Cellular Respiration

Cellular Respiration Equation

C₆H₁₂O₆ + 6O₂ + ADP + P_i → 6H₂O + 6CO₂ + ATP + heat

How can metabolic activity be measured?

energy food eaten - wastes excreted; ATP produced; heat produced; amount of H₂O produced; amount of oxygen used up/carbon dioxide produced

What is the easiest way to measure metabolism?

gas exchange; amount of oxygen used up or carbon dioxide produced

Basal Metabolic rate (BMR)

rate at which an animal consumes oxygen while at rest, with an empty stomach, under normal temperature and moisture conditions

Metabolism is required for

a minimal resting lifestyle with no spontaneous activity, no digestion of food, and no physical thermal, or psychological stress

Maximum metabolic rate (MMR)

maximum rate at which oxygen can be transported from the environment to the tissue mitochondria; can be induced by activity/stress

Aerobic energy metabolism parameters

basal metabolic rate is the flood (lower) and maximum metabolic rate is the ceiling (higher)

Aerobic scope

capacity of an organism to increase its aerobic metabolic rate above maintenance level

Aerobic scope equation

MMR - BMR

Glucose

source of energy; produced from digestion of food; stored and oxidized to provide chemical energy

Site of cellular respiration or fermentation

cytoplasm & mitochondria

Mitochondria

organelles that are membrane-bound with two different membranes

Cristae

inner membrane highly folded

Glycolysis occurs in

cytoplasm

Glycolysis

glucose → pyruvate

Glycolysis products

2 pyruvate, 2 ATP, 2 NADH

If oxygen is present, pyruvate…

enters the mitochondria for citric acid cycle

If oxygen is not present, pyruvate …

undergoes fermentation

Fermentation

pyruvate → lactate

Fermentation products

lactic acid, 2 NAD+ (regenerates for glycolysis)

Link Reaction

pyruvate → Acetyl CoA; links the products of glycolysis with the aerobic processes of the mitochondria

Link Reaction Products

acetyl CoA, 2 NADH, 2 CO₂

Krebs Cycle = Citric Acid Cycle = TCA Cycle

Acetyl CoA produces NADH and FADH₂ molecules to feed electrons in Electron transport chain to generate cell’s ATP

Krebs Cycle = Citric Acid Cycle = TCA Cycle products

2 NADH, FADH₂, GTP → ATP, 2 CO₂

Electron Transport Chain (ETC)

final stage of aerobic respiration; releases energy stored within reduced hydrogen carriers to synthesize ATP; drives transport of protons across inner membrane from the matrix to intermembrane space for a proton gradient & electrons reduce O₂ to water; hydrogens pass through ATP synthase to produce ATP into the mitochondrial matrix

Where does link reaction occur?

mitochondria matrix

Where does Krebs cycle/Citric Acid Cycle/TCA Cycle occur?

mitochondrial matrix

Where does Electron Transport Chain occur?

inner mitochondrial membrane

Oxidative Phosphorylation

ETC releases energy stored within the reduced hydrogen carriers to synthesize ATP; derived from oxidation of hydrogen carriers (NADH, FADH₂)

Proton Gradient

higher concentration of protons (H⁺) in intermembrane space than in mitochondrial matrix

Final Electron Acceptor

oxygen

ATP Synthase

proton-driven rotor and ATP-generating enzyme; F₀ unit spins as protons pass through; shaft transmits the rotation to the F₁ unit, causing it to make ATP from ADP and P_i

Summary of Cellular Respiration

electrons carried by NADH & FADH₂; products (~29-34)ATP and water; protons transported outside of inner membrane drive ATP synthase;