University of zakho
Biology department
1st stage- 1st semester
Buffers
Supervised by Mr. Anwar Rasheed Yaqoub
Ajeen hashim arsalan
Buffers
A buffer is a chemical solution that can resist changes in its pH when a small amount of acid
or base is added to it. In other words, it helps to maintain a stable pH level. Buffers are
important in many biological and chemical processes, as they can help to protect enzymes
and other molecules from the damaging effects of changes in acidity or alkalinity
we have 2 types of buffers,
1. Acidic buffers (maintains a pH below 7)
2. Basic buffers (maintains a pH above 7)
Whats in these buffers components?
Acidic buffers contain
1.Weak acid (HF)
2.The weak acids conjugate base in salt form (NaF)
The same principle can be applied for basic buffers.
Buffers
But how do buffers work?
When a small amount of acid is added to a buffer solution, the conjugate base in
the buffer solution reacts with the acid to neutralize it. This reaction can be
represented by the following equation:
HA + H⁺ ⇌ A⁻ + H₂O
Where:
HA is the weak acid
A⁻ is the conjugate base
H⁺ is the proton (hydrogen ion)
H₂O is water
Buffers
Buffer solutions are important in many biological and chemical
processes because they can help to maintain a stable pH. This is
important for many reasons, such as:
Enzyme activity: Enzymes are proteins that catalyze chemical reactions.
Enzymes are only active in a narrow range of pH. Buffer solutions can
help to maintain the optimal pH for enzyme activity.
Protein stability: Proteins are also sensitive to changes in pH. Buffer
solutions can help to maintain the stability of proteins.
Cellular processes: Many cellular processes require a stable pH. Buffer
solutions can help to maintain the pH of cells.
Buffers
Types of Buffers Used in Analytical Chemistry
Acetate Buffers: Commonly used in the pH range of 4 to 6, acetate buffers are versatile and
effective in various analytical applications.
Phosphate Buffers: Covering a wider pH range of 5 to 8, phosphate buffers are highly soluble
and provide excellent buffering capacity.
Tris Buffers: Tris buffers are particularly useful in the pH range of 7 to 9, offering good buffering
capacity and compatibility with many biological systems.
HEPES Buffers: HEPES buffers are often used in cell culture applications, providing excellent
buffering capacity in the physiological pH range of 7.2 to 7.4.
AMPSO Buffers: AMPSO buffers are suitable for use in the pH range of 8 to 10, offering good
buffering capacity and resistance to enzymatic degradation
Buffers
References:
1.Berg, J. M., Tymoczko, J. L., & Stryer, L. (2002). Biochemistry. WH
Freeman.
2.McMurry, J., & Fay, R. C. (2016). Chemistry (7th ed.). Pearson Higher Ed.
3.Zumdahl, S. S., & Decoste, D. J. (2017). Chemical principles (8th ed.).
Cengage Learning.
4.Nelson, D. L., & Cox, M. M. (2017). Lehninger principles of biochemistry. W.
H. Freeman.
5.Voet, D., & Voet, J. G. (2016). Biochemistry. John Wiley & Sons