biochem

[Rathi]

one strand of DNA have 20%A, 30%T,40%C. what is the percentage of C on other strand?

10
20
50
80
90

Please explain this
thanks

---

Members don't see this ad.

 

[dds_aspirant]

10%
The DNA strands are complementary to each other, so 10% G on this strand will have 10% of C on the other strand.

one strand of DNA have 20%A, 30%T,40%C. what is the percentage of C on other strand?

10
20
50
80
90

Please explain this
thanks

 

[rashiarora]

Solution A has a pH of 7.0 and solutionB has a pH of 6.0
both solutions are of equal volume. which of the following statements about Solution A and B is most accurate?
1> A had 1/10 as many hydrogen ions as B
2> A has 10 times mroe hydrogen ions as B
3> A has 7/6 of the hydrogen ion concentration of B
4> A has 6/7 of teh hydrogen ion concentration of B

 

[rashiarora]

another one i cud not figure out....actually it went totally over my head....

Each of the following polymers is correctly paired with its component precursor EXCEPT one. Which si teh Exception?
POLYMER COMPONENT
1. Dextran Sucrose
2. Glycogen Fructose
3. Mutan Sucrose
4. Glycogen UDP - glucose
5. Levan Sucrose

 

[rashiarora]

Coupled Respiration requires each of teh following EXCEPT________

1. ADP
2. Oxygen
3. CO2
4. electron donor
5. inorganic phosphate

also in first place i cannto figure otu wat is coupled respiration so if u can plz hint on that topic or where i cud read it from.

 

[Roni]

Hi Rashiarora,

Solution A has a pH of 7.0 and solutionB has a pH of 6.0
both solutions are of equal volume. which of the following statements about Solution A and B is most accurate?

Tha correct answer is, 1> A had 1/10 as many hydrogen ions as B.

Explanation: A change of 1pH unit results in a 10 fold change in the ratio of conjugate acid to conjugate base.

Eg: ph -[lactic acid]/[lactate]

2.8 - 100
3.8 - 10
4.8 - 1[pka for lactic acid=4.8]
5.8 - 0.1

The above table explains why i have chosen answer 1.[ simple way: solution B with pH 6 is acidic than soltution A with pH 7. So B should have more hydrogen ion when compared to A.]

Thanks,
Roni.

 

[Roni]

Hi,

Each of the following polymers is correctly paired with its component precursor EXCEPT one. Which si teh Exception?
POLYMER COMPONENT
1. Dextran Sucrose
2. Glycogen Fructose
3. Mutan Sucrose
4. Glycogen UDP - glucose
5. Levan Sucrose

Correct answer is 2. Glycogen fructose

Explanation: Glycogen if a homopolymer of glucose. other combinations like in aswers 1,3,4,5 are correct

1. Dextran Sucrose - homopolymer of glucose formed from hydrolysis of sucrose.
2. Glycogen Fructose-homopolymer of glucose linked by alpha-1,4glycosidic bonds.
3. Mutan Sucrose - homopolymer of fructose formed from hydrolysis of sucrose.
4. Glycogen UDP - glucose- see last step of glycogen synthesis.
5. Levan Sucrose - homopolymer of glucose formed from hydrolysis of sucrose.

-Roni.

 

[Roni]

Hi,

Oxygen uptake which is dependent on the presence of ADP and phosphate is termed coupled respiration. See electron transport chain(ETC) & oxidative phosphorylation.

Answer is 3.CO2

explanation: ADP, Oxygen, electron donor, inorganic phosphate are required for ETC coupled with ATP synthesis(ie oxidative phosphorylation)

Hope my explanation helps you.

Thank you,
Roni.

 

[rashiarora]

thanks Roni.
do u knwo teh answer to teh coupled respiration question?

 

[rashiarora]

Which of the following substances is the predominant source of ATP at Moderate levels (greater than 20 minutes of aerobic exercise) of muscle activity?
a. Amino acids
b. Fatty acids
c. Carbohydrates
d. Protiens

 

[rashiarora]

A person who has a long history of anabolic steroid abuse but has recently stopped is likely to exhibit each of the following characteristics EXCEPT one. Which one is this EXCEPTION?
a. Sterility
b. Low FSH levels
c. Low testosterone levels
d. decreased number of spermatids

 

[rashiarora]

Prior to surgery, an anxious patient has a higher systolic blood pressure than previously noted. Which of the following represents the MOST likely reason.
a. cardiac shock
b. anaphylactic shock
c. Atrial fibrillation
d. ventricular fibrillation
e. decreased arterial compliance

 

[rashiarora]

Each of the following occurs during prolonged starvation EXCEPT one. Which one is this EXCEPTION.

a. Circulating T4 is converted to rT3 (Reverse T3)
b. Ketoacidosis develops progressively
c. Insulin levels are depressed
d. Primary fuel is glycogen.

 

[rashiarora]

Cortisol stimulates synthesis in the liver of

a. glucokinase
b. phosphofructokinase
c. pyruvate carboxylase
d. pyruvate kinase

 

[Roni]

Which of the following substances is the predominant source of ATP at Moderate levels (greater than 20 minutes of aerobic exercise) of muscle activity?
a. Amino acids
b. Fatty acids
c. Carbohydrates
d. Protein

 

[Roni]

Cortisol stimulates synthesis in the liver of

a. glucokinase
b. phosphofructokinase
c. pyruvate carboxylase
d. pyruvate kinase

Answer:C. Pyruvate carboxylase.

Explanation: Cortisol's main function is to increase de novo synthesis of glucose, therefore it stimulates the enzymes used in gluconeogenesis. Pyruvate carboxylase is the 1st enzyme in gluconeogenesis. All other enzymes(a,b,d) are involved in glycolysis.

 

[rashiarora]

Which of the following substances is the predominant source of ATP at Moderate levels (greater than 20 minutes of aerobic exercise) of muscle activity?
a. Amino acids
b. Fatty acids
c. Carbohydrates
d. Protiens

Correct answer: B. fatty acids.

hey can u please explain why its fatty acids n not carbohydrates.

 

[Roni]

Each of the following occurs during prolonged starvation EXCEPT one. Which one is this EXCEPTION.

a. Circulating T4 is converted to rT3 (Reverse T3)
b. Ketoacidosis develops progressively
c. Insulin levels are depressed
d. Primary fuel is glycogen

Answer: d.
Explanation: during prolonged starvation, muscle uses fatty acids as the major fuel.

 

[Roni]

Originally Posted by Roni
Which of the following substances is the predominant source of ATP at Moderate levels (greater than 20 minutes of aerobic exercise) of muscle activity?
a. Amino acids
b. Fatty acids
c. Carbohydrates
d. Protiens

Correct answer: B. fatty acids.

Sorry, this question is quite tricky. i'm not sure of the right answer. I'll find out the correct explanation & get back to you.

Sorry..once again.

-Roni

Explanation:

 

[rashiarora]

Originally Posted by Roni
Which of the following substances is the predominant source of ATP at Moderate levels (greater than 20 minutes of aerobic exercise) of muscle activity?
a. Amino acids
b. Fatty acids
c. Carbohydrates
d. Protiens

Correct answer: B. fatty acids.

Sorry, this question is quite tricky. i'm not sure of the right answer. I'll find out the correct explanation & get back to you.

Sorry..once again.

-Roni

Explanation:

thanks..i realised its tricky one butut i thto teh answer wud b carbohydrates...

 

[Roni]

Yeah. The answer has to be carbohydrates.

Carbohydrates (Glucose by glycolysis) is the primary source of fuel during exercise/intense muscle contraction.

Fatty acids is the primary source of fuel during starvation.

But still having doubt, because glucose metabolism(glycolysis, tca cycle) produces 36-38 mols of ATP, whereas fatty acid oxidation produces 129mols of ATP.

Thats why I said its tricky.

 

[rashiarora]

i think crabohydrate is teh correct answer.

 

[rashiarora]

cell membrane is least permeable to which substance?

1. Oxygen
2. Carbon dioxide
3. Sodium
4. Water
5. Ethanol

 

[kilani]

cell membrane is least permeable to which substance?

1. Oxygen
2. Carbon dioxide
3. Sodium
4. Water
5. Ethanol

Well, generally speaking cell membranes don't like solutes, so I assume 3.Sodium is the right answer, gosh I forgot how much I hate biochem. !

 

[rashiarora]

Well, generally speaking cell membranes don't like solutes, so I assume 3.Sodium is the right answer, gosh I forgot how much I hate biochem. !

oh..i was hopin teh answer wud b ethanol..agreed it hates solutes but atleats i ahve heard of teh sodium pump...never heard of ethanot even gettin into teh cell....

 

[kilani]

oh..i was hopin teh answer wud b ethanol..agreed it hates solutes but atleats i ahve heard of teh sodium pump...never heard of ethanot even gettin into teh cell....

Oh, ethanol can penetrate cell membranes like they don't exist, so it's not the right answer.

 

[rashiarora]

Oh, ethanol can penetrate cell membranes like they don't exist, so it's not the right answer.

okay.Thanks a lot.

 

[rashiarora]

Which of teh following characterizes the generator potential of a receptor?

1. All or none response
2. propogated in a nondecremental manner
3. universalyy present in all nerve tissues
4. graded according to strength of stimulus

 

[rashiarora]

For which is teh first group of teh following pairs more likely to be located on teh surface of a globular protein than the second group of teh pair?

1. -CONH2 -COO-
2. -CH3 -CH(CH3)2
3. -CH2OH -NH4
4. -CH3 -CH2OH
5. -CH2SH -COO-

 

[rashiarora]

Can someone explain hwo to solve teh pH problems...
such as

calculating the hydrgogen ion concentration of a urine sample of pH 5.7

 

[rashiarora]

Formation of enamel and dentin requires adequate amounts of all these vitamins EXCEPT

1. A
2. C
3. D
4. E


pLEASE explain teh answers.

 

[rashiarora]

If teh pH becomes lower than the isoelectric point of a protein,then hwo will teh protein respond in an electrophoretic system. It will,

1. become denatured
2. migrate to negative pole
3. migrate to positive pole
4. remain stationary and unchanged
5. separate into its different monomeric forms

 

[toothydoc]

Formation of enamel and dentin requires adequate amounts of all these vitamins EXCEPT

1. A
2. C
3. D
4. E


pLEASE explain teh answers.

deficiency of vitamin a and d can lead to enamel hypoplasia, vitamin c is important for normal dentin formation, so we are left with vitamin E. when do you have your exam?

 

[toothydoc]

If teh pH becomes lower than the isoelectric point of a protein,then hwo will teh protein respond in an electrophoretic system. It will,

1. become denatured
2. migrate to negative pole
3. migrate to positive pole
4. remain stationary and unchanged
5. separate into its different monomeric forms

i think the question is incomplete....the name of the amino acid should be specified in hte question. it depends on the amino acid you are talking about.

 

[rashiarora]

i think the question is incomplete....the name of the amino acid should be specified in hte question. it depends on the amino acid you are talking about.

thats the question...the amino acid has not been specified.

however in another question ...they specifies the amoni acid to b glycine...so what wud teh answer be? here is teh other one...

Which of the following describes the movement of glycine molecules in an electric field at a pH of 6.06 (the isoelectric pH for glycine)? The glycine molecules will

1.not move
2.move to anode
3. move to cathode
4.move to both anode and cathode.

i think it shdu b "not move" but i'm nto sure.

 

[rashiarora]

The rapid emergence of new strains of human immunodeficiency virus is primarily the result of
1.The frequent genomic recombination between human immunodeficiency virus and other retroviruses
2.Frequent errors in the translation of viral proteins
3.The lack of immune response to the viral envelope glycoprotein
4.Frequent errors introduced by viral reverse transcriptase
5.The imprecision of protein cleavage by viral protease



Three days ago, a patient received her third immunization with tetanus toxoid. What class of antibodies specific for tetanus toxoid would one expect to find in her serum?
1.Similar concentrations of IgM and IgG
2.High concentrations of both IgM and IgD
3.Low concentrations of IgM; high concentration of IgE
4.Low concentration of IgM; high concentration of IgG
5.High concentration of IgM; low concentration of IgG


Rough pneumococci grown in the presence of DNA from dead smooth pneumococci develop capsules. This is an example of bacterial
1.Mutation
2.Dominance
3.Conjugation
4.Transduction
5.Transformation


Each of the following is characteristic of herpes zoster EXCEPT one. Which one is the EXCEPTION
1.Unilateral
2.Usually involves 1-3 dermatomes
3.Occurs repeatedly in immunocompetent patients
4.Only occurs in an individual having a latent VZV infection
5.More common in individuals who are immunocompromised

In fermentation, the final electron acceptor is
1.Water
2.Oxygen
3.Carbon dioxide
4.An organic compound
5.An inorganic compound

The antigenic component of which of the following vaccines is a capsular antigen
1.Influenza
2.Poliovirus
3.Hepatitis B
4.Haemophilus influenza

 

[rashiarora]

oh my exam is on 12th august

 

[rashiarora]

Which of the following is produced when a mutation occurs in an enzyme controlling a signal pathway involved in cell growth processes
1.Epigene
2.Antigene
3.Oncogene
4.Monogene
5.Transgene


Which of the following streptococcal virulence factors acts as a superantigen, mediating a variety of cytokine-induced effects that can result in life-threatening disease?
1.Pyrogenic exotoxin
2.Hyaluronidase
3.Streptokinase
4.Streptolysin O

Each of the following viruses is potentially capable of causing cell transformation EXCEPT one. Which one is this EXCEPTION?
1.Retrovirus
2.Herpesvirus
3.Picornavirus
4.Hepatitis B virus
5.Human papillomavirus


Which of the following represents the consequence of the fact that DNA strans are complementary?
1.Hairpin loop structures can be generated
2.They will always have identical sequences
3.Separated strands are able to reassociate
4.They cannot get back together once separated

Which of the following predominates in steroid producing cells?
1.Smooth endoplasmic reticulum
2.Rough endoplasmic reticulum
3.Golgi apparatus
4.Phagosomes
5.Nucleolus

 

[rashiarora]

Each of the following is a type of inflammatory exudate EXCEPT one. Which one is this EXCPETION
1.Suppurative
2.Fibrous
3.Purulent
4.Fibrinous
5.Pseudomembranous

When T-cells from patients who have chronic periodontal disease react with certain plaque bacterial antigens, they produce each of the following EXCEPT one. Which one is this EXCEPTION
1.Immunoglobulin
2.IL-2
3.TNF-B
4.IFN-y

 

[mangoduet]

Each of the following is a type of inflammatory exudate EXCEPT one. Which one is this EXCPETION
1.Suppurative
2.Fibrous
3.Purulent
4.Fibrinous
5.Pseudomembranous

When T-cells from patients who have chronic periodontal disease react with certain plaque bacterial antigens, they produce each of the following EXCEPT one. Which one is this EXCEPTION
1.Immunoglobulin
2.IL-2
3.TNF-B
4.IFN-y

Each of the following is a type of inflammatory exudate EXCEPT one. Which one is this EXCPETION
1.Suppurative
2.Fibrous
3.Purulent
4.Fibrinous
5.Pseudomembranous

When T-cells from patients who have chronic periodontal disease react with certain plaque bacterial antigens, they produce each of the following EXCEPT one. Which one is this EXCEPTION
1.Immunoglobulin
2.IL-2
3.TNF-B
4.IFN-y

 

[rashiarora]

renal compensation for chronic metabolic alkalosis involves which of these?

1.increased tubular synthesis of NH3
2. partial reabsorption of filtered HCO3-
3. elevated production fo new bicraonate
4. none.



now in thsi question is thot it was none..but teh answer acc to the released papers is 2.
i dint understand that...i bel in metabolic alkalosis teh HCO3 ion concentration incraeses so why wud teh kidney compensat e by reabsorbing the Hco3 which is already is excess..

can someoen explain this answer. its from teh set I,Q 7

 

[Roni]

The antigenic component of which of the following vaccines is a capsular antigen
1.Influenza
2.Poliovirus
3.Hepatitis B
4.Haemophilus influenza

4. Haemophilus influenza (other capsular polysaccharide vaccines: Strep.pneumoniae & Neisseria.meningitidis )

 

[Roni]

Rough pneumococci grown in the presence of DNA from dead smooth pneumococci develop capsules. This is an example of bacterial
1.Mutation
2.Dominance
3.Conjugation
4.Transduction
5.Transformation

5. Transformation

 

[Roni]

Which of the following predominates in steroid producing cells?
1.Smooth endoplasmic reticulum
2.Rough endoplasmic reticulum
3.Golgi apparatus
4.Phagosomes
5.Nucleolus

1.Smooth endoplasmic reticulum

 

[Roni]

In fermentation, the final electron acceptor is
1.Water
2.Oxygen
3.Carbon dioxide
4.An organic compound
5.An inorganic compound


Answer: 4.Organic compound (like Lactic acid or Pyruvate )

 

[Roni]

Which of the following streptococcal virulence factors acts as a superantigen, mediating a variety of cytokine-induced effects that can result in life-threatening disease?
1.Pyrogenic exotoxin
2.Hyaluronidase
3.Streptokinase
4.Streptolysin O

Answer: 1.Pyrogenic exotoxin

 

[Roni]

Each of the following viruses is potentially capable of causing cell transformation EXCEPT one. Which one is this EXCEPTION?
1.Retrovirus
2.Herpesvirus
3.Picornavirus
4.Hepatitis B virus
5.Human papillomavirus


3.Picorna virus.

 

[Roni]

The rapid emergence of new strains of human immunodeficiency virus is primarily the result of
1.The frequent genomic recombination between human immunodeficiency virus and other retroviruses
2.Frequent errors in the translation of viral proteins
3.The lack of immune response to the viral envelope glycoprotein
4.Frequent errors introduced by viral reverse transcriptase
5.The imprecision of protein cleavage by viral protease

Answer: 4.Frequent errors introduced by viral reverse transcriptase

 

[Roni]

Each of the following is characteristic of herpes zoster EXCEPT one. Which one is the EXCEPTION
1.Unilateral
2.Usually involves 1-3 dermatomes
3.Occurs repeatedly in immunocompetent patients
4.Only occurs in an individual having a latent VZV infection
5.More common in individuals who are immunocompromised

Answer: 3.Occurs repeatedly in immunocompetent patients

 

[rashiarora]

Active transport systems generally involve specific binding molecules that are
1.lipids
2.proteins
3.carbs
4.nucleic acids
5.polyphosphates