ACBS 445 Exam 2 2025 With 100% Accurate Solutions

ACBS 445 Exam 2 2025 With 100% Accurate Solutions What is the fasting blood glucose? – Answer????70 – 100 mg/dL Digestion Absorption of Glucose: Mouth – Answer????chewing allows for an increase in the surface area : volume Produces salivary alpha-amylase What does alpha-amylase do? – Answer????Breaks the alpha 1 4 linkage in glucose Digestion Absorption of Glucose: Esophagus – Answer????acts simply as a tube Digestion Absorption of Glucose: Stomach – Answer????HCl aids in breakdown/digestion, has a pH of 1-3 Produces chyme In a high protein diet, the pH of the stomach is closer to Why? – Answer????3 Proteins are able to buffer the pH In a high starch diet, the pH of the stomach is closer to – Answer????1 Chyme passes through the ____ to the _____ Answer????Pyloric sphincter, small intestine Digestion Absorption of Glucose: Small Intestine – Answer????primary site of digestion and nutrient absorption What are the three parts of the small intestine? – Answer????duodenum, jejunum, ileum What is in the gallbladder? What does it do in the small intestine? – Answer????Bile/Bile salts. They neutralize the pH of chyme in the small intestine Where are bile/bile salts produced? – Answer????The liver What does neutralized the pH in the small intestine allow us to do? – Answer????secrete enzymes from the pancreas What does the exocrine pancreas release? – Answer????pancreatic alpha-amylase After a glucose molecule is released in the small intestine... – Answer????it is taken through SGLUT1 after a sodium binds to the receptor, changing its formation How much energy does sodium potassium ATPase use? – Answer????30% What is GLUT5? – Answer????fructose transporter (from lumen into epithelium) How does glucose get from the intestinal endothelial cell to the hepatoportal vasculature? – Answer????GLUT2 Once in the hepatoportal vasculature, what order does glucose hit other parts of the body? – Answer????Pancreas, liver, skeletal muscle, adipose tissue, brain, rbc How does glucose enter beta cells in the pancreas? – Answer????GLUT2 What does glucose do when in the beta cell? – Answer????causes the release of insulin What does glucose do in alpha cells in the pancreas? – Answer????inhibits glucagon How much glucose does the liver take up that is consumed? – Answer????around 30% How does glucose enter the liver? – Answer????GLUT2 What does insulin do in skeletal muscle? – Answer????Encourages translocation of GLUT4 to the cell surface, which allows glucose to enter. What is the Km for GLUT2 – Answer????~12mM What is the Km for GLUT4 – Answer????~5 mM Can skeletal muscle take up glucose when insulin is not around? – Answer????No because without it, GLUT4 remains inside the cell How does glucose enter the brain and RBC? – Answer????GLUT1 and GLUT3 What is the Km of GLUT1 and 3? – Answer????1-3mM Why does glucose need to be phosphorylated? – Answer????To keep it inside the tissue What steps in glycolysis affect the flux of NAD/NADH ratio in the cytosol? – Answer????G3P -> 1,3 BPG Pyruvate -> Lactate When will pyruvate get converted to lactate in glycolysis? – Answer????In low oxygen conditions, in RBC, not enough mitochondria (adipose tissue) What happens to pyruvate in high oxygen conditions? – Answer????It can enter the TCA cycle What is the purpose of pyruvate turning into lactate? – Answer????So we can regenerate NAD to continue glycolysis Where does Glycolysis occur? – Answer????cytosol Where does the TCA Cycle occur? – Answer????mitochondrial matrix (inside both outer/inner layers) Which enzyme requires biotin? – Answer????pyruvate carboxykinase How much NADH2 is formed through the TCA Cycle? – Answer????4 Where is the electron transport chain located? – Answer???? Intermitochondrial space Complex I – Answer????NADH2 -> NAD 4H+ ions pumped in Complex II – Answer????FADH2 -> FAD No H ions pumped What is another name for Complex II? (e trans chain) – Answer????Succinate DHase Complex III – Answer????4H+ ions pumped Complex IV – Answer????2 H+ ions pumped How many H+ ions does it take to pump an inorganic phosphate into the inner mitochondrial space? – Answer????1 How many H+ ions does it take: ADP + Pi = ATP What is this known as? – Answer????3 Complex V or ATP synthase Cori Cycle – Answer????lactate to glucose in the liver back to RBC What tissues can preform gluconeogenesis? – Answer????Liver and Kidneys Why can gluconeogenesis only be performed by the kidney and liver? – Answer????G6P can only go to glucose if G6Phosphatase is around which is only produced in the kidney and liver What is glycogen synthesis known as? – Answer????Glycogenesis Glucagon activates ____ which activates ____ Answer????alpha s signaling pathway Adenylate cyclase Adenylate cyclase converts ___ to ___. – Answer????ATP to cAMP cAMP activates ____ - Answer????pKa What does insulin do to glucagon? What does this cause? – Answer????Opposes actions of glucagon by causing the breakdown of cAMP to 5’AMP. This decreases the activity of pKa When glucagon is around... – Answer????glucose is gone What does pKa inhibit in the liver? – Answer????glycogen synthase Pyruvate kinase PFK2 What does pKa activate in the liver? – Answer????glycogen phosphorylase F2,6BPtase What enzyme allows F6P F1,6BP – Answer????PFK1 What enzyme allows F1,6BP F6P and releases Pi? – Answer????F1,6BPtase What does F2,6BP activate? – Answer????PFK1 What does F2,6BP inhibit? – Answer????F1,6BPtase More F2,6BP encourages ____ Less F2,6BP encourages ____ - Answer????more: glycolysis Less: gluconeogenesis What happens in glycolysis when you are at high elevation? – Answer????1. 1,3 BPG 2,3 BPG (enzyme is BPG mutase) 2. 2,3 BPG 3PG (PG Phosphatase) What is the con of high elevation glycolysis? – Answer????You skip over a step that creates 2 ATP, so net ATP production is 0 What is the pro of high elevation glycolysis? – Answer????2,3BPG decreases affinity for oxygen, allowing the RBC to release oxygen at lower concentrations What happens when you replace Pi with Arsenic – Answer????you make 1,arsenic,3P rather than 1,3BPG What happens during arsenic poisoning? – Answer????ADP is turned into an arsenic molecule rather than an ATP, causing RBC death. (basically you suffocate from the inside) What two steps are involved in the malate/aspartate shuttle? – Answer????G3P 1,3 BPG OAA Malate OAA is the ___ of aspartate. Meaning it lacks ___. – Answer????carbon skeleton, amine group What is the enzyme that turns OAA into Aspartate (also changing glutamate into alpha-ketoglutarate in the same step) – Answer????Aspartate Aminotransferase (AST) How does aspartate leave the cell? – Answer????through an aspartate/glutamate antiporter (glut enters while asp leaves) What steps are involved in the glycerol phosphate shuttle? – Answer????G3P 1,3BPG DHAP G3P *G3P and DHAP are isomers How does the glycerol phosphate shuttle work? – Answer????G3P acts on complex 2, becomes oxidized and turns back into DHAP What is different about the H+ ions in the glycerol phosphate shuttle? – Answer????NADH only produces 6 H+ ions rather than 10. It is less sufficient Where do we see the glycerol phosphate shuttle happening more often? – Answer????in insects What is special about fructose metabolism? – Answer????We don’t see hormonal regulation like we do in glucose metabolism Fasted State – Answer????low insulin, high glucagon Fed State – Answer????high insulin, low glucagon What is the liver doing in the fasted state? – Answer???? Glycogenolysis, glucogenesis, TCA cycle What is the skeletal muscle doing in the fasted state? – Answer????TCA Cycle What is adipose tissue doing in the fasted state? – Answer????TCA Cycle What is the RBC doing in the fasted state? – Answer????glycolysis all the way to lactate What is the brain doing in the fasted state? – Answer????glycolysis, TCA cycle What is the liver doing in the fed state? – Answer????glycolysis, TCA cycle, glycogenesis What is the skeletal muscle doing in the fed state? – Answer????Glycogenesis, Glycolysis, TCA cycle What is adipose tissue doing in the fed state? – Answer????glycolysis, TCA cycle Why does glycogenesis not happen in adipose tissue? – Answer????It doesn’t store glycogen What is the RBC doing in the fed state? – Answer????Glycolysis all the way to lactate What is the brain doing in the fed state? – Answer????glycolysis, TCA cycle What is the substrate/product for glycolysis? – Answer????Glucose 2 Pyruvate What is the substrate/product for TCA Cycle? – Answer????Pyruvate 3 CO2 What is the substrate/product for glycogenesis? – Answer????Glucose Glycogen What is the substrate/product for gluconeogenesis? – Answer????Lactate or AA Glucose What is the substrate/product for glycogenolysis? – Answer????Glycogen Glucose What hormonally regulated step in the liver is not in the skeletal muscle? – Answer????PEP Pyruvate What receptors do we have on skeletal muscle for hormonal regulation? – Answer????insulin and norepinephrine What does pKA activate in skeletal muscle? – Answer????glycogen phosphorylase PFK2 What does pKa inhibit in skeletal muscle? – Answer????glycogen synthase F2,6BPase What does alpha s signaling cause in the liver? – Answer????gluconeogenesis What does alpha s signaling cause in the skeletal muscle? – Answer????glycolysis What does a carnivore/ruminant/ketogenic diet lack? – Answer????a lot of glucose consumption What is the liver doing in the fasted state? (carnivore) – Answer????glycogenolysis, gluconeogenesis, TCA cylce What is the skeletal muscle doing in the fasted state? (carnivore) – Answer????TCA cycle What is adipose tissue doing in the fasted state? (carnivore) – Answer????TCA cycle What is the liver doing in the fed state? (carnivore) – Answer????gluconeogenesis, TCA cycle What is skeletal muscle doing in the fasted state? (carnivore) – Answer????TCA, glycogenesis through reverse flux of glycolysis What does lactate activate in hormonal regulation? – Answer????G alpha I couple receptors What does alpha i receptor do? – Answer????Prevents the production of cAMP What is the purpose of the Cori Cycle? – Answer????to turn lactate to glucose to transport to muscles