Photosynthesis is one of 10 topics in the Grade 11 Life Sciences CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. Which leaf tissue layer, containing tall, tightly packed cells with a high density of chloroplasts, is the primary site of photosynthesis?
Palisade mesophyll
Spongy mesophyll
Upper epidermis
Lower epidermis
Answer: Palisade mesophyll — The palisade mesophyll consists of tall, tightly packed, column-shaped cells with a high density of chloroplasts, making it the primary site of photosynthesis in the leaf.
Easy
2. What are the small pores, mostly on the lower epidermis of a leaf, that regulate gas exchange called?
Stomata
Grana
Thylakoids
Nephrons
Answer: Stomata — Stomata are small pores, each flanked by a pair of guard cells, that regulate gas exchange and water loss through the leaf surface.
Medium
3. What is the function of the large air spaces found in the spongy mesophyll layer of a leaf?
They allow gases to diffuse readily to and from photosynthetic cells and the stomata
They store excess glucose produced during photosynthesis
They block light from reaching the palisade layer
They prevent any water loss from the leaf
Answer: They allow gases to diffuse readily to and from photosynthetic cells and the stomata — The loosely packed spongy mesophyll cells create large interconnected air spaces that allow carbon dioxide, oxygen, and water vapour to diffuse efficiently between the stomata and the photosynthetic cells.
