← Combined Science syllabus

SingaporeCombined Science

Biology: Plants and Nutrition

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What are enzymes, how do they speed up reactions, and how do temperature and pH affect them?

Describe enzymes as biological catalysts, explain the lock and key model and enzyme specificity, and describe the effects of temperature and pH on enzyme activity
A focused answer to the O-Level Combined Science outcome on enzymes. Enzymes as biological catalysts, the lock and key model and specificity, denaturation, and the effects of temperature and pH on the rate of an enzyme reaction.
9 min answer →

What nutrients does the body need, what does each do, and what happens if the diet is unbalanced?

Describe the nutrients needed in a balanced human diet, the function and food sources of each, and the use of food tests to identify nutrients
A focused answer to the O-Level Combined Science outcome on human nutrition. The seven components of a balanced diet, the function of each nutrient, deficiency effects, and the standard food tests for starch, sugar, protein and fat.
9 min answer →

How do plants make their own food from light, and how is the leaf adapted for the job?

Describe photosynthesis as the process that makes glucose using light energy, state its equation and limiting factors, and relate leaf structure to its function
A focused answer to the O-Level Combined Science outcome on photosynthesis. The word and balanced equations, the role of chlorophyll, limiting factors of light, carbon dioxide and temperature, and how the leaf is adapted.
9 min answer →

How do plants move water and food around, and how is water lost through the leaves?

Describe the roles of xylem and phloem, explain the uptake and transport of water and transpiration, and state the factors affecting the rate of transpiration
A focused answer to the O-Level Combined Science outcome on transport in plants. Water uptake by root hair cells, xylem and phloem and what each carries, the transpiration stream, and the factors affecting transpiration rate.
9 min answer →