Biochemistry Chapter 8: Aerobic Carbohydrate Metabolism Flashcards

1
Q

What do diabetic patients rely on for metabolism if in a state of extended hyperglycemia?

A

Fat metabolism. Therefore, ketones will be found in the urine

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2
Q

Dysglycemia

A

refers to abnormal blood glucose levels, encompassing both hyperglycemia (high blood sugar) and hypoglycemia (low blood sugar), often associated with conditions like diabetes or metabolic syndrome.

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3
Q

True or false: GLUT2 transport protein is expressed primarily in the liver and pancreas. Therefore, GLUT2 deficiency would result in stunted growth.

A

TRUE. The signaling required for glucose metabolism would be unable to effectively provide glucose to growing tissues, and glycogen stored in the liver could not be effectively released to tissues, so avoiding significant complications for a growing child would require the strictest possible dietary monitoring

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4
Q

Cyanide poisoning is the result of an impaired

A

ETC function

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5
Q

Substrate level phosphorylation

A

Add phosphate group to derivative of glucose and then add ADP

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6
Q

Oxidative Phosphorlaytion

A

NADH FADH2 etc are oxidized to create a proton gradient and then pumped back through ATP synthase to catalyze phosphorlyation of ADP into ATP

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7
Q

ETC requires oxygen _______ whereas krebs cycle require oxygen _________

A

Directly, indirectly

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8
Q

Goal of the Krebs Cycle

A

is to generate high-energy electron carriers (NADH and FADH₂) and intermediates for ATP production, which fuel the process of oxidative phosphorylation in cellular respiration

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9
Q

Location of Krebs Cycle

A

In eukaryotes, mitochondrial matrix

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10
Q

Pyruvate dehydrogenase complex (PDC)

A

converts pyruvate to acetyl-CoA before entering citric acid cycle → 1 NADH generated.

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11
Q

Net products of Critic Acid Cycle per turn

A

1 GTP, 3 NADH, 1 FADH₂, 2 CO₂.

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12
Q

Stoichiometry: each glucose molecule = how many turns of the TCA?

A

2 turns of citric acid cycle.

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13
Q

Citric Acid cycle is a metabolic crossroads in the body because

A

Byproducts of other molecules (lipids, proteins) can enter into citric acid cycle, and intermediates of citric acid cycle are precursors for other metabolic processes

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14
Q

Start of citric acid cycle

A

acetyl-CoA (2C) + oxaloacetate (4C) → citrate (6C)

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15
Q

Step 3 citric acid cycle

A

isocitrate (6C) → α-ketoglutarate (5C)

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16
Q

Step 4 citric acid cycle

A

α-ketoglutarate (5C) → succinyl-CoA (4C)

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17
Q

Principle of ETC

A

electrons transferred along series of carriers, moving from carriers with lower reduction potentials to those with higher reduction potentials

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18
Q

ETC is like what kind of electrochemical cell

A

similarly to a galvanic cell

19
Q

Energy from ETC

A

pumps protons into intermembrane space, creating proton gradient

20
Q

Electron transfer in the ETC involves what structures?

A

Complexes I, II, III, IV are embedded in inner mitochondrial membrane, and together with electron carriers Q and cytochrome c are used in electron transfer

21
Q

Final electron acceptor in ETC

A

Oxygen is the final electron acceptor in the ETC and is reduced to H₂O.

22
Q

Electrochemical energy of proton gradient is used to power

A

is used to power ATP synthase, which attaches a phosphate group to ADP to form ATP.

23
Q

↑ATP, ↑products of citric acid cycle =

A

↓citric acid cycle

24
Q

↑ADP (showing that cell needs energy)

A

↑citric acid cycle

25
Q

↑ADP = ____ oxidative phosphorylation

A

↑ETC/oxidative phosphorylation.

26
Q

electron transport chain (ETC) takes place

A

across the inner mitochondrial membrane, specifically between the mitochondrial matrix and the intermembrane space

27
Q

goal of the electron transport chain

A

To generate a proton gradient (H⁺ gradient) across the inner mitochondrial membrane, which drives the synthesis of ATP

28
Q

Input and Output of Krebs Cycle (per 1 turn)

A

Input:

1) Acetyl-CoA (2-carbon molecule): Derived from pyruvate via the pyruvate dehydrogenase complex.
2) Oxaloacetate (4-carbon molecule): Combines with acetyl-CoA to form citrate.
3) 3 NAD⁺: Electron carrier that gets reduced to NADH.
4) 1 FAD: Electron carrier that gets reduced to FADH₂.
5) 1 GDP (or ADP): Used to form GTP (or ATP) via substrate-level phosphorylation.
6) 2 H₂O: Water molecules used in enzymatic reactions during the cycle.

Output:
1) 2 CO₂: Released as byproducts of acetyl-CoA oxidation.
2) 3 NADH: High-energy electron carrier for the electron transport chain.
3) 1 FADH₂: High-energy electron carrier for the electron transport chain.
4) 1 GTP (or ATP): Usable energy via substrate-level phosphorylation.
5) Oxaloacetate: Regenerated to combine with another acetyl-CoA for the next cycle.

29
Q

Net Inputs and Outputs for 1 Glucose

A

Since 1 glucose molecule produces 2 acetyl-CoA molecules, the Krebs cycle runs twice per glucose

Inputs (2 Turns of Krebs Cycle for 1 Glucose):
2 Acetyl-CoA
6 NAD⁺
2 FAD
2 GDP (or ADP)
4 H₂O

Outputs (2 Turns of Krebs Cycle for 1 Glucose):
4 CO₂
6 NADH
2 FADH₂
2 GTP (or ATP)
2 Oxaloacetate (regenerated)

30
Q

ATP per NADH

A

2.5 molecules

31
Q

ATP per FADH2

32
Q

Grand Total ATP Yield per Glucose

33
Q

pyruvate decarboxylation produces

A

acetyl CoA for the Citric Acid Cycle

34
Q

The electron carriers in the ETC can transport a maximum of ____ electrons

35
Q

UTP tags glucose for what

A

Glycogen synthesis

36
Q

ATP consists of three phosphate groups:

A

ATP consists of three phosphate groups:

α-phosphate (alpha) – directly attached to the ribose sugar.
β-phosphate (beta) – middle phosphate.
γ-phosphate (gamma) – outermost phosphate.

37
Q

Can Glutamate be used in the krebs cycle?

A

Yes, Glutamate is converted into α-ketoglutarate, which enters the Krebs cycle (TCA cycle) to generate ATP.

38
Q

Complex I ETC name

A

NADH: ubiquinone oxidoreductase

39
Q

Complex 2 ETC name

A

succinate dehydrogenase

40
Q

Complex III ETC name

A

Ubiquinol–cytochrome c oxidoreductase

41
Q

Complex IV ETC name

A

cytochrome c oxidase

42
Q

How is ATP electrophilic even though it has a negative charge?

A

Despite being negatively charged, the phosphorus atom in ATP’s phosphate groups is still electron-deficient due to electronegative oxygen atoms pulling electron density away.

Electrostatic strain from negative charges makes ATP’s γ-phosphate highly reactive.

Magnesium ions (Mg²⁺) help stabilize negative charge, further increasing ATP’s electrophilicity.

Resonance stabilization in phosphate groups makes ATP hydrolysis favorable, encouraging nucleophilic attack.

43
Q

End result of the Conversion of 1 pyruvate to Acetyl-CoA

A

1 NADH is produced

1 CO₂ is released

1 Acetyl-CoA is formed