Table of Contents
IGCSE Coordinated Science:Plant nutrition
Plant Nutrition
Define photosynthesis as the fundamental process by which plants manufacture carbohydrates from raw materials using energy from light.
Yeah, photosynthesis is basically the process where plants manufactures carbohydrates from raw materials (water + Carbon dioxide) using the energy from light.
State the word equation for the production of simple sugars and oxygen.
127 our experts are availableright now
Make sure you learn this equation as literally everything else in this topic is based on the reactants and products.
Reaction
Basically, this covers the requirements for both 2 and 4.
Explain that chlorophyll traps light energy and converts it into chemical energy for the formation of carbohydrates and their subsequent storage.
Look at this chloroplast
The green blobs is a “pigment” which we like to call “chlorophyll”. This chlorophyll traps light and converts it to the “chemical energy” or “fuel” needed to allow Water and CO2 to form Carbohydrates and Oxygen.
Investigate the necessity for chlorophyll, light and carbon dioxide for photosynthesis, using appropriate controls.
(NEEDS EXPANDING)
Chlorophyll is required because it help absorbs the “light” required.
CO2 is important because it is converted into the sugars such as glucose we need.
Light is important because it acts as the “fuel” or energy to drive the reaction
Stuff that should be kept constant
-Temperature
-Oxygen Levels
Describe the intake of carbon dioxide and water by plants.
Plants
Water gets to the plant in a few steps. The entire process is quite complicated, but at IGCSE, I would say just memorize this:
Water first enters the plant through roots
Here:
ROOT HAIR CELL
Don’t judge everything by looks plz.
Plants absorb water into roots by osmosis. Refer to unit 2. The absorbed water is transported through the roots to the rest of the plant where it’s used for different purposes, such as for photosynthesis.
Water is then transported up the “Xylem Tube”, which is a dead hollow tube which is very good at doing its job (I’ll explain its job a little bit later), where it is then used for whatever it needs to be used for. You’re going to have to know more than that, but all in good time.
Carbon Dioxide
Leaves are adapted for photosynthesis by having a large surface area, and contain stomata (openings) to allow carbon dioxide into the leaf. Basically, CO2 enters from the surrounding air, from the stomata, which is displayed below:
Identify and label the cuticle, cellular and tissue structure of a dicotyledonous leaf, as seen in cross-section under the light microscope and describe the significance of the features of a leaf in terms of functions,to include:
- Distribution of chloroplasts –photosynthesis,
•Stomata and mesophyll cells – gas exchange,
• Vascular bundles (xylem and phloem) –transport and support.
Distribution of chloroplasts –photosynthesis
The palisade mesophyll is a layer of elongated cells containing chloroplasts found just under the upper epidermis. The majority of photosynthesis takes place within this area. These cells are long and thin like the slats on a picket fence. The chloroplasts rotate in these cells like a Ferris wheel. This allows them to be exposed to the maximum amount of light during the day. Maximum= maximum photosynthesis
Stomata and mesophyll cells – gas exchange
Leaves are adapted for photosynthesis by having a large surface area, and contain stomata (openings) to allow carbon dioxide into the leaf. These design features can result in the leaf losing a lot of water. The cells inside the leaf have water on their surface. Some of this water evaporates, and the water vapour can then escape from inside the leaf by diffusion.
As for mesophyll cells, they have air spaces which allows gases to go in and out.
Vascular bundles (xylem and phloem) –transport and support.
Xylem= water and soluble, dissolved ions
Phloem= Products of photosynthesis, i.e. sugar
The xylem provides a passage for water and dissolved ions from the root system to the leaves.
The xylem also strengthens and supports the stem.
The phloem transports synthesized organic food from the leaves to other parts of the plant.
In case you’re wondering, they look a bit like this:
Describe the importance of:
- Nitrate ions for protein synthesis,
• Magnesium ions for chlorophyll
synthesis.
Nitrate ions
Synthesize- to make protein.
Amino acids are the building blocks of Proteins. Each amino acid has got an Amino group(NH2), Carboxyl group(COOH) and an Alkyl group.
Nitrate ions are the source of nitrogen for amino acids. So without amino acids, which is a part of protein, how do you make Protein????…Answer: you can’t.
Just study the highlighted part.
Magnesium ions
The Chlorophyll molecule has a central magnesium ion, hence magnesium ions are essential for Chlorophyll synthesis. If something has magnesium in it, yet you don’t have magnesium, how can you synthesize the thing? Sounds awkward, but you get the point.
Explain the effects of nitrate ion and magnesium ion deficiency on plant growth.
Magnesium is an essential constituent of chlorophyll and is required for activation of many enzymes involved in the energy transfer processes. A deficiency of magnesium will seriously affect plant growth and development as photosynthesis is directly affected. Changes yellow.
Nitrogen is a constituent of amino acids, proteins, coenzymes, and chlorophyll. Nitrogen has a great affect on plant growth and a deficiency or excess markedly affects plant growth and fruit yield
Nitrogen is a mobile element in the plant and deficiency symptoms will develop first on lower leaves as the nitrogen is removed for use in new developing leaves. The older leaves become chlorotic (turn yellow) and eventually die. Nitrogen deficiency can have a considerable effect on final yield if it occurs for prolonged periods during critical stages of growth .
Describe the uses, and the dangers of overuse, of nitrogen-containing fertilisers.
Uses: Increases yield as it provides the plant with more minerals, amino acids, stuff needed for growth, repair.
Overuse: Eutrophication
Nitrogen rich fertilizers can leak into lakes and rivers. Algae and other plants living in the water would have all the nutrients they need to grow and so the is a rapid growth of algae and plant life. When these plants die, the plant matter starts to decompose by bacteria. This decomposition process uses oxygen and with lots of algae in the river, most of the oxygen is used up. With less oxygen other creatures cannot live such as fish and so the pond becomes stagnant
