Chapter 2 - The Nature of Life

Composition and structure Growth Reproduction Response to stimuli Metabolism Movement Complexity and organization Adaption to the environment

Covalent bonds Ionic bonds Hydrogen bonds

Increase in mass, usually accompanied by an increase in volume.

Part of atom containing protons and neutrons.

• Positively-charged part of an atom • Has mass • Affects the path of electrons around the nucleus

The smallest stable subdivision of an element that can exist

Offspring always resemble the parents more than other individuals of the same kind. (see chapter 13)

• Region occupied by electrons around the nucleus * A volume of space in which a given electron occurs 90% of the time.

Variations of elements with slightly different numbers of neutrons in the atoms, resulting in different weights but all forms behaving alike chemically

• Negative charges that whirl around the nucleus.

The combining capacity of an atom or ion based on electron number.

Form when two atoms complete their outermost energy level by sharing a pair of electrons in the outermost orbital. They hold two or more atomic nuclei together and travel between them.

• Part of an atom with no electrical charge * Has mass

Form when positively charged hydrogen atoms in polar molecules are attracted to negatively charged atoms in other polar molecules.

Chemicals that release hydrogen ions (H+) in water

Molecules that lose or gain electrons and become either positively or negatively charged particles.

A substance where 2 or more elements are united in a definite ratio by chemical bonds.

• The smallest unit of an element or compound retaining its own identity. • 2 or more atoms bound together

• Scale (0-14) to measure acidity or alkalinity • Each unit (0-14) represents a tenfold change in H+ concentration. • Pure water is 7/neutral, number of H+ and OH- is the same.

Study of energy and its conversions from one form to another.

• Feel slippery or soapy * Compounds that accept H+ ions.

Energy contained within a system and is converted from one form to another, flows from a high to a low state (heat flows from hot objects to cool surfaces).

“Many units” - formed when two or more monomers bond together

Energy is constant – it cannot be gained or lost – but can be converted from one form to another. Forms include: chemical, electrical, heat, and light.