Molecules of Life Flashcards
STRUCTURE OF AN ATOM
- A nucleus containing protons and neutrons
- Electrons moving around the nucleus
ATOMIC NUMBER (Z)
Number of protons in the nucleus.
ATOMIC WEIGHT
Total number of particles in the nucleus.
COVALENT BOND
An electron sharing arrangement with another atom (a method for getting stable).
IONIC BOND
An electric attraction between cations and anions OR an attractive force between opposite charges.
MOLECULAR CONCENTRATION
Number of moles of solute per litre of solution:
mol solute / L of solution
MW in grams of each molecule (same number of molecules, different weight of substance).
MOLECULAR WEIGHT
The sum of the atomic weight values of the atoms in a molecule.
ION
An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
IMPORTANCE OF BUFFER SYSTEMS: pH
A buffer is a solution that stops massive changes in pHlevels. Buffer systems are important as they work to combine H+ ions with other molecules as a means of resisting changes in pH where extra acids or alkalis are added to body fluids.
pH
pH is a measure of hydrogen ion concentration, a measure of the acidity or alkalinity of a solution.
ACID
Acids are substances that provide hydrogen ions (H+) and lower pH.
ALKALI
Alkalis are substances that provide hydroxide ions (OH-) and a higher pH.
OSMOSIS
The diffusion of water across a semi-permeable membrane.
DIFFUSION
Diffusion is the net passive movement of particles (atoms, ions or molecules) from a region in which they are in higher concentration to regions of lower concentration.
CHEMICAL NATURE OF SUGARS, PROTEINS, LIPIDS, NUCLEOTIDES AND ENZYMES
They are organic molecules:
- Make up living things
- Contain carbon, hydrogen and oxygen
- Carbon atoms form covalent bonds with other carbon atoms, oxygen and hydrogen
