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24 Cards in this Set
- Front
- Back
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Photosynthesis |
- the process by which plants manufacture carbohydrates from raw materials using energy from light |
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Synthesis |
- the building up of complex food molecules from simpler substances |
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Chemical equation for photosynthesis |
- carbon dioxide + water (in the presence of light) = glucose + oxygen - CO2+ H2O (in the presence of light) = C6H12O6 + O2 |
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Chlorophyll |
- A green, light-absorbing pigment - found inside chloroplasts in plant cells |
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What does chlorophyll do? |
- it converts light energy into chemical energy |
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Hypothesis |
- A supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation |
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Plants use of photosynthetic products |
- Respiration : sugar can be use to provide energy for other chemical reactions such as building up of proteins - Storage : sugar not needed for respiration is turned into starch and stored in the cells of their stems or roots. In some plants in storage organs called tubers. - Synthesis of other substances : all the substances a plant needs are synthesised from the sugar molecules and other molecules produced in photosynthesis |
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A plant can Synthesis all the substances it needs provided it has. |
- light - water - carbon dioxide - mineral salts |
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Petiole |
- Leaf stalk |
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Lamina |
- the main part of a leaf - which is joined to the rest of the plant by the petiole |
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Vascular bundles |
- A vein in a plant - contains xylem vessels and phloem tubes - runs through the mesophyll |
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Epidermis |
- A tissue made up of a single layer of cells - Covers the top and bottom of a leaf and the outside of the stem and root - do not contain chloroplasts |
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Epidermis function |
- to protect the inner layers of cells |
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Cuticle |
- A layer of wax on a leaf - secreted by epidermis |
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Stoma (plural : stomata) |
- A gap between two guard cells, usually in the epidermis on the lower surface of a leaf |
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Cuticle function |
- helps stop water from evaporating |
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Xylem vessels |
- transport water in plants - help support them - long hollow tubes made up of dead, empty cells with lignified walls. |
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Phloem tubes |
- long tubes made up of living cells with perforated end walls - transport sucrose and other substances in plants |
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Mesophyll |
- the tissues in the centre of a leaf, where photosynthesis takes place - made up of two parts : 1. palisade mesophyll 2. Spongy mesophyll |
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Palisade mesophyll |
- the upper mesophyll layer - made up of rectangular cells - these contain many chloroplasts |
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Spongy mesophyll |
- the tissue beneath the palisade layer in a leaf - made up of cells that contain chloroplasts and can photosynthesise - have many air spaces between them |
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Leaf adaptations |
- leaves are adapted to obtain carbon dioxide, water and sunlight |
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Carbon dioxide |
- Leaf is heald out into the air by the petiole and the large surface area of the lamina helps expose it to as much air as possible - obtained from air - only about 0.04% of air - the cells that need it are the mesophyll cells - carbon dioxide diffuses through the stomata into the air spaces between the spongy mesophyll and can therefore diffuse through each cell and into its chloroplasts |
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Water |
- obsorbed from soil by root hairs - carried up to leaf in xylem vessels - travels from xylem vessels to mesophyll cells by osmosis |
