WGU Biochemistry C 785 Study Guide
Page 10 Video Notes for Units 2-7
Unit 2 – Amino Acids, Peptide Bonds, Protein Structure
Amino Acid: building blocks of proteins
Monomer: single amino acid
Polymer: amino aci
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WGU Biochemistry C 785 Study Guide
Page 10 Video Notes for Units 2-7
Unit 2 – Amino Acids, Peptide Bonds, Protein Structure
Amino Acid: building blocks of proteins
Monomer: single amino acid
Polymer: amino acid chain of linked monomers called
polypeptides
Amino Group: N with at least 1 H, can be NH2 or NH3
Hydrogen Hat: between amino group and carboxyl group,
attached to alpha carbon
Variable Group “side chain” “R”: unique portion of amino acid
Carboxyl Group: C with 2 attached O’s, can be COOH, or COO
Hydrophobic Amino Acid: consists only of carbons and hydrogens
end in H, CH, CH2, CH3 – they are nonpolar –Hydrophobic
interactions occurs between two nonpolar amino acids H, CH,
CH2, CH4, are the weakest type of bond – but the most important
type for protein structure – are broken with heat (increased
temperature)
Polar Amino Acid: end in OH, NH, SH, create hydrogen bonds, can
be broken by changes in pH or changes in salt concentration.
SH: Disulfide bond/bridge made by SH side chains, is strongest,
fewest in number, and only broken with reducing agents
Peptide Bonds: form at amino group and carboxyl group, “loss of
H2O”
Ionic Bonds: occurs between two amino acids with opposite
charges (charged amino acids, -/+, negative is acidic positive is
basic), are broken with pH changes or changes in salt
concentration
Dehydration Synthesis: when two molecules are covalently
bonded with loss of a water molecule (H20) one provides
hydroxyl group OH and the other provides hydrogen H. Amino
group and carboxyl group both give up something and then they
bind and form a new bond polymer chain
Hydrolysis: addition of a water molecule H2O to break a bond,
breaks polymers
4 Levels of Protein Structure: Primary linear chain of amino
acids, Secondary alpha helix and beta sheet shapes, create by
Hydrogen bonds of polypeptide backbones Tertiary 3D,
stabilized by side chains Quaternary consists of two or more
polypeptide chains, more than one subunit – tertiary and
quaternary are mature structures that are properly folded.
Denaturation: high temperatures and various chemical treatments
will denature a protein, causing it to lose its shape and ability to
function “form=function” it may renature when chemical and
physical aspects of environment are restored to normal.
Unit 3 – Enzymology and Catalytic Mechanism
Enzymes: are proteins, they catalyze reactions when properly
folded, can be disrupted just like amino acids by heat, pH, etc.,
“enzymes are proteins that act as biological catalysts, Lactose is
a substrate that can be converted to glucose and galactose which
are products by lactase which is an enzyme (enzymes usually end
in “ase”). Enzymes lower the activation energy of a reaction
“makes it easier and quicker”. People who are lactose intolerant
do not have lactase that breaks it down into usable products.
Excessive internal heat can denature hydrophobic interactions
thus causing important enzymes to lose their function.
Enzymes bind a specific substrate and catalyze a specific reaction,
speed up reactions, and decrease activation energy “faster and
easier”
Substrates bind to an enzyme’s active site. When an enzyme is
fully folded it creates an active site for the substrate to bind to.
Tertiary/Quaternary enzymes have active sites only, fully mature
enzymes, enzymes recognize specific substrates (lock and key)
“enzyme specificity”
Enzyme 4-step Cycle: Step 1= substrate recognition, the substrate
recognized a specific enzyme a
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