Molecular Biology Ch. 6

cellular respiration

a catabolic pathway in which oxygen is consumed as a reactant along with organic fuel.

catabolic pathways

the release of stored energy by breaking up complex molecules. A catabolic pathway is composed of a series of reactions. Its opposite is anabolic.

NAD+

The acceptor of electrons from the organic compound.

nicotinamide adenine dinucleotide

reaction of glucose and oxygen to create ATP

C6H12O6 + 6O2 = 6H2O + 6CO2 + 38ATP

glycolysis

step 1 in cellular respiration.

uses polysaccharides (carbohydrates), glycerol (fat), and ATP

"breaking glucose'

net yield: 2 pyruvate (citric acid cycle), 2 ATP (from 2 ATP), and 2 NADH (from 2 NAD)

dehydrogenase

a family of enzymes that remove H (e-) from the organic compound in order to convert NAD+ to NADH.

NADH

-acquired 2 electrons from the organic compound
-contains "stored energy".

active transport protein

allows pyruvate to pass through the inner membrane of the mitochondria in order to engage in the citric acid cycle

pyruvate

-2 are created in the process of glycolysis.
-once inside the mitochondrial matrix, it loses CO2, NAD+ converted to NADH, and gains CoA to become Acetyl CoA

Acetyl CoA

-uses fatty acids (fat), but no ATP
-created from pyruvate inside the mitochondrial matrix.
-contains a partial bond, making it highly reactive.

citric acid cycle (Krebs Cycle)

-use amino acids (protein) and ATP
-step 2 in cellular respiration.
-engages Acetyl CoA in this process.
-The Acetyl CoA does: loses S-CoA, loses 3 CO2, 4 NAD+ converted to 4 NADH and 4 H+, ADP converted to ATP, FAD converted to FADH2.
-This cycle happens 2X b/c there are 2 pyruvate

oxidative phosphorylation

-use ATP
-step 3 in cellular respiration
-composed of electron transport chain and chemiosmosis
-produces a net total of 34 ATP, grand total of 38 ATP

electron transport chain
(oxidative phosphorylation)

-a chain of proteins and molecules in the inner membrane of the mitochondria.
-made up of 4 protein complexes.
-electronegativity increases along the chain.
-energy decreases along the chain
-produces 6 H20

prosthetic molecules

-move along the electrons in the electron transport chain.
-each is more electronegative than the previous

O2

-final electron acceptor in the electron transport chain.
-most electronegative
-combines w/ H2 to create H2O
-glycolysis does not require it to function whereas the citric acid cycle and oxidative phosphorylation do.

Protein complex 1

converts NADH to NAD+ (2 e-)

Protein complex 2

converts FADH2 to FAD (2 e-)

chemiosmosis
(oxidative phosphorylation)

the use of a proton gradient to transfer energy in order to create ATP

ATP synthase

-inner membrane bound enzyme that synthesizes ATP.
-it is an H+ channel
-4 main parts: rotor (H+ channel), stator, rod, knob

Knob in ATP synthase

-has 3 catalytic sites
-ADP + P = ATP

proton pumps

protein complexes 1,3,4.

fermentation

a mechanism by which cells can oxidize fuel and generate ATP in anabolic conditions

anabolic

consume stored energy. occurs in the absence of O2

alcohol fermentation

-glucose converts 2 ADP to 2 ATP, 2 NAD+ to 2 NADH and 2 H+ to create 2 pyruvate.
-pyruvate loses CO2 to b/c 2 acetylaldenhyde.
-2 Acetylaldenhyde then converts 2 NADH and 2 H+ to 2NAD+ to create ethanol
-cycle recurs

lactic acid fermentation

-glucose converts 2 ADP to 2 ATP, and 2 NAD+ to 2 NADH and 2 H+ to create 2 pyruvate.
-2 pyruvate then converts 2 NADH and 2 H+ to 2 NAD+ to create 2 lactase
-cycle recurs