[kindanotused] unit 2 Flashcards
(30 cards)
lipids (6)
- energy stores in animals & plants
-insoluble in water (except glycerol)
-dissolves in organic solvents (like alcohol)
-less dense than water
-only carbon, hydrogen & oxygen
-made of 2 types of molecules: glycerol (a type of alcohol) & fatty acids.
triglyceride (most common)
1 glycerol molecule & 3 fatty acid chains
-join together by condensation reaction
-loses water molecule per link (3 separate reactions to attach all fatty acids)
-link = ester bond
OXIDISED => triglycerides yield water = useful to desert animals (store fat for metabolic water content). function: digestion & synthesis - broken down as energy source (digestion) & synthesis (formed to store energy)
glycerol structure
made of 3C atoms in a line
Each C has hydroxyl group (-OH) on same side.
Hydrogens occupy remaining positions
fatty acid
- carboxylic acid group to hydrocarbon
(R-COOH) (CH) - CH bonds break to release energy for ADP to ATP.
Chain: ~15 to 17 hydrocarbons.
Will form Ester Bond with glycerol - the OH on the end.
fatty acid - 2 types
1st type:
- every C joined by C-C covalent bond
SATURATED (=single)
2nd
DOUBLE = UNSATURATED
1 or more C=C covalent bond
UNSATURATED.
e.g dietary protein in gut
break down into amino acids, reassembled to form needed protein
amino acids linked tgt by peptide bonds, condensation reaction
R-group
-20 different types
-gives 3d shape of protein molecules
function dependent on protein shape
peptide bonds
-links amino acids together
-carboxyl group reacts with amine group
-C(=O)NH-
release H2O
single bonds on either side of C-N bond
allow rotation, FLEXIBLE
Structure
1, 2, 3, 4 degree.
primary = sequence of amino acids connected by peptide bonds
secondary = folding/coiling
tertiary = 3D, loops
quaternary = multiple chains, polypeptide
primary
-order of amino acids changes function. Order of amino acids to make polypeptide chain
-one amino terminus, one carboxyl terminus
secondary (2 types)
alpha helix: coiled into right-handed helix by hydrogen bonds between N-H group of a peptide bond AND C=O group of a peptide bond 4 amino acids away.
beta sheet: polypeptide chains linked together side by side formation by hydrogen bonds. Parallel and antiparallel depending on R-groups.
tertiary - different types of bonds
-hydrophobic interactions and van der Waals interactions. Polypeptide backbone
quaternary
at least 2 polypeptide chains (2+)
form a co)mplex
stabilised mainly by weak interactions between amino acids
-will always have hydrogen bonds
ionic bc it is charged (SOMETIMES)
4 types of bonds
-hydrogen bonding
-ionic bonds
-disulfide bonds
-hydrophobic interactions
hydrogen bonds
-between polar H(delta+) and some O (delta negative) and N (delta negative) atoms in a polypeptide chain
-opposite charges attract
-Broken by an increase in temp and change in pH
ionic bonds
-between charged groups that are NOT joined by a peptide bond
-stronger than H-bonds
-affected by temperature and pH too
disulfide bonds
-bridge between amino acids containing sulfur atoms
-structural purposes, keratin, collagen
-very STRONG
hydrophobic interactions
-between NON-POLAR side chains
-clump together and push hydroPHILIC groups OUTward (like water = out)
CARBOHYDRATE - hydrophobic interactions
globular protein
(BLOB-looking)
-curled up
-hydrophilic R-groups face outward
hydroPHOBic R-groups face inward
-soluble in water
-easily transported
e.g all enzymes, antibodies, many hormones, HAEMOGLOBIN
fibrous protein
-Long chains (not curled up)
-Hydrophobic R-groups exposed
-Insoluble (in water)
Not easily transported
Structural properties
E.g., collagen and keratin
haemoglobin structure (2 components)
-GLOBULAR
-4 polypeptide chains, 2 alpha globin, 2 beta globin/chains
-prosthetic group (haem), iron binds to oxygen. 4 haem groups, 1 iron per chain/at each haem group.
-mostly alpha helix/helices
-quaternary structure
haemoglobin function
- blood = transport medium for respiratory gases (oxygen & carbon dioxide)
-most oxygen carried by Hb in RBC
haemoglobin mechanism
INHALE OXYGEN
-oxygen diffuses (simple diffusion) into bloodstream
-4 oxygen molecules bind to each haemoglobin molecule (1 at each haem) in RBC
-binding leads to conformational change in protein structure
-RBC travel around body
-reach tissues with lower oxygen concentrations
-protein conformational change again to release oxygen
