Proteins Flashcards
What are proteins composed of?
Amino acids
How are amino acids composed?
An amino group to the left, carbonyl group on the right, with a CH in the middle called the alpha carbon
The only difference is there r group therefore it’s used to identify them
Where does proteins building stem from?
Amino acids
What are proteins?
These are amino acids joined together by polypeptides
Most diverse and most important molecule in living organisms
What are the functions of proteins?
Structural building blocks
Cellular functions (immune defence, cell to cell transport, oxygen transport)
Genetic operations (growth, repair, and protection)
make enzymes
make hormones
build and maintain tissue
In emergency or starvation they can be broken down or used as an energy source
What does the iodized amino acid look like?
N+ O-
non polar
R group is a hydrocarbon structure
If sulphur or hydrogen is present it is within the group (not at the bottom)
Electrons are shared relatively equally
Polar
The R groups contains sulphur, nitrogen, and/or oxygen
These elements have a higher electronegativity and draw electrons to them resulting in a polar molecule
(But no overall charge is present in the r group)
Electrically Charges Acidic
lost H+ ions in the solution, therefore R group is left with negatively charged
Basic
accept H ions from the solution, therefore R group is left with a positive charge
what is the SNO rule for polarity?
if the R group contains a sulphur, nitrogen, or oxygen then it is polar
what makes an amino acids positive or negatively charged?
if it loses H+ ions in the solution, then it is negative=acidic
if it gains H+ ions in the solution, then it is positive=basic
what are the eight essential amino acids
must be obtained through the diet Isoleusine leucine Lysine methionine phenylalanine threonine tryptophan valine
complete protein
food that has full set of all 8 essential amino acids
these foods include animal meat such as red meat, pork, and fish
what is an amide linkage?
this is a carbon to nitrogen bond
what is the first level of protein folding and what is it known for?
this is called primary,
this is a chain of 50 amino acids linked by peptide bonds
the type of amino acids present or the sequence itself, varied from molecule to molecule
amide linkages are formed between an NH2 (amino group) and a COOH (carboxyl group)
what is the second level of protein folding and what is it known for?
this is called secondary,
coiling stages in two ways, alpha helix, and beta pleated sheets
consists of interactions with the polypeptide backbone
alpha helix vs beta sheets
alpha helix: two parts of a polypeptide chain are coiled together, hydrogen are always four amide linkages away between the carboxyl group and amino group
two parts of a polypeptide chain lie parallel, Hydrogens (the stabilizer) form between carbonyl and amino groups
hydrophobic vs hydrophilic acid chains
hydrophobic has carbon rich side chain, doesn’t react well with water
hydrophilic molecules interact well with water
what is the third level of protein folding and what is it known for?
this is called tertiary,
strong forces of attraction and repulsion between the polypeptide and its environment force it to undergo additional folding (stringy like hair follicles)
Hydrogens bond between the polar side
Ionic bonds between the oppositely charged side (acid/base)
Vander Waals forces between nonpolar side chains
Disulphide bridges between two cysteines (S-S) (strong stabilizers of tertiary structure
Proline Kinks
what is a proline kink
naturally bends the alpha helix or beta-pleated sheets where needed
what is the fourth level of protein folding and what is it known for?
this is called quaternary,
two or more polypeptide subunits must come together to form a functional protein
eg fibrous protein found in hair, hemoglobin
denaturation
a change in the protein structure formation caused by temperature, ionic concentration, Ph, or environmental factors
