Chapter 2 Flashcards
Matter
Anything that occupies space and has mass
Mass
Amount of matter in any object, which does not change
Weight
The force of gravity acting on matter, does not change
What are the major elements?
- Oxygen
- Carbon
- Hydrogen
- Nitrogen
What are the eight lesser elements?
Calcium
Phosphorus
Potassium
Sulfur
Sodium
Chlorine
Magnesium
Iron
What are elements made up of?
Atoms
Oxygen
65% of body mass, part of water and many organic molecules. Used to generate ATP. Used by cells to temporarily store chemical energy
Carbon
18.5% of body mass, forms backbone chains and rings of all organic molecules: carbohydrates, lipids, proteins, nucleic acids (DNA and RNA)
Hydrogen
9.5% of body mass, constituent of water and most organic molecules; ionized from H+ makes body fluids more acidic
Nitrogen
3.2% of body mass, component of all proteins and nucleic acid
Calcium
1.5% of body mass, contributes to hardness of bones and teeth; ionized from Ca2+ needed for blood clotting, release of some hormones, contraction of muscle, and many other processes
Phosphorus
1.0% of body mass, component of nucleic acids and ATP; required for normal bone and tooth structure
Potassium
.35% of body mass, ionized from K+ is the most plentiful cation (positively charged particle) in intercellular fluid; needed to generate action potentials
Atomic number
Number of protons in the nucleus of an atom
Mass number
Sum of an atoms protons and neutrons
Isotopes
Atoms of an element that have different numbers of neutrons and therefore different mass numbers
Radioactive isotopes
Unstable, nuclei decay into a stable configuration emitting radiation
Compound
A substance that contains atoms of two or more different elements
Ion
An atom that gives up or gains electrons
Molecule
When two or more atoms share electrons, molecules can consist of two atoms of the same kind
Chemical bonds
Forces that hold together the atoms of a molecule or a compound
Ionic bond
The force of attraction that holds together ions with opposite charges
Cation
Positively charged ion
Anion
Negatively charged ion