Chapter 2 - Chemistry of Life (Concepts of Biology)

These flashcards cover key vocabulary from Chapter 2 - Chemistry of Life, focusing on essential terms related to matter, atomic structure, water properties, and biological molecules.

Matter

Anything that occupies space and has mass.

Elements

Pure substances composed of only one type of atom; cannot be broken down by chemical means.

Periodic Table

Lists all known elements by atomic number.

Atom

Smallest unit of an element retaining its chemical properties.

Proton

Subatomic particle with a positive charge (+1), located in the nucleus.

Neutron

Subatomic particle with a neutral charge (0), located in the nucleus.

Electron

Subatomic particle with a negative charge (-1), orbits the nucleus.

Atomic Number

Number of protons in an atom, defines the element.

Mass Number

Sum of protons and neutrons in an atom.

Isotope

Variants of elements with different neutron numbers.

Radioactive Isotopes

Emit particles/energy as they decay to stable forms; used in dating fossils and medical diagnostics.

Electron Shell

Energy levels where electrons are likely to be found.

Valence Electrons

Electrons in the outermost shell, determine chemical reactivity.

Octet Rule

Atoms tend to form bonds to achieve 8 electrons in their valence shell.

Ion

Atom with a net charge due to loss/gain of electrons.

Cation

Positively charged ion due to loss of electrons.

Anion

Negatively charged ion due to gain of electrons.

Ionic Bonds

Transfer of electrons; attraction of oppositely charged ions.

Covalent Bonds

Sharing of electrons; can be polar or nonpolar.

Hydrogen Bonds

Weak bonds between partially charged atoms.

Van der Waals Interactions

Temporary dipole attractions; important in macromolecular structures.

Polarity of Water

Water is a polar molecule; oxygen is partially negative, hydrogen is partially positive.

Cohesion

Water molecules stick together; contributes to surface tension.

Adhesion

Water sticks to other surfaces; enables capillary action.

High Specific Heat

Water stabilizes temperature by absorbing heat with minimal temperature change.

Heat of Vaporization

High energy required to change liquid to gas; cooling effect.

Density of Ice

Ice floats; solid water is less dense than liquid, protecting aquatic life.

pH Scale

Measures H+ ion concentration; ranges from 0 (acid) to 14 (base).

Acids

Donate H+ ions (e.g., HCl).

Bases

Donate OH- ions or absorb H+ (e.g., NaOH).

Buffers

Maintain stable pH; e.g., carbonic acid-bicarbonate buffer in blood.

Carbohydrates

Macromolecules with elements C, H, O (1:2:1 ratio), includes monosaccharides, disaccharides, and polysaccharides.

Lipids

Hydrophobic molecules for energy storage and membrane formation.

Triglycerides

Glycerol + 3 fatty acids; includes saturated and unsaturated fats.

Phospholipids

Amphipathic molecules essential in membrane structure.

Proteins

Composed of amino acids; linked by peptide bonds.

Nucleic Acids

Include DNA and RNA; store and transmit genetic information.

Nucleotide

Composed of sugar, phosphate, nitrogenous base.

DNA

Double-stranded nucleic acid with A-T, G-C base pairing.

RNA

Single-stranded nucleic acid involved in protein synthesis (A-U, G-C).