Biochemistry Flashcards
(125 cards)
Subatomic Particles in Atoms
Protons (+), Neutrons and Electrons (-)
Ground State
If all electrons in an atom are in the lowest available energy levels.
Excited State
When an atom absorbs, its electrons move to a higher energy level.
Isotopes
Atoms of one element that vary only in the number of neutrons in the nucleus. Chemically, all isotopes of the same element are identical because they have the same number of electrons in the same configuration.
Half-Life
The rate at which an isotope decays. Enables us to measure the age of fossils or to estimate the age of the Earth.
Tracer
Radioisotopes that can be incorporated into a molecule and use to trace the path in a metabolic pathway.
Atom Bonds
Atoms bond when two atomic nuclei attract the same electron/s. Energy is released when a bond is formed and energy must be supplies to break a bon. Atoms bonds to acquire a stable outer shell, a stable configuration.
Ionic Bonds
Results from the transfer of electrons. An atom that gains electrons becomes an anion and an atom that loses an electron becomes a cation.
Ions Necessary for Normal Nerve Function
Na+, Ca++, and Cl-
Ions Necessary for Normal Nerve Function
Na+, Ca++, and Cl-
Covalent Bonds
Form when atoms share electrons and the resulting structure is a molecule. Single covalent bonds results when two atoms share a pair of electrons; double occurs when two atoms share two pairs and so on.
Non-Polar Bond
Occurs when electrons are shared equally between two identical atoms. Found in diatomic molecules such as H2 or O2.
Polar Bonds
If electrons are shared unequally between two atoms.
Polar Bonds
If electrons are shared unequally between two atoms.
Polar and Non-Polar Molecules
Polar molecules are unbalanced and contain strong attractions. Non-Polar molecules are the opposite. Polar molecules will generally only dissolve in polar molecules and the opposite is true for non-polar molecules.
Polar and Non-Polar Molecules
Polar molecules are unbalanced and contain strong attractions. Non-Polar molecules are the opposite. Polar molecules will generally only dissolve in polar molecules and the opposite is true for non-polar molecules.
Hydrophobic and Hydrophilic
Substances that are polar will dissolve in water while substances that are non-polar will not. Lipids are hydrophobic and don’t dissolve in water this is the reason why oils separate when mixed with water. This is also the reason why only non-polar substances can pass through the plasma membrane. Large polar molecules must pass through hydrophilic protein channels.
The Water Molecule
One side of the molecule has a negative charge (O) and one has a positive charge (H).
The Water Molecule
One side of the molecule has a negative charge (O) and one has a positive charge (H). In addition, two molecules of water can be held together by hydrogen bonding.
Hydrogen Bonding
A weak bond created as a result of the electrostatic attraction between a negative molecule and a positive molecule.
Specific Heat Definition
The amount of heat a substance must absorb to increase one gram of the substance by one degree celsius.
Water and Specific Heat
Water has a high specific heat and therefore, can provide a stable environmental temperature for the organisms that live there. In addition, because large bodies of water exhibit little temperature change, they moderate the climate of the nearby land.
Water and Vaporization
Water has a high heat of vaporization. This means that evaporating water required a relatively great amount of heat. As a result, the evaporation of sweat significantly cools the body.
Water as a Solvent
Since water is a highly polar molecule, it dissolves all polar and ionic substances.