Additonal science notes.

Gene therapy, food production, Nitrogen/carbon cycle, Plant hormones,Growth in plants, using microorganisms (I,II)

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Using Micro-organisms (I)

Microorganisms produce useful by-products.

They respire - use an external food source for their energy - breakdown of sugars into simple molecules = fermentation. respire aerobically or anaerobically.

mycroprotein = a fungus used in meat substitution for veggies-quorn. Fungus respires aerobically so oxygen - supplied to fermenter

other bacteria - respire - anaerobically   to make lactic acid. Bacteria - added to milk = cheese - convert lactose sugar into lactic acid = acidifies the milk curdles & forms cheese.

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Antibiotics. Human Proteins.

Antibiotics used to destroy bacteria that cause disease. Antibiotics are the product of microorganisms.

Penicilin - antibiotic - made by - growing mould in fermenter. Mould - grown in liques culture medium - containing sugar + other nutrients e.g. source of N2 to make proteins. sugar used up as mould grows.

Micro..-genetically engineered - make medicines. Some diseases caused-lack of working protein - diabetes - insulin. Gene codes for working protein can be taken from healthy human & put into microorganism - grown in fermenters - treat disease in large amounts.

loop of DNA - plasmid taken from bacteria. human insulin gene = cut out from dna by enzymes -also used cut plasmid from bacteria and then put back into bacteria.

Bacteria-cultivated-soon there are millions of identical bacteria w/ human insulin purified - used to treat sufferers. Before genetic engineering diabetics treated w/ pig insulin - foreign to human - rejected-allergic reactions.

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Using Microorganisms (II)

mycroprotein - fungus - meat substitutes-quorn Fungus -grown in fermenters - gluecose syrup as food. fungus - respires-aerobically-  needs supply O2.

Advantages

grow v. quickly - easy to look after ( all needed is something to grow them in/food/O2/right temperature) can be produced whether hot/cold. some places = unsuitable to grow crops/rais animals = best to use micros. microorganisms use waste prducts from agriculture/industry as food for Life processes. Cheap.

Fermenters

fermenters provide right conditions for microorganisms to grow in. carbs (sugars) nitrates to make proteins etc. Air piped in to supply oxygen if respiration is aerobic.

Have to be at right temperatuure for optimum growth - too cold - growth slows. too hot - enzyms denature. Microorganisms produce heat when respiring so fermenters - cooled - done by water jacker that cools fermenter. Right pH level needed - instruments - aseptic conditions - stop contaminations. Motorised stirrer to keep moving and stop sinking to the bottom.

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Growth in plants.

6 Factors affect growth.

1 - soi nutrients - contain nutrients essential for plant growth - nitrates to make proteins. Phosphates used in photosynthesis & respiration. Magnesium used to make chlorohpyll.

2 - Light - plants need it for photosynthesis. w/out it can't photosynthesis and don't get gluecose they need for energy & growth.

3 - Temperature -  plants grow best when warm, but not too hot. Reactions for synthesis happen quicker when warm - rate of synthesis grows. BUT if too hot enzymes denature - growth stops.

4-CO2 - Only 0.04% of co2 in atmosphere - plants need it for synthesis - if not enough - plant growth rate slows down.

5- o2-need it for respiration - which provides energy for growth - plants absorb o2 from atmosphere & also create it as by-product of photosynthesis.

6- plant hormones - stimulate growth.

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