Module 13 Flashcards
When supplies of glucose and glycogen have been depleted during a fast, the process of __________ is initiated. This releases abundant acetyl CoA, but the Krebs cycle cannot generate enough __________ to process it. Consequently, __________ is/are released, causing a state of __________ to occur.
beta-oxidation; oxaloacetate; ketone bodies; ketosis - When fatty acids are being actively oxidized during beta-oxidation, large numbers of acetyl CoA molecules are formed. If the Krebs cycle is unable to process all of the acetyl CoA, due to a lack of oxaloacetate, ketone bodies will be formed. The condition called ketosis results when high levels of ketone bodies are found in the blood. Extreme ketosis (usually due to diabetes), which acidifies the blood, is called ketoacidosis.
The anabolic pathway called __________ converts amino acids, fatty acids, or lactate into pyruvate and then glucose.
gluconeogenesis (occurs when glucose and glycogen stores are depleted in the body, or when lactate builds up in oxygen-stressed muscle)
The process by which fatty acids are catabolized is called __________. It involves the step-by-step removal of __________ and their transformation into __________, which often enter the Krebs cycle for further processing.
beta-oxidation (involves the stepwise oxidation of the beta-carbon at the carboxyl end of a fatty acid); 2-carbon units; acetyl CoA
When amino acids are catabolized, the nitrogenous units may be processed via __________ and the carbon skeletons may enter __________; amino acid degradation releases __________, which is/are processed via __________.
oxidative deamination (also utilizes transamination); the Krebs cycle (or glycolysis pathway); ammonium ions; the urea cycle
A pathway which can perform both catabolic and anabolic functions is called a/an __________ pathway. Two examples are __________ and __________.
amphibolic; glycolysis; the Krebs cycle - making precursors for other molecules such as DNA heme, amino acid, and lipids
Which of the following statements is not true regarding the metabolic pathway known as glycolysis?
it is aerobic - Glycolysis is a primitive anaerobic pathway that takes place in the cytoplasm of all living cells.
Glycogenesis is stimulated by the hormone __________, while glycogenolysis is stimulated by the hormone __________. The first hormone responds to __________, while the latter hormone responds to __________.
insulin; glucagon; hyperglycemia; hypoglycemia
Which of the following statements is not true concerning the Krebs cycle?
the Krebs cycle has a low energy yield - The Krebs cycle carries out the aerobic oxidation of glucose, via pyruvate from glycolysis (which is next converted to acetyl CoA). In the cycle, the acetyl CoA is first bound to oxaloacetate, and undergoes several reactions; this process releases carbon dioxide and ATP, then sends electrons to the electron transport system, where they are used to power ATP synthase. The electrons finally bind to oxygen, the terminal electron receptor. Aerobic respiration is a high-efficiency process, yielding 18 times more energy than anaerobic respiration. It occurs in the cellular organelles called mitochondria.
Dietary lipids are transported to the duodenum, where they are emulsified by __________. Then, enzymes called __________ break them down to form __________. These are absorbed and changed into __________, which travel through the lymphatic system to the bloodstream, where they release __________. These may be oxidized for energy, or stored in __________.
bile salts; lipases; micelles; chylomicrons; fatty acids; adipocytes
Which of the following processes is not generally carried out by the liver as part of the normal range of metabolism?
releases insulin and glucagon - this is done by the pancreas
