Plant organs
1. Plant Cell
Cell wall → supports and strengthens the cell.
Cell membrane → controls substances entering and leaving.
Nucleus → controls cell activities.
Chloroplast → contains chlorophyll and carries out photosynthesis.
Vacuole → contains cell sap and keeps the cell firm.
Mitochondria → site of respiration.
2. Plant Tissues
Epidermis → protects the plant.
Mesophyll → carries out photosynthesis.
Xylem → transports water and minerals.
Phloem → transports sucrose/food.
Meristem → produces new cells for growth.
3. Leaf
Waxy cuticle → reduces water loss.
Upper epidermis → protects the leaf.
Palisade mesophyll → contains many chloroplasts; main site of photosynthesis.
Spongy mesophyll → contains air spaces for gas exchange.
Lower epidermis → contains stomata.
Stomata → allow gases to enter and leave.
Veins → contain xylem and phloem.
4. Spongy Mesophyll
Cells are loosely packed.
Contains large air spaces.
Allows gases to diffuse through the leaf.
Contains some chloroplasts, so it also does photosynthesis.
5. Leaf Adaptations
Large surface area → absorbs more light.
Thin → gases have a short distance to travel.
Many chloroplasts → more photosynthesis.
Stomata → gas exchange.
Air spaces → help gas movement.
Xylem → supplies water.
Phloem → carries sugars away.
Waxy cuticle → reduces water loss.
6. Xylem & Phloem
Xylem: roots → leaves; carries water + minerals.
Phloem: carries sucrose/food around the plant. This is called translocation.
7. Male & Female Flowers
Monoecious → male and female flowers on the same plant.
Dioecious → male and female flowers on different plants.
Examples: maize, pumpkin and cucumber.