2.1 Nutrition in Plants

• Parts of a leaf, external and internal
• Adaptations of the leaf to photosynthesis
• Structure of chloroplasts: membranes, grana and stroma
• The process of photosynthesis
• Conditions necessary for photosynthesis

• identify the external and internal parts of a leaf
• explain the adaptations of the leaf to photosynthesis
• describe the process of photosynthesis
• investigate the conditions necessary for photosynthesis
• appreciate the process of photosynthesis in nature

“What is the importance of photosynthesis in nature?”

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1. Why photosynthesis matters
   40 min · 1 practice tasks · quiz
   Food, oxygen and a breathable atmosphere all come from one process happening in leaves.
2. The external parts of a leaf
   40 min · 1 practice tasks · quiz
   Lamina, midrib, veins, petiole, margin and apex: what a hand lens shows.
3. Network and parallel venation
   40 min · 1 practice tasks · quiz
   Two patterns of veins, and they tell you what kind of plant you are holding.
4. Inside a leaf: the layers
   40 min · 1 practice tasks · quiz
   Five layers from top to bottom, arranged so the light reaches the right cells.
5. The cuticle and the epidermis
   40 min · 1 practice tasks · quiz
   Two see-through layers whose job is to keep water in without keeping light out.
6. Palisade and spongy mesophyll
   40 min · 1 practice tasks · quiz
   One layer is built to catch light, the other to move gases.
7. Stomata and guard cells
   40 min · 1 practice tasks · quiz
   Two guard cells opening and closing a pore: gases in daylight, water saved in drought.
8. Xylem and phloem in the leaf
   40 min · 1 practice tasks · quiz
   Two pipelines running side by side: water in, food out, and the lamina held flat.
9. How a leaf is adapted to photosynthesis
   40 min · 1 practice tasks · quiz
   Seven features, one purpose: every part of a leaf makes photosynthesis faster or cheaper.
10. The structure of a chloroplast
    40 min · 1 practice tasks · quiz
    Membranes, grana and stroma: the structure that traps the light.
11. Grana and stroma
    40 min · 1 practice tasks · quiz
    The grana catch the light and the stroma does the chemistry.
12. Chlorophyll and light
    40 min · 1 practice tasks · quiz
    Leaves look green because green is the light chlorophyll does not use.
13. Raw materials and products
    40 min · 1 practice tasks · quiz
    Carbon (IV) oxide and water in; glucose and oxygen out.
14. The word equation
    40 min · 1 practice tasks · quiz
    Raw materials on the left, products on the right, conditions on the arrow.
15. Testing a leaf for starch
    40 min · 1 practice tasks · quiz
    Kill it, decolourise it, soften it, test it. Blue-black means starch.
16. Showing that light is necessary
    40 min · 1 practice tasks · quiz
    Cover part of a leaf, and only the lit part makes starch.
17. Showing that carbon (IV) oxide is necessary
    40 min · 1 practice tasks · quiz
    Take the gas away from one leaf and it stops making starch.
18. Showing that chlorophyll is necessary
    40 min · 1 practice tasks · quiz
    A variegated leaf gives the fairest test of all: two tissues, identical conditions.