Biochemistry Flashcards
matter
anything that takes up space and has mass.
element
a substance that cannot be broken down into other substances by chemical reactions. There are 92 of these found in nature. gold, copper, carbon, and oxygen are all examples.
compound
a substance consisting of two or more different elements combined in a fixed ratio. Examples include sodium chloride (NaCl), and water (H2O).
essential elements
elements an organism needs to live a healthy life and reproduce easily. These elements may vary by domain.
Trace elements
elements required by an organism is minute (very small) quantities
Toxic Elements
Some elements are toxic to organisms. One example is arsenic being very toxic to humans.
Atom
the smallest unit of matter that still retains the properties of an element.
subatomic particles
particles of matter that makeup atoms, each with a specific role.
neutrons
a subatomic particle with a neutral charge (or no charge). These particles are found in the nucleus of the atom. These particles are approximately one dalton in mass.
proton
a subatomic particle with a positive charge. These particles are found in the nucleus of the atom. These particles are approximately one dalton in mass.
electron
a subatomic particle with a negative charge. These particles are found surrounding the nucleus. These particles have a mass that is approximately 1/2000 of a dalton.
Atomic nucleus
a dense core at the center of the atom packed with protons and neutrons.
dalton
a unit of measurement equal to one atomic mass unit.
atomic number
The number of protons found in an element. This number is unique to each specific element. Written as a subscript to the left of the symbol for the element.
mass number
In daltons, the sum of the number of protons and neutrons in the nucleus of the atom. This number can be given in daltons or atomic mass units (amu). Subtracting the atomic number from this number allows the number of neutrons to be deduced. This number is written as a superscript to the left of the element’s symbol. This number is an approximation of the total mass of the atom.
Isotopes
Atoms of an element which have a different number of neutrons, thus having a different atomic mass or mass number. Carbon-14 is one example.
radioactive isotope
an isotope which is unstable or radioactive. The nucleus of these isotopes decays spontaneously, giving off particles and energy.
radioactive tracers
radioactive isotopes can be used to follow atoms through the process of metabolism.
Energy
the capacity to cause change (normally by doing work.)
potential energy
is the energy that matter possesses because of its location or structure.
Electron shells
An electron’s energy level is correlated with its average distance from the nucleus. Each shell has a characteristic average distance and energy level.
Valence Electrons
the electrons found in the outermost shell of the atom. The number of these electrons determines the behavior of the atom.
ion
an atom or molecule with an electric charge
cation
an ion with a positive charge
anion
an ion with a negative charge
ionic bond
the attraction between cations and anions
Hydrogen bonds
a noncovalent attraction between a hydrogen atom and an electronegative atom.
Van der Waals Interactions
individually weak attractions that occur only when atoms and molecules are very close to each other.
chemical equilibrium
when two chemical reactions offset one another equally.
polar molecule
a molecule in which there is an unequal sharing of electrons.
cohesion
when water molecules attract to one another
adhesion
when water molecules attract to
