Exam 2 Terms - Chapters 4-6

The Science of Nutrition

Carbohydrates

One of the three energy-yielding macronutrients, a compound made up of carbon, hydrogen, and oxygen that is derived from plants and provides energy.

Glucose

The most abundant sugar molecule, a monosaccharide generally found in combination with other sugars; the preferred source of energy for the brain and an important source of energy for all cells.

Photosynthesis

A process by which plants use sunlight to fuel a chemical reaction that combines carbon and water into glucose, which is then stored in their cells.

Simple Carbohydrates

A monosaccharide or disaccharide; commonly called sugar.

Monosaccharide

The simplest of carbohydrates; consists of one sugar molecule; the most common is glucose.

Disaccharide

A carbohydrate compound consisting of two monosaccharide molecules joined together.

Fructose

The sweetest natural sugar; a monosaccharide that occurs in fruits and vegetables; also called levulose or fruit sugar.

High-Fructose Corn Syrup

A type of corn syrup in which part of the sucrose is converted to fructose, making it sweeter than sucrose or regular corn syrup.

Galactose

A monosaccharide that joins with glucose to create lactose.

Ribose

A five-carbon monosaccharide that is located in the genetic material of cells.

Lactose

Also called milk sugar, a disaccharide consisting of one glucose molecule and one galactose molecule.

Maltose

A disaccharide consisting of two molecules of glucose; does not generally occur independently in foods; also called malt sugar.

Fermentation

The anaerobic process in which an agent causes an organic substance to break down into simpler substances and results in the production of ATP.

Sucrose

A disaccharide composed of one glucose molecule and one fructose molecule; sweeter than lactose or maltose.

Alpha Bond

A type of chemical bond that can be digested by enzymes produced by the small intestine.

Beta Bond

A type of chemical bond that cannot be easily digested by enzymes in the small intestine.

Complex Carbohydrate

A nutrient compound consisting of long chains of glucose molecules, such as starch, glycogen, and fibre.

Oligosaccharides

Complex carbohydrates that contain 3 to 10 monosaccharides.

Raffinose

An oligosaccharide composed of galactose, glucose, and fructose. Also called melitose.

Stachyose

An oligosaccharide composed of two galactose molecules, a glucose molecule, and a fructose molecule.

Polysaccharide

A complex carbohydrate consisting of long chains of glucose.

Starch

The storage form of glucose (as a polysaccharide) in plants.

Glycogen

The storage form of glucose (as a polysaccharide) in animals.

Dietary Fibre

The nondigestible carbohydrate parts of plants that form the support structures of leaves, stems, and seeds.

Functional Fibre

The nondigestible forms of carbohydrate that are extracted from plants or manufactured in the laboratory and have known health benefits.

Total Fibre

The sum of dietary fibre and functional fibre.

Soluble Fibres

Fibres that dissolve in water.

Viscous

Having a gel-like consistency; these fibers form a gel when dissolved in water.

Insoluble Fibres

Fibres that do not dissolve in water.

Fibre-Rich Carbohydrates

A group of foods containing either simple or complex carbohydrates that are rich in dietary fiber. These foods, which include most fruits, vegetables, and whole grains, are typically fresh or moderately processed.

Salivary Amylase

An enzyme in saliva that breaks starch into smaller particles and eventually into the disaccharide maltose.

Pancreatic Amylase

An enzyme secreted by the pancreas into the small intestine that digests any remaining starch into maltose.

Maltase

A digestive enzyme that breaks maltose into glucose.

Sucrase

A digestive enzyme that breaks sucrose into glucose and fructose.

Lactase

A digestive enzyme that breaks lactose into glucose and galactose.

Insulin

A hormone secreted by the beta cells of the pancreas in response to increased blood levels of glucose; it facilitates uptake of glucose by body cells.

Glucagon

A hormone secreted by the alpha cells of the pancreas in response to decreased blood levels of glucose; it stimulates the liver to convert stored glycogen into glucose, which is released into the blood-stream and transported to cells for energy.

Glycemic Index

A rating of the potential of foods to raise blood glucose and insulin levels.

Glycemic Load

The grams of carbohydrate in a serving of food multiplied by the glycemic index of the carbohydrate and divided by 100.

Ketosis

The process by which the breakdown of fat during fasting states results in the production of ketones.

Ketones

Substances produced during the breakdown of fat when carbohydrate intake is insufficient to meet energy needs; provide an alter-native energy source for the brain.

Ketoacidosis

Excessive blood ketone level, which causes the blood to become very acidic and can be fatal.

Nutritive Sweeteners

Sweeteners, such as sucrose, fructose, honey, and brown sugar, that contribute energy.

Non-Nutritive Sweeteners

Also called alternative sweeteners or high-intensity sweeteners; manufactured sweeteners that provide little or no energy.

Acceptable Daily Intake (ADI)

An estimate made by the Food and Drug Administration of the amount of a non-nutritive sweetener that someone can consume each day over a lifetime without adverse effects.

Hyperglycemia

A condition on which blood glucose levels are higher than normal.

Diabetes

A chronic disease in which the body can no longer regulate blood glucose.

Type 1 Diabetes

A disorder in which the pancreas cannot produce enough insulin.

Type 2 Diabetes

A progressive disorder in which body cells become less responsive to insulin.

Insulin Insensitivity (Insulin Resistance)

A condition in which the body becomes less sensitive (or more resistant) to a given amount of insulin, resulting in insulin having a biological effect that is less than expected.

Impaired Fasting Glucose

Fasting blood glucose levels that are higher than normal but not high enough to lead to a diagnosis of type 2 diabetes.

Prediabetes

A term used synonymously with impaired fasting glucose; it is a condition considered to be a major risk factor for both type 2 diabetes and heart disease.

Hypoglycemia

A condition marked by blood glucose levels that are below normal fasting levels.

Lactose Intolerance

A disorder in which the body does not produce sufficient lactase enzyme and therefore cannot digest foods that contain lactose, such as cow's milk.

Cardiovascular Disease (CVD)

A general term that refers to abnormal conditions involving dysfunction of the heart or blood vessels, including coronary heart disease, stroke, and hypertension.

Lipids

A diverse group of organic substances that are insoluble in water; include triglycerides, phospholipids, and sterols.

Triglyceride

A molecule consisting of three fatty acids attached to a three-carbon glycerol backbone.

Glycerol

An alcohol composed of three carbon atoms; it is the backbone of a triglyceride molecule.

Fatty Acid

An acid composed of a long chain of carbon atoms bound to each other as well as to hydrogen atoms, with a carboxyl group at the alpha end of the chain.

Phospholipids

A type of lipid in which a fatty acid is combined with another compound that contains phosphate; unlike other lipids, these are soluble in water.

Sterols

A type of lipid found in foods and the body that has a ring structure; cholesterol is the most common one that occurs in our diets.

Short-Chain Fatty Acids

Fatty acids fewer than six carbon atoms in length.

Medium-Chain Fatty Acids

Fatty acids that are 6 to 12 carbon atoms in length.

Long-Chain Fatty Acids

Fatty acids that are 14 or more carbon atoms in length.

Saturated Fatty Acid (SFA)

Fatty acids that have no carbons joined together with a double bond; these types of fatty acids are generally solid at room temperature.

Monounsaturated Fatty Acids (MUFAs)

Fatty acids that have two carbons in the chain bound to each other with one double bond; these types of fatty acids are generally liquid at room temperature.

Polyunsaturated Fatty Acids (PUFAs)

Fatty acids that have more than one double bond in the chain; these types of fatty acids are generally liquid at room temperature.

Trans Fatty Acid

Type of fatty acid in which the hydrogen atoms are attached on diagonally opposite sides of the double carbon bond.

Hydrogenation

The process of adding hydrogen to unsaturated fatty acids, making them more saturated and thereby more solid at room temperature.

Essential Fatty Acids (EFAs)

Fatty acids that must be consumed in the diet because they cannot be made by the body. The two examples are linoleic acid and alpha-linolenic acid (ALA).

Linoleic Acid

An essential fatty acid found in vegetable and nut oils; an omega-6 fatty acid.

Alpha-Linolenic Acid (ALA)

An essential fatty acid found in leafy green vegetables, flaxseed oil, soy oil, fish oil, and fish products; an omega-3 fatty acid.

Eicosapentaenoic Acid (EPA)

A metabolic derivative of alpha-linolenic acid; also available from marine foods.

Docosahexaenoic Acid (DHA)

A metabolic derivative of alpha-linolenic acid; also available from marine foods.

Micelle

A spherical compound made up of bile salts and biliary phospholipids that transports lipid digestion products to the intestinal mucosal cell.

Lipoprotein

A spherical compound in which fat clusters in the center and phospholipids and proteins form the outside of the sphere.

Chylomicron

A lipoprotein produced in the enterocytes; transports dietary fat out of the intestinal tract.

Lipoprotein Lipase

An enzyme that sits on the outside of cells and breaks apart triglycerides, so that their fatty acids can be removed and taken up by the cell.

Visible Fats

Fats we can see in our foods or see added to foods, such as butter, margarine, cream, shortening, salad dressings, chicken skin, and untrimmed fat on meat.

Invisible Fats

Fats that are hidden in foods, such as the fats found in baked goods, regular-fat dairy products, marbling in meat, and fried foods.

Atherosclerosis

A disease in which arterial walls accumulate deposits of lipids and scar tissue, which build up to a point at which they impair blood flow.

Very-Low-Density Lipoprotein (VLDL)

A lipoprotein made in the liver and intestine that functions to transport endogenous lipids, especially triglycerides, to the tissues of the body.

Low-Density Lipoprotein (LDL)

A lipoprotein formed in the blood from VLDLs; transports cholesterol to the cells of the body; often called "bad cholesterol."

High-Density Lipoprotein (HDL)

A lipoprotein made in the liver and released into the blood; transports cholesterol from the tissues back to the liver; often called "good cholesterol."

Proteins

Large, complex molecules made up of amino acids and found as essential components of all living cells.

Amino Acids

Nitrogen-containing molecules that combine to form proteins.

Essential Amino Acids

Amino acids not produced by the body, or not produced in sufficient amounts, so they must be obtained from food.

Nonessential Amino Acids

Amino acids that can be manufactured by the body in sufficient quantities and therefore do not need to be consumed regularly in our diet.

Transamination

The process of transferring the amine group from one amino acid to another in order to manufacture a new amino acid.

Conditionally Essential Amino Acids

Amino acids that are normally considered nonessential but become essential under certain circumstances when the body's need for them exceeds the ability to produce them.

Peptide Bond

Unique type of chemical bond in which the amine group of one amino acid binds to the acid group of another in order to manufacture dipeptides and all larger peptide molecules.

Gene Expression

The process of using a gene to make a protein.

Nucleotide

A molecule composed of a phosphate group, a pentose sugar called deoxyribose, and one of four nitrogenous bases: adenine(A), guanine (G), cytosine (C), or thymine (T).

Transcription

The process through which messenger RNA copies genetic information from DNA in the nucleus.

Translation

The process that occurs when the genetic information carried by messenger RNA is translated into a chain of amino acids at the ribosome.

Denaturation

The process by which proteins uncoil and lose their shape and function when they are exposed to heat, acids, bases, heavy metals, alcohol, and other damaging substances.

Limiting Amino Acid

The essential amino acid that is missing or in the smallest supply in the amino acid pool and is thus responsible for slowing or halting protein synthesis.

Incomplete Proteins

Foods that do not contain all of the essential amino acids in sufficient amounts to support growth and health.

Complete Proteins

Foods that contain sufficient amounts of all nine essential amino acids.

Mutual Supplementation

The process of combining two or more incomplete protein sources to make a complete protein.