Electron Transport Chain and Chemiosmosis

Carbohydrate Catabolism

breaking down carbohydrates into simpler compounds to generate energy.

Cellular respiration

generating ATP in cells

oxidative phosphorylation

cells transfer energy from NADH and FADH₂ to the phospho-anhydride bonds of ATP

Cristae (inner mitochondrial membrane)

provide area for assembly of protein complexes involved in electron transport and ATP synthesis

mitochondrial matrix

space enclosed by inner membrane- enzymes involved in metabolism

enzymes

protein complexes associated with inner mitochondrial membrane

intermembrane space: high

matrix: low

oxidative phosphorylation intermembrane space has high/low hydrogen ions

oxidative phosphorylation matrix has high/low hydrogen ions

oxidative redox reactions

electrons are transferred from NADH/FADH₂ to O₂, which forms water (exergonic reactions)

electrons from NADH are transferred to O₂ through Complex I, III, and IV

H+

Complex I, III, and IV are also proton pumps, they move ____ into intermembrane space using energy released from redox reactions

this energy released from electron transfer reactions is used to move ___ into membrane space, which sets up proton gradient

oxidative phosphorylation

proton pumping is essential to

electron transport chain

proton pumps transfer protons from the matrix to intermembrane space as electrons move through the _______

chemiosmosis

the electrochemical gradient generated by the electron transport chain drives what?

generate ATP

uses the flow of protons down their concentration gradient to…

oxidative phosphorylation

coupling of proton flow with ATP synthesis=

ATP synthase

proton channel combined with ATP synthesis enzyme

H+ diffuses through this channel

Subunit rotates

Rotation causes this subunit to change its three-dimensional shape to expose the active site for ATP synthesis

26-28 ATP

8-10 NAD+ → glycolysis/citric acid cycle

2-4 FAD → citric acid cycle

12 H₂O

net products of oxidative phosphorylation (per molecule of glucose)

catabolic pathway

breakdown of energy rich compounds to generate energy

cellular respiration

must be regulated through balanced amounts of energy, ATP

the cell must also generate a number of intermediate compounds that are used in the anabolism and catabolism of macromolecules

GLUT (glucose transporter)

control passage of glucose into the cells of specific tissues

rate of the reaction

there are two different enzymes in reversible reactions, what do they control

allosteric effectors

alteration of the protein’s (the enzymes) structure either increase or decrease the rate of the reaction

key molecules (enzymes, proteins, carriers, pumps)

catalyze irreversible reactions in glycolysis, citric acid cycle, and electron transport chain

cell’s energy needs (ATP, ADP, AMP

enzyme activity depends on what?

the control of glycolysis begins with the first enzyme

inhibited hexokinase

glucose diffuses out of the cell

glycolysis

regulated at three enzymatic steps 1, 2, 7- involves hydrolysis of ATP

Hexokinase, Phosphofructokinase (PFK), and Pyruvate Kinase

what are the three key regulatory steps (1,2,7) of glycolysis

cells rely on anaerobic metabolism to prpduce energy

NAD+ is essential in glycolysis

what happens when oxygen level is low?

How can glycolysis keep running if oxygen is low?

fermentation

anaerobic (non-oxygen requiring) pathway for breaking down glucose

reduced

during fermentation, is pyruvate oxidized or reduced to regenerate NAD+?