Question

which answer helps to explain why all living cells need ph buffers?
nucleic acids must have positive charges to form double helices.
hydrogen bonds only form at medium ph values.
amino acid side chains have many carboxyl and amino groups.
atp will not deliver energy if it is ionized.

part f
to make a buffer, you need to...
(a) combine equal amounts of a strong acid and a strong base in water.
(b) put either a strong acid or a strong base in water.
(c) adjust the ph to 7.0.
(d) have a weak acid or a weak base half ionized in water.
both (a) and (c).

Explanation:

For the first part, amino - acid side chains have carboxyl and amino groups which are sensitive to pH changes. Buffers help maintain a stable pH for these groups to function properly. For the second part, a buffer is made by having a weak acid or a weak base half - ionized in water as it can resist pH changes. A strong acid and strong base combination will neutralize each other and not form a buffer, and just putting a strong acid or base in water won't create a buffer either, and adjusting pH to 7.0 doesn't define a buffer.

Answer:

First part: Amino acid side chains have many carboxyl and amino groups.
Second part: (d) have a weak acid or a weak base half ionized in water.