Lecture 1: Protection Structure and Function, Part 1 Flashcards
What are building blocks?
Subunits that are used to form macromolecules
What are macromolecules?
Large organic molecules
How are macromolecules formed?
Macromolecules are formed by generating strong covalent bonds between small organic molecules powered by hydrolysis and condensation reactions
What are the 4 building blocks of cells?
Sugars, Amino Acid, Nucleotide, and Fatty Acids
What macromolecule do sugars make and how are they linked?
Sugar makes polysaccharide (includes glycogen and starch
Linked by glyosidic bonds
What macromolecule do amino acids make and how are they linked?
Amino acids make proteins
Linked by peptide bonds
What macromolecule do nucleotides make and how are they linked?
Nucleotides make nucleic acids
Linked by phosphodiester bonds
What macromolecule do fatty acids make and how are they linked?
Fatty acids make up fats and membrane lipids
Linked by ester bonds
What are condensation reactions?
Two molecules combine to form single molecule often by removal of water
Energetically unfavorable and not spontaneous
What are hydrolysis reactions?
Molecules broken by adding water
Energetically favorable and spontaneous
Why do cells couple hydrolysis condensation reactions?
By coupling both condensation (energetically unfavorable) and hydrolysis reactions (energetically favorable) is able to power the reaction
What is the general structure of amino acid?
Alpha carbon attached to amino group, carboxyl group, and unique side chain
How is the structure of an amino acid in water (pH 7)?
In water, free amino acids exist in ionized from
Amino group accepts a proton and carboxyl group donates a proton
Overall charge is neutral
How do amino acids differ?
Amino acids differ through 20 different side chains
What is N-terminus?
First amino acid in polypeptide backbone
What is C-terminus?
Last amino acid in polypeptide backbone
What is side chain/ R group?
a chemical group attached to the alpha carbon which distinguishes one amino acid from another, accounts for different chemical properties that are critical for protein structure and function
What are polar amino acids?
Hydrophilic amino acids that form hydrogen bonds and prefer to interact with water
What amino acids are polar?
Uncharged: STQNY
Negative: DE
Positive: KRH
What are nonpolar amino acids?
Hydrophobic amino acids that cannot form hydrogen bonds and repel water
What amino acids are nonpolar?
GAVC LIMP
What amino acids can from hydrogen bonds?
Polar amino acids which have free hydroxyl group
STQNY, DE, KRH
Which amino acids can from electrostatic repulsions?
Charged amino acids
DE and KRH
What amino acids can from hydrophobic forces?
Nonpolar amino acids
GAVC LIMP
What is role of covalent bonds in protein structure?
Covalent peptide bonds link amino acids in polypeptide chain
Nonpolar amino acids cluster in core
What is role of noncovalent bonds in protein structure?
Include hydrogen bonds, electrostatic interactions, van der waals attractions
Exist between polar amino acids influence 3-D shape of protens
What is role of hydrophobic interactions in protein structure?
Plays critical role in determining shape of protein as nonpolar amino acids cluster in core
What is the tertiary structure of proteins?
collection of secondary structures in protein and is 3-D arrangement of all atoms in a protein of single polypeptide chain and involves interactions between side chains
What is the primary structure of proteins?
linear amino acid sequence by covalent peptide bonds (polypeptide chain)
What is the secondary structure of proteins?
ordered 3-D arrangement in space of backbone atoms in polypeptide chain by hydrogen bonds
ex. alpha helices and beta sheets
Why are alpha helices and beta sheets common structures in proteins?
Common secondary protein structures stabilized by hydrogen bonds formed between backbone atoms of amino acids
What is the quaternary structure of proteins?
binding of different polypeptide chain/ multiple subunits and is stabilized by noncovalent forces
What are protein domains?
Referred in tertiary structure
Segment of amino acids that can perform specific function/ job
What are protein subunits?
One polypeptide chain in protein with quaternary structure
What are disulfide bonds?
Disulfide bonds are covalent bonds between cysteine residues (S-S)
What types of proteins have disulfide bonds?
Observed in proteins that are secreted by the cell and attached to the outer surface of plasma membrane
Why are disulfide bonds important for protein structure?
Disulfide bonds stabilize protein structure and can combine different polypeptide chains
What is a ligand?
Any substance that is bound by a protein
What is a binding site?
cavity with amino acid side chains that bind to ligand
How does a ligand interact with a binding site?
Binding site uses electrostatic interactions and hydrogen bonds to selectively bind to 1 ligand
