2.5 - Organic Compounds Essential to Human Functioning

Carbohydrates

Hydrophilic organic molecules with the formula (CH₂O)n - functions: energy, dietary fiber, modification of proteins and lipids

Monosaccharides

Simple sugars - ex: glucose (main energy source), fructose (fruit sugar), galactose (part of milk sugar), deoxyribose and ribose (DNA/RNA components)

Disaccharides

Two monosaccharides joined together - ex: sucrose (table sugar), lactose (milk sugar), maltose (malt sugar)

Polysaccharides

Long chains of monosaccharides - ex: starch (energy storage in plants), glycogen (energy storage in animals—liver and muscle), cellulose (structural in plants; dietary fiber in humans)

Dehydration Synthesis

A reaction that joins monomers together by removing water

Hydrolysis

A reaction that breaks polymers apart by adding water

Lipids

A diverse group of molecules including fatty acids, triglycerides, phospholipids, steroids, and prostaglandins

Fatty Acids

Used for energy; stored in the body as part of triglycerides in adipose cells; provides 9 kcal/g (vs. 4 kcal/g for carbohydrates) - can be saturated or unsaturated

Triglycerides

Storage form of fatty acids within adipocytes; provide energy, cushioning, and thermal insulation

Phospholipids

Composed of two fatty acids, glycerol, and a phosphate group; structural component of cell membranes

Sterols

Ring-shaped lipids (e.g., cholesterol); precursors for bile acids and sex hormones

Prostaglandins

Derived from unsaturated fatty acids; act as signaling molecules; sensitize nerves to pain

Amino Acids

The building blocks of proteins; there are 20 types, differing in their R (side chain) groups

Peptide Bond

The covalent bond between amino acids, formed by dehydration synthesis

Protein

A polypeptide chain folded into a functional 3D structure. Functions depend on the sequence of amino acids

Nucleotides

Building blocks of nucleic acids; consist of a sugar, a phosphate group, and a nitrogenous base

DNA

The genetic material of the cell; stores the code for the cell's functioning; made of deoxyribonucleotides

RNA

Made from DNA; used to make proteins; made of ribonucleotides

ATP

A ribonucleotide used to carry out energy-consuming reactions in cells; the cell's main energy currency