IASM 38-50.1

OAA can be converted into phosphoenolpyruvate (PEP) and then into glucose.

Amino acids are converted to urea.

To ensure the brain has a constant supply of energy.

70-100 mg/dL

In late adulthood, often associated with obesity.

Fat breakdown is accelerated, leading to high production of ketone bodies.

Bioenergetics is the study of cellular energy transformation, where dietary fuels from carbohydrates, fats, and proteins are oxidized to conserve energy as ATP.

Red blood cells only use glucose, and the brain prefers glucose.

Glutamine and alanine serve as amino group carriers from skeletal muscles to other tissues and help transport nitrogen to the liver for urea formation.

They are broken down into free amino acids, absorbed into circulation from the small intestine, and travel to the liver to form proteins, essential nitrogen-containing compounds, triglycerides, or glucose.

Oxygen is essential for ATP synthesis because it acts as the final electron acceptor in the electron transport chain. Without oxygen, no ATP production occurs, leading to cell death.

Glutamine synthetase catalyzes the reaction of glutamate with NH4+ and ATP to form glutamine, ADP, and Pi.

Surplus nitrogen is converted to urea for disposal via urine.

The TCA cycle is inhibited by ATP and NADH.

Acetoacetate can form acetone in the blood.

Pepsinogen is activated to pepsin in the stomach by chief cells.

They are segregated into different cellular compartments, maintaining different concentrations of intermediates, enzymes, and regulators.

Glutamine carries ammonia (NH3) to the kidney for excretion of protons and serves as fuel for the kidney and cells of the immune system.

Amino acids are used for protein synthesis, as fuel, or for the synthesis of essential compounds, supported by the net degradation of skeletal muscle proteins.

Cortisol stimulates amino acid mobilization from muscle protein, gluconeogenesis in the liver, and fatty acid release from adipose tissue.

The two main parts of oxidative phosphorylation are the electron transport chain (ETC) and chemiosmosis.

The proton gradient in the intermembrane space drives ATP synthase to generate ATP by moving H+ down the gradient from the intermembrane space to the mitochondrial matrix.

Malonyl CoA provides the 2-carbon units for the elongation of growing fatty acids.

The primary source of amino acids in the fasting state is the degradation of skeletal muscle.

Insulin and glucagon

Epinephrine; it stimulates glucose production from glycogen and fatty acid release from adipocytes.

Each acetyl CoA produces 12 ATP when converted to CO2 and H2O by the TCA cycle.

Glycerol is used for gluconeogenesis.

Metabolic homeostasis is the balance between the intake, oxidation, and storage of carbohydrates, fats, and proteins to ensure a constant supply of ATP and fuel for cellular functions.

Because it overwhelms GLUT5 due to its passive transport mechanism.

Low lactase levels or intestinal injury.

Muscle protein is broken down into amino acids, which are then used for gluconeogenesis in the liver.

NH4+ enters the urea cycle to form urea, which is then excreted in urine.

Physical exercise alone can increase GLUT4 translocation onto the cell surface independent of insulin.

OAA + Acetyl CoA → citrate → isocitrate → α-KG + NADH → succinyl CoA + NADH → succinate + GDP/ADP convert to GTP/ATP → fumarate + FADH2 → malate → OAA + NADH

Fatty acids undergo beta-oxidation and glycerol is used for gluconeogenesis.

An amino acid consists of an amino group, a carboxyl group, a hydrogen atom, a side chain, and an alpha carbon.

They are a fast method to find abnormalities.

The liver deaminates and transaminates amino acids.

It causes a reduction in blood pH, leading to ketoacidosis.

Ribose-5-phosphate and NADPH.

An FPG test measures blood glucose in a person who hasn't eaten anything for 8 or more hours.

Glucose, but it can use ketone bodies during starvation.

The energy released when two phosphate groups are removed from ATP is 7.3 kcal/mol.

1. Deamination with NAD+ to form α-KG, NADH, and NH4+. 2) Transamination with OAA to form α-KG and Asp.

Protein turnover demands a balanced supply of amino acids to meet the needs for peptide-like molecules and to support the free amino acid pool.

ATP synthase pumps H+ to generate ATP by catalyzing the addition of phosphate to ADP, capturing energy from the proton gradient.

Amino acids come from the diet and protein turnover.

Pyruvate + HCO3- + NADPH → malate + NADP+ via malic enzyme.

Most tissues are partially or totally dependent on glucose for ATP generation or the production of precursors for other pathways.

Excess solutes draw water into the colon, causing discomfort and diarrhea, and bacteria ferment the sugar, producing excess gas.

No, the liver cannot metabolize the ketone bodies it produces.

Insulin-dependent or juvenile diabetes.

By diluting glucose, leading to excess urination and thirst.

By measuring the optical density of the brown color with a spectrophotometer, the concentration of oxidized chromogen in the test mixture can be determined, which can be traced back to the quantity of glucose in the original sample.

To repay the oxygen debt and support oxidative phosphorylation for ATP replenishment.

To maintain nitrogen balance in the body and get rid of excess NH3/NH4+.

Its carbon is used for gluconeogenesis, and its NH4+ is used for urea biosynthesis.

Activated trypsin cleaves other zymogens as they enter the GI lumen from the pancreas.

When one phosphate group is removed from ATP, ADP (adenosine diphosphate) is produced, and energy released is 7.3 kcal/mol.

4-5.5 mmol

Isocitrate dehydrogenase is the rate-limiting enzyme of the TCA cycle.

The complexes and coenzymes involved in the ETC are Complexes 1, 2, 3, 4, CoQ, and CytC.

Yes, FADH2 can still donate electrons via Complex 2 even if Complex 1 is inhibited.

OAA can be converted into aspartate (Asp) and asparagine (Asn), which can then be used to make pyrimidines.

The liver uses fatty acids to make ATP via the TCA cycle or to produce ketone bodies for use elsewhere.

It usually develops early in life.

Elevated blood sugar levels.

Peroxidase catalyzes the reduction of hydrogen peroxide to water and oxygen, which then oxidizes a colorless chromogen substrate to a brown color that can be measured spectrophotometrically.

It converts to creatine to provide a rapid source of energy.

NH3 can freely diffuse across cell membranes, whereas NH4+ cannot.

It transports nitrogen to the liver.

Activated enzymes include trypsin, chymotrypsin, elastase, and carboxypeptidases.

Amino acids that pass through the liver are converted into proteins in cells of other tissues.

It inhibits the proton channel of ATP synthase.

Lactic acidosis.

Insulin promotes storage of fuels and glucagon promotes degradation of storage to maintain fuel availability.

Glutamine brings NH4+ to the kidneys for excretion of protons and serves as fuel for the kidney, gut, and immune cells.

Fatty acids are carried by albumin in the blood.

Acetyl CoA is converted into ketone bodies for release into the bloodstream during prolonged fasting.

Glycerophospholipids and sphingolipids are the major components of cell membranes synthesized from fatty acids.

Removing TCA cycle intermediates reduces ATP generation and slows acetyl CoA metabolism because there is not enough OAA to react with acetyl CoA to form citrate.

By SGLT1 in the apical membrane of enterocytes, moving glucose into the cell against its gradient.

They are converted to pyruvate and then to glucose through gluconeogenesis.

Due to the depletion of oxaloacetate (OAA) for glucose production, leading to an accumulation of acetyl-CoA.

TG in adipose tissue is broken down into glycerol and other amino acids, which are used for gluconeogenesis.

A random plasma glucose test measures blood glucose without regard to when the person being tested last ate.

A metabolic cooperation where muscles generate lactate during exercise, which is then converted to glucose in the liver and returned to muscles.

Acetyl CoA is used to make cholesterol, which can become steroid hormones or bile salts.

Hyperammonemia

In all tissue cells.

Alpha-keto acids can enter the TCA cycle at various points and can also be used to make amino acids.

It causes accumulation of protons in the intermembrane space because the H+ channel is blocked, preventing H+ from flowing back into the mitochondrial matrix.

Alanine transfers ammonia from skeletal muscle, gut, and kidneys to the liver, where the nitrogen part is converted to urea for excretion.

Transamination and deamination.

Oxidative phosphorylation occurs in the inner mitochondrial membrane.

Rotenone (a common insecticide) and some barbiturates like sedatives (amytal) can inhibit Complex 1.

Acetyl CoA is oxidized in the TCA cycle, and the electrons carried by NADH and FADH2 are funneled to the electron transport chain to generate ATP.

Liver hepatocytes, kidney tubular cells, pancreatic beta cells, and intestinal enterocytes.

Glucagon helps mobilize TAG (triacylglycerol) into fatty acids for use by the liver and muscle.

Autoimmune destruction of pancreatic beta cells.

The OGTT must begin in the morning because glucose tolerance exhibits a diurnal rhythm with a significant decrease in the afternoon.

The glucose quantification assay is enzyme-based and uses glucose oxidase to catalyze the formation of gluconic acid and hydrogen peroxide, which is then measured using a chromogenic reaction.

It accumulates and favors ketone body synthesis due to a lack of oxaloacetate from amino acid breakdown.

It acts as a hub for maintaining the amino acid pool.

The pancreas secretes zymogens (inactive enzymes) that eventually become activated.

Amino acids and Na+ are carried into enterocytes via sodium ion-dependent carrier transport, and Na+ is pumped out of the enterocyte in exchange for K+ by the Na+/K+ pump.

After degradation, ubiquitin is released intact and recycled, leaving amino acids to rejoin the intracellular amino acid pool.

The carbon skeletons of excess amino acids are usually converted to glucose or triglycerides (TGAs).

The central nervous system (CNS).

Catabolic pathways are convergent, while anabolic pathways are divergent.

Glutaminase converts glutamine to glutamate, releasing NH4+.

The carbon skeletons, or alpha-keto acids, can enter the TCA cycle to generate ATP, convert to ketone bodies, carbohydrates, or be stored as glycogen or triglycerides.

NADH is converted to NAD+ in Complex 1, donating electrons to supercharge Complex 1 and pump H+ from the mitochondrial matrix to the intermembrane space.

De novo fatty acid synthesis occurs in the cytosol.

The initial breakdown of dietary proteins occurs in the stomach.

Solid matrix chemistry.

Muscles use fatty acids to produce ATP.

Insulin resistance.

The body thinks it is starving and enters a fasting state.

Enzymes are kept in lyophilized (freeze-dried) forms to preserve their activity. They can be reconstituted with water and chemical buffers to initiate the enzymatic assay.

In the liver hepatocytes.

Pepsin is activated through a self-cleavage process due to the acidic pH caused by the secretion of HCl.

Enterocytes take in free amino acids, dipeptides, and tripeptides from the intestinal lumen, but only free amino acids get across into blood circulation.

Traces of polypeptides can pass into the blood and may cause allergies, especially in premature infants.

Administering oxygen.

They uncouple oxidative phosphorylation, which can cause fever in toxic overdoses.

ATP (adenosine triphosphate) is a high-energy molecule that stores and provides energy for many cellular processes. It is essential for cell functioning and survival.

The main goal of the TCA cycle in the mitochondria is to generate 3 NADH and 1 FADH2 for the electron transport chain to produce ATP.

Alanine transfers its amino group to the liver, resulting in the formation of pyruvate, which can be used to make glucose.

Ketone bodies are used as alternative fuels for peripheral cells.

Glucose undergoes glycolysis to form pyruvate, which is converted to acetyl CoA. Acetyl CoA enters the TCA cycle to form citrate, which is then converted back to acetyl CoA for fatty acid synthesis.

Citrate is removed for the biosynthesis of lipids, including fatty acids and sterols.

Muscle begins to be used for fuel.

Fatty acids are oxidized to acetyl-CoA.

Liver glycogen.

Via the blood to make tissue proteins.

To release heat and keep organs warm in low temperatures.

Muscle glycogen, producing lactate anaerobically.

As urea or NH4+ in the urine.

Glucose produced from amino acids in the fed state can be stored as glycogen or released into the blood if blood glucose levels are low.

Ground apricot pits used to treat cancer.

Insulin promotes the storage of fuels, synthesis of glycogen, conversion of glucose to triglycerides, amino acid uptake, and protein synthesis.

Poorly controlled glucose homeostasis, indicating abnormal glucose metabolism.

The TCA cycle is stimulated by ADP, which indicates a lack of ATP.

2 Acetyl CoA → acetoacetyl CoA → acetoacetate → acetone or 3-hydroxybutyrate.

Without oxygen, no ATP is generated because electrons back up in the chain, preventing proton pumping and H+ gradient formation.

Dietary proteins are broken down into free amino acids, which enter the blood via enterocytes in the intestines.

Pathways are reciprocally regulated, meaning when one pathway is active, the other is suppressed.

By facilitated GLUT5, which operates passively and does not require energy.

Within 8 hours of fasting.

It acts as the main factory for energy production and detoxification.

Lactate from red blood cells is converted into pyruvate in the liver, which is then used for gluconeogenesis.

They bind to albumin.

It breaks down into acetone, which is expelled via breath, giving a sweet smell.

They are transaminated or deaminated to yield pyruvate and CAC intermediates.

Lipid synthesis occurs in the liver and is stored in adipose tissue, while lipid breakdown occurs in adipose tissue.

Urea

Exopeptidases are enzymes that act on small peptides and are secreted by enterocytes, present in and on the brush border of enterocytes.

Amino acids are carried by facilitated transporters down their concentration gradient into the blood.

They bind to hemoglobin, blocking oxygen binding and transport.

Glucagon promotes the degradation of storage, stimulates the release of glucose from liver glycogen, gluconeogenesis, and mobilizes fatty acids from adipocytes.

The TCA cycle occurs twice for each glucose molecule because each glucose produces two pyruvates.

The oxidation of one molecule of palmitoyl CoA to CO2 and H2O yields a high amount of energy.

Oxygen is the final electron acceptor in the ETC, splitting into half and taking up protons to form water.

The convergent point is at yielding acetyl CoA.

In blood erythrocytes, brain barrier endothelial cells, and fetal cells.

It is converted to glucose-6-phosphate (G6P).

An OGTT is done to diagnose hyperglycemic conditions and is often used for people suspected of having metabolic disorders.

Fuel storage due to its large lipid droplet.

They enter the liver, leading to high blood sugar and insulin release, which promotes glucose uptake and conversion to acetyl CoA and fatty acids for storage.

To maintain the pH balance of the blood.

An example is Aspartate + a-ketoglutarate ←PLP→ oxaloacetate + glutamate.

Cyanide binds to iron in the heme of complex 4’s cytochrome component, preventing electron transport to oxygen and stopping ATP production, leading to cell death.

Obesity induces the synthesis of uncoupler proteins in insulin-making cells, leading to lower ATP concentrations required for insulin secretion, which can cause type 2 diabetes.

Blood glucose rises, insulin levels increase, and insulin induces GLUT4 expression on cell surfaces to increase glucose uptake into cells.

Antimycin, an antibiotic, inhibits Complex 3, preventing the transport of electrons from before Complex 3 to after Complex 3.

Anaplerotic reactions are mechanisms that replenish TCA cycle intermediates to ensure the cycle can continue.

It is fermented by bacteria, breaking down lactose to lactic acid and releasing gas, causing bloating, cramps, and diarrhea.

Acetyl CoA, which can be used for energy oxidation or as a precursor for fatty acids and cholesterol.

It is converted to ketone bodies and released into the blood.

The bicarbonate buffering system.

By producing alanine from pyruvate in the glucose-alanine cycle or glutamine from free ammonia, which then carry the amino group to the liver.

They pick up nitrogen disposal in the form of NH4+ and transport it to the liver.

Zymogens are identified by the prefix 'pro-' or the suffix '-ogen' when they are inactive.

The sodium ion-dependent carrier transport of amino acids into enterocytes is an example of secondary active transport.

Lysosomal enzymes are part of the autophagy process, where unwanted intracellular components are surrounded by membranes, fused with lysosomes, and cleaved into free amino acids by cathepsins.

The reversible process of TCA intermediates being used to make amino acids allows the liver to use proteins as an energy source when there is no glucose.

They create a proton leak, allowing H+ to re-enter the mitochondrial matrix without energy being captured as ATP, releasing energy as heat instead.

1. Control the concentration of nutrients/metabolites in the blood. 2. Use hormones to carry messages about the physiological state and nutrient supply/demand. 3. Use neural signals from the CNS to control metabolism in tissues.

Glucose and galactose.

The nitrogen-containing amino group is made into urea for excretion via the kidneys.

Fatty acids

They decrease blood pH, increasing hydrogen ion concentration, leading to ketoacidosis.

Fatty acids, ketone bodies, and glucose, producing CO2.

a-Ketoglutarate (a-KG) and ammonium ion (NH4+)

Directly or after being converted to glucose by gluconeogenesis.

TGAs are packaged and secreted from the liver in very low-density lipoproteins (VLDLs).

In air, soil, water, and foods such as almonds and the pits of apricots, peaches, and cherries.

Type 1 (insufficient insulin production) and Type 2 (insulin resistance).

They are precursors for protein synthesis, biosynthesis of nucleotides, hormones, and nitrogenous compounds.

Blood glucose is measured after the person fasts for 8 or more hours and then 2 hours after the person drinks a glucose-containing drink.

Dramatic weight loss.

30-60 micromoles

Trypsinogen is activated to trypsin by enteropeptidase secreted by brush border cells of the small intestine.

Pinocytosis is an active, energy-consuming process where extracellular fluid and solutes are taken up into a cell via small vesicles. It is a type of endocytosis.

Transamination is a process where the amino group of one amino acid is transferred to a carbon skeleton (a-keto acid), forming a new amino acid and a new a-keto acid.

Diseases caused by mutations in mitochondrial DNA (mtDNA) that affect the nervous system and muscles.

Muscles must use glycolysis as the primary source of energy, leading to lactate accumulation and muscle soreness or pain.

To provide glucose for the brain by breaking down glycogen and performing gluconeogenesis.

It is converted to urea and excreted by the kidneys.

By alanine and glutamine.

The ubiquitin-proteasome system is an intracellular mechanism where ubiquitin is covalently linked to a protein, which is then degraded into small peptides by proteasomes in an ATP-dependent manner.

It forms acetyl CoA, which is essential for ATP generation.

It can be converted to glucose/glycogen or acetyl CoA for oxidation via the CAC or lipid storage.

One NH4+ from glutamate and one amino group from aspartate.

During exercise or starvation when muscles use blood-borne glucose.

As gastric content empties into the intestine, the pH rises due to bicarbonate, allowing endopeptidases to collectively cleave proteins into free amino acids for absorption.

They inhibit complex 4 (the terminal ETC complex).

Cells are incapable of pyruvate oxidation in the TCA cycle, leading to the conversion of pyruvate to lactate, which accumulates and is released into the blood.

The two general concerns are the fate of the nitrogen component and the fate of the carbon skeleton.

Dinitrophenol (DNP).