Structure Of The Leaf | Plant | Biology | The FuseSchool

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Structure Of The Leaf | Plant | Biology | The FuseSchool

Plants make food through photosynthesis. Using their leaves, plants combine sunlight, carbon dioxide and water to make glucose and oxygen. A leaf is like a plant's food factory, collecting all of the components into one place so that photosynthesis can happen.

Let's start with sunlight. The top of a leaf is exposed to the most sunlight, and so the cells specialised for trapping light are on top of the leaf. These specialised cells are called palisade mesophyll cells. They are packed full of chlorophyll - the green chemical that plants used to absorb light. Most leaves have a large surface area so that they can trap as much sunlight as possible.

Moving onto carbon dioxide. This is where the bottom of the leaf comes in. There are little pores on the bottom of the leaf called stomata. The stomata open up so that carbon dioxide can diffuse into the leaf. The stomata are controlled by 'sausage shaped' guard cells, which open up to let carbon dioxide in. The guard cells can also close the stomata, to stop other things inside the leaf, like water, from escaping.

The carbon dioxide comes in from the stomata, and then makes its way up through the leaf, through the gaps in the spongy mesophyll layer in the bottom part of the leaf and heads up to the palisade cells where photosynthesis occurs. Leaves are thin so that the carbon dioxide doesn't have too far to travel.

The final reactant needed for photosynthesis is water. Water comes into the plant through the roots, moves up the stem and enters the leaf through the vascular bundle. The vascular bundle contains a hollow tube specifically for water movement called the xylem. The veins on a leaf are actually the vascular bundle, allowing water to be spread out through the leaf.

The leaves palisade cells now have sunlight, carbon dioxide and water. They are ready to photosynthesis to make glucose and oxygen.

How do leaves manage to let in the wanted things (like water and carbon dioxide) but prevent unwanted things like bacteria getting in and also prevent the reactants from escaping before being used? At the top and bottom of the leaf are epidermis cells. These produce a protective waxy cuticle layer. The waxy cuticle seals up the leaf so that the only way in and out are through the stomata, which are regulated by the guard cells.

So from top to bottom, a leaf's structure:
- Waxy cuticle and epidermis cells
- Palisade cells (where photosynthesis occurs)
- Spongy mesophyll (with vascular bundle running through for water transport)
- Epidermis and cuticle, with stomata and guard cells spread throughout (allowing carbon dioxide in).

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zarico
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You're seriously much better, well spoken, and easier to understand than any tutor I have ever had.

zv
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I know y'all heard her eating before she started talking 🤣

Le_Confuzzlement
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i'm not one tp comment on youtube videos but this ones a lifesaver! thank you to whoever made this!

lily
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thank you so much this is more understanding then my actual science teacher

kisataito
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Such a good explanation, deserves more than 10k likes and 1mil followers

cooperzheng
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jesus, the quality for something that came out in 2013 is pretty amazing, I thought this video came out recently.

jacc
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Loved dis video... My teacher explained dis in a very complicated way thank u soo much💕💕💕❤️❤️❤️❤️

scarletisabelle
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This video helped a lot, and the way you talk so well and explain everything so simple and great. Thank you so much!

MrGuest
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leepy
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nameahyes
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thanx helped a lot needed the revision

HassanAli-lemr
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I'm watching this in school right now..

meow
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Great and Amazzzzing video
Thank you so much 😊🇮🇳

eatandrepeatt
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We can learn well thank to prepare this

anuraranasingha
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let it be known stoma and guard cells can also be found in the top of the  leaf, just not as many, could drown leaf.

JakQ
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Very well done help me learn very easily

jimmybanks
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Cheers-This Would Help Me With My Science Test-I rlly Want To Do Well Because My Dad Has Pressurised Me D: He says "If you don't do well, i will remove your phone..EVERYTHING" just plz wish me luck everyone D:

kashofficial
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oops i wasn’t paying attention time to watch this again

kanalet
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prob some of u got this from ur teacher







*right? ;-;*

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