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Biology

GCSE · Edexcel

QuestionsFlashcards

Photosynthesis
Plant Structure
Transport in Plants
Plant Hormones
- Plant Hormones & Growth
  7
- Using Plant Hormones Commercially
  7

Transport in Animals
- The Need for Transport
  7
- Factors Affecting the Rate of Diffusion
  7
Respiration
- Respiration
  6
- Practical: Investigating Respiration
  5
Gas Exchange
Circulatory System
- The Blood & Blood Vessels
  6
- The Circulatory System
  8

Structure of the Leaf Flashcards

All 7 cards in this deck

Name the tissues of a leaf in order from the upper surface to the lower surface.: Waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll (with vascular bundles), lower epidermis containing stomata and guard cells.
Which leaf cells contain the most chloroplasts, and why are they positioned there?: Palisade mesophyll cells — they are near the top of the leaf to absorb the most light for photosynthesis.
How is the spongy mesophyll adapted for gas exchange?: It has many air spaces, giving a large surface area for carbon dioxide and oxygen to diffuse quickly.
How do stomata open?: The guard cells take in water by osmosis, become turgid and change shape (bulge), opening the pore.
Why is it an advantage to a plant to have stomata on the lower leaf surface and none on the upper surface?: Stomata on the lower surface still allow gas exchange for photosynthesis, while having none on the upper surface reduces water loss by transpiration.
In a drawing of a leaf peel, how do you recognise one stoma?: A pore (gap) surrounded by two sausage-shaped guard cells.
True or false? The waxy cuticle of a leaf is a layer of living cells that carry out photosynthesis.: False. It is a non-living waxy layer secreted by the upper epidermis; it is transparent and reduces water loss.