BCM 3053Study guide 3
1. What is the approximate pH of an acetic acid solution where the
concentration [REDACTED]? The pKa of acetic acid is 4.76.
Example: answer is 3.2
What is the pH of an acetic acid solution where the concentration of acetic acid is 70mM and the
concentration of sodium acetate is 2mM? The pKa of acetic acid is 4.76.
• A- is the base
• HA is the acid
2. Which amino acids [REDACTED] at [REDACTED]? (select all that apply)
Which of the following amino acids is/are likely [positive/negative] at physiological pH? (Select
all that apply)
• Lysine (K), Arginine (R)
• Aspartate (D), Glutamate (E)
3. The sequence shown below has what overall net charge [REDACTED]?
[REDACTED] a) +1 b) +2 c) 0 d) -1 e) -2
Example question: The answer is Zero
The sequence shown below has what overall net charge at physiological
pH? P-L-I-V-R-E-F-C-S-A
• At physiological pH acids have a negative charge and bases have a positive charge.
• Nonpolar and polar do not matter at physiological pH.
4. From those shown, which one is not an amino acid used in the 20 common amino
acids (ignore chirality and ignore protonation)?
, BCM 3053Study guide 3
5. Histidine...
• imidazole side chain
• This idea will apply conceptually to any amino acid with a side chain that can accept or
lose protons.
• At physiological pH it has a net of zero.
6. Given a [REDACTED] concentration of [REDACTED] what is the pH?
Example could be: Given a OH- concentration of 1 x 10^-5, what is the pH
Read these notes and questions carefully!
1. What is the approximate pH of an acetic acid solution where the
concentration [REDACTED]? The pKa of acetic acid is 4.76.
Example: answer is 3.2
What is the pH of an acetic acid solution where the concentration of acetic acid is 70mM and the
concentration of sodium acetate is 2mM? The pKa of acetic acid is 4.76.
• A- is the base
• HA is the acid
2. Which amino acids [REDACTED] at [REDACTED]? (select all that apply)
Which of the following amino acids is/are likely [positive/negative] at physiological pH? (Select
all that apply)
• Lysine (K), Arginine (R)
• Aspartate (D), Glutamate (E)
3. The sequence shown below has what overall net charge [REDACTED]?
[REDACTED] a) +1 b) +2 c) 0 d) -1 e) -2
Example question: The answer is Zero
The sequence shown below has what overall net charge at physiological
pH? P-L-I-V-R-E-F-C-S-A
• At physiological pH acids have a negative charge and bases have a positive charge.
• Nonpolar and polar do not matter at physiological pH.
4. From those shown, which one is not an amino acid used in the 20 common amino
acids (ignore chirality and ignore protonation)?
, BCM 3053Study guide 3
5. Histidine...
• imidazole side chain
• This idea will apply conceptually to any amino acid with a side chain that can accept or
lose protons.
• At physiological pH it has a net of zero.
6. Given a [REDACTED] concentration of [REDACTED] what is the pH?
Example could be: Given a OH- concentration of 1 x 10^-5, what is the pH
Read these notes and questions carefully!
