Mastering Biology Chapter 2B Flashcards

Questions and Answers

Which statement is true of pH buffers? (Select all that apply)

They keep the pH of the blood constant.

They consist of strong acids and strong bases.

They consist of weak acids and weak bases. (correct)

Both (a) and (b).

Both (b) and (c). (correct)

How does this system buffer a solution against decreases in pH? (Select all that apply)

HA dissociates and releases H+ and A- into solution.

A- reacts with H+ to become HA. (correct)

As the solution loses H+, HA replaces the lost H+.

Both (a) and (c). (correct)

None of the above.

Buffers work best when ____.

about half of the buffer molecules are dissociated.

How does the way a buffer stabilizes pH during addition of acid differ from the way the same buffer stabilizes pH during addition of base?

It's the same reaction running backward or forward. Signup and view all the answers

Which answer helps to explain why all living cells need pH buffers?

Amino acid side chains have many carboxyl and amino groups. Signup and view all the answers

To make a buffer, you need to:

Have a weak acid or a weak base half ionized in water. Signup and view all the answers

The brackets are indicating a(n) ____ bond.

hydrogen Signup and view all the answers

What name is given to the bond between water molecules?

hydrogen Signup and view all the answers

What is the arrow pointing to?

hydronium ion Signup and view all the answers

Which one of these is an amino group?

Refer to provided online resource. Signup and view all the answers

Study Notes

pH Buffers

pH buffers consist of weak acids and weak bases, which help maintain stable pH levels.
They are crucial for keeping blood pH constant.

Buffer Components

A buffer is composed of undissociated acid (HA) and its dissociated ion (A-).
The buffering action against pH decreases involves A- reacting with H+ to form HA.

Buffer Efficiency

Buffers are most effective when about half of their molecules are dissociated.

Buffering Mechanisms

Buffers stabilize pH changes through reversible reactions: adding acid or base causes the same reaction to run in reverse or forward.

Importance of Buffers in Cells

Living cells require pH buffers because amino acid side chains contain many carboxyl and amino groups, which can affect protein structure and function.

Creating Buffers

A buffer is created by having a weak acid or weak base that is half ionized in water.

Nature of Water Bonds

The hydrogen bond is the interaction between water molecules and is essential for various biological processes.

Understanding Molecular Interactions

Identifying molecules, such as recognizing hydroxide ions, hydronium ions, or hydrogen ions, is key for understanding acid-base chemistry.

Amino Groups

Familiarity with functional groups, like amino groups, is important for studying biochemistry and molecular biology.

Description

Test your knowledge of pH buffers and their functions with these flashcards from Mastering Biology Chapter 2B. Understand the roles of weak acids and bases in maintaining pH levels. Perfect for biology students looking to solidify their understanding of this crucial concept.