Chapter-wise Biochemistry Questions with Solutions and Exam Tips
Biochemistry is an important field in biology that focuses on the chemical processes happening inside living organisms. It is a discipline that brings together aspects of biology and chemistry to understand the structure, function, and interactions of essential molecules like proteins, carbohydrates, lipids, and nucleic acids found in all forms of life.
By studying biochemistry, students build a strong foundation to understand how life operates at the molecular level. This knowledge is crucial for deeper learning in physiology, genetics, biotechnology, and medicine. Biochemistry connects textbook concepts to real-life phenomena such as digestion, energy production, and genetic information flow.
What is Biochemistry?
Biochemistry is the branch of science that studies the chemical substances and vital processes occurring in living organisms. It examines how biomolecules interact within cells to support growth, development, and survival.
Biochemistry looks at the arrangement of atoms in biological molecules, the types of reactions they undergo, and the role of enzymes in speeding up these reactions. For example, during digestion, biochemistry explains how enzymes break down food molecules into nutrients.
Key Concepts and Processes in Biochemistry
At its core, biochemistry deals with four main classes of biomolecules:
- Proteins: Large, complex molecules made of amino acids. They function as enzymes, structural components, and signaling molecules.
- Carbohydrates: Organic compounds that store and provide energy. Examples include glucose, starch, and cellulose.
- Lipids: Non-polar molecules such as fats and oils. They are vital for cell membrane structure and long-term energy storage.
- Nucleic Acids: DNA and RNA, which carry genetic information in living organisms.
Enzymes play a central role in biochemistry by acting as biological catalysts. They speed up chemical reactions necessary for metabolism, without being consumed themselves.
Step-by-Step: Enzyme Action
1. The substrate (reactant) binds to the active site of the enzyme.
2. The enzyme-substrate complex forms, reducing the activation energy needed for the reaction.
3. The substrate is converted to product, which is released from the enzyme.
4. The enzyme is now free to catalyze the same reaction again with a new substrate molecule.
This process is crucial for all cellular activities, including respiration, DNA replication, and protein synthesis.
Table: Comparison of Biomolecules
| Biomolecule | Main Elements | Primary Function | Examples |
|---|---|---|---|
| Proteins | C, H, O, N, S | Structure, enzymes, transport | Hemoglobin, Amylase |
| Carbohydrates | C, H, O | Energy source, storage | Glucose, Starch |
| Lipids | C, H, O | Membranes, energy, insulation | Triglycerides, Phospholipids |
| Nucleic Acids | C, H, O, N, P | Genetic information | DNA, RNA |
Scientific Significance
Biochemistry explains how nutrients are converted into energy, how genetic information is stored and transmitted, and how cells maintain their structure and function. These concepts are the basis for advancements in medicine, agriculture, biotechnology, and research.
For example, understanding the action of enzymes helps in the development of medicines and treatments for diseases. Similarly, the study of DNA and RNA has opened doors to genetic engineering and molecular diagnostics. You can learn more about genetics and related concepts at Genetics and Evolution.
Examples of Biochemical Principles
- Glucose Breakdown: The process of glycolysis helps convert glucose into energy (ATP) inside cells.
- Protein Synthesis: DNA provides the instructions for building proteins, which are then assembled using ribosomes and different types of RNA. For more, read Protein Structure and Function.
- Cell Membranes: Lipids form the basic structure of cell membranes, allowing cells to maintain their internal environment. Explore this topic at Cell Structure and Function.
Key Definitions in Biochemistry
- Enzyme: A biological catalyst that speeds up chemical reactions in cells.
- Metabolism: The sum of all biochemical reactions in a cell or organism.
- ATP (Adenosine Triphosphate): The main energy-carrying molecule in cells. For details, visit Energy Currency of the Cell.
- Gene: A segment of DNA carrying genetic information.
- Substrate: The molecule upon which an enzyme acts.
Practice Questions for Students
- List the main classes of biomolecules and examples of each.
- Explain the steps involved in enzyme action with a simple example.
- Compare the structure of DNA and RNA in tabular form. Reference: Difference Between DNA and RNA.
- Describe the importance of ATP in living organisms.
Next Steps and Deeper Learning
For thorough understanding and more resources, explore:
Biochemistry Important Questions |
Biomolecules |
Enzymes |
Genetics and Evolution
Keep practicing questions and reviewing diagrams to improve retention. Consistent revision of key terms and processes makes biochemistry easier to understand and helps connect theory to its applications in everyday life.
FAQs on Biochemistry Important Questions and Answers for NEET & Boards
1. What are the most important questions in biochemistry for NEET?
Key NEET biochemistry questions focus on the structure, function, and examples of biomolecules, enzyme mechanisms, metabolism pathways like glycolysis, and differences between DNA and RNA. Students should prepare:
- MCQs on proteins, carbohydrates, lipids, and nucleic acids
- Differences between cofactors and coenzymes
- Questions on enzyme action and inhibition
- Steps and regulation of glycolysis and ATP production
- Conceptual questions on DNA vs RNA, and their roles
2. How to prepare biochemistry for medical entrance?
To prepare biochemistry for medical entrance exams like NEET, follow these steps:
- Study NCERT texts for all biomolecule chapters and metabolic pathways
- Create comparative tables for confusing terms (DNA vs RNA, cofactors vs coenzymes)
- Practice MCQs and sample papers regularly
- Draw diagrams (enzyme action, cycles) for quick recall
- Review previous year questions and focus on high-weightage topics
3. What is the 5 importance of biochemistry?
Biochemistry holds key importance in:
- Understanding life processes: Explains chemical reactions essential for living beings.
- Medical and healthcare: Forms the basis for diagnosis, treatment, and biotechnology.
- Genetics: Helps in decoding genetic information and heredity.
- Metabolism: Explains how cells obtain and use energy.
- Drug development: Used in designing medicines and vaccines.
4. How do enzymes work?
Enzymes act as biological catalysts that speed up chemical reactions in cells by lowering the activation energy. Key points:
- They are mostly proteins with a specific 3D structure
- The active site binds the substrate (lock-and-key model)
- Transforms substrate into product and remains unchanged after reaction
- Factors like pH, temperature, and inhibitors affect enzyme activity
5. What is asked in biochemistry viva?
Biochemistry viva questions usually cover:
- Definitions and functions of biomolecules (proteins, carbohydrates, lipids, nucleic acids)
- Examples of enzymes and their actions
- Explanation of metabolic pathways like glycolysis
- Differences between DNA and RNA
- Practical aspects such as reagent use and result interpretation
6. What is the difference between DNA and RNA?
DNA is usually double-stranded with deoxyribose sugar and bases A, T, G, C, while RNA is single-stranded with ribose sugar and replaces thymine (T) with uracil (U). DNA stores genetic information, whereas RNA helps in protein synthesis.
- DNA: Stable, stores genetic code
- RNA: Acts as messenger, transfer, or ribosomal RNA involved in protein formation
7. Give two differences between competitive and non-competitive enzyme inhibition.
Competitive inhibition occurs when an inhibitor competes with the substrate for binding at the enzyme’s active site; non-competitive inhibition occurs when the inhibitor binds at a different site, altering enzyme shape. Summary:
- Competitive inhibitor: Blocks active site, can be overcome by excess substrate
- Non-competitive inhibitor: Binds elsewhere, cannot be overcome by adding more substrate
8. List four functions of proteins in biological systems.
Proteins perform many essential functions in living organisms:
- Enzymatic: Act as enzymes to speed up biochemical reactions
- Structural: Provide support (collagen in skin, keratin in hair)
- Transport: Carry molecules (hemoglobin transports oxygen)
- Defense: Form antibodies to fight infections
9. What are cofactors and coenzymes? Give examples.
Cofactors are non-protein molecules required for enzyme activity; they can be metal ions (like Mg2+, Zn2+). Coenzymes are organic cofactors, often derived from vitamins (e.g., NAD+, FAD). Both help enzymes catalyze reactions efficiently.
10. What is ATP and why is it called the energy currency of the cell?
ATP (Adenosine Triphosphate) is a molecule that stores and transports chemical energy within cells. It is called the energy currency because:
- It provides immediate energy for cellular processes (muscle contraction, biosynthesis, active transport)
- Its phosphate bonds release energy when broken
11. Outline the main steps of glycolysis.
Glycolysis is a ten-step metabolic pathway that breaks down glucose into pyruvate:
- Glucose phosphorylation forms glucose-6-phosphate
- Isomerization to fructose-6-phosphate
- Further phosphorylation and splitting into two 3-carbon molecules
- ATP and NADH generation
- Final product is pyruvate
12. How can I memorize biochemical pathways and terms effectively?
To memorize biochemical pathways and terms:
- Use flowcharts or summary tables for each pathway
- Link functions to simple mnemonics (e.g., OIL RIG for oxidation-reduction)
- Revise key diagrams and practice drawing them
- Review repeatedly and teach concepts to someone else
