Exam I

Question 1

L designation

Answer 1

The stereoisomer of amino acids that are incorporated into proteins in vivi

In Fischer projection, amine group points LEFT

Question 2

Zwitterion

Answer 2

Occurs around physiological pH. Carboxyl group is deprotonated and amino group is protonated

Question 3

pKa amino acid terminals

Answer 3

C -> 2.2

N -> 9.4

Question 4

L Dopa

Answer 4

A Tyrosine derivative drug with an extra hydroxyl on the ring. Used to treat Parkinson’s

Question 5

Branched chain AA

Answer 5

Valine
Leucine
Isoleucine

Question 6

Histidine (His) (H)

Answer 6

Aromatic; pKa of 6; co-ordinates metal ions in hemoglobin

Question 7

Basic AA

Answer 7

Lysine, Arginine

Helps stabilize the negative phosphate backbones of DNA

Question 8

Phenylalanine (Phe) (F)

Answer 8

Aromatic; Promotes efficient stacking of protein (especially in cellular membranes)

Question 9

Glycine (Gly) (G)

Answer 9

Achiral;

Most flexible AA; usually found in tight places and helps avoid steric hindrance

Question 10

Sulfur Containing AA

Answer 10

Met -> Start codon

Cys –> Tertiary structure ( disulfide bridges); can be disrupted by urea/ethanomercaptol

Question 11

Alcohol Containing

Answer 11

Involved in phosphorylation reactions; forms phosphate esters

Involved in protein signaling (glycoproteins)

Ser, Thr, Tyr

Question 12

Proline (Pro) (P)

Answer 12

A pyrollidine heterocyclic;

Forms kinks and tight turns

Found in Elastin (nonhydroxylated)

Found in Fibrous proteins as Hydroxyproline (usually as “x” in Gly-X-Y motif); stabilized triple helix

Found in hairpin loops at the sharp turn (pos 2)

Question 13

Modified AA

Answer 13

4-hydroxyproline and 5-hydroxyglycine help stabilize protein

Question 14

Vitamin K

Answer 14

Essential in coagulation cascade; activated by gamma-carboxyglutamate (modified AA)

Deficiency leads to hemmorhaging

Question 15

Monoasaccharides

Answer 15

Glucose (diabetes/hyperglycemia)

Fructose (fructose accumulation/hypoglycemia)

Galactose (hydrolysis of lactose; mammalian mill synthesis)

Question 16

Disaccharides

Answer 16

Sucrose (1a, 2b linkage); Glucose + Fructose

Lactose (b 1,4 linkage); Glucose + Galactose

Maltose (a 1,4 linkage); Glucose + Glucose

Question 17

Other saccharine Containing compounds

Answer 17

Glycoproteins: Oligo + proteins

Glycolipids: Oligo + lipids

Proteoglycan: Glycosaminoglycan + proteins

Question 18

Sphingolipids

Answer 18

Serine and Palmitic acid derivative

Forms ceramides by attaching sphingosine backbone to amino group

Question 19

Gaucher Disease

Answer 19

Glucocerebrosidase deficiency

Lysosomal (cellular) accumulation of glucocerebroside in bones, lungs, liver, spleen

Question 20

Tay-Sachs Disease

Answer 20

Hexominodase deficiency

Build up of GM2 ganglioside

Question 21

Niaman-Pick Disease

Answer 21

Sphingomyelinase deficiency; cherry spots visible in eye

Build up of sphingomyelin

Question 22

Alpha Helices

Answer 22

Stabilized by H bonding parallel to helix axis; 3.6 aa/turn

Amphipathic aa are at protein surface; hydrophilic project outwards towards solvent; hydrophobic project onward towards protein core

Question 23

Beta Sheets

Answer 23

Parallel (same direction wrt terminals); Antiparallel (opposite directions, stronger interactions) ; Mixed (both)

Stabilized by H bonding

Provide bulk of hydrophobic core due to optimal dense packaging

Question 24

Reverse Turn; Hairpin Loop; Beta Turn

Answer 24

Comprised of 4 amino acids; Proline at pos 2 and Glycine at pos 3

Stabilized by H bonding (carbonyl of aa 1 and amide proton of aa 4)

Question 25

Rossman Fold (Super-secondary structure)

Answer 25

Several Beta & Beta motifs; A helix connects two parallel Beta sheets Usually found in glycolysis enzymes

Question 26

Prions

Answer 26

Contains only proteins; lacks DNA & RNA Propagates misfolding of proteins

Question 27

Prion derivative diseases

Answer 27

Infection: Mad Cow Diseass Genetic Mutation: Creutzfeldt-Jakob disease (CJD)

Question 28

Tertiary structure

Answer 28

Hydrogen (acid/base) ionic (salt) Disulfide (urea/mercaptoethanol) Hydrophobic interactions (detergent)

Question 29

Actin fold

Answer 29

Structural domain in G-actin Region of protein that folds independently; super-secondary structures

Question 30

Triple Helix

Answer 30

Common for fibrous proteins Repeat Gly-X-Y motif; X being Proline and Y being lysine (both hydroxylated)

Question 31

Vitamin C

Answer 31

Required for Proline and Lysine hydroxylation; deficiency leads to inadequate X-Y and leads to scurvy

Question 32

Ehlers Danlos Syndrome

Answer 32

Mutations in formation of Collagen type I and Collagen type III

Question 33

Osteogenesis Imperfecta *

Answer 33

Also known as Brittle Bone Disease Type I Collagen mutation

Question 34

Elastin

Answer 34

Elastic connective tissue in lungs, arterial walls, etc Composed of small nonpolar AA (G, V, A) as well as P and K

Question 35

Alzheimer's

Answer 35

Accumulation of B Amyloid

Question 36

Cystic Fibrosis

Answer 36

Deletion of 3 base pairs (phenylalanine at pos 508) Thick mucus accumulation in lungs

Question 37

Amyloidosis

Answer 37

Accumulation of amyloid proteins Primary amyloidosis --> multiple myeloma Secondary amyloidosis --> Tuberculosis, Chron's Diabetes T2 --> Amyllin in pancreas Dialysis associated amyloidosis --> Accumulation in blood seen in long term Dialysis patients

Question 38

Sickle Cell Anemia

Answer 38

B globin

Question 39

Huntington's

Answer 39

Poly-Glutamine Repeat Neurodegenerative

Question 40

Parkinson's

Answer 40

Alpha Synuclein

Question 41

Heat Shock Proteins

Answer 41

Cellular levels are increased during elevated temp in order to reduce protein unfolding HSP60, HSP70, Chaperones Utilize ATP

Question 42

Histones

Answer 42

Alkaline proteins; package DNA into nucleosides and then into dhromatin Interact with negatively charged phosphate backbones with Lysine + Arginine residues