Lecture 9
No description yet. This curated deck is ready for daily study.
Card preview (24)
What is the structure of an AA?
central C attached to Amino group, R group and Acrboxylic acid group
What % of C,O,N,H,S is in proteins?
Carb 50% O 22% N 16% H 7% S little
What is protein condensation?
When 2 AA come together, carboxylic acid and AA from 2 different groups come together and release 1 molecule of water to form a dipeptide
What is the bond that connects 2 AAs?
Peptide bond is the bond between the AA
What is a hybrid or twitter ion?
AA that is ampthoteric -AA can carry +/- charge at the same time on same molecule
What happens to a twitter ion when pH increases or decreases?
Low ph will appear in acid form -net charge + Increase ph go to basic form -net chargee is -1
What are the characteristics of acid coagulation of casein?
Fresh Milk pH ~ 6.6 “Colloidal Suspension” Net Negative Charge on Casein Add Acid Coagulation (Protein Denaturation) Iso-electric point of casein: PI = 4.6 net charge = 0
What situation would be desireable/undesireable use of acid coagulation of casein?
Desireable if you want yogurt you want coagualtion of casein or in cheese Undesirable curdling of milk in a smoothie
What are the uncharged R groups of AAs?
Serine Threonine Cysteine Glyceine
What are the negatively charged AAs?
Aspartate Glutamate
What is the one positively charged AA?
Lysine
What are the non polar R groups?
Methionine Phenylalanine Alanine Valine
What are the essential AAS?
Valine Leucine Isoleucine Phenylalanine Tryptophan Lysine Arginine Histidine Methionine Threonine
What are the R groups for Gly, Asp, Set, Lys, Ala, Phe, Cys, Glu?
Gly: R= H Asp: R = CH2COOH Ser: R = CH2OH Lys: R = CH2-CH2-CH2-CH2- NH2 Ala: R = CH3 Phe: R = CH2=Benzene ring Cys: R = CH2SH Glu: R = CH2-CH2-COOH
What is the Pka?
PKA: Ph at which you have equal amount of acid and base pH at which [Acid] = [Base]
What is the isoelectric point?
Ph when net charge on protein is 0 PI = PKa1 + PKa2/2
How can you calculate the pH if you only know the Pka and acid base concentrations?
PH = Pka + log [A-]/[HA] HA>H+ + A- HA = ACID A- = BASE
What is the primary structure of proteins ?
AAs joined by peptide bonds
What are the factors that fact the physical/chemical properties of proteins?
Peptide bonds R-groups Type of AA Sequence of AA
What is the secondary structure of protein ?
α-helix Collagen helix Beta Pleated sheet Held together and maintain structure by : • S-S • H-Bond
What is the tertiary protein structure?
Results from folding of 2o structure on itself Maintained by: • H bond • S-S • Ionic Bond
What is the quaternary structure?
Protein consisting of more than one amino acid chain
What are the 2 kinds of proteins?
Globular Protein >Myoglobin *Protein helix is folded back on itself Fibrous Protein > Collagen *Extended polypeptide chain
What is the nutrition breakdown of egg yolks?
(30% Fat, 18% Protein, 50% Water) Lipids Protei: -Lipoprotein (Lipovittellin): Emulsifying property -Non-Lipoprotein (Phosvitin): High in P