Cellular Energy Flashcards
Where does glycolysis occur?
The cytosol
Fermentation is an __________ pathway/process
Anaerobic
What does fermentation rely on?
Glycolysis
What is the primary purpose of fermentation?
To oxidize NADH back to NAD+ so that glycolysis can continue to make ATP —> regenerating NAD+ means that glycolysis can continue to make ATP
Lactic acid fermentation
Oxidizes 2 NADH from glycolysis back to NAD+ by reducing the 2 pyruvate into 2 lactic acid
Oxidation of NADH will transfer its electrons to pyruvate which regenerates NAD+
The Cori cycle
Converts lactate back into glucose once oxygen becomes available again
The Cori cycle in myocytes
The Cori cycle transports lactate from the myocyte (muscle cells) to the liver cells (hepatocytes), where it is oxidized back into pyruvate. Pyruvate can then be used to form glucose through gluconeogenesis which can be used for more ideal energy generation
Alcohol fermentation
Uses 2 NADH from glycolysis to convert the 2 pyruvate into 2 ethanol and therefore oxidizing NADH back to NAD+ but WITHOUT reducing pyruvate
How does alcohol fermentation regenerate NADH?
- 2 pyruvate are decarboxylated and lose 2 CO2 molecules, converting into acetaldehyde
- Acetaldehyde is reduced by NADH into ethanol and thereby oxidizing NADH to NAD+
Obligate aerobes
Organisms that can only metabolize using aerobic respiration —> oxygen must be present in order to survive
Obligate anaerobes
Organisms that only metabolize their fuel source via anaerobic respiration or fermentation, oxygen is toxic
Facultative anaerobes
favor aerobic respiration because it generates the most ATP, BUT can utilize anaerobic respiration or fermentation
Microaerophiles
only perform aerobic respiration (oxygen present) BUT high concentrations of oxygen are harmful to them
Aerotolerant organisms
Only undergo anaerobic respiration or fermentation, but oxygen is not poisonous to them
lipolysis
Digesting triglyceride with a lipase
Lipase
Enzymes that break down triglycerides
What are the products of oxidative phosphorylation?
NAD+
FAD
H2O
ATP
What can glycerol be directly converted into?
When a glycerol molecule travels to the liver:
it can be converted to glucose via gluconeogenesis to enter glycolysis
or it can be converted to glycogen via glycogenesis
What is a waste product that is produced at the end of the ETC?
water
the final electron acceptor is oxygen. oxygen molecules combine with protons to form water
What are the products of beta-oxidation?
Acetyl-CoA
NADH
FADH2
What do lipases convert triglycerides into?
Free fatty acids and alcohols (ex: glycerol molecules, monoglycerides)
How many ATP molecules can be produced from one FADH2 coenzyme?
2 ATP —> this is because FADH2 reduces a later complex
From one glucose, ________ pyruvate manipulations occur which produces:
2
Releases: 2 carbon dioxides
Reduces: 2 NAD+ into 2 NADH
Produces: 2 acetyl-CoA
What is the first step of pyruvate manipulation?
Decarboxylation: a pyruvate molecule (3-C) will be decarboxylated to release a carbon atom as carbon dioxide
Where in the cell does pyruvate manipulation take place?
Mitochondrial matrix
Where is the electron transport chain located in prokaryotic cells?
Along the cell membrane
What is the net ATP yield for every glucose during fermentation?
2 ATP
Why are carbohydrates a better fuel source than fatty acids?
Although fats yield 9 kcal/gram (as opposed to carbohydrates yielding 4 kcal/gram), carbohydrates are a better fuel source because it requires much less energy input to break up than fatty acids, which require much more energy input. Carbohydrates therefore are much easier for the body to digest and use for energy, which is why they are the first choice.
Which process directly depends on oxygen?
oxidative phosphorylation directly depends on oxygen as the final electron acceptor of the aerobic ETCs.
Which process indirectly depend on oxygen?
Aerobic pyruvate oxidation and the Krebs cycle
Where do humans absorb digested fasts? What is the process?
Through the enterocytes of the small intestine
- Free fatty acids and monoglycerides enter the cell
- once contained within the enterocyte, the free fatty acids and monoglycerides will reform into triglycerides
- once the triglycerides have reformed, they will pair up with proteins, phospholipids and cholesterol int the enterocytes
Amino acid byproducts can enter cellular respiration at which molecules?
Depending on the starting amino acid, amino acid byproducts created via oxidative deamination can enter enter cellular respiration by converting to pyruvate, acetyl-CoA, and several of the Krebs cycle intermediates
what organisms convert ammonia into uric acid before excretion?
Insects, reptiles and birds
What is the net ATP yield for every glucose in fermentation?
2 ATP per glucose
How can fatty acids travel in their free state in the bloodstream?
By binding to protein called albumin
Free state = not esterified to glycerol
During which process is FADH2 produced?
The Krebs cycle
Where does the Krebs cycle take place?
In the mitochondrial matrix
How many ATP molecules can be produced from one FADH2 coenzyme?
2
Why is the process of oxidative phosphorylation labelled as “oxidative”?
Electron carriers, NADH and FADH2, are oxidized in order to release high-energy electrons they carry
Why do fatty acid chains have a high potential for ATP production compared to glucose?
Fatty acid chains contain many highly reduced carbons, which can contribute to the production of “bonus” electron carriers and acetyl-CoA through beta-oxidation
What is the pathway that represents the movement of protons within the mitochondria to generate ATP?
Inter membrane space to the mitochondrial matrix
What pathway represents the movement of protons within the mitochondria to generate a proton gradient?
Mitochondrial matrix to the intermembrane space
Which body cells are capable of performing the Cori cycle?
Liver cells (hepatocytes)
What are the 5 catabolic process?
Glycolysis - breaking down glucose
Oxidative deamination - breaking down amino acids
Glycogeonlysis - breaking down glycogen
Lipolysis - breaking down triglycerides
Beta oxidation - breaking down fatting acids
during cellular respiration, what occurs in response to low glucose levels?
- glycolysis is inhibited through the inhibition of the enzymes hexokinases and glucokinases, which catalyze the first step of glycolysis
in the small intestine, what are triglycerides broken down into?
- monoglycerides and fatty acids
- catalyzed by the eznyme lipase
