kin 3515 exam 2 crammyyy cram

Bioenergetics / Metabolism

How living things make and use energy / Sum of chemical processes in the body

Catabolism / Anabolism

Breaks down fuel molecules and releases energy / Builds larger molecules and stores energy

Kinetic energy / Potential energy

Energy of motion / Stored energy related to position or state

Exergonic reaction / Endergonic reaction

Releases free energy; products have less free energy / Requires energy input; stores energy and increases free energy

Hydrolysis / Condensation

Uses water to break a chemical bond / Forms a bond while releasing water

Oxidation / Reduction

Loss of electrons / Gain of electrons

Redox reaction / Allosteric enzyme

Transfer of electrons between molecules / Enzyme regulated by a molecule binding away from its active site

Rate-limiting enzyme / Enzyme

Enzyme controlling the rate of a metabolic pathway / Protein that speeds a specific reaction by lowering activation energy; not consumed

Activation energy / First law of thermodynamics

Energy needed for a reaction to proceed / Energy cannot be created or destroyed; it changes form

Second law of thermodynamics / Coupled reactions

Energy transformations degrade some usable energy to heat / Energy released by an exergonic reaction drives an endergonic reaction

Three forms of biological work / Peptide/protein hormone

Chemical, mechanical, and transport work / Hormone that binds a cell-surface receptor; may activate adenyl cyclase → cAMP → protein kinase

Steroid hormone / Insulin

Can enter cells and bind intracellular receptors to alter activity / Promotes glucose storage, lipid storage, and protein synthesis; generally decreases during exercise

Glucagon / Epinephrine

Promotes glucose release and lipid release; supports blood glucose during exercise / Promotes glucose and fatty-acid release and increases metabolic rate

Cortisol / Growth hormone

Promotes glucose availability, lipid release, and protein breakdown / Promotes lipid release, protein synthesis/growth, and glucose synthesis

Testosterone / Glycogen

Promotes protein synthesis and growth / Stored carbohydrate made of branched glucose units

Glycogenesis / Glycogenolysis

Synthesis of glycogen from glucose / Breakdown of glycogen to release glucose units

Gluconeogenesis / Glycolysis

Synthesis of glucose from non-carbohydrate intermediates / Breakdown of glucose to pyruvate with ATP production; occurs in cytosol

Esterification / Lipolysis

Joins fatty acids to glycerol to form triacylglycerol (TAG) / Breakdown of stored TAG into fatty acids and glycerol

Essential amino acid / Monosaccharide

Amino acid the body cannot synthesize adequately; must come from diet / Single sugar unit

Disaccharide / Polysaccharide

Two monosaccharides bonded together / Many monosaccharide units bonded together

Major exercise carbohydrates / Approximate stored carbohydrate

Glucose and glycogen / ~400 g muscle and ~100 g liver

Four glucose/glycogen processes / Four uses of carbohydrate

Glycogenesis, glycogenolysis, glycolysis, gluconeogenesis / Fuel intense exercise; spare protein; provide substrates for complete fat oxidation; fuel CNS/nerve tissue

Simple lipids / Compound lipids

Primarily neutral fats/TAG / Lipids combined with other chemical groups; examples include phospholipids, glycolipids, lipoproteins

Derived lipids / TAG

Fatty acids, steroids, and hydrocarbons derived from other lipids / Triacylglycerol; major stored form of fat in adipose tissue

Four major lipoproteins / Chylomicrons

Chylomicrons, VLDL, LDL, HDL / Transport dietary TAG to tissues

VLDL / LDL

Transports TAG from liver to tissues such as muscle and adipose / Lipoprotein that delivers cholesterol to tissues

HDL / Nine essential amino acids

Lipoprotein involved in returning cholesterol toward the liver / Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine

Nitrogen balance / Excess amino-acid nitrogen

Relationship between protein breakdown and protein synthesis / Converted to urea and eliminated mainly in urine

Largest energy store / ATP

Fat/lipid / Adenosine triphosphate; the cell’s immediate energy donor

Metabolic mill / Aerobic metabolism

Linked pathways that generate ATP, including glycolysis, TCA cycle, and ETC/oxidative phosphorylation / Mitochondrial metabolism that uses oxygen as the final electron acceptor

Anaerobic metabolism / Why ATP is a limited currency

ATP production without directly requiring oxygen, especially phosphagen system and glycolysis / Only small stores are present; resting stores support ~2–3 seconds of maximal exercise, so ATP must be resynthesized

Major fuel stores / Acetyl-CoA

ATP and PCr in muscle; glycogen in muscle/liver; TAG in adipose/muscle; blood glucose; circulating fatty acids/glycerol; amino-acid carbon skeletons / Two-carbon intermediate connecting carbohydrate, fat, and protein metabolism; enters TCA cycle

ATP hydrolysis / ATPase

ATP → ADP + Pi; releases energy to support cellular work / Enzyme that hydrolyzes ATP

Creatine kinase (CK) / Myokinase/adenylate kinase

Transfers phosphate between phosphocreatine and ADP/ATP to rapidly resynthesize ATP / 2 ADP → ATP + AMP

Synthase / Phosphatase

Enzyme that forms a product, often using energy from a coupled reaction / Enzyme that removes a phosphate group

Hexokinase / GLUT2

Adds phosphate to glucose to form glucose-6-phosphate / Glucose transporter associated with organs that release glucose into blood, especially liver

GLUT4 / Muscle vs liver glycogen

Glucose transporter in skeletal muscle/adipose; recruited to membrane by insulin and muscle activity / Muscle glycogen fuels muscle itself; liver glycogen helps maintain blood glucose

Glycogen synthase / Glycogen phosphorylase

Enzyme that synthesizes glycogen / Enzyme that breaks down glycogen

Immediate/phosphagen system / Glycolysis location

Supplies ATP immediately for very short maximal efforts using stored ATP and PCr / Cytosol

Glycolysis phase 1 / Glycolysis phase 2

Energy investment phase; ATP is used to phosphorylate sugar and prepare it to split / Energy generation phase; G3P is oxidized, NADH forms, and ATP is generated

PFK / Substrate-level phosphorylation

Phosphofructokinase; uses ATP to convert fructose-6-phosphate to fructose-1,6-bisphosphate; key glycolysis regulator / Direct transfer of phosphate to ADP to form ATP

Glycolysis from one glucose / Glycolysis from muscle glycogen

Produces 2 pyruvate and 2 NADH; net 2 ATP from free glucose / Net 3 ATP per glucose unit entering as glycogen-derived glucose-6-phosphate

ATP investment in glycolysis from glucose / NAD+

2 ATP invested in the standard pathway; ATP yield depends on the starting substrate and class framing / Oxidized electron carrier that accepts electrons/H during oxidation

NADH / Three fates of pyruvate

Reduced electron carrier carrying high-energy electrons to the ETC / Conversion to acetyl-CoA; conversion to lactate; conversion to alanine

Pyruvate → acetyl-CoA / Pyruvate → lactate

Aerobic mitochondrial route; produces NADH and CO2 / Lactate dehydrogenase regenerates NAD+ so glycolysis can continue

Pyruvate → alanine / Cori cycle

Transamination adds an amino group; alanine carries carbon and nitrogen from muscle to liver / Lactate travels from muscle to liver for glucose production; glucose returns to muscle

Glucose-alanine cycle / Muscle gluconeogenesis

Alanine carries carbon and nitrogen from muscle to liver and supports glucose production/nitrogen handling / Muscle cannot perform gluconeogenesis to release free glucose into blood

Mitochondria / Mitochondrial cristae

Organelles central to aerobic ATP production / Folds of inner membrane that increase surface area

TCA cycle location / ETC location

Mitochondrial matrix / Inner mitochondrial membrane

Oxidative phosphorylation / Acyl-CoA

ATP formation driven by ETC electron transfer and the proton gradient / Activated fatty acid attached to coenzyme A

Ketosis / Pyruvate dehydrogenase complex

Increased production/use of ketone bodies when carbohydrate availability is low and fat oxidation is high / Converts pyruvate to acetyl-CoA, producing NADH and CO2

TCA cycle sequence / TCA yield per acetyl-CoA

Acetyl-CoA + oxaloacetate → citrate → isocitrate → alpha-ketoglutarate → succinyl-CoA → succinate → fumarate → malate → oxaloacetate / 3 NADH, 1 FADH2, 1 ATP/GTP directly, 2 CO2; 10 ATP equivalents using class values

Citrate synthase / TCA inhibitors emphasized in class

Combines acetyl-CoA with oxaloacetate to form citrate / Citrate, NADH, and ATP inhibit citrate synthase; ADP favors energy production

Malate-aspartate shuttle / Glycerol-3-phosphate shuttle

Transfers cytosolic NADH electrons into mitochondria so they enter as mitochondrial NADH; higher ATP yield / Transfers cytosolic NADH electrons to mitochondrial FAD-linked carriers; lower ATP yield than malate-aspartate shuttle

ETC Complex I / ETC Complex II

Accepts electrons from NADH / Accepts electrons from FADH2

ETC Complex III and IV / Final electron acceptor

Pass electrons along the chain; proton pumping helps establish the gradient / Oxygen; combines with electrons and H+ to form water

ATP synthase / ATP exit from mitochondria

Uses the proton gradient to make ATP from ADP + Pi / Adenine nucleotide translocase exchanges mitochondrial ATP for ADP across the inner membrane

Class ATP equivalent: NADH / Class ATP equivalent: FADH2

1 NADH ≈ 2.5 ATP / 1 FADH2 ≈ 1.5 ATP

Class ATP equivalent: acetyl-CoA through TCA / Hormone-sensitive lipase (HSL)

10 ATP equivalents per acetyl-CoA / Major enzyme associated with mobilizing stored TAG/fatty acids

Hormonal control of lipolysis / Fatty-acid activation

Epinephrine, cortisol, and growth hormone promote lipolysis; insulin promotes storage and inhibits lipolysis / Fatty acid attaches to CoA to form fatty acyl-CoA; costs 2 ATP equivalents

Carnitine shuttle / CPT / Beta oxidation

Transports long-chain fatty acyl groups into mitochondria; CPT = carnitine palmitoyl transferase / Mitochondrial cyclic breakdown of fatty acyl-CoA into 2-carbon acetyl-CoA units

Beta-oxidation products per round / Even-chain beta-oxidation rounds formula

1 NADH, 1 FADH2, and shortening of the fatty acyl chain by 2 carbons; acetyl-CoA is released / Rounds = (number of carbons ÷ 2) − 1

Even-chain acetyl-CoA formula / Beta-oxidation NADH formula

Acetyl-CoA = number of carbons ÷ 2 / NADH produced = number of beta-oxidation rounds

Beta-oxidation FADH2 formula / Beta-oxidation gross ATP formula

FADH2 produced = number of beta-oxidation rounds / Gross ATP = (NADH × 2.5) + (FADH2 × 1.5) + (acetyl-CoA × 10)

Beta-oxidation net ATP formula / Palmitate (16C) ATP yield

Net ATP = gross ATP − 2 ATP equivalents for fatty-acid activation / 7 rounds; 8 acetyl-CoA; 7 NADH; 7 FADH2; gross 108 ATP; net 106 ATP

Stearate (18C) ATP yield / 12-carbon saturated fatty acid

8 rounds; 9 acetyl-CoA; 8 NADH; 8 FADH2; gross 122 ATP; net 120 ATP / 5 rounds; 6 acetyl-CoA; 5 NADH; 5 FADH2; gross 80 ATP; net 78 ATP

14-carbon saturated fatty acid / 20-carbon saturated fatty acid

6 rounds; 7 acetyl-CoA; 6 NADH; 6 FADH2; gross 94 ATP; net 92 ATP / 9 rounds; 10 acetyl-CoA; 9 NADH; 9 FADH2; gross 136 ATP; net 134 ATP

Odd-chain fatty acid endpoint / Fats burn in a carbohydrate flame

Produces a 3-carbon propionyl-CoA that enters metabolism differently from acetyl-CoA / Complete fat oxidation depends on carbohydrate-derived TCA intermediates, especially oxaloacetate

Glycerol metabolism / Glucogenic amino acid

Glycerol can be converted to intermediates that enter glycolysis or gluconeogenesis; class notes one ATP investment / Carbon skeleton can enter pathways that support glucose production

Ketogenic amino acid / Amino acid classification counts

Produces acetyl-CoA/acetoacetate and contributes to ketone-body/fat metabolism / 18 glucogenic-only, 2 ketogenic-only, and 5 both glucogenic and ketogenic

Amino-acid carbon skeleton entry points / VO2

Pyruvate, acetyl-CoA, alpha-ketoglutarate, succinyl-CoA, fumarate, oxaloacetate, and linked intermediates / Oxygen consumption

Oxygen deficit / Lactate threshold

Lag between oxygen required for exercise and oxygen actually consumed at exercise onset / Exercise intensity at which blood lactate begins rising disproportionately

OBLA / Hypoglycemia

Onset of blood lactate accumulation / Abnormally low blood glucose; class quiz used below 2.5 mM

Crossover concept / Primary fuel at rest

As exercise intensity increases, fuel use shifts toward greater carbohydrate contribution / Nearly 100% of ATP production is aerobic; fat contributes substantially

Short, maximal exercise energy system / High-intensity exercise energy system

stored ATP and PCr; highest power, lowest capacity / Anaerobic glycolysis contributes strongly and rapidly; carbohydrate/glycogen use rises

Longer-duration exercise energy system / 400 m sprint (~50–60 seconds)

Aerobic metabolism predominates; carbohydrate and fat contributions depend on intensity and duration / Anaerobic glycolysis is predominant, but all energy systems contribute

Power vs capacity of energy systems / Lactate formation purpose

Phosphagen = highest power/lowest capacity; glycolysis = rapid ATP with more capacity; aerobic = lower immediate power/high capacity/high yield / Regenerates NAD+ so glycolysis can continue when glycolytic demand is high

Lactate and fatigue / Active recovery and lactate

High-intensity exercise is associated with H+ accumulation and lower pH, which can impair muscle contraction and enzyme function / Active recovery can facilitate lactate removal more than passive recovery; the heart can oxidize lactate

Factors determining glycogen use / Exercise hormone pattern

Exercise intensity, duration, training/fuel status, and hormonal/allosteric regulation / Epinephrine, glucagon, cortisol, and growth hormone generally rise; insulin generally falls

Why hormones change during exercise / Glycogenolysis intensity finding

Increase fuel availability and match ATP supply to exercise demand / Rate of glycogenolysis is greatest at the highest listed intensity (90%)

Total glycogen use and intensity / EPOC

Total use can be higher at a more sustainable intensity (e.g., 75%) if exercise can be maintained longer / Excess post-exercise oxygen consumption; oxygen uptake remains elevated during recovery

Oxygen deficit vs EPOC / EPOC rapid phase

Oxygen deficit occurs at exercise onset; EPOC is elevated oxygen consumption after exercise / Restores ATP/PCr and oxygen stores in blood/myoglobin

EPOC slow-phase contributors / Seven EPOC contributors

Lactate oxidation/removal, lactate-to-glycogen processing, elevated temperature, hormone effects, and elevated HR/ventilation/other functions / ATP/PCr resynthesis; restore O2 in blood/myoglobin; lactate converted to glycogen; lactate oxidized; elevated temperature; hormone effects; elevated HR/ventilation/other functions

Oxygen repayment fraction / Steady-rate recovery

About 20% of elevated recovery oxygen repays the initial oxygen deficit, per class material / Usually passive recovery is appropriate after steady-rate exercise

Non-steady/high-intensity recovery / Muscle glycogen restoration

Greater EPOC due to more PCr depletion, lactate accumulation, elevated temperature, hormonal changes, and physiological strain / Carbohydrate intake supports replenishment; recovery timing and diet affect storage

Glucose-alanine vs Cori cycle / ATP yield per glucose vs glycogen

lactate from muscle to liver; alanine cycle: alanine (carbon + nitrogen) from muscle to liver / net 2 ATP from glycolysis; muscle glycogen unit: net 3 ATP; both yield 2 NADH

Glycolysis intermediates to recognize / PFK reaction

Glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, glyceraldehyde-3-phosphate (G3P), 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate (PEP), pyruvate / Fructose-6-phosphate + ATP → fructose-1,6-bisphosphate + ADP

Pyruvate kinase / Lactate dehydrogenase

Catalyzes the final glycolysis step to form pyruvate and ATP / Catalyzes pyruvate ↔ lactate while regenerating NAD+ in lactate formation

Alanine aminotransferase/transamination / Acetyl-CoA formation yield

Converts pyruvate to alanine by transferring an amino group / Each pyruvate converted to acetyl-CoA produces NADH and CO2

TCA intermediate pair at entry / TCA CO2-producing steps

Acetyl-CoA combines with oxaloacetate to form citrate / Isocitrate → alpha-ketoglutarate and alpha-ketoglutarate → succinyl-CoA each produce CO2 and NADH

Succinate oxidation / Malate oxidation

Succinate → fumarate produces FADH2 / Malate → oxaloacetate produces NADH

ETC proton gradient / Why oxygen matters

Protons pumped across inner mitochondrial membrane store potential energy used by ATP synthase / Oxygen accepts electrons at the end of the ETC, enabling continued electron flow and efficient oxidative phosphorylation

Glycogenolysis muscle vs liver / Lipoprotein that carries liver TAG

Muscle uses released glucose units locally; liver can release glucose to help maintain blood glucose / VLDL

Fuel storage in adipocytes / Protein sparing

TAG is the main stored lipid in adipose tissue / Carbohydrate availability reduces the need to use protein for energy

Hormonal response with exercise intensity/duration

Exercise hormones mobilize fuels; changes generally increase with exercise demand, with intensity and duration affecting patterns.