number of protons (or # of electrons if atom is neutral)
# of protons plus # of neutrons
1st inner orbital holds 2 electrons (lowest energy)
2nd and 3rd outer orbitals hold 8 electrons each (the farther out, the HIGHER energy)
# of electrons that are required to complete the outermost shell
ie: carbon, has a valency of 4...so needs 4 electrons to fill the 2nd shell & get 8 total in that shell
Properties of water.
Hydrogen bonds produces a polar molecule�so can DISSOLVE compounds. It makes up about 70% of organisms by weight. Acidity is based on ionization of water to H+ (acid) and OH- (base), so when equal, pH is neutral.
Why is water such a good solvent?
Hydrogen bonds produces a polar molecule�so can DISSOLVE compounds.
STRONGEST of bonds. Involves sharing of electrons between atoms. These are difficult to break. They can be polar or non-polar.
Non-polar involves no charge, atoms with similar electronegativies
Polar has a slight charge, ie: O-H, with oxygen having the higher electronegativity it is slightly negative, and H is slightly positive.
Formed by an atom GAINING or LOSING electrons
Ie: NaCl, where Na gives up its electron to Cl. So it�s Na+ and Cl-
WEAKEST of the three bonds. Formed from attraction of positively charged hydrogen (H) atom. This can be with Nitrogen or Oxygen commonly.
Hydrogen bonds occur in molecules such as water, or in DNA between molecules (C & G and A & T creating double helix)
very large molecules. All macromolecules are polymers and when they join, water is lost, so the reaction is a dehydration synthesis
divided into 4 classes
2. polysacchardies (carbs)
4. nucleic acids
occurs when water is lost due to polymers joining together to form macromolecules
happens when macromolecules breakdown into smaller subunits, and water is added
Functional parts of the cell
Function depends on the SHAPE of the protein
50% of cell dry weight
made of AMINO ACIDS (AA's)
Bonds formed with proteins
peptide bonds: occur between an amino group (-) and the carboxyl group (+) of AA's.
the peptide bond formation is a dehydration synthesis reaction
2 AA's = dipeptide
>2 AA's = polypeptide
3 AA's = tripeptide
A protein is a polymer, and an Amino Acid is a monomer
Functions and/or role of proteins
enzymes that catalyze reactions
aid in shaping of certain BACTERIAL structures
involved in GENE regulation
nutrient procurement (takes nutrients)
Structures of proteins
primary: made of peptide bonds
secondary: hydrogen bonds
tertiary: hydrogen bonds plus Ionic bonds b/w side chains
quaternary: same as tertiary
contain Carbon, hydrogen and Oxygen
polysaccharides: large molecules made of carbohydrates
oligosaccharide: short chain of carbohydrates
monosaccharide: 1 carbohydrates
classified by number of carbons present in the carbohydrate
ie: five carbon sugars = pentose (ribose & deoxyribose)
ie: six carbon sugars = hexose (glucose, fructose, galactose)