Biological Molecules - Chapter 03

Vocabulary flashcards covering key terms and concepts from the notes on Biological Molecules, including carbohydrates, fats, proteins, vitamins, minerals, water, and common food tests.

Carbohydrates

Organic molecules of C, H and O with a roughly 2:1 H:O ratio; main immediate energy source; classified as monosaccharides, disaccharides and polysaccharides.

Monosaccharides

Single sugars; basic units of carbohydrates; e.g., glucose and fructose; small enough to diffuse through cell membranes.

Glucose

A hexose monosaccharide (C6H12O6); primary energy source in respiration.

Fructose

A hexose monosaccharide (fruit sugar); isomer of glucose.

Disaccharides

Double sugars formed from two monosaccharides; e.g., maltose, sucrose, lactose.

Maltose

Disaccharide formed from two glucose molecules.

Sucrose

Disaccharide formed from glucose and fructose; common cane sugar.

Lactose

Disaccharide formed from glucose and galactose; milk sugar.

Polysaccharides

Complex carbohydrates formed from many monosaccharide units; e.g., starch, cellulose, glycogen.

Starch

Plant storage polysaccharide; insoluble in water and not to alter water potential.

Cellulose

Plant cell wall polysaccharide; structural and insoluble.

Glycogen

Animal storage polysaccharide; stored mainly in liver and skeletal muscles.

Glycogen and Starch as Storage Materials

Storage polysaccharides that are insoluble, large, and easily broken down for energy; glycogen in animals, starch in plants.

Fats (Lipids)

Organic molecules made of glycerol and three fatty acids; energy-rich and hydrophobic; triglycerides.

Glycerol

Three-carbon alcohol that forms the backbone of fats.

Fatty Acids

Fatty acid chains attached to glycerol; vary in saturation.

Saturated Fats

Fats with no double bonds; mostly animal fats; solid at room temperature.

Unsaturated Fats

Fats with one or more double bonds; mostly plant fats; liquid at room temperature.

Functions of Fats

Long-term energy storage; insulation; solvent for fat-soluble vitamins; components of cell membranes; reduce water loss.

Proteins

Macromolecules made of amino acids; polypeptides fold into specific 3D shapes to form proteins.

Amino Acids

Building blocks of proteins; 20 standard amino acids used to form polypeptides.

Polypeptides

Long chains of amino acids; fold to form functional proteins.

Vitamins

Organic micronutrients that support immune function, wound healing and hormonal regulation.

Minerals

Inorganic nutrients that regulate body processes, nerve transmission, muscle contractions and bone strength.

Water

Biological solvent; medium for chemical reactions; used in hydrolysis; transport medium; major component of protoplasm and body fluids; helps regulate temperature.

Nutrients

Essential substances in the diet, including water, carbohydrates, fats, proteins, vitamins and minerals.

Test for Starch (Iodine Test)

Reagent: iodine solution; starch presence turns the solution blue-black; absence remains yellow-brown.

Test for Reducing Sugars (Benedict’s Test)

Reagent: Benedict’s solution; detects reducing sugars with color change from blue to green/yellow/orange/brick-red depending on amount.

Test for Fats (Ethanol-Emulsion Test)

Reagents: ethanol and water; fats form a white emulsion when mixed and diluted.

Test for Protein (Biuret Test)

Reagents: dilute NaOH and copper(II) sulfate; blue solution turns violet in the presence of proteins.