ap 2 exam 3

Glycolysis

The metabolic pathway that breaks down glucose into pyruvate, producing a small amount of ATP and NADH.

Intermediate stage

The process of converting pyruvate into acetyl-CoA in the mitochondria, linking glycolysis to the citric acid cycle.

Citric acid cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrates, fats, and proteins.

Electron transport chain

A series of protein complexes in the inner mitochondrial membrane that produces the majority of ATP in cellular respiration using oxygen.

Substrate-level phosphorylation

The direct production of ATP from a substrate during glycolysis and the citric acid cycle.

Oxidative phosphorylation

The indirect production of ATP, utilizing electron carriers NADH and FADH₂ in the electron transport chain.

Acetyl-CoA

A crucial molecule in cellular respiration formed from pyruvate, it serves as the entry point into the citric acid cycle.

Pyruvate

The end product of glycolysis, a 3-carbon molecule that can be converted into lactate under anaerobic conditions.

Pyruvate dehydrogenase

An enzyme that converts pyruvate into acetyl-CoA during the intermediate stage of respiration.

Fatty acids

Long-chain hydrocarbons that are oxidized to acetyl-CoA, entering the citric acid cycle for ATP production.

Amino acids

Building blocks of proteins that can be deaminated and enter cellular respiration at different points after removal of the nitrogen group.

NAD⁺

A coenzyme that accepts electrons and becomes NADH, which is usable in the electron transport chain.

NADH

The reduced form of NAD⁺ that carries electrons to the electron transport chain, playing a key role in ATP production.

Citrate

The first molecule formed in the citric acid cycle, created by the combination of acetyl-CoA and oxaloacetate.

Oxaloacetate

A four-carbon molecule that combines with acetyl-CoA to form citrate in the citric acid cycle.

ATP

A high-energy molecule produced in cellular respiration, which serves as the main energy currency of the cell.

ADP

A low-energy molecule that, when phosphorylated, converts to ATP, thus storing energy.

Allosteric inhibition

Regulation of enzyme activity by binding of a molecule at a site other than the enzyme's active site, like ATP inhibiting PFK in glycolysis.

Metabolic pathways

A series of linked biochemical reactions catalyzed by enzymes, resulting in the conversion of substrates into products.

Pyruvate → lactate

The conversion of pyruvate to lactate under anaerobic conditions, which regenerates NAD⁺.

Carbon skeleton of amino acids

The remaining structure of an amino acid after deamination, which can enter various pathways for energy production.

Cristae

The folds of the inner mitochondrial membrane where the electron transport chain occurs.

Hydrogen gradient

The difference in hydrogen ion concentration across a membrane, used by ATP synthase to synthesize ATP.

Glycolysis control point

Phosphofructokinase (PFK) inhibited by ATP, controlling the flow through glycolysis.

Lacteals

Lymphatic vessels in the intestines that absorb and transport lipids into the lymphatic system.

Cholecystokinin (CCK)

A hormone that stimulates gallbladder contraction to release bile and pancreatic enzyme secretion.

Insulin

A hormone released when blood glucose is high; it promotes glucose uptake into cells and glycogen storage.

Glucagon

A hormone secreted when blood glucose is low; it promotes the conversion of glycogen to glucose.

Gastrin

A hormone that increases gastric acid secretion and motility in response to food in the stomach.

Bile

A digestive fluid produced by the liver that emulsifies fats, aiding in their digestion and absorption.

Pepsinogen

An inactive precursor of pepsin, activated by hydrochloric acid in the stomach for protein digestion.

Amino acid deamination

The removal of an amino group from an amino acid, allowing the remaining carbon skeleton to enter metabolic pathways.

Proteins

Macromolecules made of amino acids that serve various functions including structural, enzymatic, and regulatory roles.

Liver function

The production of bile, synthesis of proteins, and detoxification of metabolites.

Small intestine

The primary site of digestion and absorption of nutrients in the digestive tract.

Mucosa

The innermost layer of the GI tract wall, involved in secretion and absorption.

Serosa

The outermost layer of the GI tract wall, providing protection and supporting structure.

Peristalsis

The coordinated contraction and relaxation of smooth muscles in the GI tract to move contents forward.

Segmentation

A localized contraction of intestinal muscles that mixes food and increases absorption.

Nutrient absorption pathways

The process whereby absorbed nutrients enter circulation, with most nutrients going into blood and fats entering lymph.

Fats

Lipids composed of fatty acids and glycerol, serving as long-term energy sources and insulation.

Glucose

A simple sugar that is a primary energy source for cells and enters glycolysis during cellular respiration.

Fructose

A simple sugar found in fruits; it can be metabolized into glucose or used directly for energy.

Sucrose

A disaccharide composed of glucose and fructose, which can be broken down into its components.

Lipoproteins

Complexes of lipids and proteins that serve to transport lipids in the blood.

Glycogen

The stored form of glucose in animals, primarily found in the liver and muscles.

Carbohydrate digestion

The process of breaking down carbohydrates into glucose, which can then be utilized for energy or stored.

Fat digestion

The emulsification of fats by bile followed by the breakdown by lipase in the small intestine.

Protein digestion

The breakdown of proteins into amino acids through the action of enzymes like pepsin and proteases.

Chymotrypsin

An enzyme produced by the pancreas that digests proteins into peptides.

Trypsin

A protease enzyme produced in the pancreas that helps to break down proteins in the small intestine.

Fiber

A type of carbohydrate that is not digestible and aids in intestinal movement.

Minerals

Inorganic substances required for various physiological functions, such as calcium for bones and iron for oxygen transport.

Vitamins

Organic compounds that are essential for various metabolic processes in the body, divided into water-soluble and fat-soluble categories.

Essential nutrients

Nutrients that must be obtained from dietary sources because the body cannot synthesize them.

Non-essential nutrients

Nutrients that can be synthesized by the body and do not need to be obtained through diet.

Continuous muscular tube

Describes the structure of the GI tract, functioning in sequential segments for digestion and absorption.

Hydrochloric acid (HCl)

An acid produced in the stomach that aids in digestion by activating pepsin and denaturing proteins.

Motility

The ability of the digestive system to move food through peristalsis and segmentation.

Energy balance

The relationship between energy intake from food and energy expenditure from metabolic processes.

Absorption process

The uptake of nutrients from the digestive tract into the bloodstream or lymphatic system.

Fluid balance

The maintenance of the proper amount and distribution of water and electrolytes in the body.

Caloric intake

The number of calories consumed through food and beverages.

Caloric expenditure

The number of calories burned through metabolic processes and physical activity.

Nutritional balance

Achieving appropriate levels of macronutrients and micronutrients for overall health.

Sphincter muscles

Muscle rings that control the passage of food through the digestive tract.

Digestive enzymes

Biological molecules that speed up the digestion of food into absorbable units.

Hydration

The process of absorbing water necessary for various physiological functions.

Nutrient requirements

The specific amount of each nutrient that individuals need for optimal health.

Polyunsaturated fats

Fats that contain more than one double bond in their fatty acid chains and are beneficial for heart health.

Saturated fats

Fats that are solid at room temperature and can raise cholesterol levels if consumed in excess.

Dietary fiber

Parts of plant-based foods that cannot be digested, helping to regulate the body's use of sugars.

Unsaturated fats

Fats that are liquid at room temperature and are generally healthier than saturated fats.

Complete proteins

Proteins that contain all essential amino acids needed by the body.

Incomplete proteins

Proteins that lack one or more essential amino acids.

Nutritional deficiencies

Health problems resulting from inadequate intake or absorption of essential nutrients.

Therapeutic diet

Diets specifically designed to treat or manage health conditions.