Term
| What is the difference between anabolic and catabolic pathways? Are cellular respiration and photosynthesis anabolic or catabolic? |
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Definition
An anabolic pathway is when more complex molecules are built from simpler ones. Thus, photosynthesis would be anabolic, because sugar is made from CO2, H2O and sunlight.
A catbolic pathway is when more complex molecules are broken down into simpler ones. Thus, cellular respiration would be catabolic, because glucose is broken down into CO2 and H2O. |
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Term
| What goes into cellular respiration and what comes out? |
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Definition
C6H12O6 + O2 -> CO2 + H2O + energy
(note: not the correct number of molecules) |
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Term
| What is the significance of NAD+ during cellular respiration? |
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Definition
| NADH, the reduced version of NAD+, is used to transport energy (through electrons) to the electron transport train, which creates the H+ gradient, critical to the synthesis of ATP. |
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Term
| What happens during glycolysis? What are the major products? How many endothermic and how many exothermic steps are there? How is ATP created during this process? |
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Definition
During glycolysis, glucose (a six carbon molecule) is broken into two pyruvate (a three carbon molecule) with the help of many enzymes.
There are five endo- and five exothermic steps.
NADH is created from NAD+ when pyruvate is oxidized. This NADH is turned into FADH2 in order to enter the mitochondrion.
During these reactions, phosphate groups are added to ADP from a transition state of the broken down glucose in a process known as substrate phosphorylation. |
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Term
| What happens after pyruvate enters the mitochondrion? What goes in and what comes out? Where does this occur? What is the purpose of this reaction? |
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Definition
Pyruvate + Coenzyme A + NAD+ -> Acetyl CoA + CO2 + NADH
The CO2 comes from the pyruvate.
The reaction occurs in the mitochondrion matrix.
The purpose of this reaction is to prepare pyruvate for the Krebs cycle and to reduce more NAD+ with electrons for the electron transport train. |
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Term
What happens in the Krebs cycle? What are the reactants and what are the products?
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Definition
NAD+ and FAD+ are reduced in order to supply electrons for the electron transport train, which occurs in the matrix.
Acetyl CoA + NAD+ + FAD+ + ADP -> ATP + NADH + FADH2 + CO2
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Term
What happens during the electron transport chain?
Where does it take place in the mitochondria? |
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Definition
Electron rich NADH or FADH2 bring electrons which are passed down the electron transport chain, releasing energy. The protons leave NADH and FADH2 and they are deprotonated. The final acceptor of the electrons is molecular oxygen, which is reduced to water.
The energy released from the ETC is used to pump the protons up their concentration gradient, into the intermembrane space of the mitochondrion. These protons then travel back down their concentration gradient through ATP synthase, which phosphorylates ADP and creates ATP.
It takes place on the inner membrane.
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Term
| What is the differenece between oxidative phosphorylation and chemiosmosis? |
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Definition
Oxidative phosphorylation is driven by the concept of chemiosmosis and is when ATP is made from ADP through the oxidation of NADH and FADH2.
Chemiosmosis is the process by which ATP is produced through protons flowing down their concentration gradient, into the mitochondrion matrix, through ATP synthase. The protons are originally pumped up their concentration gradient, into the intermembrane space through the energy given off by the electron transport chain. |
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Term
| What is fermentation? Why does it occur? What are two possible products of this process? |
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Definition
Fermentation occurs when there is no oxygen present. Thus, there is no electron transport chain, because there is no molecular oxygen to accept the electrons at the end.
Thus, all of the energy in fermentation comes from substrate-level phosphorylation.
After pyruvate is oxidized by NAD+, it oxidizes NADH and becomes either ethanol or lactic acid. |
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