Biological Molecules
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Carbohydrates, lipids and proteins
SubtopicCarbohydrates, lipids and proteins under Biological Molecules for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Which element is found in all proteins but is typically absent from pure carbohydrates and lipids?
A.Carbon
B.Nitrogen
C.Oxygen
D.Hydrogen
- 2.
Which of the following carbohydrates is used by plants to store energy?
A.Cellulose
B.Glycogen
C.Sucrose
D.Starch
- 3.
What are the basic building blocks (monomers) that make up a protein molecule?
A.Amino acids
B.Fatty acids
C.Glucose molecules
D.Nucleotides
Download the worksheet for Biological Molecules - Carbohydrates, lipids and proteins to practice offline. It includes additional chapter-level practice questions.
Structure of DNA
SubtopicStructure of DNA under Biological Molecules for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
In the simplified diagram of a DNA nucleotide, which label identifies the pentose sugar?
A.Part A
B.Part B
C.Part C
D.All of the above
- 2.
What is the specific name given to the twisted ladder shape of a DNA molecule?
A.Single strand
B.Triple helix
C.Double helix
D.Circular loop
- 3.
In the DNA double helix, which nitrogenous base always pairs with Guanine ()?
A.Adenine
B.Cytosine
C.Thymine
D.Uracil
Download the worksheet for Biological Molecules - Structure of DNA to practice offline. It includes additional chapter-level practice questions.
Chemical tests for nutrients
SubtopicChemical tests for nutrients under Biological Molecules for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
When testing for the presence of Vitamin C using DCPIP, what observation confirms a positive result?
A.The blue DCPIP solution turns red
B.The blue DCPIP solution becomes colorless
C.The colorless DCPIP solution turns blue
D.A purple precipitate forms at the bottom of the tube
- 2.
Which of the following is the correct final step for the ethanol emulsion test to identify fats?
A.Heat the mixture in a water bath at
B.Add an equal volume of cold water to the ethanol mixture
C.Add a few drops of dilute hydrochloric acid
D.Add iodine solution dropwise until a color change occurs
- 3.
During a Biuret test, a solution changes color from blue to purple. This indicates the presence of which biological molecule?
A.Reducing sugars
B.Starch
C.Lipids
D.Proteins
Download the worksheet for Biological Molecules - Chemical tests for nutrients to practice offline. It includes additional chapter-level practice questions.