1. Specialised cells
1.1. Guard cells
1.1.1. They are a special kidney shape which allows them to open and close
1.1.2. When the plant has large amounts of water the guard cells fill with it and go plump and turgid. This makes it open so that gases can be exchanged for photosynthesis.
1.1.3. When the plant is short of water the cell closes and becomes flaccid making the stomata close.
1.1.4. The inner walls are thick therefore making the opening and closing of the cell work.
1.1.5. They are sensitive to light therefore when it is night they close to save the water for photosynthesis.
1.2. Palisade Leaf Cells
1.2.1. They are packed with chloroplasts for photosynthesis. More of them are crammed into the top of the cell - so they're nearer the light
1.2.2. Tall shape means that there is a lot of surface area, letting them absorb more CO2 from the air in the leaf
1.2.3. Thin shape allows them to be packed together nearer the top where most of the photosynthesis happens.
1.3. Red Blood Cells
1.3.1. Concave shape gives a big surface area for absorbing oxygen, it also helps them pass smoothly through capillaries
1.3.2. They are packed with hemoglobin- a pigment which helps absorb oxygen
1.3.3. They have no nucleus to give more room for oxygen to be stored
1.4. Sperm And Egg Cells
1.4.1. The egg cell contains huge food reserves to nourish the embryo, they also carry female DNA
1.4.2. When a sperm fuses with the egg cell, it's membrane instantly changes to stop anymore sperm getting in
1.4.3. The function of a sperm is to to get the male DNA to the female DNA, it has a long tail and a streamlined head to help it swim to the egg, there are a large amount of mitochondria to supply the sperm with energy.
1.4.4. Sperm also carry enzymes ion their heads to digest the egg membrane.
2. Cells
2.1. Plant and animal cells
2.1.1. Ribosomes - This is where protiens are made inside of a cell
2.1.2. Mitochondria - This is where reactions for respiration take place
2.1.3. Nucleus - Contains genetic material
2.1.4. Cytoplasm - Substance where chemical reactions take place, contraining enzymes
2.1.5. Cell Membrane - Holds the cell together and controls what goes in and out of the cell.
2.1.6. Cell Wall - Made of cellulose. It supports and strengthens the cell.
2.1.7. Permanent Vacuole - Contains cell sap
2.1.8. Chloroplasts - Where photosynthesis occurs and what turns the cell green using chloroplasts.
2.2. Bacterial Cells
2.2.1. Bacteria cells are single celled organisms they have no nucleus and the genetic material floats in the cytoplasm
3. Diffusion
3.1. Definition: Spreading out of particles from an area of high concentration to an area of low concentration
3.1.1. Used in cell membranes to let things in and out of the cells
3.1.1.1. They migrate particles from high to low concentrations
3.2. It happens in gases and solution ONLY
3.2.1. This is because there particles are free to move randomly
4. Cell organisation
4.1. Similar cells are Organised into Tissue
4.1.1. A tissue is a group of similar cells that work together to carry out a particular function.
4.1.1.1. There are 3 different types of tissue
4.1.1.2. 1) Muscular Tissue, this contracts to move whatever it is attached to
4.1.1.3. 2) Glandular Tissue, This makes and secretes chemicals like enzymes and hormones
4.1.1.4. 3) Epithelial tissue, this covers some parts of the body
4.2. Tissues are organised into Organs
4.2.1. An organ s a group of different tissues that work together to perform a certain function e.g. the stomach
4.3. Organs are organised into Organ Systems
4.3.1. An organ system is a group of organs working together to perform a particular function e.g. the digestive system
5. Plant Structure
5.1. Plant cells are organised into Tissues and Organs
5.1.1. Types of plant tissue:
5.1.2. 1) Mesophyll tissue - This is where most of the photosynthesis in the plant occurs
5.1.3. 2) Xylem and Phloem - They transport things such as water, mineral ions and sucrose around the plant
5.1.4. 3) Epidermal Tissue - This covers the whole plant
6. Photosynthesis
6.1. Photosynthesis is the process that produces 'food' in plants and algae. The food produced is glucose.
6.2. Photosynthesis occurs in the chloroplasts, they contain a green substance called chlorophyll which absorbs sunlight and uses it's energy to converts carbon dioxide(from the air) and water (from the soil) into glucose
6.3. Oxygen is a by-product of this reaction
6.4. Photosynthesis happens inside the leaves of all green plants.
7. Limiting Factors Of Photosynhesis
7.1. A limiting factor just means that it is stopping photosynthesis happening any faster.
7.2. Which factor is limiting depends on the environmental condition: at night it's light, in winter it's temperature.
7.2.1. Temperature is usually the limiting factor when it is to cold because the enzymes work slowly, but when its too hot (45°C) this is because the enzymes will become damaged
7.2.2. Light slows down the rate of photosynthesis because it provides the energy needed, but that's only till a certain point as it will either be the temperature or the CO2 level which is the limiting factor.
7.2.3. CO2 is one of the raw materials needed for photosynthesis, as with light intensity the amount of CO2 will only increase the rate up to a certain point. As long as CO2 and light are in plentiful supply then the limiting factor will be temperature.
7.3. You can Artificially create the Ideal conditions for Farming using Greenhouses, paraffin burners and artificial lights.
7.3.1. Greenhouses trap the suns heat and make sure that the temperature doesn't become a limiting factor,
7.3.1.1. In the winter farmers use paraffin burners to increase the heat, this also increases the amount of CO2 as it is a by-product of paraffin burners.
7.3.2. Most farmers use artificial light, so that after the sun goes down the plants can still perform photosynthesis
7.3.3. Being in a greenhouse also protects the plants from pests and diseases, this also means that farmers can use fertilisers to provide all of the minerals needed
8. How Plants Use Glucose
8.1. Respiration
8.1.1. 1) Plants Manufacture glucose in their leaves
8.1.2. 2) They then use some glucose for respiration
8.1.3. 3) This releases energy which enables them to convert the rest of the glucose into various other useful substances used to build and grow new cells
8.1.4. 4) To produce sine of these substances they also need to gather a few minerals from the soil
8.2. Making Cell Walls
8.2.1. Glucose is converted into cellulose for making strong cell walls
8.3. Making Proteins
8.3.1. Glucose is combined with nitrate ions (absorbed by the soil) to make amino acids, which are then made into proteins
8.4. Stored as Seeds
8.4.1. Glucose is turned into lipids (fats and oils) for storing in seeds.
8.5. Stored as Starch
8.5.1. Glucose is turned into starch and stored in the roots, stems and leaves ready for winter. Starch is insoluble (incapable of being dissolved) which makes it much better for storing than glucose
8.5.1.1. A cell with a large amount of glucose would draw in lots of water and swell up