depends -
Solubility on the ability to make bonds between the solute and solvent.
Electronegativity: High - O > N > S = C ~ H = P - Low
In aqueous environment strength of bond order = Covalent > Ionic > Ion Perm Dipole >
PDPD > PDID > IDID
Cytoplasmic membranes are made from molecules called phospholipids = form bilayers
that are non-polar in the middle.
Phospholipid bilayer is not station it has kinetic energy
Water passes through the bilayer the fasted, then non polar then polar then charged,
< 100 molecular weight passes fast
Uncharged, non polar and relatively small molecules pass the fastest through the
phospholipid bilayer water breaks this rule.
In a mixture of water and hydrophobic molecules the hydrophobic molecules clump
together, this maximizes entropy of water/ mixture = hydrophobic effect
Small non polar molecules > small uncharged polar molecules > large uncharged polar
molecules > ions, permeability.
Materials move across the cell membrane in 3 diff ways,
Diffusion: movement of solutes from high to low concentration
When conc gradient exists molecules move randomly but the net flow in from high conc
to low
Carrier proteins called permeased positioned in the membrane allow transport of some
molecules the bilayer alone will not allow through
Ion channels : specialized proteins that circumvent the membrane impermeability to
charged compunds
Electrochemical gradient: concentration gradient and a charge gradient nwhen ions build
up on one side
Channels opens / closes due to voltage change.
Facilitaed diffusion uses permeased but not energy
GLUT 1 = permease cause conformation change in membrane to bring in glucose
Pumps are membrane proteins that provide active transport against the gradient
ATP -> ADP when phosphate binds to membrane for active transport,
Cells try to maintain high sodium outside and high potassium inside
Water moves low from solute concentrations to high solute concentrations
To combat osmotic pressure bacteria use a net to surround the cytoplasm and in some
cases another barrier
The bacterial net : Peptidoglycan: Parralel strands joined together by hydrogen bonds ,
does not affect transport
Gram positive has lots of peptidoglycan, resistant to osmotic pressure; Gram negative
less peptidoglycan, not as many bonds but has an additional membrane that helps with
osmotic pressure.
Eukaryotes do not have a cell wall
Eukaryotes deal with osmotic pressure by exisiting in an isotonic environment or by
having a membrane containing aquaporins, cholesterol also stabalizes the membrane by
making it less permeable to water
Amino side chains look at pic on notes
Primary: sequence of amino acids
-
Secondary: some stretches of amino acids adopt special conformation; beta pleated sheets
and alpha helices
Tertiary: the entire peptide chains fold into a specific shape, the beta pleated sheets and
alpha helices are maintained.
Quatenary: in some cases more than one protein chain forms a complex
A polypeptide is flexible and has directionality ( the N terminus has a free amino group
and the C terminus has a free carboxyl group.
The side chains of the amino acids thats make the protein determine what structure if any
is created as a secondary structure.
Chapter 4
4.1 Nucleic Acid:
- Nucleic acids are made up of nucleotides
- Components of a nucleotide are: a sugar, a nitrogenous base and a phosphate group
- Ribonucleuotide, sugar = ribose
- Deoxyribonucleotide, sugar = deoxyribose
- Nucleuic acids are formed when a phosphate group of one nucleotide and the hydroxyl
group of another bond through a condensation reaction called the posphodiester linkage
- The addition of phosphate groups raises the potential energy of the substrate molecules
enough to make an endergonic reaction possible
4.2 DNA structure/function