DAT BIO Cellular Energy

First law of thermodynamics?

Energy cannot be created or destroyed, only transformed

Second law of thermodynamics?

Entropy (disorder) of the universe is always increasing

Third law of thermodynamics?

Entropy of a substance at absolute zero is zero

What is entropy?

Measure of disorder/randomness

What is metabolism?

All metabolic pathways occurring in an organism.

Catabolic reactions do what?

Break down molecules and release energy

Catabolic reactions increase or decrease entropy?

Increase entropy

Anabolic reactions do what?

Build larger molecules using energy

Anabolic reactions increase or decrease entropy?

Decrease entropy

Main function of mitochondria?

Produce ATP through cellular respiration

Cristae are what?

Folds of inner mitochondrial membrane

Krebs cycle occurs where?

Mitochondrial matrix

Electron transport chain occurs where?

Inner mitochondrial membrane

ATP stands for what?

Adenosine triphosphate

Components of ATP?

Adenine, ribose, 3 phosphate groups

ATP is considered what?

Cellular energy currency

ATP hydrolysis converts ATP into what?

ADP + phosphate

ATP hydrolysis releases or requires energy?

Releases energy

What is reaction coupling?

Using exergonic reactions to power endergonic reactions

Exergonic reactions have what ΔG?

Negative ΔG.

Endergonic reactions have what ΔG?

Positive ΔG

Overall stages of aerobic respiration?

Glycolysis → pyruvate decarboxylation → Krebs cycle → oxidative phosphorylation.

Final electron acceptor in aerobic respiration?

Oxygen (O₂)

Glycolysis occurs where?

Cytosol

Does glycolysis require oxygen?

No

Glycolysis occurs in aerobic, anaerobic, or both?

Both

Products of glycolysis?

2 ATP, 2 NADH, 2 pyruvate.

Glycolysis begins with what molecule?

Glucose

What is substrate-level phosphorylation?

ATP production by direct phosphate transfer to ADP.

Glycolysis has what two phases?

Energy investment phase and energy payoff phase

Glycolysis Steps — Hexokinase does what?

Phosphorylates glucose to glucose-6-phosphate

Glycolysis Steps — Why is glucose phosphorylated early in glycolysis?

Prevents glucose from leaving the cell

Glycolysis Steps — Glucose-6-phosphate is converted into what?

Fructose-6-phosphate

Glycolysis Steps — Key regulatory enzyme of glycolysis?

Phosphofructokinase (PFK).

Glycolysis Steps — Phosphofructokinase converts fructose-6-phosphate into what?

Fructose-1,6-bisphosphate

Glycolysis Steps — Fructose-1,6-bisphosphate splits into what?

Two G3P molecules

Glycolysis Steps — G3P oxidation produces what?

ATP, NADH, and pyruvate

Glycolysis Steps — Net ATP yield from glycolysis?

2 ATP

Glycolysis Steps — Total ATP produced during glycolysis?

4 ATP

Glycolysis Steps — ATP invested during glycolysis?

2 ATP

Pyruvate Decarboxylation — Pyruvate decarboxylation is also called what?

Pyruvate oxidation

Pyruvate Decarboxylation — Pyruvate decarboxylation occurs where?

Mitochondrial matrix

Pyruvate Decarboxylation — Enzyme responsible for pyruvate decarboxylation?

Pyruvate dehydrogenase

Pyruvate Decarboxylation — Products of pyruvate decarboxylation?

CO₂, NADH, acetyl-CoA.

Pyruvate Decarboxylation — What happens during decarboxylation?

CO₂ is removed.

Pyruvate Decarboxylation — What happens during oxidation?

NAD⁺ is reduced to NADH

Pyruvate Decarboxylation — Coenzyme A combines with what molecule?

Acetyl group

Pyruvate Decarboxylation — Acetyl-CoA enters what pathway next?

Krebs cycle

Krebs Cycle — Other names for Krebs cycle?

Citric acid cycle and TCA cycle

Krebs Cycle — Krebs cycle occurs where?

Mitochondrial matrix

Krebs Cycle — Main products per acetyl-CoA?

3 NADH, 1 FADH₂, 1 ATP, 2 CO₂.

Krebs Cycle — Acetyl-CoA combines with what to form citrate?

Oxaloacetate

Krebs Cycle — Citrate contains how many carbons?

6 carbons.

Krebs Cycle — Oxaloacetate contains how many carbons?

4 carbons.

Krebs Cycle — Citrate rearrangements produce what?

CO₂ and NADH.

Krebs Cycle — Krebs cycle ATP is produced by what mechanism?

Substrate-level phosphorylation

Krebs Cycle — FAD is reduced into what?

FADH₂.

Krebs Cycle — NAD⁺ is reduced into what?

NADH

Krebs Cycle — What molecule is regenerated in Krebs cycle?

Oxaloacetate