ch 5. cellular respiration and metabolism

part 1 ; practice oxidative phosp

What is metabolism?

sum of all reactions in an organism

What is anabolism?

energy input; large molecules synthesis

making larger molecules from smaller ones; building things

What is catabolism?

energy output; breakdown of large molecules

all the chemical reactions involved with breaking down large to small

What is glycolysis?

occurs in cytoplams; anaerobic

What is citric acid Krebs cycle?

occurs in mitochondrial matrix; aerobic O2

What is electron transport?

occurs on cristae of mitochondrial inner membrane; aerobic

What happens in glycolysis?

Glucose (6C) → 2 Pyruvate (3C each)

glucose + 2 ADP (the reason the step is energy investment as you have to use atp to make more n get the process started)

+2 pyruvid acid + 2 NADH + 2 ATP (energy payoff)glyoclytic ac

 What happens to pyruvate in mitochondria?

Pyruvate → Acetyl-CoA → enters TCA cycle → fully oxidized to CO₂.

this step harvests high-energy electrons for oxidative phosphorylation.

Which of the following is a zymogen?

Pepsinogen

What happens in ETC?

NADH & FADH₂ → donate electrons to electron carriers in inner mitochondrial membrane

Which of the following is CORRECT?

ATP hydrolysis can drive endergonic reaction

Divide glycolysis into 3 phases.

1. Energy investment: 2 ATP used to phosphorylate glucose → fructose-1,6- bisphosphate

2. Cleavage phase: 6C sugar split into two 3C molecules (G3P)

3. Energy payoff: 4 ATP + 2 NADH produced → net 2 ATP

 Why is ATP both a substrate and inhibitor in glycolysis?

ATP is used for phosphorylation but also signals energy sufficiency, inhibiting PFK-1 to prevent unnecessary glucose breakdown.

What is the net yield per glucose molecule?

• 2 ATP (net)

• 2 NADH

• 2 Pyruvate

What is lactic acid fermentation?

anaerobic process in which pyruvate is reduced to lactate to regenerate NAD⁺, allowing glycolysis to continue.

Key point: no additional ATP beyond glycolysis, main purpose is NAD⁺ regeneration.

 Why do cells perform lactic acid fermentation?

• Allows glycolysis to continue without oxygen

• Produces 2 ATP per glucose for quick energy

• Lactate can later be converted back to pyruvate in the liver (Cori cycle)

How much ATP is produced per glucose via glycolysis + lactic acid fermentation?

2 ATP per glucose (substrate-level phosphorylation).

What happens to pyruvate after glycolysis under aerobic conditions?

• Transported into mitochondrial matrix

• Converted to Acetyl-CoA by pyruvate dehydrogenase complex (PDC)

• NAD⁺ → NADH (reducing equivalents)

• CO₂ released

What is the product of the kreb cycle?

3 NADH, 1 FADH, 1 ATP

What does oxidative phosphorylation do?

FADH2 and NADH donate e - go down etc and release energy - drives atp production

What is chemiosmotic theory?

energy from e descent used to pump H+ into intermembrane space - through ATP synthase = atp made