Exam 3 Terms

Calorimeter

A special instrument in which food can be burned and the amount of heat that is released can be measured; this process demonstrates the energy (caloric) content of the food.

Anabolism

The synthesis of larger molecules from smaller ones.

Catabolism

The breakdown, or degeneration, of larger molecules to smaller molecules.

Adenosine Triphosphate (ATP)

A high-energy compound made up of the purine adenine, the simple sugar ribose, and three phosphate units; it is used by cells as a source of metabolic energy.

Adenosine Diphosphate (ADP)

A metabolic intermediate that results from the removal of one phosphate group from ATP.

Adenosine Monophosphate (AMP)

A low-energy compound that results from the removal of two phosphate groups from ATP.

Dehydration Synthesis

An anabolic process by which smaller, chemically simple compounds are joined and a molecule of water is released; also called condensation.

Hydrolysis

A catabolic process by which a large, chemically complex compound is broken apart with the addition of water.

Phosphorylation

The addition of one or more phosphate groups to a chemical compound.

Oxidation-Reduction Reactions

Reactions in which electrons are lost by one atom or molecule (it is oxidised) and simultaneously gained by another (it is reduced)

Flavin Adenine Dinucleotide (FAD)

A coenzyme derived from the B-vitamin riboflavin; readily accepts electrons (hydrogen) from various donors.

Cofactor

A small, nonprotein substance that enhances or is essential for enzyme action; trace minerals such as iron, zinc, and copper function as this.

Coenzyme

Organic (carbon-containing) cofactor; many are derived from B-vitamins.

Glycolysis

A sequence of chemical reactions that converts glucose to pyruvate.

Nicotinamide Adenine Dinucleotide (NAD)

A coenzyme form of the B-vitamin niacin; readily accepts electrons (hydrogen) from various donors.

Lactate (Lactic Acid)

A three-carbon compound produced from pyruvate in oxygen-deprived conditions.

Acetyl CoA

Metabolic intermediate resulting from the reaction between coenzyme A, which is derived from the B-vitamin pantothenic acid, and two-carbon acetate.

TCA Cycle

Repetitive series of eight metabolic reactions, located in cell mitochondria, that metabolizes acetyl CoA for the production of carbon dioxide, high-energy GTP, and reduced coen-zymes NADH and FADH2.

Electron Transport Chain

A series of metabolic reactions that transports electrons from NAHD or FADH2 through a series of carriers, resulting in ATP production.

Lipolysis

The enzyme-driven catabolism of triglycerides into free fatty acids and glycerol.

Albumin

A serum protein, made in the liver, that transports free fatty acids from one body tissue to another.

β-oxidation (fatty acid oxidation)

A series of metabolic reactions that oxidise free fatty acids, leading to the end products of water, carbon dioxide, and ATP.

Carnitine

A small, organic compound that transports free fatty acids from the cytosol into the mitochondria for oxidation.

Ketone Bodies

Three- and four-carbon compounds (acetoacetate, acetone, and β or 3-hydroxybutyrate) synthesised by the liver when acetyl CoA levels become elevated.

Proteolysis

The breakdown of dietary proteins into single amino acids or small peptides that are absorbed by the body.

Carbon Skeleton

The unique “side group” that remains after deamination of an amino acid; also referred to as a keto acid.

Keto Acid

The chemical structure that remains after deamination of an amino acid.

Glucogenic Amino Acid

An amino acid that can be converted to glucose via glucoeogenesis.

Ketogenic Amino Acid

An amino acid that can be converted to acetyl CoA for the synthesis of free fatty acids.

Alcohol Dehydrogenase (ADH)

An enzyme that converts ethanol to acetaldehyde in the first step of alcohol oxidation.

Aldehyde Dehydrogenase (ALDH)

An enzyme that oxidises acetaldehyde to acetate.

Microsomal Ethanol Oxidising System (MEOS)

A liver enzyme system that oxidises ethanol to acetaldehyde; its activity predominates at higher levels of alcohol intake.

Gluconeogenesis

The synthesis of glucose from noncarbohydrate precursors, such as glucogenic amino acids.

Lipogenesis

The synthesis of free fatty acids from nonlipid precursors, such as ketogenic amino acids or ethanol.

De Novo Synthesis

The process of synthesising a compound “from scrat

Ketones

Formed when there is an ABUNDANCE of acetyl CoA molecules.

Acetyl CoA

When ENERGY is needed, glucogenic and ketogenic amino acids are converted to this molecule.

Pyruvate

When GLUCOSE is needed, glucogenic amino acids are first converted to this molecule.

Acetyl CoA

During beta-oxidation (fatty acid oxidation), fatty acid chains are broken down 2-carbons at a time to form this molecule.

Acetyl CoA

In the presence of oxygen, pyruvate from glucose is converted to this molecule.

Lactic Acid

In the absence of oxygen, pyruvate from glucose is converted to this molecule.

Pyruvate

Three-carbon compound that is the end product of glycolysis.

Anabolism

The process of building large molecules from small molecules. Predominates after a meal has been consumed.

Catabolism

The process of breaking down large molecules to release energy. Predominates in-between meals or during times of fasting and

Cofactor

A enzyme helper that contains carbon.

Lipolysis

The breakdown of triglycerides in the body.

Anaerobic Glycolysis

The breakdown of carbohydrates that does NOT require oxygen

Aerobic Glycolysis

The breakdown of carbohydrates that requires oxygen.

Proteolysis

The breakdown of large protein chains to single amino acids.

Gluconeogenesis

Pathway that produces glucose from noncarbohydrate sources.

Transamination

Synthesis of nonessential amino acids.

ATP

The primary high-energy molecule needed for and produced during human metabolism.

TCA Cycle

Pathway that accepts acetyl Co from glycolysis and beta-oxidation (fatty-oxidation).

Beta-oxidation (Fatty-acid oxidation)

Breakdown of fatty acid chains 2-carbons at a time to form acetyl CoA.

Lipogenesis

Production of triglycerides in the b

Beriberi

A disease caused by thiamin deficiency, characterised by muscle wasting and nerve damage.

Ariboflavinosis

A condition caused by riboflavin deficiency.

Pellagra

A disease that results from severe niacin deficiency.

Homocysteine

An amino acid that requires adequate levels of folate, vitamin B6, and vitamin B12 for its metabolism. High levels of this in the blood are associated with an increased risk for cardiovascular disease.

Intrinsic Factor

A protein secreted by cells of the stomach that binds to vitamin B12 and aids its absorption in the small intestine.

Atrophic Gastritis

A condition, frequently seen in people over the age of 50, in which stomach-acid secretions are low.

Acetylcholine

A neurotransmitter that is involved in many functions, including muscle movement and memory storage.

Goiter

Enlargement of the thyroid gland; can be caused by iodine toxicity or deficiency.

Cretinism

A unique form of mental impairment that occurs in infants when the mother experiences iodine deficiency during pregnancy.

Hypothyroidism

A condition characterised by low blood levels of thyroid hormone.

Hyperthyroidism

A condition characterised by high blood levels of thyroid hormone.

B-Vitamins

Thiamin (B1), Riboflavin (B2), Vitamin B6, Niacin (B3), Folate (B9), Vitamin B12 (Cobalamin), Pantothenic Acid, Bi

Body Mass Index (BMI)

A measurement representing the ratio of a person’s body weight to his or her height (kg/m2).

Underweight

Having too little body fat to maintain health, causing a person to have a weight that is below an acceptable defined standard for a given height, a BMI less than kg/m2.

Normal Weight

Having an adequate but not excessive level of body fat for health.

Overweight

Having a moderate amount of excess body fat, resulting in a person having a weight that is greater than some accepted standard for a given height but is not considered obese; a BMI of 25 to29.9 kg/m2.

Obesity

Having an excess of body fat that adversely affects health, resulting in a person having a weight that is substantially greater than some accepted standard for a given height; a BMI of 30 to 39.9 kg/m2.

Morbid Obesity

A condition in which a person’s body weight exceeds 100% of normal, putting him or her at very high risk for serious health consequences; a BMI \= of 40 kg/m2or higher. Also called severe obesity.

Body Composition

The ratio of a person’s body fat to lean body mass.

Body Fat Mass

The amount of body fat, or adipose tissue, a person has.

Lean Body Mass

The amount of fat-free tissue, or bone, muscle, and internal organs, a person has.

Energy Intake

The amount of energy a person consumes; in other words, the number of kcal consumed from food and beverages.

Energy Expenditure

The energy the body expends to maintain its functions and to perform all levels of movement and activity.

Direct Calorimetry

A method used to determine energy expenditure by measuring the amount of heat released by the body.

Indirect Calorimetry

A method used to estimate energy expenditure by measuring oxygen consumption and carbon dioxide production.

Doubly Labelled Water

A form of indirect calorimetry that measures total daily energy expenditure through the rate of carbon dioxide production. It requires the consumption of water that is labeled with nonradioactive isotopes of hydrogen (deuterium, or 2 H) and oxygen (18 O).

Basal Metabolic Rate (BMR)

The energy the body expends to maintain its fundamental physiologic functions.

Thermic Effect of Food (TEF)

The energy expended as a result of processing food consumed.

Energy Cost of Physical Activity

The energy that is expended on body movement and muscular work above basal levels.

Non-Exercise Activity Thermogenesis (NEAT)

The energy expended to do all activities above BMR and TEF, but excluding volitional sporting activities.

Thrifty Gene Hypothesis

A hypothesis suggesting that some people possess a gene (or genes)that causes them to be energetically thrifty, resulting in their expending less energy at rest and during physical activity.

Set-Point Hypothesis

A hypothesis suggesting that the body raises or lowers energy expenditure in response to increased and decreased food intake and physical activity. This action maintains an individual’s bodyweight within a narrow range.

Protein Leverage Hypothesis

A hypothesis suggesting that the body has a fixed daily dietary protein target, and because our current diets are proportionally higher in carbohydrates and fats and lower in protein, we overeat to meet this target.

Drifty Gene Hypothesis

A hypothesis suggesting that random mutation and drift in the genes that control the upper limit of body fatness can help explain why some people become obese and others do not.

Leptin

A hormone, produced by body fat, that acts to reduce food intake and to decrease body weight and body fat.

Ghrelin

A protein synthesised in the stomach that acts as a hormone and plays an important role in appetite regulation by stimulating appetite.

Peptide YY (PYY)

A protein produced in the gastrointestinal tract that is released after a meal in amounts proportional to the energy content of the meal; it decreases appetite and inhibits food intake.

Brown Adipose Tissue

A type of adipose tissue that has more mitochondria than white adipose tissue and can increase energy expenditure by uncoupling oxidation from ATP production. It is found insignificant amounts in animals and newborn humans.

Adipokines

Cell signalling proteins secreted by adipose tissue; some promote inflammation.

Metabolic Syndrome

A clustering of risk factors that increase one’s risk for heart disease, type 2 diabetes, and stroke, including: abdominal obesity; higher-than-normal triglyceride levels; lower-than-normal HDL-cholesterol levels; higher-than-normal blood pressure (greater than or equal to130/85 mm Hg); and elevated fasting blood glucose levels.

Multifactorial Disease

A disease that may be attributable to one or more of a variety of causes.

Bariatric Surgery

Surgical alteration of the gastrointestinal tract performed to promote weight loss.

Mindful Eating

The nonjudgmental awareness of the emotional and physical sensations one experiences while eating or in a food-related environment.

Intuitive Eating

An approach developed to help people move away from chronic dieting that includes choosing foods without feeling guilty, honouring one’s hunger, respecting fullness, and enjoying the pleasure of eating.

Abdominal Obesity

defined as a waist circumference greater than or equal to 102 cm (40 inches) for men and 88 cm (35 inches) for wo