Proteins I
True or False:
Proteins have 2 functions
False!
What is the monomer of a Protein?
Amino Acids! (AA)
-*don't get it confused w/ Nucleic Acids*
What type of bond links AA's to form a protein polymer known as a 'polypeptide'?
Peptide Bond!
Another name for a single AA in a polypeptide chain
What is a 'Subunit'?
a slow-acting, virtually indestructible infectious protein *double pts if you can explain why they're "virtually indestructible"?*
What is a Prion?
*You need to denature the protein w/ acids*
What 2 functions of proteins do we focus on in this class?
Enzyme Proteins and Transport Proteins
How many different amino acids are there?
20
What functional group corresponds with the 'N-Terminus' and 'C-Terminus' of a polypeptide chain?
*Bonus 100: In which direction do we read the AA sequence?*
N-Terminus= amiNo end
C-Terminus= Carboxyl end
*N to C*
What type of chemical reaction forms a Peptide Bond?
Dehydration Reaction
How do 'Prions' effect proteins?
causes them to misfold and hence lose their function
Which 'functional group' would be attached to an Acidic AA Sidechain?
*Bonus 200 for Basic AA Sidechain func. group*
Carboxyl
Amino Group at 'terminal end'
Describe the structure of an amino acid. (What functional groups does it contain?)
Amino Group on left
'Central carbon'
Carboxyl Group on right
'variable sidechain' (R)
When changes in pH, temperature, etc. cause a protein to "unravel" and hence lose its function
What is Denaturation?
Which chemical reaction "costs" an H2O, and which chemical reaction "creates" an H2O?
Hint: the names for lengthening or shortening a polymer
Hydrolysis Reaction costs an H2O *lyse= to cut*
Dehydration Reaction creates an H2O
What tiny change in a protein causes Sickle-Cell Anemia?
Order of AA in primary structure changes, which changes EVERYTHING
How do you determine if an Amino Acid 'R Group' is Nonpolar? What about Polar?
Nonpolar R Groups would be mainly just 'hydrocarbons'
Polar R Groups are caused by O, S, and N, which are highly electronegative
What are the 3 types (classifications) of Amino Acids?
*bonus 200 if you tell us how they're determined*
Nonpolar AA's
Polar AA's
Basic/Acidic AA's
*determined by their sidechains!*
Did Collagen and Hemoglobin have Quaternary Structure? What shape did they form?
*DOUBLE PTS if you can give their functions after answering both questions*
Yes, collagen forms (structural) helices and Hemoglobin transports O2 in a 'globular' shape.
A protein loses its shape and hence loses its function. What is it called when it comes back together again?
Renaturation
A hereditary condition in which a person has mucus buildup in their lungs
What is Cystic Fibrosis?
How can the mutation of a gene affect a protein (leading to disease)?
The mutated gene produces a "defective protein"
Kindly describe the difference between Primary Structure, Secondary Structure, Tertiary Structure, and Quaternary Structure.
'Primary Structure' is simply the sequence. 'Secondary Structure' is when Hydrogen Bonds form between the AA backbone. 'Tertiary Structure' is formed by chemical interactions between the sidechains. 'Quaternary Structure' is when two separate polypeptide chains bond to form one molecule.
What are the 2 ways we describe shapes formed from the Tertiary Structure of a protein?
*Bonus 200: Can a protein be functional at this level of folding, or does it need Quaternary Structure?*
Alpha Helix
Beta-Pleated Sheets
*Tertiary-lvl proteins can be functional*
Explain the significance of Gene Expression.
-(what is Gene Expression?)
Genes encode proteins and proteins dictate cell function
Cystic Fibrosis patients have a nonfunctional _______ _______.
Chloride Transporter (aka memb. transport protein)