NTRI 2000 Exam 2: Vocabulary Flashcards

Vocabulary practice cards covering key terminology across Carbohydrates, Lipids, and Proteins for NTRI 2000 Exam 2.

Photosynthesis

Process where plants combine carbon dioxide ($CO_2$), water ($H_2O$), and solar energy to synthesize glucose ($C_6H_{12}O_6$).

Glucose

Essential monosaccharide energy source for all tissues and sole fuel for RBCs.

Fructose

Monosaccharide known as fruit sugar; the sweetest simple sugar.

Galactose

Monosaccharide component of lactose that is converted to glucose in the liver.

Sucrose

Disaccharide composed of Glucose + Fructose (table sugar).

Lactose

Disaccharide composed of Glucose + Galactose (milk sugar).

Maltose

Disaccharide composed of Glucose + Glucose, produced during starch breakdown.

Starch

Plant storage form of glucose; highly digestible polysaccharide.

Glycogen

Animal storage form of glucose stored in liver and skeletal muscle.

Fiber

Plant structural polysaccharide containing indigestible bonds.

Soluble Fiber

Fiber type that dissolves in water, forms viscous gels, and is readily fermented by colonic bacteria (e.g., in oats, barley, legumes).

Insoluble Fiber

Fiber type that does not dissolve in water, forms structural parts of plants, and resists fermentation (e.g., in whole wheat, wheat bran).

Insulin

Hormone released by pancreatic beta cells when blood glucose rises; promotes cell glucose uptake, glycogen synthesis, and fat conversion in the liver.

Glucagon

Hormone released by pancreatic alpha cells when blood glucose drops; signals the liver to break down stored glycogen into glucose.

Gluconeogenesis

The breakdown of structural protein to manufacture glucose for the brain and RBCs when dietary carbohydrate is lacking.

Ketone Bodies

Fat breakdown products that accumulate during carbohydrate deprivation to provide alternative fuel for brain cells.

Ketosis

Metabolic state incurred by the accumulation of ketone bodies during carbohydrate deprivation, which disrupts acid-base balance.

Glycemic Index (GI)

A measure of how rapidly and high a food raises blood glucose compared to pure glucose.

Glycemic Load (GL)

A measure that adjusts the GI based on the actual carbohydrate content of a standard serving of food.

Type 1 Diabetes

Autoimmune destruction of pancreatic beta cells leading to absolute insulin deficiency; usually diagnosed in youth.

Type 2 Diabetes

Metabolic disorder characterized by insulin resistance where target cells fail to respond to circulating insulin.

Hypoglycemia

Abnormally low blood glucose levels ($<70\,\text{mg/dL}$), caused by poorly managed diabetes.

Triglycerides

Lipid structure composed of 1 glycerol backbone + 3 fatty acid chains; primary storage form of fat in food and body tissue (95% of lipids).

Phospholipids

Lipids composed of 1 glycerol + 2 fatty acids + a phosphate group; structural components of cell membranes and emulsifiers.

Sterols

Multi-ring lipid structures, including animal-derived cholesterol and plant-derived phytosterols.

Cholesterol

Animal sterol used by the body to synthesize bile, vitamin D, and sex hormones.

Phytosterols

Plant sterols that inhibit cholesterol absorption in the human digestive system.

Saturated Fatty Acids (SFA)

Fatty acids fully saturated with hydrogen containing zero double bonds ($C-C$); solid at room temperature.

Monounsaturated Fatty Acids (MUFA)

Fatty acids with one double bond ($C=C$); liquid at room temperature and cloudy when chilled.

Polyunsaturated Fatty Acids (PUFA)

Fatty acids with two or more double bonds; liquid both at room temperature and when chilled.

Trans Fatty Acids

Hydrogenated unsaturated fats possessing a $trans$ bond configuration; semi-solid or firm at room temperature.

Chylomicron

Lipoprotein that carries dietary triglycerides from the intestine to tissues via the lymphatic system.

VLDL

Very-Low-Density Lipoprotein; transports endogenous triglycerides synthesized in the liver to body cells.

LDL

Low-Density Lipoprotein; delivers cholesterol to body tissues ('bad' cholesterol linked to plaque buildup).

HDL

High-Density Lipoprotein; performs Reverse Cholesterol Transport, taking cholesterol to the liver for disposal ('good' cholesterol).

Omega-6 ($\omega-6$) Family

Essential fatty acid family starting with linoleic acid ($18:2$), which derives pro-inflammatory arachidonic acid.

Omega-3 ($\omega-3$) Family

Essential fatty acid family starting with alpha-linolenic acid / ALA ($18:3$), which derives anti-inflammatory EPA & DHA.

Hydrogenation

Process forcing hydrogen gas into unsaturated oils to increase saturation, firmness, and shelf stability, creating trans fats.

Amino Acid

Building block of proteins consisting of a central carbon, an amino group ($-NH_2$), an acid group ($-COOH$), a hydrogen atom, and a unique side chain (R-group).

Essential Amino Acids (EAAs)

The 9 amino acids that must be obtained from the diet because the body cannot synthesize them.

Non-Essential Amino Acids

The 11 amino acids that the body can synthesize via transamination.

Conditionally Essential Amino Acid

A non-essential amino acid that becomes essential under illness or metabolic stress (e.g., Tyrosine in PKU).

Positive Nitrogen Balance

State where nitrogen intake exceeds output ($N_{in} > N_{out}$), causing nitrogen retention for tissue synthesis (e.g., in growing children, pregnancy, bodybuilders).

Negative Nitrogen Balance

State where nitrogen loss exceeds intake ($N_{in} < N_{out}$), occurring in starvation, severe burns, trauma, infections, and weightlessness.

Deamination

Removal of the nitrogen-containing amine group from an amino acid, forming toxic ammonia ($NH_3$) which is converted to urea.

Complete Protein

Protein source containing all 9 essential amino acids in optimal ratios (e.g., animal proteins, soy, quinoa).

Incomplete Protein

Protein source low in $\ge 1$ essential amino acid (limiting amino acid; e.g., grains, legumes).

Complementary Proteins

Combining plant foods to supply missing essential amino acids across dietary sources (e.g., rice + beans).

Kwashiorkor

Severe protein deficiency with adequate calories, characterized by edema (swollen belly), fatty liver, and impaired immunity.

Marasmus

Severe starvation caused by deficiency in both energy and protein, leading to extreme muscle wasting and growth failure.