Question from 2009 ADA Practice Test

[predentalstudent9]

Can someone explain to me two questions from the bio section on the 2009 practice test, please?

#14) Which of the following is the major intracellular buffer?
Answer choices: A) TRIS, B) Acetate, C) Phosphate, D) Bicarbonate, E) Calcium Carbonate

Why is the answer D) Bicarbonate? I thought phosphate was intracellular buffer and bicarbonate was extracellular buffer?

#39) An experiment was conducted to determine the effect of a new antiviral agent on HIV-infected cells in laboratory cultured cells. The following data was obtained:
Time (week) Percent Cells Alive
0 100
1 72.6
2 55.9
3 38.8
4 25.1
5 18.6
6 14.3
7 14.1
8 10.2
According to the data, during which one week period did more cells die than any other week?
Answer choices: A) week 1, B) week 3, C) week 4, D) week 5, E) week 7
The right answer is A) week 1.
I don't understand why its A?

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[BoomerSooner-ang]

Can someone explain to me two questions from the bio section on the 2009 practice test, please?

#14) Which of the following is the major intracellular buffer?
Answer choices: A) TRIS, B) Acetate, C) Phosphate, D) Bicarbonate, E) Calcium Carbonate

Why is the answer D) Bicarbonate? I thought phosphate was intracellular buffer and bicarbonate was extracellular buffer?

#39) An experiment was conducted to determine the effect of a new antiviral agent on HIV-infected cells in laboratory cultured cells. The following data was obtained:
Time (week) Percent Cells Alive
0 100
1 72.6
2 55.9
3 38.8
4 25.1
5 18.6
6 14.3
7 14.1
8 10.2
According to the data, during which one week period did more cells die than any other week?
Answer choices: A) week 1, B) week 3, C) week 4, D) week 5, E) week 7
The right answer is A) week 1.
I don't understand why its A?

A quick google search can answer you first question.

As for the second question,

week one is from the first day (week 0) to the beginning of week two (end of week one). so from 0-1 you see that there is the largest percentage decrease, meaning that the most cells died in this time frame than in any other. Hopefully that makes sense.

 

[SDDDAT]

Make sure to look up the errors on the 2009 answer sheet! http://forums.studentdoctor.net/threads/bioqs-from-2009-ada-sample-test.712196/