AAMC FL#2

Question 1

Equilibrium constants (Keq,Ka, Kb, Kw) are all….

Answer 1

temperature dependent

Question 2

A higher wavelength means higher or lower energy level?

Answer 2

Higher wavelength is lower energy level so less absorbed photon energy

Question 3

k cat is???

Answer 3

k cat is the number of substrate molecules converted to product per enzyme per second

Question 4

Venturi effect

Answer 4

volume flow rate has to be same through different parts of tubes so that water will flow faster in areas with smaller radii –> meaning this area will have lower pressure (bernoulli’s equation)

Question 5

Why G-C bonds are stronger?

Answer 5

they have pi-bond stacking strength

Question 6

what are the storage lipids?? their structure?

Answer 6

triacylglycerols - 3 FAs ester linked to a single glycerol

Question 7

charles law

Answer 7

V/T

Question 8

If kf (constant of formation) is > 1 then delta G is….

Answer 8

kf = products/reactants and delta G = -RT ln (k) at equilibrium so if kf is >1, then delta G is negative because reaction is spontaneous and products are favored

Question 9

coordinate covalent bonds

Answer 9

coordinate covalent bonds are usually Lewis acid/base reactions and are mostly between a metal ion and an electron pair donor

Question 10

Metals have ________ ionization energies than nonmetals

Answer 10

Metals have lower ionization energies than nonmetals

Question 11

If Ka is lower, then the acid is stronger or weaker?

Answer 11

weaker acid because there is less dissociation - think math - because acid is on denominator of equation

Question 12

Bond dissociation energy

Answer 12

delta H = sum of H of (BONDS BROKEN) - sum of H of (BONDS FORMED)

Question 13

H of formation

Answer 13

Hf(products) - Hf(reactants)

Question 14

What functional group is this?

Answer 14

nitro group

Question 15

Protein secondary structure is characterized by the pattern of hydrogen bonds between

Answer 15

backbone amide protons and carbonyl oxygens

Question 16

facts about diverging lens

Answer 16

ALWAYS create a virtual, upright image that is reduced; Image is always on object’s side of the lens

Also diverging lens are concave lens

Also has a -f (focal length) and -r (radius of curvature)

Question 17

formula relating sound level and intensity

Answer 17

Intensity = Power/Area

Question 18

PFK-1 inhibited by ___ and activated by _____

How does fructose-2,6BP play in the activation/inhibition scenario?

Answer 18

PFK-1 is inhibited by ATP and citrate and activated by AMP.

Insulin indirectly stimulates PFK-1 (while glucogon indirectly inhibits) in HEPATOCYTES (where most PFK-2 are found); insulin STIMULATES PFK-2 first, which converts some Fructose-6P to Fructose 2,6-BP; Fructose 2,6-BP then ACTIVATES!!!! PFK-1 to override inhibition by ATP !!!! – glcolysis proceeds

Question 19

substrate level phosphorylation

Answer 19

uses high energy intermediate to create ATP through direct phosphorylation

Question 20

pyruvate kinase is activated by______

Answer 20

by fructose 1,6-BP from the PFK-1 reaction; this is a feed forward activation - so product of earlier reaction stimulates later reaction

Question 21

hexokinase vs glucokinase

Answer 21

hexokinase - widely distributed in tisssues; inhibited by its produt - glucose -6P; has LOW Km(reaches maximum velocity at low [glucose]

glucokinase - found ONLY in liver and pancreatic beta-islet cells; in liver, glucokinase is induced by insulin; along with GLUT 2, it acts as a glucose sensor; has HIGH Km (acts on glucose proportionally to its concentration)

Question 22

lactate dehydrogenase

Answer 22

oxidizes NADH to NAD+ in mammalian fermentation by changing pyruvate into lactate; pyruvate and lactate are 3 carbon molecules; NAD+ now used in glycolysis to make ATP!

In yeast fermentation; pyruvate (3C) converted to ethanol (2C) and carbon dioxide (1C) but also makes NAD+!!!!!

Question 23

other roles of DHAP

Answer 23

DHAP - dihydroxyactone phosphate in glycolysis forms glycerol-3-phosphate, which is then conerted to glycerol for TRIACYLGLYCEROL SYNTHESIS in HEPATIC and ADIPOSE TISSUE

Question 24

What is the special RBC enzyme?

Answer 24

bisphosphoglycerate mutase - which produces 2,3-bisphosphoglycerate (2,3-BPG) from 1,3BPG;

2,3-BPG binds ALLOSTERICALLY to beta chains of HbA and DECREASES its affinity for O2

2,3BPG DOESNT bind well to HbF - fetal Hb - so HbF has HIGHER affinity for O2 than maternal HbA

Question 25

where are secretory proteins synthesized?

Also, where are transcription factors found

Answer 25

in the Rough ER; secretory proteins are synthesized and FOLDED in the rough ER

Transcription factors are found in the nucleus and so they need a nuclear localization sequence

Question 26

Ubiquitination

Answer 26

this tags a protein with ubiquitin, which signals it for degradation by a proteasome in short peptides

Question 27

histone acetylation is what kind of modification?

Answer 27

histone acetylation is a posttranslational modification of proteins - so it is analyzed by Western Blotting

Question 28

ADH/Vasopressin - how does it increase blood volume

Answer 28

inserts aquaporins into apical membrane of epithial cell in the collecting duct

Question 29

Schwann cells vs oligodendrocytes

Answer 29

Schwann cells - make myelin in peripheral nervous system

oligodendrocytes - central nervous system

Question 30

prion

Answer 30

an abnormally folded protein that induces a normally folded version of the protein to also adopt the abnormal structure, which is often deleterious

Question 31

Blood from small intestine goes where?

Answer 31

blood from the small intestine is transported first to the liver, which regulates nutrient distribution and removes toxins from the blood

Question 32

Internalization of viral particles through endocytosis is mediated by

Answer 32

endosomes