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Week 10 > Energy and Metabolism > Flashcards

Energy and Metabolism Flashcards

1
Q

what is the first law of thermodynamics

A

energy can neither be created nor destroyed but is transferred from one form to another or from one place or another

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2
Q

what is the second law of thermodynamics

A

energy doesn’t transform without entropy in the universe (usually lost as heat)

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3
Q

what is metabolism

A

the sum of all chemical reactions in which energy is made available and consumed in the body

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4
Q

examples of metabolism

A

oxidation of fuel to CO2 and water
- achieved by a series of biochemical reactions
production of energy (ATP) and loss of energy (heat)

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5
Q

what does the body need energy for

A

contraction of muscle
- skeletal, cardiac, smooth -> blood vessels and gut
accumulation of ions and other molecules against conc. gradients (nerve impulses)
biosynthesis -> building of tissues
waste disposal -> getting rid of the end products of bodily function
generation of heat -> maintenance of body temperature

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6
Q

reaction to create glucose 6 phosphate

A

glucose + PO4^2 –> glucose 6 phosphate
reaction cannot happen spontaneously because the energy of the products is higher than the sum of the energy of the reactants
in order for this equation to become spontaneous, we need to couple it with another equation
ATP -> ADP + PO4 2-

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7
Q

rules of gibbs free energy

A

if the product contains more energy than the substrate -> delta G is +ve
if the product contains less energy than the substrate -> delta G is -ve

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8
Q

is the catabolism of nutrients exergonic or endogonic?

A

exergonic
the cells can harness this energy as ATP

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9
Q

ATP basic info

A

energy currency of living organisms
- hydrolysis to give ADP and Pi liberates a large amount of energy

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10
Q

ATP equations

A

ATP (+ H2O) –> ADP + Pi
- delta G = -30kJ/mol
- in cells, delta G = -50kJ/mol
ADP + Pi –> ATP + H2O
- delta G = +30kJ/mol
- in cells +50 kJ/mol

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11
Q

endergonic definition

A

products of greater free energy than the reactants; non-spontaneous

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12
Q

free energy definition

A

the energy available in a system to do useful work

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13
Q

exergonic definition

A

reactants of greater free energy than the products; spontaneous

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14
Q

The tricarboxylic acid cycle (TCA)

A

also known as Krebs cycle
acetyl CoA (2 carbon) condenses with oxaloacetate (4 carbon) to produce citrate (6 carbon)
this occurs in 2 phases
- deoxycarbylation (citrate -> succinyl CoA (4 C )) -> 2 C molecules lost as CO2
- reductive (succinyl CoA to oxaloacetate)

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15
Q

what is the overall reaction for TCA

A

acetyl CoA + 3NAD+ + FAD + GDP + Pi + 2H2) –> CoA + 2CO2 + 3NADH + FADH2 + GTP (ATP) + 3H+

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16
Q

what are the products of 1 turn of TCA cycle

A

3 x NADH
1 x FADH2
^ molecules produce ATP in the ETC

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17
Q

what are the main components of the ETC

A

four protein complexes
ATP synthase
intermembrane space in mitochondria
FADH2
NADH
H+
co-enzyme Q
cytochrome C

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18
Q

progress of e- through the ETC

A

intermembrane has a higher conc. of protons because of pump
1- co-enzymes donate 2e- and H+ to the ETC
2- electrons passed through redox centre (in the complex)
- moved between redox centres
- each one has a higher affinity
- produces ATP (used to pump protons against conc. gradient)
3- co-enzyme Q passes the electrons to the next protein complex (1-> 2 -> 3)
4- cytochrome C -> complex 4
5- when e- reaches the end of complex 4
- 2H+ + 1/2O2 -> H2O
O2 is the terminal electron carrier

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19
Q

where does FADH2 enter the ETC

A

complex 2

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20
Q

what is oxidative phosphorylation

A

ATP synthase
- only way H+ can get back into matrix
- ADP + Pi -> ATP
- main generator of ATP

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21
Q

what is the ATP yield of the TCA (incl. ETC)

A

produced by substrate level phosphorylation: 1 GTP (equal to ATP) + 3NADH + 1FADH
generally accepted that each___ oxidised by the ETC produces
- NADH = 2.5 ATP
- FADH2 = 1.5 ATP
- therefore, the total yield/ acetyl CoA is 1 + (3 x 2.5) + (1 x 1.5) = 10 ATP

22
Q

what is glycolysis

A

glucose -> pyruvate (3 C)
occurs in the cytosol of cells
- can occur in all cells (e.g. RBCs and cells with shortage of O2)
exogonic reaction
2 phases
- endogonic (ATP investment)
- exogonic (generation)

23
Q

describe the process of ATP investment (stage 1 of glycolysis)

A

glucose –> glucose 6 phosphate
- hexokinase, uses 1 ATP
glucose 6-phosphate –> fructose 6 phosphate
- phosphoglucose isomerase (reversable)
fructose 6 phosphate –> fructose 1,6 bisphosphate
- phosphofructokinase, uses 1 ATP
fructose 1,6 bisphosphate –> dihydroxyacetone phosphate
- triose phosphate isomerase
OR
fructose 1,6 phosphate –> glyceraldehyde 3 phosphate
- aldolase

24
Q

describe the process of generation (stage 2 of glycolysis)

A

glyceraldehyde 3 phosphate –> 1,3 bisphosphoglyceral
- glyceraldehyde 3-phosphate dehydrogenase, catalyses PNAD+ conversion to NADH (reversible)
1,3 bisphosphoglyceral –> 3-phosphoglycerate
- phosphoglycerate kinase, catalyses ADP conversion to ATP (reversible)
3-phosphoglycerate –> 2-phosphoglycerate
- phosphoglycerate mutase (reversible)
2-phosphoglycerate –> phosphoenolpyruvate
- enolase, produces H2O (reversible)
phosphoenolpyruvate –> pyruvate
- pyruvate kinase, catalyses ADP -> ATP

25
Q

outline the anaerobic conditions of glycolysis

A

pyruvate is converted to lactate
- regenerated NAD+ (oxidised form) to keep glycolysis going
- ATP is localised -> each cell needs to make it for itself

26
Q

describe fermentation

A

glucose –> 2 pyruvate
- glycolysis
- 2ADP + 2Pi –> 2ATP
- 2NAD+ + 2NADH +2H+ ]

2 pyruvate –> 2 lactate
- 2NADH + 2H+ -> 2NAH+

27
Q

overall equation for anaerobic glycolysis

A

C6H12O6 + 2ADP + 2Pi –> 2 lactate + 2ATP

28
Q

describe process of the link reaction

A

pyruvate is transported into the mitochondrion and converted to acetyl CoA by the action of pyruvate dehydrogenase
(1- pyruvate enters the mitochondrion through a transport protein
2- CO2 produced
3- NAD+ –> NADH + H+
4- CoA reacts
5- acetyl CoA produced)

29
Q

overall reaction of the link reaction

A

CH2-CO-CO2- (pyruvate) + NAD+ + CoASH -> CH3-CO-SCoA (acetyl CoA) + CO2 + NADH

30
Q

describe fatty acid degradation

A

beta-oxidation
1- 16 C long chain (palmitic acid)
2- carbon backbone cleaved between the alpha and beta carbons (proximal to the carboxy terminus)
3- forms acetyl CoA
4- oxidation reaction
happens 7 times
produces 8 acetyl CoA molecules

31
Q

overall products of one C16 molecule (palmitic acid)

A

b-oxid -> 7 x NADH + 7 x FADH2 + 8 x AcCoA
TCA -> 8 x (3 x NADH) + (1 x FADH2) + (1 x ATP)
total -> 31 NADH + 15 FADH2 + (8 x ATP) - 2 x ATP + (31 x 2.5 ATP) + (15 x 1.5 ATP) + 6 ATP
= 106 ATP

32
Q

simplified process of fatty acid metabolism

A

1- fatty acids are transported in the blood as a complex with albumin (most prolific plasma protein) (to make it hydrophilic) and are taken up by cells for oxidation
2- fatty acid modification (essential for entry into mitochondria) and entry into mitochondria
3- B-oxidation leading to energy (ATP) formation

33
Q

detailed fatty acid metabolism

A

1- free fatty acid + CoA + 2ATP –> fatty acyl CoA (acyl-CoA synthase)
2- fatty acyl CoA –> fatty acyl carnitine (carnitine -> CoA)
3- fatty acyl carnitine enters mitochondrial matrix through transport protein
4- fatty acyl carnitine –> fatty acyl CoA (CoA –> carnitine)
5- fatty acid degradation

34
Q

what are the two stages of protein metabolism

A

transamination and deamination

35
Q

describe transamination

A

important because it releases the carbon backbone to be turned into intermediates of the Krebs cycle
a-ketoglutarate most common to accept residue
- produces glutamate (PROTEIN) and a-ketoacid
- alanine -> pyruvate
- aspartate -> oxaloacetate
- all the intermediates of the Krebs cycle

36
Q

describe deamination

A

in the liver
production of ammonium
cells have to be able to remove ammonium -> turns into urea
glutamate -> a-ketoglutarate

37
Q

what are glucogenic acids

A

glucose
pyruvate
oxaloacetate
intermediate of TCA

38
Q

what are ketogenic acids

A

fatty acids
acetyl CoA
acetoacetyl CoA
only lysine and leucine are totally ketogenic

39
Q

what happens to a-ketoacids

A

after they have been converted into intermediates they then
- TCA cycle
- recycled for fatty acid synthesis
gluconeogenesis

40
Q

metabolic adaptations to starvation

A

1- fat -> triglycerides in adipose tissue which is sufficient to prolong life for 3 months
2- protein -> provides approx. 14 days’ worth of energy but is spared for as long as possible to permit mobility
other sources: glycogen, glucose

41
Q

what is the basal energy expenditure (BEE)

A

used to estimate the energy required to maintain basic functions
- also known as basal metabolic rate (BMR)
- when the person is lying down, relaxed (not asleep), in a normal ambient temperature

42
Q

what is the equation for calculation BEE for males

A

BEE = 66.5 + 13.75W + 5.003H - 6.775A

43
Q

what is the equation for calculation of BEE in females

A

BEE = 655.1 + 9.563W + 1.850H - 4.676A

44
Q

BMI basic info

A

body mass index
BMI = W/H2
- weight in Kg
- height in M
<20 = underweight
20-25 = ideal weight
25-30 = overweight
>30 = obese

45
Q

why is the BMI not always a good measure of an individual

A

doesn’t account for muscle mass/ cardiovascular condition
although helpful, should be used with some degree of caution

46
Q

fatigue symptoms

A

tiredness
lack of energy
weakness
exhaustion
sleepiness
some of the causes are metabolic in nature

47
Q

what causes fatigue in short bursts of exercise

A

phosphocreatine depletion

48
Q

what causes fatigue in middle bursts of exercise

A

phosphocreatine depletion and proton accumulation

49
Q

what causes fatigue in long times of exercise

A

glycogen depletion

50
Q

explanation of phosphocreatine depletion

A

entropy and loss of energy of heat
- depletes energy stores in the body
- phosphocreatine used when ATP is depleted (only for a short time)
- stored ATP only lasts for about 2 seconds in sprinting

51
Q

explanation of glycogen depletion

A

anaerobic glycolysis of stored glycogen starts to occur as the length of run increases
- lactic acid
- reduces the pH of the blood
- only short time

52
Q

what happens in intense sustained exercise

A

glycogen stores are depleted
hitting the wall
move to fat metabolism

Week 10 (3 decks)

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