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 11 IGCSE.
Preview questions (no answers)
- 1.
What is a primary function of lipids in living organisms?
A.Providing immediate energy for respiration
B.Acting as the primary component of plant cell walls
C.Long-term energy storage and insulation
D.Carrying genetic information
- 2.
Which chemical reagent is used to test for the presence of starch in a leaf?
A.Benedict's solution
B.Biuret reagent
C.Ethanol
D.Iodine solution
- 3.
What are the basic building blocks (monomers) of proteins?
A.Fatty acids
B.Amino acids
C.Glucose molecules
D.Glycerol
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 11 IGCSE.
Preview questions (no answers)
- 1.
What is the specific name of the pentose sugar found in the backbone of DNA?
A.Glucose
B.Ribose
C.Fructose
D.Deoxyribose
- 2.
According to the complementary base-pairing rules in DNA, which base always pairs with Cytosine ()?
A.Adenine ()
B.Guanine ()
C.Thymine ()
D.Uracil ()
- 3.
Which of the following terms best describes the physical shape of a DNA molecule?
A.Single-stranded coil
B.Triple-layered sheet
C.Double helix
D.Circular loop
Download the worksheet for Biological Molecules - Structure of DNA to practice offline. It includes additional chapter-level practice questions.
Chemical tests for molecules
SubtopicChemical tests for molecules under Biological Molecules for Grade 11 IGCSE.
Preview questions (no answers)
- 1.
To detect the presence of lipids (fats) in a solid food sample, the sample is first crushed and mixed with ethanol. What is the final step to observe a positive result?
A.Boil the ethanol mixture
B.Add the ethanol extract to a test tube of water
C.Add iodine solution to the ethanol extract
D.Neutralize the mixture with an alkali
- 2.
When testing for reducing sugars, which of the following procedures must be followed to obtain a result?
A.Shake the mixture vigorously and leave for 5 minutes
B.Add the reagent and look for an immediate color change at room temperature
C.Filter the mixture through a fine mesh
D.Heat the mixture in a water bath
- 3.
A student tests a solution of egg white using the Biuret test. What color change indicates a positive result for protein?
A.Blue to blue-black
B.Blue to brick-red
C.Blue to purple
D.Blue to yellow
Download the worksheet for Biological Molecules - Chemical tests for molecules to practice offline. It includes additional chapter-level practice questions.