Lecture Quiz 4 Flashcards
What is the overall reaction of the oxication of glucose?
C6H12O6 + 6O2 –> 6H2O + 6CO2 + 32 ATP + heat
What happens during glycolysis (vague)?
glucose is oxidized into pyruvic acid
NAD+ is reduced to NADH + H+
ATP is synthesized by substrate-level phosphorylation
What is the fate of pyruvic acid?
moves on to Krebs cycle in an aerobic pathway
is reduced to lactic acid in an anaerobic environment
What happens during phase one of glycolysis?
sugar activation
2 ATP molecules activate glucose into fructose-1,6-diphosphate
What happens during phase two of glycolysis?
oxidation and ATP formation
3 carbon sugars are oxidized, reducing NAD+
inorganic phosphate groups are attached to each oxidized fragment
terminal phosphates are cleaved and captured by ADP to form 4 ATP
What are the final products of glycolysis?
two pyruvic acid molecules
two NADH+ H+ molecules
net gain of two ATP molecules
What is the importance of glucose?
neurons and RBCs rely almost entirely on glucose for energy
What happens with excess glucose?
converted to glycogen or fat
Where does the Krebs cycle take place?
mitochondrial matrix
What fuels the Krebs cycle?
pyruvic acid and fattys acids
8 step cycle
What happens during the decarboxylation of the Krebs cycle?
carbon is removed from pyruvic acid
CO2 is released into bloodstream
What happens during oxidation of the Krebs cycle?
hydrogen atoms are removed from pyruvic acid
NAD+ is reduced to NAD+ H+
What is the final step of the Krebs cycle?
formation of acetyl CoA
resulting acetic acid is combined with coenzyme A, a sulfur containing coenzyme, to form acetyl coA
What are the final products of the Krebs cycle?
3 NAD+ H+ 1 FADH2 2 CO2 1 ATP 1 glucose = 2 acetyl CoAs entering the Krebs cycle aka 1 glucose = 2 krebs cycles
What happens during the electron transport chain?
glucose is oxidized
hydrogens are transported by coenzymes NADH and FADH2
they enter a chain of proteins bound to metal ions (cofactors)
combine with molecular oxygen to form water
release energy
What happens to the energy released by electron transport chain?
harnessed to attach inorganic phosphate groups to ADP, making ATP through oxidative phosphorylation
Describe what happens to the hydrogens in the mechanisms of oxidative phosphorylation
split into protons and electrons
protons are pumped across the inner mitochondrial membrane by NADH dehydrogenase, cytochrom b-ci, cytochrome oxidase
What happens to the electrons?
electrons are delivered to oxygen, forming oxygen ions
oxygen ions attract H+ to form water
H+ pumped into intermembrane space
diffuses back to the matrix via ATP synthase
releases energy to make ATP
How much ATP is created from NADH + H+?
2.5 ATP
How much ATP is created from FADH2?
1.5 ATP
Break down the energy generated from one glucose molecule
1 glucose
glycolysis - 2 ATP
Krebs - 2 ATP
ETC - 28 ATP
What does the electrochemical proton gradient across the inner membrane do?
creates a pH gradient
generates a voltage gradient
these gradients cause H+ to flow back into the matrix via ATP synthase