Metabolism Overview

• Glycolysis is a catabolic process.
• Gluconeogenesis is an anabolic process.
• Glycogenesis is an anabolic process.
• β-oxidation of fatty acids is catabolic.
• The Krebs cycle is amphibolic.
• The citric acid cycle is the central hub and final common pathway, also known as the TCA cycle.
• Aconitase is the enzyme required for citrate to isocitrate conversion.
• Steps 3 and 4 in the Krebs cycle produce carbon dioxide and NADH.
• Isocitrate dehydrogenase is the rate-limiting enzyme in the Krebs cycle.
• Oxidative phosphorylation goes by another name.
• 4 protons are pumped in complex 1 of the electron transport chain (ETC) from the matrix to the intermembrane space.
• FADH2 enters the electron transport chain at complex II.
• The ATP yield of one NADH molecule when it enters the ETC is 2.5 ATP.
• The ATP yield of one FADH2 molecule when it enters the ETC is 1.5 ATP.
• Acetyl CoA is the gateway molecule that enters the Krebs cycle.
• Hexokinase and phosphofructokinase (PFK-1) are the energy-spending steps where ATP is used in glycolysis.
• Step 6 produces NADH in glycolysis.
• Pyruvate is the primary product of glycolysis.
• The net ATP yield during glycolysis is 2 ATP.

Fates of Pyruvate

• Conversion to acetyl-CoA for entry to the Krebs cycle

• Fermentation to lactate in anaerobic conditions

• Fermentation to ethanol in yeast and some bacteria

• The malate-aspartate shuttle transfers NADH into the mitochondrial inner membrane.

• Glycogenesis is the formation of glycogen from glucose and reduced blood glucose.

• Phosphatase enzyme removes a phosphate group from a molecule.

• The pentose phosphate pathway is also known as the hexose monophosphate shunt.

• 4 protons are required to generate ATP molecules.

Functions of Lipids

• Energy storage

• Structural components

• Insulation

• Protection

• An ester bond links glycerol to fatty acids.

• Pancreatic lipase breaks down TAGs into free fatty acids and monoacylglycerol.

Order of Breaking Down Fatty Acids

• FA activation

• FA transport

• Beta oxidation of FA

• 2 ATPs are spent in the activation of fatty acids.

• Acyl CoA reacts with carnitine to form acylcarnitine.

• Eicosanoic acid is the systematic name of arachidic acid.

• Step 3 produces 1 NADH in β-oxidation of fatty acids.

• Acetoacetate is an example of a ketone body.

• Protein digestion starts in the mouth, and gastrin triggers the secretion of hydrochloric acid only is false.

• H⁺: Moving through ATP synthase facilitates phosphorylation, which is how the ion drives ATP synthase and generates ATP during ATP synthesis through oxidative phosphorylation.

• A peptide bond is the type of bond that links one amino acid to another.

• Vitamin B6 is the active form of pyridoxal phosphate.

• Ornithine and aspartate are substrates in the urea cycle.

• Phenylalanine, isoleucine, arginine and lysine are essential.

• The liver recycles lactate back to glucose and supplies energy to muscles

Liver Advantage in Cori Cycle

• Recycles lactate back to glucose

• Supplies energy to muscles

• NADH donates electrons to complex I to initiate proton pumping in the electron transport chain

• Oxidative phosphorylation uses a proton gradient to synthesize ATP.

• A high blood glucose level triggers the release of insulin.

• Acetyl-CoA is the initial substrate that supplies energy for the first reaction in the Citric Acid Cycle (Krebs Cycle).

• The role of the liver to the Cori cycle from set 7 no. 1 is the same as question 46.

• The nitrogen atom of degraded amino acids is ultimately excreted from the body in the form of urea.

• ATP is the form of energy produced during glycolysis.

• Disruption to a cell's mitochondrial membrane would stop or slow down the transport of electrons.

• FADH2 in the electron transport chain transfers electrons to a lower energy complex in the ETC, affecting the amount of ATP produced.

• Lactate dehydrogenase is responsible for the conversion of lactate back to pyruvate in the liver during the Cori Cycle.

• Glucagon is administered to raise blood glucose levels and initiates glycogen breakdown specifically in the liver, but not in the muscle.

• The liver stores the most glycogen.

• Glucagon raises blood glucose by stimulating glycogen breakdown, particularly relevant to individuals with diabetes.

• During extended fasting, triglycerides (TAGs) are oxidized through β-oxidation to form acetyl CoA, which then enters the citric acid cycle or contributes to ketone body formation as an energy source.