Exam 2

Question 1

essential fatty acid for development of infants and children

Answer 1

Polyunsaturated fats (PUFS)..best known is omega 3

Question 2

how do free FA circulate in blood stream?

Answer 2

carrier protein: serum albumin

Question 3

what are the derivatives of FA

Answer 3

esters and amides

Question 4

What are the most abundant FA in animals?

Answer 4

oleate (18:1), palmitate (16:0), and stearate (18:0)

Question 5

polyunsaturated fats that must come from diet

Answer 5

linoleate (plant oils) and linolenate (fish oils)

Question 6

which position in triacylglycerol is usually unsaturated

Answer 6

2nd position

Question 7

how are triacylglycerols stored

Answer 7

adipocytes (animals) and oils (plants)

Question 8

what hydrolases cleave TAGs?

Answer 8

lipases

Question 9

what are the main digestion products with bile salts?

Answer 9

FA’s and monoacylglycerols

Question 10

what are waxes?

Answer 10

esters of long chain saturated and unsaturated FA’s with long chained alcohols

Question 11

key biological role of lips in membranes?

Answer 11

glycerophospholipids, sphingolipids, steroids/sterols

Question 12

glycerophospholipids

Answer 12

glycerol 3-phosphate core molecule. phosphate in 3 position and is attached to head group.

Question 13

fake fats in real goods

Answer 13

6-8 FA attached to sucrose rather than 3 FA attached to glycerol in TAGs

Question 14

ceramide

Answer 14

when FA attached in amide linkage at position C2 (in sphingolipids)

Question 15

sterols

Answer 15

• characterized by 4 fused rings
• not aromatic, not planar
• OH group makes one end polar (attached at C3)
• diversity in alkyl side chain at C17

Question 16

three types of lipid aggregates

Answer 16

micelle, bilayer, vesicle

Question 17

what are cell membranes not and what does this mean?

Answer 17

monotonous (it is an active process and the distinct compositions have functional consequences.)

Question 18

membranes acting 2D

Answer 18

Uncatalyzed lateral diffusion (energetically neutral) and uncatalyzed transbilayer diffusion (slow and unfavorable)

Question 19

flippase (catalyzed transbilayer translocation)

Answer 19

outside to inside (out to cytosolic leaflet)

Question 20

floppase (catalyzed transbilayer translocation)

Answer 20

inside to outside (cytosolic to outer leaflet)

Question 21

scramblase

Answer 21

moves lips in either direction, toward equilibrium

Question 22

heterokaryons

Answer 22

fused cells

Question 23

topology

Answer 23

distinct inner and outer faces of integral membrane proteins

Question 24

hydropathy index

Answer 24

used to predict whether some AA stretch might by a transmembrane-spanning alpha helical region. Graphed based on free energy of transfer from hydrophobic solvent into water. Greater than zero- hydrophobic

Question 25

what AA are positioned at interface between FA and polar head groups?

Answer 25

Tyr and Trp

Question 26

what AA are found in aqueous phase on TM

Answer 26

Lys, Arg, Glu, Asp, charged residues

Question 27

integrin (membrane protein)

Answer 27

sends signal to cytokine

Question 28

cadherin (membrane protein)

Answer 28

Ca dependent and allows cells to stick together specifically

Question 29

N-cam (membrane protein)

Answer 29

neural cell adhesion and is important in sticking neurons together (immunoglobulin like domains)

Question 30

selectin

Answer 30

binds carbs and helps with sticking cell to suitable matrix

Question 31

carriers

Answer 31

are saturable and substrate specific

Question 32

Glut1

Answer 32

expressed in all fetal tissues and in RBC in adults. Only responsible for basal glucose transport

Question 33

GLUT2

Answer 33

liver, pancreas, gut, high capacity but low affinity

Question 34

GLUT3

Answer 34

brain, high affinity

Question 35

GLUT4

Answer 35

insulin regulated, adipose tissue, muscle

Question 36

in chymotrypsin where does Product 1 gain a proton from?

Answer 36

from water via ser195 via His 57

Question 37

in chymotrypsin where does Product 2 gain a proton from?

Answer 37

directly from water

Question 38

turnover number (kcat)

Answer 38

number of substrate molecules converted into product per enzyme molecule per unit time when the enzyme is saturated with substrate (directly proportional to the kinetic efficiency of the enzyme)

Question 39

Km

Answer 39

inversely proportional to the affinity of the enzyme for its substrate (high then poor affinity and low km is high affinity for substrate)

Question 40

specificity constant (Kcat/Km)

Answer 40

represents the catalytic efficiency of an enzyme at substrate concentration significantly below saturation

Question 41

Vmax

Answer 41

velocity at which all E is always saturated with S

Question 42

competitive inhibition

Answer 42

substrate and inhibitor are often structurally similar. Inhibitor binds active site, therefore competes with S. No effect on Kcat or Vmax, but increase in apparent Km.

Question 43

uncompetitive inhibition

Answer 43

inhibitor binds to ES directly (but not to E). I binding results in conformation change that distorts active site. Decrease in kcat (or Vmax) and cannot be reversed by higher S. Decrease in the apparent Km.

Question 44

noncompetitive inhibition

Answer 44

Inhibitor can bind to E or to ES. Inhibitor does Not bind active site on E. Usually affects both Km and kcat. Higher S cannot restore full activity.