Principles of Anatomy and Physiology: Chapter 2: Chemical Organization Flashcards
Matter
Anything that occupies space and has mass
Matter exists as
Solid, liquid, or gas
Mass
The amount of matter a substance contains
Weight
Force of gravity acting on a mass
Energy
The capacity to do work (put mass into motion)
Two types of energy is
Potential and kinetic energy
Potential energy
Inactive or stored energy
Kinetic energy
Energy of motion
Forms of energy include
Radiant, electrical, heat, chemical, and mechanical
Mass and energy can neither be created nor destroyed, but
One can be converted into the other
All forms of matter are composed of
Chemical elements
Elements are given letter abbreviations called
Chemical symbols
Oxygen, Carbon, Hydrogen, and Nitrogen make up ___ of body weight
96%
Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus make up ___ of total body weight
98.5%
Units of matter of all chemical elements are called
Atoms
Atoms consist of
A nucleus, which contains protons and neutrons (nucleons) and electrons that move about the nucleus in energy levels
Different atoms of an element that have the same number of protons but different numbers of neutron are called
Isotopes
Certain isotopes are unstable and may emit radiation that can be monitored with radiation detectors are called
Radioisotopes
Radioisotopes can be used to
Study both the structure and function of particular tissues
Chemical reaction occurs when
Atoms combine or break apart from other atoms
Electrons revolve around the nucleus of an atom, tending to spend of the time in specific atomic regions called
Shells
Each shell can hold a certain maximum number of electrons; the outermost shell is called
Valence shell
To achieve stability, atoms tend to either empty their valence shell or fill it to the maximum extent by
- Giving up, accepting, or sharing electrons with other atoms in the simplest manner possible
- Atoms that have completely filled outer shells are called inert elements and do not participate in chemical reactions
- Atoms with incompletely filled outer shells tend to combine with each other in chemical reactions
Two or more atoms combine in a chemical reaction to form a
Molecule
Compound
Substance that can be broken down into two or more different elements by chemical means
The atoms of a molecule are held together by forces of attraction called
Chemical Bonds
Ionic bond
Outer-energy-level electrons are transferred from one atom to another. The transfer forms ions, whose unlike charges attract each other and form ionic bonds
Cations
Positively charged ions that have given up one or more electrons
Ex. They are electron donor
Anions
Negatively charged ions that have picked up one or more electrons that another atom as lost
Ex. They are electron acceptors
Covalent bond
There is sharing of pairs of outer-energy-level electrons
Single, double, or triple covalent bonds are formed by
Sharing one, two, or three pairs of electrons
Covalent bonds may be
Nonpolar or polar
Hydrogen bonds
Two other atoms (usually oxygen or nitrogen) associate with a hydrogen atom
Factors that determine if a chemical (metabolic) reaction
- Concentration of particles
- The speed at which particles are traveling (temperature and size)
- Activation energy
- Proper orientation of the colliding particles
Synthesis reactions involve
The combination of reactants to produce a new molecule; anabolism reaction (anabolism)
Anabolism
Bonds are formed
Decomposition reactions
Substance break down into other substances; catabolic reactions (catabolism)
Exchange reactions involve
The replacement of one atom or atoms by another atom or atoms
In reversible reactions
End products can revert to the original combining molecules
In oxidation-reduction reactions
Electrons are taken from the atom being oxidized by the atom being reduced
Exergonic reaction
One in which the bond being broken has more energy than the one formed so that extra energy is released, usually as heat
Endergonic reaction
The opposite of exergonic; it requires energy, usually from a molecule called ATP, to form a bond, as in bonding amino acid molecules together to form proteins
Inorganic substances
Usually lack carbon and are small molecules
Organic substances
Always contains carbon and hydrogen. Most organic substances contain covalent bonds
When molecules or inorganic acids, bases, or salts dissolve in water, they undergo
Ionization or dissociation
Acids
Ionize into one or more hydrogen ions (H+) and one or more anions
Anions
Negative ions
Bases
Dissociate into one or more hydroxide ions (OH-) and one or more cations
Cations
Positive ions
Water
The most abundant substance in the body
Salt, when dissolved in water
Dissociates into cations and anions, neither of which is H+ or OH-
Solution consists of
A solute dissolved in a solvent
Standard unit that expresses the number of molecules of solute in a liter of solution is called
Molarity = moles/liters
Mole
Name for the number of atoms in an atomic weight of that element, or the number of molecules in a molecular weight of that type of molecule
The properties that make water a vital compound living systems
- An excellent solvent and suspending medium
- Chemical reactions
- it absorbs and releases heat very slowly; it has a high heat capacity
- It requires a large amount of heat to change from a liquid to a gas; it has a high heat capacity
- It requires a large amount of heat to change from a liquid to a gas; its heat of vaporization is considered to be high
- It serves as a lubricant
Buffer systems
Usually consist of a weak acid and a weak base
CO2 + H2O = H2CO3 = H+ + HCO3-