plz ans these questions

[drarch]

1.) Assuming that P50 = 26 torrs, under conditions where PO2 = 30 torrs, the average number of O2 molecules bound per hemoglobin molecule is closest to:

a) 0.5
b) < 1
c) almost 2
d) > 2
e) > 3

2.) For a reaction catalyzed by an enzyme with a Km = 1mM, which of the following represents the effect on velocity if is changed from 10mM to 20mM (assuming that the enzyme obeys Michaelis-Menten kinetics)

a) Small decrease
b) Small increase
c) Two fold decrease
d) Two fold increase
e) Twenty fold increase

Please answer them with explanations.

Thanks.

---

Members don't see this ad.

 

[drarch]

Anyone there.........plz ans these question.

 

[drarch]

plz someone tell me the ans & explanation . no one is replying my questions.they r from released 1996 papers but i m not getting them so plz can anyone explain me ans of these questions.

 

[enamelina]

question 1......answer D

we have to use the "oxygen dissociation equation for Hb" here,

y=(po2)n / (po2) n +(p50)n (everything to the power of n )

wherein y=fractional occupancy of oxygen binding sites
P50=partial pressure of oxygen at which 50% of sites are filled
Po2=partial pressure of unbound o2.
n= 2.8 dissociation constant for Hb.

now, Substitute the numbers.....we get y= 0.6 or 60% of the sites are bound.
since the available Hb is more than 50% saturated with o2,>2 oxygen molecules are bound....(choice D).



question 2.........answer B.

we must use Michelis Menton Equation here.

V=Vmax
_________
+ Km

wherein V= Rate of catalysis
= substrate concentration
Vmax = max.velocity of catalytic reaction
Km = michelis constant.

now, substitute =10mM

V=Vmax [10]
______ = vmax (0.90)

[11]

now when =20mM,

v=vmax [20]
_______ = vmax (0.95)
[21]

so the velocity of rxn is INCREASED by a SMALL amount (choice B).

 

[drarch]

thanx Enamelina. i really appreciate it.

 

[mam6701e]

1.) Assuming that P50 = 26 torrs, under conditions where PO2 = 30 torrs, the average number of O2 molecules bound per hemoglobin molecule is closest to:

a) 0.5
b) < 1
c) almost 2
d) > 2
e) > 3

.

The answer is in this web
http://forums.studentdoctor.net/showthread.php?t=128307&highlight=P50+torrs

 

[drarch]

The answer is in this web
http://forums.studentdoctor.net/showthread.php?t=128307&highlight=P50+torrs

thank you.

 

[drarch]

1. Which of the following is the only part of the gastrointestinal system that has villi, goblet cells, and mucous-secreting glands in the submucosa ?
a) Ileum
b) Stomach
c) Jejunum
d) Duodenum
e) Esophagus

2. Which of the following differentiates cementumfrom enamel ?
a) Presence of collagen fibers
b) Presence of incremental lines
c) Presence of hydroxyapatite crystals
d) Derived from the dental papilla

3. The sympathetic innervation to structures of head and neck is distributed via the
a) blood vessels
b) fascial planes
c) lymphatic vessels
d) hyoid musculature
e) cranial nerves III, VII, IX and X

4. Usually, a periapical abscess of a mandibular first premolar drains lingually into which of the following spaces
a) Sublingual
b) Submandibular
c) Parapharyngeal
d) Retropharyngeal
e) Pterygomandibular

5. Which of the following characterizes the generator potential of a receptor ?
a) An all-or-none response
b) Propagated in a non-decremental manner
c) Universally present in all nerve tissues
d) Graded according to the strength of the stimulus

6. At which stage in the process of gene cloning are restriction nucleuses used ?
a) Isolation of mRNA
b) Synthesis of double-stranded cDNA
c) Insertion of the cDNA into the vector DNA
d) Expression of the cloned genes by the bacteria
e) Introduction of the recombinant DNA into a bacterial cell

7. During oxidative phosphorylation, the hydrogen ion gradient is created using energy from which of the following ?
a) ADP transport
b) ATP synthesis
c) ATP hydrolysis
d) Reduction of NAD
e) Electron transfers

8. Transmission of impulses from the motor nerve to the muscle cell regularly produces
a) an action potential in the muscle cell
b) a graded potential in the muscle cell
c) hyperpolarization of the muscle cell
d) hypopolarization of the muscle cell
e) alteration in the threshold potential of the muscle cell

9. Destruction of the left spinocerebellar tract at T2 would be expected to eliminate positional sense on
a) Right side of the body above T2
b) Right side of the body below T2
c) Left side above T2
d) Left side below T2


Would really appreciate explanations !!! Thanks.

 

[drarch]

staphylococus aureus most commonly cause

1) skin infection
2) septicemia