B4
All Of Main Points For biology Unit 4
- Created by: Jake Cubbage
- Created on: 15-05-12 17:15
Leaf Structure
Waxy cuticle - Helps prevent water loss, stops leaf from drying out
Upper Epidermis - Protective skin, No chloroplast so cells are transparent and sunlight passes through
Palisade Layer - Regular shaped cells packed tightly together, cells contains lots of chlorephyll- main photosynthesis layer
Spongy Mesophyll Layer - Cells are irregular shapes allowing lots of air spaces. These increase the efficency of diffusion (co2 + O2) contains chlorophyll to trap any sunlight that has passed through the pallisade layer.
Lower Epidermis - Protective layer, Guard cells surround pores in the lower epidermis called stomata. Stomata allow
Vein (vascular bundle) - Xylem - carries water and dissolved nutrients to the leaf Phloem - transports glucose around the plants for the leaves
Leaf Diagram
Osmosis
Osmosis - is the net movement of water molecules across a partially permeable membrane.
Nitrates,Phosphates
- A plant uses nitrates to make proteins
- Proteins are needed for growth
- Nitrogen in the nitrates is used to make amino acids
- Amino acids are joined to make different proteins such as enzymes
- No Nitrate - Poor Growth, Yellow Leaves
- A plant uses phosphates in respiration (releasing energy)
- Phosphates are also needed for growth especially in roots
- Phosphorus in phosphates is used to make cell membrane and DNA
- DNA carries genetic information
- No phosphates - poor root growth, discoloured leaves
Pottasium,Magnesium
- Plants use these in respiration and in photosynthesis
- Pottasium is used to help make some enzymes, Ensymes speed up chemical reactions
- Enzymes are needed in photosynthesis and respiration
- No pottasium - Poor fruits and flowers, Discoloured leaves
- A plant needs magnesium to photosynthesis
- Magnesium is used to make chlorophyll molecules
- No magnesium - Yellow leaves
Tracking Energy Flow
Each level in a food chain is called a trophic level
Rose Bud - Aphid - Spider - Starling
Producer - Primary Consumer - Secondary Consumer - Tertiary Consumer
Two types of pyramid number and biomass
Pyramid of number
Tracking Energy Flow Part 2
Pyramid of biomass
Biomass is the mass of living organisms
Pyramid of biomass are beneficial because they gave a clearer indication of the amount of matter at each trophic level.
The negative aspect is that in order to record mass you must disturb or destroy the habitat
Energy Transfer Efficency
Efficency = Useful Energy/Energy Input x 100
Input=3000kj
Respiration = 1900kj
Excretion = 950kj
Growth = 150kj
150/3000 x 100 = 5% efficency
Biofuels
These are fuels made from or by living organisms
Examples Wood, Biogas, Alcohol, Plant Oils
Wood - We can use fast growing trees like willow or grasses ( elephant grass)
Biogas - Excrement from cows, for example are rich sources of methane when put in big digesters that methane can be collected and used landfill sites also give off methane
Alcohol - Some countries (Brazils) produce lots of sugar cane, which can be used with microbes (respiration) to produce alcohol. This carn be mixed with petrol to fuel cars.
Oils - Plant oils like **** seed oil can be mixed with diesel to fuel vehicles
Farming
Organic Farming
- natural/traditional techniques
- No Chemicals - Pesticides - Kills Pesticides
- Herbicides - kills weeds
- Insectisides - kills insects
- Artificial Fertiliser
- Drugs
- Labour Intenstive - Weeding,Maintaining Lifestock
- Less Product per acre
- More Expensive
- Better Taste
- Better nutritional value
Farming
Alternative To Pesticides
Biological control - the introduction of a predator to pests ( e.g ladybirds to kill aphids) This doesn't totally wipe out posts but reduces them to acceptable levels
Intensive Farming
- Uses chemicals not used in organic farming
- Higher yield = more profit
- Live stock - cramped conditions e.g battery farms - Cruelty to animals
- Food is loaded with chemicals can be dangerous to consumers
- Cheaper for consumers - economic advantage in times of heartship
- Higher yield beneficial for supporting countries with food shortages
Hydroponics are crops which are grown in tanks of water with no soil
Advantages - No soil - reduces chances of diesease _ Controls the quantities of nutrients added to water for most effective growth
Disadvantages - initel set up costs are high _ Artificial nutrients expensive
Carbon Cycle
Nitrogen Cycle
Decay
Is essential for recycling vital elements like carbon and nitrogen
Microbes cause decay as they feed off dead organisims
Like all living organisims these microbes need to respire. For decay to occur effectivley they need to respire anerobically
Anerobic respiration creates acidic conditions, slowing decay
Optimum Conditions - 37 for bacteria 25 for fungi Moist Oxygen - For aerobic respiration
Saphrophyte - usually fungi - extremley digest dead matter by secreting enzymes to break them into simple molecules and then absorbing these
Preserving Food - Freezing,Vacum Packed,Dehydration,Canning,Pickling,Preserving
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