day (of each = sodium, potassium and chloride)
2) 30ml per kg per day

32
Q

What causes the disease pellegra?

A

Deficiency in niacin vitamin

33
Q

Deficiencies in which 2 vitamins can cause anaemia?

A

B12

Folate

34
Q

Why can’t humans break down the polysaccharide cellulose? (a polymer of glucose)

A

Because humans don’t have the enzymes needed to break down the beta-1,4 links in cellulose

35
Q

What is the RNI and what is it used for?

A

Reference Nutrient Intake

Used for proteins, vitamins and minerals

36
Q

What is EAR and what is it used for?

A

Estimated Average Requirement
Used for energy
Is the approximate value that the mean person requires (50% will require more)

37
Q

What is LRNI?

A

Lower reference nutrient intake
Intakes below this are insufficient for most people
It is the what the average person at 2.5% on graph requires

38
Q

What is RNI?

A

Reference nutrient intake

It is what the average person at 97.5% on the graph requires

39
Q

How is daily energy expenditure calculated?

3 measurements

A

1) BMR - basal metabolic rate
2) DIT - diet induced thermogenesis (energy to process food)
3) PAL - physical activity levels

40
Q

How is BMI calculated?

A

Body Mass Index

BMI = weight (kg) / height2 (m2)

41
Q

What is the normal fasting plasma concentration for glucose?

A

3.3-6.0 mmol/L

42
Q

What is the enzyme in saliva and what does it do?

A

Amylase

Breaks down starch and glycogen into dextrins

43
Q

What is broken down in the small intestine and what are the enzymes involved?

A

Amylase is secreted through ducts in the pancreas into the duodenum which breaks down monosaccharides (breaks down the alpha-1,4 bonds)
The cells attached to the villi of epithelium secrete disaccharidases which break down glucose lactose and maltase

44
Q

What causes a lactose intolerance?

A

Lack of enzyme lactase so the lactose is not broken down properly

45
Q

Explain the following:

1) Primary lactose deficiency
2) Secondary lactose deficiency
3) Congenital lactose deficiency

A

1) an absence of lactase persistence allele (can’t break down lactose)
2) caused by injury to small intestine
3) extremely rare - autosomal recessive defect in lactase gene means baby cannot digest breast milk

46
Q

Active transport is used in small intestines to move monosaccharides into bloodstream across 2 sides of the epithelium lumen. What are these sides and what are the transporters?

A

1) Apical side (facing lumen of small intestines) = the SGLT1 transporter is used (sodium dependent glucose transporter 1) where co transport of 2 sodium ions with 1 glucose
2) Basolateral side = the GLUT2 transporter used to move into blood supply (uniport)

47
Q

How is glucose taken up in the cells from the blood?

A

Via facilitated diffusion (GLUT1-5 transporters)

48
Q

Where are GLUT2 tranporters primarily found?

A

In the kidney, liver, pancreatic beta cells and small intestine

49
Q

Where are GLUT4 transporters primarily found?

A

In adipose tissue, skeletal muscle and insulin regulated

50
Q

Give 4 examples of cells for which glucose is an absolute requirement (only source of energy)

A

1) Erythrocytes
2) Neutrophils
3) Innermost cells of kidney medulla
4) Lens of the eye

51
Q

What is glycolysis?

A

Oxidation of glucose (monosaccharide) to 2 pyruvate molecules

52
Q

What is the net gain of ATP in glycolysis?

A

2
First reaction in glucose catabolism uses 2 ATP molecules
2nd reaction creates 4 ATP molecules

53
Q

How many units of NADH are produced during glycolysis?

A

2 NADH molecules per 1 molecule of glucose

54
Q

What are the 3 key enzymes in glycolysis and what intermediaries do they convert?

A
  1. Hexokinase (glucokinase in liver)
    Converts glucose into Glucose-6-phosphate
  2. Phosphofructokinase-1
    Concerts Fructose-6-phosphate into Fructose 1,6-bis-phosphate
  3. Pyruvate kinase
    Coverts Phosphoenolpyruvate into Pyruvate
55
Q

What does phosphorylation of glucose to glucose-6-phosphate do?

A

Makes glucose negatively charged

Prevents glucose moving back across cell down concentration gradient

56
Q

What does having a large negative delta G mean?

A

That the reaction is irreversible

57
Q

What enzyme is the key regulator of glycolysis?

A

Phosphofructokinase

58
Q

In which 2 ways is phosphofructokinase regulated?

A
  1. Allosteric regulation
    (High ATP = inhibits PFK activity, high AMP = stimulates PFK activity)
  2. Hormonal regulation
    (Large intake of nutrients = stimulation of activity of PFK by insulin, and inhibited by glucagon)
59
Q

Explain how levels of NADH and NAD+ are metabolically regulates

A

High levels of NADH or low levels of NAD+ = high energy signals
Cause inhibition of glycolysis

60
Q

How is the enzyme pyruvate kinase regulated?

A

Activity of enzyme increases when there is a high insulin:glucagon ratio e.g. high levels of insulin and low levels of glucagon

61
Q

Where is glucagon produced and what does it do?

A

It is a hormone produced by alpha cells of the pancreas

It raises the levels of glucose in the bloodstream (causes liver to convert stores glycogen into glucose)

62
Q

Where is insulin produced and what does it do?

A

It is a hormone produced by beta cells of the pancreatic islets of langerhans
Promotes the absorption of glucose and anabolism (converting glucose into glycogen stores)

63
Q

NAD+ is needed in glycolysis as it converts to NADH. NAD+ can be regenerated from 2 routes what are they?

A

Regenerated from NADH

Regenerated by lactate dehydrogenase (LDH)

64
Q

What does lactate dehydrogenase convert?

A

NADH + H+ + pyruvate –> NAD+ + lactate

65
Q

What is the process called when pyruvate is converted back to glucose and where does this take place?

A

Glucogenesis

In the liver and kidney

66
Q

What is lactic acidosis and what does it cause?

A

It is a plasma lactate level of over 5mM (above the renal threshold level = kidneys can no longer excrete it)
It lowers the blood pH

67
Q

Deficiency in which 3 enzymes can cause galactosaemia?

A
  1. Glactokinase
  2. Uridyl tranferase
  3. UDP-galactose epimerase
68
Q

What are the 2 main enzymes involved in metabolising fructose?

A

Fructokinase

Aldolase

69
Q

What is essential fructosuria?

A

Missing enzyme fructokinase

Leads to fructose in urine but no clinical signs

70
Q

What is fructose intolerance?

A

Missing enzyme aldolase

Fructose-1 phosphate accumulates in the liver and can lead to liver damage

71
Q

What enzyme is the start of the pentose phosphate pathway and what does it convert?

A

Glucose 6 phosphate dehydrogenase enzyme

Converts glucose 6 phosphate to 6-phosphogluconolactone

72
Q

What is the end product of the pentose phosphate pathway and what does it produce along the way?

A

Along the way NADPH is produced (needed for fatty acid and steroid biosynthesis)
Pentose phosphate pathway produces ribose 5 phosphate (needed for DNA and RNA synthesis)

Metabolism - Alex's Cards (ESA2) (8 decks)

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