other pathways

Question 1

Protein lipid catabolism

Answer 1

• energy reserves are stored as triglycerides, that can be hydrolyzed to glycerol and fatty acids through lipases (enzyme)
• Glycerol can be metabolized by glycolysis upon oxidation to DHAP.
• Both electrons are fed into the electron transport chain.
  Fatty acids follow a different pathway.

Question 2

what form of oxidation occurs in the mitochondria

Answer 2

β-oxidation
- it has to be activated before entering mitochondria, and the activation happens in the cytoplasm

• the activation is the transformation of the fatty acids into acetyl-CoA derivatives.
• The fatty acid is essentially broken at every two carbons in the hydrocarbon chain. These molecules then enter the Krebs’ cycle.

Question 3

protein catabolism

Answer 3

• proteins can be used for energy: polypeptide chains are broken down via hydrolysis into individual amino acids.
• Amino acids are generated by the digestion of proteins in the intestine or by the degradation of proteins within the cell. Cellular proteins are constantly being degraded and resynthesized. Some proteins are incredibly stable, others are very short lived.
• If amino acids are needed to synthesize new proteins, they will be used, otherwise they will be degraded.

Question 4

Where does amino acid degradation occur in mammals

Answer 4

• liver, the amino acids are removed from a compound to form alpha-ketoacids
• the amino group is converted to NH3, and enzymes convert it so its lost as urea (waste product formed from broken down protein) in urine
• The α-ketoacids are metabolized so that the carbon skeletons can enter metabolism as citric acid cycle intermediates, depending on their R-group.

Question 5

anaerobic respiration: fermentation

Answer 5

• way to generate atp without oxygen, by recycling the NAD+ molecules used to oxidize molecules in glycolysis
• produces NAD+ and allows glycolysis to continue

Question 6

alcohol fermentation

Answer 6

• done by yeast and some bacteria
• convert sugars in ethanol and carbon dioxide.
• begins after glucose enters the cell, its broken down into pyruvate.

-Pyruvate is then converted to CO2, and Acetaldehyde (2C). This 2 Carbon molecule then receives electrons from NADH, becoming ethanol, and allowing NADH to be oxidized into NAD+.

Question 7

lactic acid fermentation

Answer 7

• pyruvate will be fermented into lactic acid when o2 becomes depleted in muscles : converting glucose to lactic acid
• results in localized anaerobic conditions

-This lactic acid causes the muscle stiffness someone may feel after exercise programs.

-The stiffness goes away after a few days since the cessation of strenuous activity allows aerobic conditions to return to the muscle, and the lactic acid can be converted into ATP via the normal aerobic respiration pathways.

Question 8

role of the liver in lactic acid fermentation

Answer 8

• Your liver and kidneys filter lactic acid out of your blood after it’s created in other tissue. They break it down and convert it into new glucose that your body can use for energy in the future.