Biochemistry (Molecules)

Biochemistry

the study of the chemical substances and processes essential for life

Organic Compound

contains carbon and hydrogen and is associated with living things

Inorganic Compound

lacks carbon and is generally simpler

Water

most abundant inorganic compound in the body

Properties of Water

high heat capacity, polarity/solvent properties, chemical reactivity, cushioning

Salts

dissociate into ions in water

Function of Salts

regulate body functions and act as electrolytes

Acid

releases hydrogen ions (H+); proton donor

Base

releases hydroxyl ion (OH-); proton acceptor

Neutralization Reaction

acid and base react to form water and a salt

Dehydration Synthesis

builds macromolecules by removing water

Hydrolysis

breaks down macromolecules by adding water

Function of Carbohydrates

quick, short-term energy storage

Carbohydrate

chemical grouping H—C—OH with 2 hydrogens per oxygen

Monosaccharides

simple sugars (5-6 carbons) providing immediate energy

Disaccharides

two sugars joined by dehydration synthesis

Sucrose Disaccharide

made of glucose and fructose

Polysaccharides

complex carbohydrates with many glucose units

Examples of Polysaccharides

starch, glycogen, cellulose

Starch and Glycogen

readily stored forms of glucose

Insulin

promotes storage of glucose as glycogen

Cellulose

plant cell wall carbohydrate; indigestible fiber

Benefit of Fiber

lower incidence of heart disease and cancer

High-Fiber Foods

beans, peas, nuts, fruits, vegetables, whole grains

Proteins

macromolecules made of amino acids

Elements in Proteins

carbon, hydrogen, oxygen, nitrogen, sometimes sulfur

Number of Amino Acids

20

Amino Acid Structure

central carbon bonded to H, amino group, carboxyl group, and R group

R group

determines amino acid differences

Peptide Bond

bond between amino acids formed by dehydration synthesis

Peptide Bond Breakdown

hydrolysis

Functions of Proteins

structure, enzymes, transport, defense, hormones, motion

Protein Denaturation

irreversible shape change due to heat, pH, radiation, or chemicals

Fibrous Proteins

structural, stable proteins (collagen, keratin)

Globular Proteins

functional proteins; easily denatured

Lipids

insoluble, nonpolar molecules

Elements in Lipids

carbon, hydrogen, oxygen

Triglyceride

one glycerol and three fatty acids

Functions of Fats

long-term energy storage, insulation, cushioning organs

Fats vs. Oils

fats are solid; oils are liquid at room temperature

Types of Fats

saturated, unsaturated, and trans fats

Trans Fats

most harmful type of fat

Phospholipids

lipids that form cell membranes

Steroids

lipids including cholesterol, bile salts, vitamin D, hormones

Cholesterol

precursor for all steroid hormones

Nucleic Acids

DNA and RNA

Function of DNA

stores genetic information; blueprint of life

Function of RNA

directly involved in protein synthesis

Nucleotide Parts

phosphate group, pentose sugar, nitrogenous base

DNA Base Pairing

A—T and G—C

RNA Base Pairing

A—U and G—C

DNA Structure

double helix with complementary base pairing

DNA Replication

occurs before cell division

ATP

main energy currency of the cell

ATP Energy Release

breaking high-energy phosphate bonds

Why ATP is High-Energy

last two phosphate bonds are unstable

ATP Breakdown

ATP loses a phosphate to form ADP and release energy

ATP Regeneration

adding phosphate using energy from glucose breakdown

Oxygen Limitation

limits ATP production