Respiration and Fermentation Flashcards
4 stages of cellular respiration
- glycolysis
- pyruvate processing
- krebs cycle
- ETC
Is the process linear?
no
do not always have to start with glucose
made up of anabolic and pathways
Where are catabolic intermediates used?
in anabolic pathways
anabolic
synthesize new molecules
catabolic
break down molecules
Example of a catabolic intermediate
Acetyl-CoA
Oxidation/reduction reactions
make up cellular respiration
Where does glycolysis take place?
outside the mitochondria, in the cytoplasm
Main goal of glycolysis
to break down glucose to make pyruvate
What does glycolysis produce?
2 molecules pyruvate, 2 net ATP, 2 NADHS
Is glycolysis anaerobic or aerobic?
Anaerobic (no O2)
What are the two phases glycolysis?
- energy investment (input 2 ATP)
2. energy payoff
What happens during energy investment in glycolysis?
Free energy increases
Substrate-level phosphorylation
direct process where ATP is bounded directly to an enzyme
occurs in glycolysis
In overall equation, what is being oxidized and what is being reduced?
glucose is being oxidized
O2 is being reduced
What does NAD+ get reduced to?
NADH
this is the form that it is carrying more electrons in
What type of molecules serve as electron acceptors?
Molecules with low potential energy
Where do all the carbons of glucose end up when glucose is completely oxidized?
CO2
*think about net equation
If glucose was labeled with radioactive carbons, where would you expect the carbons to end up?
all biological molecules
intermediates in cellular respiration can go on to form other things besides going to the ETC
Ex: Acetyl-CoA is used in synthesis of fatty acids
Reducing agent
The molecule that is doing the reducing, therefore it is giving up electrons and being OXIDIZED
it will have less electrons and lower potential energy
What process will proceed whether oxygen is present or not?
glycolysis
metabolism
the sum of chemical reaction that take place within each cell of a living organism and provide energy for the entire organism
Phosphofructokinase
an allosteric enzyme that catalyzes an early stage of glucose (breaks down fructose)
negative feedback of ATP regulates
Where does pyruvate processing take place?
In the mitochondrial matrix
What is pyruvate processing catalyzed by?
Pyruvate dehydrogenase
Negative feedback by ATP
Net products of pyruvate processing
2 Acetyl-CoA
2 NADH
2 CO2
What happens in pyruvate processing?
two carbons from pyruvate combine with co-A
Which energy storing molecule carries the highest amount of chemical energy?
NADH
Since it releases the most free energy when formed
Where does the citric acid cycle take place?
mitochondrial matrix
What happens to each Acetyl-CoA?
oxidized to two molecules of CO2
What is produced from the citric acid (krebs) cycle?
3 NADH, 1 FADH2, 1 GTP or 1 ATP
Where does substrate level phosphorylyzation occur in the citric acid cycle?
When GDP is transformed into GTp
Where is CO2 produced?
pyruvate processing
the citric acid cycle
Why is the overall production of ATP in cellular respiration considered indirect?
Because it is pumped by the ETC and not directly synthesized by substrate-level phosphorylation
What is the O2 consumed during respiration directly used for?
accepting electrons at the end of the electron transport chain
Where is most water produced during cellular respiration?
the ETC
What is different about Q?
it is not a protein. it is lipid soluble and can move through the membrane
What is the synthesis of ATP an example of?
endergonic reaction coupled with an exergonic reaction
What goes into the ETC?
10 NADH
2 FADH2
O2
What is produced by the ETC?
Roughly 29-34 ATPs
H2O
Where does chemosynthesis take place in prokaryotes?
on the outer cell membrane rather than in the mitochondrial membrane
Oxidative phosphorylation?
proton gradient formed by pumped hydrogens
ATP synthase
hydrogen ions spin a rotor as they are moved back into mitochrondrial matrix
What is the most effective electron acceptor?
oxygen because it is the most electronegative
it will pull the electrons
Alcohol fermentation
characteristic of yeasts and bacteria
pyruvate gets reduced to an intermediate
results in toxic carbon 2 ethanol
Why is alcohol fermentation selected for in evolution?
produces a toxin that could kill potential predators
Lactic acid fermentation
characteristic of animals and bacteria
pyruvate is directly reduced to lactic acid, no intermediate
