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need help fast!

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5 Posts

abiguar79
Forum Junior

Topics: 14
Posts: 29

10/26/04 - 07:36 PM

Hi! I'm actually new to this site. I was told that i can get some help from here so if anyone can lend me a helping hand that will be great. I'm taking step 1 in 3 wks for the 2nd time so need some help. I have a few questions that i'm a little confused about. I hope someone out there can at least tell me the answer or explain it to me..thanks a lot!! JJ

1.Normal Healthy child is able to mount a diverse antibody response to several thousand different antigen. This processed is based primarily on which DNA mechanism?
Choices: Amplification, COnformation, REcombination, REpair, Replication

2. Anticodon of yeast serinly-trna 5'agc3', what is the serine codon?

3. Which following procedure improves immunogencity of vaccines that use capsular polysaccaride as antigen?
choices: heat denaturation, liposome incorporation, Oligosacaride reduction, Protein conjugation

4. dd DNA denatured with heat and then renatured by cooling.Renaturation under conditions of high stringency has which effect?
choices: 1.COnsiderable bas mismatch is permitted
2.GC base pair is inhibited
3. GT base pairing is promoted
4. Mismatched DNA hybridization is prevented

Renegade
Forum Elite

Topics: 18
Posts: 171

10/27/04 - 07:30 PM

"abiguar79" wrote:

3. Which following procedure improves immunogencity of vaccines that use capsular polysaccaride as antigen?
choices: heat denaturation, liposome incorporation, Oligosacaride reduction, Protein conjugation

I'll take this one. The answer is Protein conjugation. As you may know, polysaccarides are poor imunogenic molecules, unlike peptides. The obvious solution would be to associate proteins to these polysaccarides and, because of their imunogenic power, toxoids are usually chosen, like diphtheric and tetanic toxoids. This way, vaccines not only elicit a strong primary antibody response, but also induction of memory, and can be used in children.
Can u name 3 toxoid-conjugated vaccines?

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MLF
Forum Elite

Topics: 36
Posts: 386

10/27/04 - 07:35 PM

"abiguar79" wrote:

1.Normal Healthy child is able to mount a diverse antibody response to several thousand different antigen. This processed is based primarily on which DNA mechanism[/b]?
Choices: Amplification, COnformation, REcombination, REpair, Replication

The answer to this one is Recombination. There are so many different antigens out there that attack our body, and we should have some mechanism to fight most of the, and the way our immune system does that is by recombination within the genes of chromosomes that are in homology with each other, meaning have similarities between each other to produce a vast number of antibodies specific for these antigens. Hope this helps.

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abiguar79
Forum Junior

Topics: 14
Posts: 29

10/27/04 - 07:59 PM

thank u so much for helping me out..I hope someone can just help me with the last 2 questions...I wish my brain can work like that...

Malaysian
Forum Guru

Topics: 28
Posts: 778

11/06/04 - 09:33 AM

1.recombination
2.5-GCT-3
3.protein conjugation
4.The last choice on preventing a mismatch.

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