7. Metabolism Flashcards
What is a catabolic rxn?
A rxn that breaks down molecules and produces E
What is an anabolic rxn?
Synthesis of molecules and requires E
What is internal vs external respiration?
Internal: respiration btw blood and cells
External: respiration btw outside air and lungs
Aerobic vs anaerobic respiration
Aerobic: O2 present
Anaerobic: O2 not present
Aerobic respiration of glucose step by step
Glycolysis
Pyruvate decarboxylation
Kreb cycle
ETC
Anaerobic respiration of glucose step by step
Glycolysis
Fermentation
Where does glycolysis happen
Cytoplasm
Describe the 3 stages of glycolysis
Energy investment:
- glucose is converted to intermediate molecule
- 2 atp is used to charge molecules
Cleavage:
Intermediate molecule is broken into 2 molecules
Energy payout:
- intermediate molecule is converted to pyruvate
- 4 atp is produced
- 2 nadh is produced
Where does pyruvate decarboxylation happen?
Mitochondrial matrix
Explain the process of pyruvate carboxylation.
Pyruvate is converted to acetyl-CoA
- CO2 is leaving group (instead if Co-A)
- 1 nadh is produced
Where does kreb cycle happen?
Mitochondrial matrix
Explain kreb cycle.
Acetyl-CoA reacts with oxaloacetate in a cycle to generate:
- 2 CO2
- 1 gtp
- 1 fadh2
- 3 nadh
Where does ETC located?
Imbedded in the inner mitochondrial membrane
What is the ETC mostly made up of?
Cytochromes
What are cytochromes?
Electron carriers with active sites that contain iron.
Can be easily oxidized and reduced.
What is the electron donor in the ETC?
NADH
FADH2
What is the electron acceptor in ETC?
O2
What is ATP synthase?
The protein complex that uses the proton motive force to pump H+ to generate atp
In which direction does atp synthase pump H+?
from the intermembrane space to the mitochondrial matrix
What is substrate level phosphorylation?
ATP generated directly from redox rxn
What is oxidative level phosphorylation?
ATP generated through ETC and electron carriers
How much atp does 1 nadh produce?
3
How much atp does 1 fadh2 produce?
2
State the number and type or electron carriers and atp used or produced during glycolysis through substrate LP, oxidative LP, and in total from 1 glucose.
Substrate LP:
- 2 atp used
- 4 atp produced
Oxidative LP: 2 nadh produced
Total: 8 atp
State the number and type or electron carriers and atp used or produced during pyruvate decarboxylation through substrate LP, oxidative LP, and in total from 1 glucose.
Substrate LP: 0
Oxidative LP: 2 nadh
Total: 6 ATP
State the number and type or electron carriers and atp used or produced during kreb cycle through substrate LP, oxidative LP, and in total from 1 glucose.
Substrate LP: 2 gtp
Oxidative LP:
- 6 nadh
- 2 fadh2
Total: 24 ATP
How many atp are generated from 1 glcuose molecule using aerobic respiration?
36 to 38
What happens during fermentation metabolically?
Atp cant be produced
Cell works to replenish nad+ used in glycolysis
What occurs during alcohol fermentation?
Pyruvate converted to ethanol
What occurs during lactic acid fermentation?
Pyruvate is converted to lactic acid
Which form of fermentation do human muscle cells and most bacteria undergo?
Lactic acid fermentation
Generically speaking, how are other carbohydrates used as fuel source?
Glycogen turns into glucose intermediate
Disaccharides undergo hydrolysis to form monosaccharides, which in turn is converted to glucose intermediate
Which source of metabolic energy produces the most atp for the body?
fats
Explain in relative detail how triglycerides are broken down.
- TAG is broken into fatty acid and glycerol by lipases enzyme
- Glycerol turns into glucose intermediate
- Fatty acids undergo beta-oxidation rxn and are converted into shorter fatty acid chains and acetyl-CoA
What are the net products of beta-oxidation per round?
1 nadh
1 fadh2
Under what conditions are proteins broken down for energy?
Low energy emergency situations
In relative detail explain how proteins are broken down in the body.
- Proteins undergo transamination rxn and are converted into alpha-ketos.
- The rxn also produces acetyl-CoA, pyruvate or kreb cycle intermediates that are used for to produce atp
- The rxn also releases NH4+ which undergoes oxidative deamination into ammonia, uric acid, or urea
What two reactions make up photosynthesis?
Light rxn
Dark rxn
What is the unbalanced formula for photosynthesis?
6co2 + 12h2o + light -> c6h12o6 + 6h2o + 6o2
What are the two methods for light rxn to occur?
Cyclic electron flow
Non-cyclic electron flow
Which photosystems does cyclic electron flow use?
Photosystem 1
Which photosystems does non-cyclic electron flow use?
Photosystem 2 and 1
Explain cyclic electron flow in relative detail.
Photosystem 1:
- Light photons reach p700 chlorophyll cells
- P700 cells release an excited electron
- The electron travels through an ETC
- The ETC pumps H+ in one direction creating a gradient
- ATP synthase uses the proton motive force to generate ATP
- The electron returns to the p700
Explain non-cyclic electron flow in relative detail.
Photosystem 2:
1. Photon excites the p680 chlorophyll cells
2. P680 uses light energy to converts h2o into o2
3. P680 releases 2 excited electrons
4. The electrons travel through an ETC
5. ETC pumps and generates ATP
Photosystem 1:
6. The electrons travel to the p700 cells
7. P700 uses the electrons to convert nadp+ into nadph
Chronically when does the dark rxn happen?
Only during the day
Give a summary of the calvin cycle.
- Co2 is converted to unstable sugar intermediates
- nadph oxidizes the intermediates
- Atp is used to form glucose
