Flashcards Food & Nutrition Exam 2 Ch. 5 - 7

General structure of a triglyceride

A single glycerol backbone attached to three fatty acid chains.

Monounsaturated and polyunsaturated fats

Heart-healthy fats that lower LDL cholesterol; found in olive oil, avocado, and salmon.

Saturated fats

Fats solid at room temperature linked to higher cholesterol; found in butter and cheese.

Trans fats

Unhealthy fats that increase LDL cholesterol and lower HDL cholesterol.

Omega-3 fatty acids

Essential polyunsaturated fats that reduce inflammation; found in fatty fish, flaxseeds, and walnuts.

Omega-6 fatty acids

Essential polyunsaturated fats that support immunity; found in plant oils, poultry, and nuts.

Risks of overconsuming omega-3 supplements

Can cause bleeding risks and poor blood clotting.

Overconsumption of refined omega-6 relative to omega-3

Promotes a pro-inflammatory environment by competing for metabolic enzymes.

Symptoms of essential fatty acid deficiency

Scaly skin, poor growth, and a weakened immune system.

Function of LDL (Low-density lipoprotein)

Transports cholesterol from the liver to cells; high levels build arterial plaque.

Function of HDL (High-density lipoprotein)

Collects excess cholesterol from tissues and blood vessels, returning it to the liver.

Role of lingual lipase in the mouth

Initiates the chemical breakdown of triglycerides during chewing.

Fat digestion in the stomach

Churning creates chyme while gastric lipase breaks down short- and medium-chain fatty acids.

Role of CCK in fat digestion

Hormone released by fat in the small intestine; triggers bile and pancreatic lipase release.

Function of bile in lipid digestion

Emulsifies fat into micelles in the small intestine to aid absorption.

Function of pancreatic lipase

Breaks down triglycerides into free fatty acids and monoglycerides.

Fat absorption and transport into lymph

Micelles enter enterocytes, reassemble into triglycerides, and are packaged into chylomicrons.

Basic chemical structure of an amino acid

Central carbon attached to an amino group (NH2), carboxyl group (COOH), and R group.

Four levels of protein structure

Primary (sequence), Secondary (helices/sheets), Tertiary (3D folding), and Quaternary (multiple chains).

Classification of amino acid types by dietary need

9 essential (dietary), 11 nonessential (body-synthesized), and conditionally essential (needed during stress).

Definition of gluconeogenesis

Process of synthesizing glucose from non-carbohydrate sources like amino acids.

Role of stomach acid (HCl) in protein digestion

Denatures protein structures and activates pepsinogen to pepsin.

Role of pepsin in protein digestion

Breaks peptide bonds of denatured proteins in the stomach.

Small intestine protein digestion end-products

Pancreatic and brush border enzymes break polypeptides into single amino acids, dipeptides, and tripeptides.

Amino acid absorption process

Active transport across enterocytes into the bloodstream, traveling directly to the liver.

Transcription in protein synthesis

mRNA copies genetic code instructions from DNA inside the nucleus.

Translation in protein synthesis

tRNA brings specific amino acids to ribosomes to build a polypeptide chain.

Definition of deamination

The removal of an amino group (NH2) from an amino acid.

Amino acid pool

Circulating supply of amino acids available for tissue repair, protein synthesis, or energy.

Seven major functions of proteins

Transport, enzymes, fluid balance, acid-base balance, immunity, hormones, and energy source.

Complete vs incomplete proteins

Complete proteins contain all 9 essential amino acids; incomplete proteins lack one or more.

Complementary proteins

Combining two incomplete protein sources to provide all essential amino acids (e.g., rice and beans).

Nutrient deficiency risks in plant-based diets

Potential shortages of vitamin B12, iron, zinc, calcium, and omega-3 fatty acids.

Kwashiorkor

Severe protein deficiency with adequate calories, causing edema, swollen belly, and brittle hair.

Marasmus

Severe deficiency of both protein and total calories, leading to muscle wasting and thin appearance.

Anabolism definition and state

Energy-requiring metabolic process building complex molecules from smaller ones during positive energy balance.

Catabolism definition and state

Metabolic breakdown of large molecules releasing energy (ATP) during negative energy balance.

Energy yields of macronutrients per gram

Carbohydrates: 4 kcal/g; Proteins: 4 kcal/g; Fats: 9 kcal/g.

Lipoprotein Lipase (LPL)

Enzyme that extracts fat from blood to store as triglycerides in adipocytes.

Hormone-Sensitive Lipase (HSL)

Enzyme that breaks down stored triglycerides into fatty acids during fasting or exercise.

Fat cell hypertrophy vs hyperplasia

Hypertrophy is the enlargement of existing fat cells; hyperplasia is the formation of new fat cells.

Primary cause of initial rapid weight loss on ketosis

Depletion of stored glycogen and associated body water.

Metabolic adaptation during calorie restriction

Body conserves energy by lowering BMR, heart rate, NEAT, leptin, and raising ghrelin.

Three main components of daily energy expenditure

Basal Metabolic Rate (60-75%), Physical Activity (15-30%), and Thermic Effect of Food (~10%).

Ghrelin vs Leptin functions

Ghrelin triggers hunger before meals; Leptin promotes long-term satiety from fat stores.

Effect of CCK and GLP-1 on appetite

Gut hormones released after meals that slow stomach emptying and increase fullness.

Primary limitation of Body Mass Index (BMI)

Does not distinguish between muscle mass and fat mass, misclassifying athletic or elderly populations.

Four common body fat measurement methods

Bioelectrical Impedance (BIA), Skinfold calipers, Bod Pod (Air Displacement), and Underwater Weighing.

Hunger vs Appetite

Hunger is a physiological need for food; appetite is a psychological desire to eat.

Restrictive mechanism of weight loss surgery

Reduces stomach size to limit physical food intake volume.

Malabsorptive mechanism of weight loss surgery

Bypasses parts of the small intestine to decrease calorie and nutrient absorption.