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Fundamentals Block 3 > Intro to metabolism > Flashcards

Intro to metabolism Flashcards

1
Q

the principal donor of free energy in biological systems

A

ATP

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2
Q

used primarily to generate ATP

A

NADH

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3
Q

used primarily in reductive biosynthesis

A

NADPH

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4
Q

what causes PKU

A

there’s a defect in phenylalanine hydroxylase so phenylalanine can’t be degraded and tyrosine cant be made
-tetrahydrobiopterin is a cofactor

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5
Q

what is downregulated in PKU

A

-tissue proteins
-melanin
-catecholamine
-fumarate acetoacetate

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6
Q

what is upregulated in when phenylalanine is not degraded?

A

phenylpyruvate, phenyllactate, phenylacetate
-toxic compounds in neurological tissue that cause intellectual disabilities

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7
Q

how is tetrahydrobiopterin synthesized

A

in the body from GTP

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8
Q

what is the treatment for PKU?

A

-restrict phenylalanine in diet (not completely)
-supplement with tyrosine

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9
Q

if you discontinue your tyrosine rich diet, what you happen to you?

A

your IQ can decline

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10
Q

atypical non-classical malignant phenylketonuria

A

-defect in either the synthesis of tetrahydrobiopterin or dihydropterin reductase, which regenerates the cofactor
-severe CNS disorders that don’t respond to diet change

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11
Q

how can neurological symptoms that arise from atypical PKU be resolved?

A

L-dopa and 5-hydroxytryptophan

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12
Q

THB is a cofactor that is required for synthesis for________________________________

A

dopamine, epinephrine, norepinephrine, and serotonin

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13
Q

the absorptive state

A

-store energy as fat
-perform anabolic reactions (repair what might’ve broken down during fast)
-fed state after meal

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14
Q

the fasting state

A

-maintain blood glucose
-limit proteolysis

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15
Q

glycolysis

A

metabolize glucose to pyruvate + energy

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16
Q

gluconeogenesis

A

synthesize glucose from precursors

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17
Q

fatty acid oxidation

A

Metabolize fatty acids to acetyl CoA + energy

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18
Q

citric acid cycle

A

metabolize acetyl CoA to carbon dioxide + energy

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19
Q

glycogenesis

A

convert glucose to glycogen for storage

20
Q

glycogenolysis

A

convert glycogen to glucose when needed

21
Q

pentose phosphate pathway

A

convert glucose to ribose-5-phosphate for nucleotide synthesis + energy + NADPH

22
Q

ketone body synthesis

A

produce an alternative energy source during starvation

23
Q

oxidative phosphorylation

A

convert energy to ATP

24
Q

urea cycle

A

convert excess ammonia to urea for excretion

25
Q

what is stage 1 of catabolism

A

Complex macromolecules of starch, protein,
and triacylglycerols are broken down into smaller units,
such as monosaccharides, amino acids, glycerol, and
fatty acids. During this stage, little or no free energy
is trapped.

26
Q

what is stage 2 of catabolism

A

The simple molecules of different kinds are
catabolized to a few molecules that can be oxidized to
carbon dioxide and water along a common pathway. In
this stage, some free energy is trapped as ATP.

27
Q

what is stage 3 of catabolism

A

It consists of the citric acid cycle, the electron
transport system and oxidative phosphorylation.
Together, these processes oxidize acetyl CoA to CO2
and water, and produce most of the ATP in the cell.

28
Q

where are pathways compartmentalized

A

-cytosol (glycolysis, pentose phosphate pathway, fatty acid synthesis)
-mitochondrial matrix (citric acid cycle, oxidative phosphorylation, oxidation of fatty acids, ketone body formation)
-cytosol plus mitochondrial matrix (gluconeogenesis, urea cycle)

29
Q

signals the fed state, the availability of glucose in the blood

A

insulin

30
Q

signal the fasting state in which the level of glucose in the blood is low

A

glucagon and epinephrines

31
Q

signals stressful states when mobilization of fuel is required

A

epinephrine

32
Q

what are some non-hormonal regulation of metabolic pathways

A

-availability of substrates
-allosteric control
-gene expression

33
Q

interplay of hormonal and non-hormonal regulation of metabolic pathways

A

-covalent modification: hormone-triggered reaction cascades result in the covalent modification of a key enzyme of a pathway
-ex. glucose—->glycogen glycogen—->glucose

34
Q

glucose —-> glycogen (fed state)

A

glycogenesis

35
Q

glucose —–> pyruvate (fed state)

A

glycolysis

36
Q

glycogen —-> glucose (fasting state)

A

glycogenolysis

37
Q

pyruvate —-> glucose (fasting state)

A

gluconeogenesis

38
Q

flow of key metabolic intermediates

A

glucose 6-phosphate
pyruvate
acetyl CoA

39
Q

what are the different pathways that glucose 6-phosphate is involved in?

A

-glucose in gluconeogenic tissues
-glucose 1-phosphate used in glycogen synthesis
-pyruvate via glycolysis
-ribose 5-phosphate for nucleotide synthesis, via pentose phosphate pathway

40
Q

what pathways is pyruvate involved in?

A

-oxaloacetate and metabolized via the citric acid cycle
-acetyl coA by pyruvate dehydrogenase
-alanine via transamination
-lactate in muscle tissue

41
Q

what pathways is acetyl coA involved in?

A

-oxidized to CO2 via the citric acid cycle
-fatty acid synthesis
-3-hydroxy-3-methylglutary CoA, a precursor of cholesterol, ketone bodies

42
Q

liver in metabolism

A

-maintenance of blood glucose levels
-during fed state, it takes up excess glucose and stores it as glycogen or converts it to fatty acids
-during the fasting state, it exports glucose derived from glycogen and gluconeogenesis
-fatty acid synthesis
-ketone body synthesis during fasting state
-synthesis of plasma lipoproteins

43
Q

skeletal muscle in metabolism

A

-maintains large stores of glycogen which provide a source of glucose for energy during exertion
-in resting muscle the preferred fuel is fatty acids
-muscle protein may be mobilized as a fuel source

44
Q

heart muscle in metabolism

A

contains essentially no fuel reserves and must be continuously supplied with fuel from the blood, primarily fatty acids

45
Q

adipose in metabolism

A

-primary function is storage of metabolic fuel in the form of triacylglycerols
-during the fed state, it synthesizes triacylglycerols from glucose and fatty acids
-during the fasting state triacylglycerols are converted to glycerol and fatty acids

46
Q

brain in metabolism

A

-normally uses glucose as an exclusive fuel, except during starvation when it can adapt to use ketone bodies
-contains essentially no fuel reserves and must be continuously supplied with fuel from the blood

Fundamentals Block 3 (15 decks)

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