10 millimoles of a tribasic acid (pH3) was titrated with a NaOH soln. Select the most probable pH of the soln when 20 meq of NaOH are added. (pK's= 2, 4, 8)
pH= 12
what is the pH of an aqueous soln containing .01 M methylamine (base) and .10 M methylammonium chloride (acid)? the pK for methylammonium ion at this temp is 10.5. (log 2= .3, log 3= .47, log 5=.7)
- pH= 9.5
pH=pKa + log (base/acid)
pH= 10.5 + log (.01M/.1M)
pH= 10.5 + log (1/10)
pH= 10.5 - log (10/1)--> (log 10= 1)
pH= 10.5-1
pH= 9.5
Given the concen of Na2CO3 as 100mM/L, the mOSM/Kg concen is computes as:
- 3 x 10^2
OSM= (M)(# of species Na2CO3)
OSM= (100)(3)
the buffering regions in Fig. 92 are best represented by points:
(sorry dont have the graph)
- b, d, f
Soln A has the pH of 7, while B has pH of 6. Both solns are of equal volume. Which statement about A and B is correct?
- A has 1/10 of the hydrogen ion concentration of B
(A is more basic than B so it has more H+)
which pKa value represents the weakest acid?
- 9.4
(high pKa= low acid strength)
The pka of a buffer system (for an acid HA) is 6.1. The pH of a specimen in this system was found to be 7.1. What is the ratio of ionized to unionized HA?
- 10:1
pH= pKa + Log (Base/acid)
7.1= 6.1 + log (base/acid)
1= log (base/acid)
1= log 10
1= log (10/1)
An amino acid which has the net positive charge at pH= 6 is:
- lysine
(+) AA:
- Lysine
- Arginine
- Histidine
In this structure the gamma carbon is carbon number:
(sorry no structure)
- 5
(gamma carbon is the 3rd carbon from the carbon that is attached to functional group: alpha is 1st, beta is 2nd)
Which of the following groups contains amino acids with side chains that are all strong absorbers of UV radiation?
- tyrosine and tryptophan
(aromatic AA)
In Hbs the mutation is manifested due to the substitution of a single amino acid. This mutation:
- GLU--> VAL, on the 6th position in beta chain
(Hbs= sickle cell)
Carboxypetidase B:
a. is an endopeptidase
b. is an exopeptidase
c. cleaves the last amino acid (AA) in the peptide sequence
d. A and C
e. B and C
- E ( B and C)
The precursor for heme group is:
- protoprophyrin IX
CO is carried in the blood in greatest amounts as:
- carboxyhemoglobin
Which of the following functional groups of hemoglobin can bind either carbon dioxide or protons?
- certain terminal amino groups
Given a polypeptide with the following sequence, how many peptides should result from chymotryptic cleavage?
Asp-Glu-Pro-Pro-Lys-Phe-Gly-Gly-Glu-Tyr-Arg-Phe-Glu-Pro-Lys-Tyr
- 4
(chymotryptic cleaves aromatic AA: Phe, Tyr, Trp)
The pKa of a buffer system (for an acid HA) is 6.1. The pH of a specimen in this system was found to be 7.1. What is the ratio ionized HA to uniozed HA?
- 10:1
In the following peptides: trypsin could hydrolyze which of the peptide bonds?
H2N alanine-a- tyrosine-b-alanine-c-lysine-d-alanine-COOH
- D
(trypsin cleaves after Lys, Arg)
Which AA residue is least likely to be found on surface of globular proteins in aqueous soln?
- Valine
(hydrophobic (non polar) AA)
The presence of a prolyl residue in a segment of peptide chain will cause a break in:
- alpha helix structure
Sulfhydral group activators:
- Glutathione, BME, Cysteine
Other than hexokinase, where is ATP consumed in glycolysis?
- Phosphofructokinase 1
The anomeric carbon of ribulose is carbon:
- 2
Which of the following best characterizes glucokinase?
- found primarily in liver
The net products of anaerobic glycolysis are:
- lactate, ATP
The most important allosteric inhibitor of phosphofructokinase 1 in a resting muscle is:
ATP
In the pyruvate dehydrogenase complex, the decarboxylation step (catalyzed by the pyruvate dehydrogenase component, E1) uses the coenzyme:
-Thiamine pyrophosphate (TPP)
The ring structure in fig one represents: (sorry no picture, quiz 3; ques 7)
- alpha- D fructose 6 phosphate
The major site for carbohydrate digestion is the:
- small intestine
Given: galactose 1P <--> galactose 6P
delta G= delta G ^0 + RTln( CD/AB)
(Keq= 10, R= 2 x 10^-3, T=300, ln=2.3 x log)
What is delta G ^0?
A) -1.380
(300)(2.3)(2x10^-3)(log 10= 1)
Calculate delta G^0 for reaction B--> D:
A-->B = 5
C-->A = 5
C-->D = 10
- 0
(-5 + -5 + 10)
When aerobic cells are incubated under anaerobic conditions, they may metabolize glucose and generate some ATP. However, when oxygen is introduced into this medium, which enzymatic step reverses direction and eventually shuts off?
- lactate dehydrogenase
At equilibrium, the standard free energy change of a reaction is:
- equal to -RTLnKeg
After the complete metabolism of one molecule of glucose to carbon dioxide and water via the TCA cycle, what will be the net change in the amount of oxaloacetate in the mito?
- unchanged
Which of the following enzymes utilizes FAD as a coenzyme?
- Succinate Dehydrogenase
Gluconeogenesis:
- occurs in the liver
You administered sodium pentachloropheol (barbituate) to a patient who had already self medicated himself before coming to the clinic for a tooth extraction. Now the patient has a large amount of barbituate in his system. If his tissues were anaylized, wh
-Best answer: reduced Complex I function
- will also accept: reduced flow of electrons through electron transport
What is the terminal component in the electron transport chain that reduces oxygen to form water and that can be poisoned by cyanide?
- cytochrome oxidase
The basic structure of glycogen is based on which type of glycosidic linkage between glucose residues?
- alpha [1,4] links
Which of the following enzymes cleaves glucose residues from the non reducing ends of gylcogen?
- glycogen phoshorylase
All the feeling are intermediates or products of the pentose phosphate pathway except:
- NADH
The principal tissue involved in gluconeogenesis to provide glucose for the resynthesis of muscle glycogen following prolonged exercise is:
- liver
The immediate donor for glucose units in the synthesis of glycogen is:
- UDP- glucose
Which of the following pairs of metabolites are common to both pentose phosphate pathway and the glycolytic pathway:
- Glucose 6P and glyceraldehyde 3P
Which reaction in the krebs cycle is not physiologically reversible?
- formation of citrate
The transaldolase and transketolase enzymes in the HMS pathway share which of the following common features?
- both transfer from a ketose to an aldose
The complete hydrolysis of phosphatidylcholin, isolated from a plasma membrane, would be expected to result in the formation of:
- gylcerol, phosphoric acid, cholin, and a mixture of saturated and unsaturated FA
Behenic acid, a 22 carbons long FA is ingested and completely metabolized to carbon dioxide and water. The potential number of moles of ATP (NET) that could be generated is closest to:
10 ATPs/Acetyl CoA, 2.5 NADH + H+, 1.5 ATPs/FAD2
- 148
A molecule of sphingomyelin is similar to a molecules of lysolecithin in that they both contain:
- only one FA residue
An intermediate common to the biosynthesis of cholesterol and the biosynthesis of ketone bodies is:
- HMG- CoA
Among the differences between FA synthesis and FA oxidation is the fact that:
- synthesis uses only NADPH and oxidation uses both NADH and FADH2
Phospholipase D is predominantly present in carrots. the reaction of phospholipase on phosphatidyl ethanolamine will produce the products:
- phophatidic acid + ethanolamine
Which of the following compounds is required for the translocation of activated FA inside the mito for the metabolic pathway of beta-oxidation?
- carnitine
If acetate labeled with 14c in the carboxyl group is fed to a mammal, cholesterol subsequently isolated from the liver would to be expected to contain 14c in:
- about half the carbon atoms
Which of the phopholipids is deficient in the lungs of patients (newborn) with ARDS (acute respiratory distress syndrome)?
- phosphatidylcholin (surfactant)
A 35 year old man was instructed to fast overnight to allow a blood draw for lipoprotein anaylsis. After refrigeration at 4 degrees C, examination of the plasma specimen appearance was slightly cloudy and appeared to be milky. Plasma electrophoretic patte
- III
Post heparin lipoprotein lipase test is generally used to distinguish between lipoprotein disorders: this test is useful in identifying the primary lipoproteinemia of type:
- I from V
A 45 year old male patient tells you that he has been told to increase his intake of omega 3 FA by eating fish at least twice per week. He tells that he doesnt like fish and asks if you have any suggestions and if there are oils that he can use. You sugge
- canola oil
Excess oral intake of vitamins may cause toxicity. These are:
- A and D
Consider that a food product provides a total 250 calories (kcal) per serving. How much carbohydrates (g) should be present to provide 160 calories (kcal)?
- 40
Symptoms of night blindness indicate that there is a difficulty in dark adaptation. This may be due to the deficiency of the vitamin:
- which is lipid soluble, vit A
You were asked by the patient to suggest appropriate vitamins for, pellegra, overall dermatitis, and skin conditions. You provided the following information that the patient should take:
- Niacin and olive oil
What percentage of calories in the food bearing the label below is provided by protein?
Total calories= 160
protein= 6g
- 15%
Regarding nitrogen balance (NB) and protein:
a. (-) NB indicated that intake of protein is less than consumption
b. (+) NB indicated that intake of protein is greater than consumption
c.blood nitrate concen is a measure of protein-nitrogen in the circulat
- A and B only
The dietary deficiency disease caused primarily by insufficient protein intake is:
- kwashiorkor
The requirement for fat in the diet:
- is for essential FA and enough fat for absorption of Fat soluble vit
Nutritional requirements are dependent on all of the factors except:
- ethnicity