1st Year Biology Chapter 2 Notes

• Our comprehensive 1st Year Biology Chapter 2 Notes will ensure you're fully prepared for your exams.
• Important Fill in the blanks of Chapter Number 2: Biological Molecules of First-year Biology.
• Important Short Questions of Chapter Number 2: Biological Molecules of First-year Biology.
• 1. Which one of the following is not lipid? (a) Cholesterol  (b) Wax (c) Keratin (d) Terpenes
• 2. Of the total dry weight of the living cells proteins constitute over:  (a) 30 % (b) 40 % (c) 50 % (d) 60 % 
• 3. The most abundant organic compound in mammalian cell:  (a) Water (b) Lipids (c) Proteins (d) Carbohydrates
• 4. Conjugated histone proteins are: (a) Structural Only (b) Regulatory only (c) Transport proteins (d) Structural and Regulatory
• 5. The amino acids are mainly different from each other due to the type and nature of:  (a)  Amino group (b) R-group (c) Carboxyl group (d) Peptide bond 
• 6. The molecule formed by two amino acids is called: (a)  Peptide bond (b) Dipeptide (c) Poly peptide linkage (d) Peptide linkage
• 7. Keratin in an example of Fibrous Protein present in:  (a) Blood (b) Muscle (c) Nail and Hair (d) Bones
• 8. Total number of amino acid in insulin are:  (a)  50 (b) 151 (c) 141 (d) 51 
• 9. The most abundant organic compound in the cells is the: (a)  Carbohydrate (b) Ptotein (c) ATP (d) Lipid
• 10. Peptide bond is a: (a)  N-H link (b) C-O link (c) C-N link (d) C-H link
• 11. Insulin is a protein consisting of two polypeptide chains of amino acids held together by: (a) Peptide bonds (b) Covalent bonds (c)  Glycosidic bonds (d) Disulfide bonds 
• 12. How many water molecules are formed when glycylalanine is formed: (a) 4 (b) 3 (c) 2 (d) 1
• 13. The number of proteins in the human body is over: (a) 25,000 (b) 20,000 (c) 10,000 (d) 15,000
• 14. Iron containing protein is:  (a) Cytochrome (b) Ferredoxin (c) Plastocyanin (d)  Plastoquinone
• 15. Hemoglobin is a: (a) Fibrous proteins (b) Globular proteins (c) Coiled proteins (d)  Double protein
• 16. Which of the following is not a fibrous protein: (a) Keratin (b) Myocin (c) Hormones (d)  Fibrin
• Define Biochemistry. Why study of biochemistry is essential in the field of biology or in the study of living organisms? Ans: Biochemistry is a branch of Biology, which deals with the study of chemical components and the chemical processes in living organisms. Importance of Biochemistry: A basic knowledge of biochemistry is essential for understanding anatomy and physiology, because all of the structures of an organism have biochemical organization. Photosynthesis, respiration, digestion, muscle contraction can all be described in biochemical terms.
• Why carbon is considered as the basic element of organic compounds? Ans: Carbon is considered as the basic element of organic compounds, because it is tetravalent. Due to its unique properties, carbon occupies the central position in the skeleton of life. It can react with oxygen, hydrogen, nitrogen, phosphorus and sulphur forming covalent bonds. It is also important due to following associations.
• How water works as a temperature stabilizer for living organisms? Ans: Water has great ability of absorbing heat with minimum of change in its own temperature. This is because much of the energy is used to break hydrogen bonds. Water thus works as temperature stabilizer for organisms in the environment and hence protects living material against sudden thermal changes. 
• How water act as an effective lubricant? Ans: Water is effective lubricant that provides protection against damage resulting from friction. For example, tears protect the surface of eye from the rubbing of eyelids, water also forms a fluid cushion around organs that helps to protect them from trauma.