Biomolecules for NEET UG
Carbohydrates, proteins, nucleic acids and vitamins are the chemicals of life. This chapter looks at their structures from a chemist's point of view.
ChemistryClass 1272 MCQs3 lessons13 flashcards2 memory tricks
What you'll learn
- Carbohydrates
Classify carbohydrates, explain reducing sugars and the structures of glucose and sucrose. - Proteins and enzymes
Describe peptide bonds, the levels of protein structure and denaturation. - Nucleic acids and vitamins
Compare DNA and RNA and classify vitamins.
Memory tricks
Phenylalanine, Valine, Threonine, Tryptophan, Isoleucine, Methionine, Histidine, Arginine (semi-essential), Leucine, Lysine.
DNA uses A, G, C and T; RNA uses A, G, C and U (uracil replaces thymine). DNA has deoxyribose; RNA has ribose.
Try 3 NEET-style questions
Q1. The sugar present in DNA is
- D-ribose
- 2-deoxy-D-ribose
- D-glucose (an aldohexose)
- D-fructose (a ketohexose)
Show answer
Answer: (2) 2-deoxy-D-ribose
DNA contains 2-deoxy-D-ribose, which lacks an –OH at C-2. RNA contains D-ribose.
Q2. Insulin, the hormone that lowers blood glucose, is chemically a
- steroid
- amino acid derivative
- polypeptide (protein)
- lipid
Show answer
Answer: (3) polypeptide (protein)
Insulin has two polypeptide chains, A (21 amino acids) and B (30), joined by disulphide bonds.
Q3. α-D-Glucose and β-D-glucose differ only in the configuration at
- C1
- C2
- C4
- C5
Show answer
Answer: (1) C1
In the ring form, C1 (the anomeric carbon) can have its –OH on either side. The two forms, α and β, are anomers that differ only at C1.
Practise all 72 questions Free · explanations for every option · see where you go wrong