Here below are 15 core Molecules and Their Interaction Relevant to Biology topics across five parts. Choose Easy, Medium or Difficult for each topic to practise 15 questions per level. Answers show the correct option and explanation immediately.
Part 1: Topics 1–3
Amino Acids and Their Properties
Protein Structure and Folding
Enzymes and Enzyme Kinetics
Part 2: Topics 4–6
Carbohydrates and Polysaccharides
Lipids and Biological Membranes
Nucleotides and Nucleic Acid Structure
Part 3: Topics 7–9
Chemical Bonds and Molecular Interactions
pH, Buffers and Biological Solutions
Bioenergetics and Thermodynamics
Part 4: Topics 10–12
Carbohydrate Metabolism
Lipid Metabolism
Amino Acid Metabolism
Part 5: Topics 13–15
Oxidative Phosphorylation and Electron Transport
Vitamins, Coenzymes and Cofactors
Biochemical Pathways and Metabolic Regulation
Frequently Asked Questions
Why does glycine lack optical activity?
Its alpha carbon carries two hydrogen atoms, so it is not a chiral center.
How does competitive inhibition affect Km and Vmax?
It increases the apparent Km while leaving Vmax unchanged in classical reversible competitive inhibition.
How is the isoelectric point of a neutral amino acid estimated?
Average the two pKa values that surround the zwitterionic form.
What is the difference between an alpha helix and a beta sheet?
An alpha helix uses intrahelical backbone hydrogen bonds, whereas a beta sheet is stabilized by hydrogen bonds between extended strands.
How can I calculate reaction velocity from Km and Vmax?
For simple Michaelis–Menten kinetics, use v = Vmax[S]/(Km + [S]) with consistent concentration units.