chapter nine part two Flashcards
Krebs (citric acid) cycle
2C acetyl CoA + 4C oxaloacetate (oxaloacetic acid) –> 6C citric acid
how many Krebs cycles per glucose
2
vitamins needed for coenzyme NAD
niacin
vitamins needed for coenzyme FAD
riboflavin
vitamins needed for coenzyme CoA
pantothenic acid
products of pyruvate oxidation
2 acetyl CoA
2 CO2
2 NADH + H+
products of one acetyl CoA molecule per Krebs cycle
2 CO2
3 NADH
1 ATP (by SLP)
1 FADH2
products of one acetyl CoA per glucose
4 CO2
6 NADH
2 ATP
2 FADH2
how are NADH and FADH2 changed to ATP energy
electron transport chain - use high-energy electrons carried by NADH and FADH2
oxidative phosphorylation - ADP to ATP
how many ATP does oxidative phosphorylation produce?
30-32 ATP
what does oxidative phosphorylation involve?
free-energy change during electron transport
electron tranport chain
electrons move down chain of multi protein complexes, releasing free energy at every step
- includes cytochromes
- proteins and prosthetic groups
what is the final electron accepter?
oxygen - reacts w/ H+ to form water
where NADH enters the chain, how many ATP are made?
3 ATP per molecule
where FADH2 enters chain, how many ATP are made?
2
- comes later into chain and doesn’t build up as good as a gradient
ATP synthase
enzyme that makes ATP from ADP and P
- uses energy of existing ion gradient to power synthesis
- difference in concentration of H+ on either side of mitochondrial emmbrane
chemiosmosis
process in which energy stored in the form of H+ gradient across membrane is used to drive cellular work like synthesis of ATP
chemiosis in mitochondria
energy for gradient formation comes from exergonic redox reactions along ETC, ATP synthesis work is performed
- chemical energy converted to ATP energy
chemiosis in chloroplasts
ATP generated during photosynthesis
- light energy converted to ATP energy
chemiosis in bacteria and other prokaryotes
plasma membrane generates H+ gradient across PM
proton motive force and pump
force that promotes movement of protons across membrane down electrochemical potential
- force drives H+ back across membrane through H+ channels provided by ATP synthase
total ATP produced from glucose molecule in heart muscle, kidneys, and liver
38 - higher end
total ATP produced from glucose molecule elsewhere
36 - lower end
fermentation
harvesting chemical energy w/o O2 or ETC to produce ATP (less efficient)
2 types of fermentation
- alcoholic fermentation of glucose
- lactic acid fermentation
alcoholic fermentation of glucose
pyruvate converted to ethanol by:
1. releasing CO2 from pyruvate, which is converted to 2C compound acetaldehyde
2. acetaldehyde reduced by NADH to ethanol
lactic acid fermentation
pyruvate reduced directly by NADH to form lactate, regenerating NAD+ w/o release of CO2
1. SLP during glycolysis
- NADH used in conversion of pyruvate to lactate, so 2 ATP are the entire output of energy, vs. 32 if oxygen is present
2. excess lactate shuttled to other tissues for oxidation or to liver/kidneys for production of glucose/glycogen
obligate anaerobes
carry out only fermentation and anaerobic respiration
facultative anaerobes
organisms that can make enough ATP to survive using fermentation or respiration
control of cellular respiration
feedback inhibition - end product of anabolic pathway inhibits enzyme that catalyzes an early step of the pathway
negative feedback mechanisms
if ATP concentration begins to drop, cellular respiration speeds up and vise versa
phosphofructokinase
- negative feedback - catalyzes step 3 of glycolysis
- can speed/slow catabolic process
- allosteric enzyme w/ receptor sites for specific inhibitors/activators
- inhibited by ATP, stimulated by AMP
what types of carriers are present within the ETC?
FeS and cyto C carriers
is glucose oxidized or reduced to form pyruvate?
oxidized
when is the only time FAD is necessary in cellular respiration?
Krebs cycle
