CELL1010 Chapter 7: Cellular Respiration and Fermentation

what is the primary aim of cellular respiration?

to make ATP

glycolysis simplified

glucose is metabolized to 2 pyruvate molecules (with 3 carbons each), producing a new energy yield of 2 ATP molecules and 2 NADH molecules; occurs in cytosol (in eukaryotes); can happen under aerobic or anaerobic conditions

glycolysis inputs and outputs

input: glucose, 2 ATP

output: 2 pyruvates, 4 ATP, 2 NADH

pyruvate oxidation simplification

breakdown of pyruvate to release an acetyl group; the 2 pyruvate molecules enter the mitochondrial matrix, each is broken into an acetyl group and one CO2 molecule; one NADH molecule is made by the reduction of NAD+

pyruvate oxydation inputs and outputs

inputs: pyruvate, CoA; no energy needed

outputs: 1 CO2, 1 NADH, 1 acetyl CoA

citric acid cycle simplification

acetyl group (2 carbons) is removed from acetyl CoA and attached to oxaloacetate (4 carbons) → citrate/citric acid; takes place in the matrix of mitochondria in eukaryotes and in the cytosol in protaryotes

citric acid cycle inputs and outputs

inputs: 1 acetyl CoA, 3 NAD+, 1 FAD, 1 ADP + Pi

outputs: 2 CO2, 3 NADH, 1 FADH, 1 GTP

oxidative phosphorylation simplification

electrons removed from NADH and FADH2; release energy to produce an H+ electrochemical gradient

cellular respiration

a metabolic process that cells use to turn food into usable energy

aerobic respiration

O2 is used and CO2 is released (breathing)

glucose

primary universal molecule that cells use to store and efficiently release energy; store a lot of chemical potential energy; when glucose is metabolized, a large amount of free energy is lost (some lost to heat, most used to make energy intermediates such as ATP, NADH, and FADH2)

metabolic pathways of cellular respiration

glycolysis, breakdown of pyruvate to release an acetyl group, citric acid cycle, oxidative phosphorylation

rate of glycolysis is regulated by…

availability of substrates and feedback inhibition

what is the rate liming step of glycolysis?

step 3 (phosphofructokinase catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-biphosphate)