Macromolecules - Proteins

amino acid

building blocks of proteins, monomer

20 amino acids groups into 4 different categories

attached to alpha carbon

alpha carbon

center carbon in an amino acid

N, H, R group, and another C attached to it.

polypeptide

multiple peptide bonds are bonded forming a chain

peptide bond

amino acids linked by these bonds to form proteins

dehydration occurs to make these bonds, amino and carboxyl group eliminated to do this

R group

4 groups of amino acids classified by chemical properties

N-terminus

start/end of amino acid on amino group side

C-terminus

start/end of amino acids on carboxyl side

Primary stucture

a single chain of polypeptides written from N-C terminus

secondary structure

short regions of folding, either beta sheet or alpha helix, from the polypeptide backbone, intramolecular h-bonding with itself.

Tertiary structure

more folding from interactions between R groups, if they are hydrophobic or hydrophilic, will contribute to shape

quaternary structure

multiple amino acid chains coming together to form a complex protein

ex. hemoglobin proteins contains 4 polypeptide subunits

Alpha helix

circularm secondary structure occurs from polypeptide backbone H-bonding

Beta sheet

folded over each other, secondary structure, occurs from polypeptide backbone H-bonding

disulfide bond

sulfur bonded to another sulfur, occurs in tertiary structure from R groups interacting

denaturation

interactions disrupted will cause protein to unfold and not unable to function anymore, virtually impossible to reverse

can occur by heat, change in pH, salt concentration, or solvent polarity

renaturation

process of unfolded proteins coming back together

ex, DNA coming back together after getting separated during translation

nonpolar amino acid

alanine

phenylalanine

glycine

isoleucine

leucine

methionine

proline

valine

tryptophan

polar amino acid

Cysteine

asparagine

glutamine

serine

threonine

tyrosine

charged (-) acidic amino acid

aspartate

glutamate

charged (+) basic amino acid

histidine

lysine

arginine

why changes in temperuature, pH and other factors can lead to the denaturation of proteins

proteins have conditions that need to be met in order to function and when those conditions are changed they aren’t able to work

example if heat is added weak bonds are able to easily come apart

Explain how interactions between amino acids, the polypeptide backbone and water contribute to protein structure

amino acids are bonded through a peptide bond from dehydration of the amino and carboxyl group the backbone then begins and h-bond to each other. If this structure is in water the R groups will start to cause the structure depending if they are hydrophobic or hydrophillic.