Function and structure of leaves
Leaves are designed for making food.
- It's commonly asked in I/GCSE Biology,
- The waxy cuticle stops it losing water and drying out
- The palisade cells contain the most chloroplasts
- They are long to maximize the chance of the light hitting them and although you cant see it on this diagram they have spaces to allow gas diffusion - increase surface area (Carbon dioxide in, oxygen out)
- The vascular bundle (also know as the leaf vein) contain the xylem and phloem (Phloem = Food). These cover all the leaf and bring water, while taking away the glucose created in photosynthesis.
- The stomata are tiny pores which let carbon dioxide in, and oxygen and water vapour out. However, if the water supply they close automatically so the plant doesn’t dry up.
- The guard cells actually close the stomata. Open = Turgid --- Closed = Flaccid. While this stops loss of water vapour by transpiration, it also stops photosynthesis. (Below is the diagram of the guard cell👇)
- The leaf is very thin which minimises the distances which carbon dioxide has to travel
- They are also arranged in the best way for absorbing the maximum amount of light energy without blocking out the light for other leaves
The shape of the leaf also aids it!
- Do you remember the content ofI/GCSE Biology regarding diffusion?
- The leaf is very thin which minimizes the distances which carbon dioxide has to travel by diffusion
- Because it is thin and flat, it has a increased surface area
1. "Biology B3 - Plants and Transpiration". Document in I/GCSE Biology, https://getrevising.co.uk/revision-
2. "The internal structure and biochemistry of leaves within a canopy control the optical signatures observed by remote sensing instrumentation", https://www.researchgate.net/publication/342371888/figure./fig2/AS:906115948752898@1593046285910/The-internal-structure-and-biochemistry-of-leaves-within-a-canopy-control-the-optical.ppm.
3. "Stomatal movements", https://i1.wp.com/orbitbiotech.com/wp-content/uploads/2018/04/stomata-Orbit-Biotech-Training.gif?fit=464%2C249&ssl=1.
That's the end of the topic!
Drafted by Alyssa (Biology)