Week 4 Flashcards
_____________ the building blocks of proteins.
Amino Acids.
Amino acids contain ____________ and _____________ functional groups.
Amine and carboxylic acid.
In nature the ___________ enantiomer of the amino acid is commonly found.
L
______________ is a molecule that possesses both a positive and negative charge.
Zwitterion
_____________ side chains are non polar and incapable of hydrogen bonding.
Hydrophobic
_____________charged amino acids contain a carboxyl group and are commonly ____________ at physiological pH.
Negatively, deprotonated.
______________ charged amino acids include lysine, arginine, and histidine.
Positively
Amino acids serve a variety of roles in biochemistry including:
- Lipid metabolism
- Amino acid catabolism
- Neurotransmission
Why is proline the least flexible amino acid?
Its side chain is bonded to its amino group.
_________ is the linkage between two amino acids.
Peptide bond.
A peptide bond is an _________ linkage between the __________ group of amino acid and the ___________ group of the next.
Amide,carboxyl, amino.
A _____________ molecule is removed in order for an amide bond to form.
Water.
_____________ are nonprotein groups required for protein binding or activity.
Cofactor.
Cofactors can be divided into two common categories:
Minerals(metal and ions) and vitamins (small organic groups.
___________ are enzymes that catalyze phosphorylation reaction.
Kinases.
____________ is typically the source of phosphate.
ATP.
______________ can change the activity of an enzyme and is thought to act as switch in the cell.
Phosphorylation.
A peptide bond is normally an amide but also is capable of mildly acting as what?
An oxime.
What are the 4 levels of protein structure?
- Primary
- Secondary
- Tertiary
4.Quaternary
The _____________ structure is the linear arrangement of amino acids.
Primary.
The ____________ structure is held together by hydrogen bonding.
Secondary.
The secondary structure consists of two major structural elements:
Alpha helix and Beta sheet
____________ is the most common structure observed in proteins.
Alpha helix
_____________ can be parallel or anti-parallel.
Beta sheet.
In anti-parallel beta sheets the hydrogen bonds are __________.
Linear.
In parallel beta sheets the hydrogen bonds are __________.
Horizontal.
___________ and ____________ limit the flexibility of the peptide chain.
Hairpin and Loops.
____________ structure gives the overall shape of the protein.
Tertiary.
___________ are combinations of secondary structure.
Motifs
___________ pieces of a protein that retain their structure in the absence of the rest of the protein.
Domains.
What are the bonding forces involved in stabilizing tertiary structure?
- Hydrogen bonding
- London dispersion forces
- Dipole-dipole interactions
- Salt bridges
- Cation interactions
- Disulfide bonds
___________ describes the phenomenon in which hydrophobic groups cluster together.
Hydrophobic effect.
____________ structure is a complex structure that incorporates multiple subunits or different proteins.
Quaternary
Which amino acid can donate the most hydrogen bonds?
Arginine.
__________ a protein that acts as a pore in the membrane, it selectively allows water to pass in and out of the cell.
Aquaporin.
Aquaporin is a ___________ protein that consists of 6 transmembrane alpha helices.
Transmembrane.
__________ is an enzyme that cleaves dietary into peptides.
Chymotrypsin.
Chymotrypsin is produced by the _________ and secreted into the ____________.
Pancreas, Intestinal lumen.
Chymotrypsin is composed of __________ beta barrels and ____________ short alpha helix.
Two and one.
__________ is a fibrous protein mostly concentrated in muscle and connective tissue.
Collagen.
Collagen is composed of a triple helix that contains __________, _____________, and ______________.
Glycine, proline, and hydroxyproline.
____________ is a globular, tetrameric protein found in red blood cells.
Hemoglobin.
Hemoglobin uses heme as a ___________ for each subunit.
Cofactor.
Hemoglobin is a ____________ protein.
Transport.
Collagen is a __________ protein.
Structural.
_____________ are molecules of the immune system that recognize and bind to antigens.
Immunoglobulins.
Immunoglobulins are __________ proteins.
Binding.
____________ is a protein hormone produced by pancreatic beta cells.
Insulin.
Interrupted or impaired insulin signaling can result in __________.
Diabetes.
____________ diabetes is a failure to produce insulin.
Type I
___________ diabetes insulin is not received.
Type II
__________ acts as molecular motor in which energy is used to elicit a muscle contraction and transport vesicles in the cell.
Myosin.
Myosin contains___________ chains and ____________ chains.
Heavy and light.
_____________ chain interacts with the cytoskeletal protein_________.
Heavy, actin.
__________ chain plays a role in binding Ca+2.
Light chains.
Myosin is a _____________ protein.
Molecular motor.
How many subunits does hemoglobin have?
4
