Biology

Biology

The nervous system
1. Stimulus
  1. Receptor
    1. Sensory Neuron
      1. CNS
        Central nervous system
        Motor Neurons
        Effector
        Eg muscle
        Responce
        Eg move arm away
  2. e.g. put hand near flame
2. Iris Relex
  1. In bright light
    1. Circular muscle contractions
    2. Radial muscles relax
    3. pupil is smaller
  2. In dim light
    1. Radial muscles contract
    2. Circular muscle relax
    3. Larger pupil
  3. Close Objects
    1. Ciliary muscles contract
    2. Suspensory ligaments relax
    3. Eyes get tired
    4. Iris blobby
  4. Far Away Objects
    1. Ciliary muscles relax
    2. suspensory ligaments tighten
    3. Iris pulled flat
  5. Blind spot
    1. In each eye where the optic nerve leaves the retina
Reproduction
1. The menstrual cycle
  1. Oestrogen
    1. Released by the ovaries
    2. Stops FSH being produced
      1. FSH starts the development of an egg
    3. Repairs the lining
  2. Progesterone
    1. Keeps the lining thick
  3. 28 day cycle
    1. Day 14 egg realesed
  4. Sperm
    1. Made by the testes
    2. Stored in the epididymis
    3. Travels out in the Urethra
2. Asexual and Sexual
  1. Asexual (natural clones)
    1. Advantages
      1. Fast reproduction
      2. No need to find a mate
    2. Disadvantages
      1. All individuals (clones) may die if there is a dies of climate change as there is no variation to survive this
  2. Sexual (with a mate)
Food production
1. Selective breeding
  1. Microproperganda
    1. Take a cutting
      1. Mash the cutting
        Into individual cells
        Add to agar and glucose and amino acids
        Mash up again
        Add to agar and glucose and amino acids
        Add Auxin
        To promote growth
        Move the plants to a greenhouse
        To acclimatise them
        Move plants outside
        Grow to plantlets
  2. Take cuttings and grow them
  3. Breed selected animals
2. Making Yogurt
  1. Get some milk
    1. Pasteurise it
      1. 85ºc for 15-30 mins
        Don't boil was it changes the taste
      2. Homogenise it
        Stir so it is an even consistency
        Cool to 40ºc
        Add lactobacillus
        Incubate for several hours
        cool to 4ºc
        bacteria division/growth/respiration slowed
        Add sugar/fruit
        For flavouring
        convert lactose to lactic acid
        So there is fast reproduction
3. Making beer
  1. Get barley seeds
    1. Because it stores a lot of starch
    2. Let the seeds germinate
      1. Kill the seed
        Before the maltose is used up in respiration
        Crush them
        Filter and add water to make molt
        Sterilise it
        Kill all micro-organisms
        boil it
        Add hops for taste
        Add yeast
        Fermentation
        (Anaerobic respiration)
        Produces ethanol and carbon dioxide
        Filter again
        Pasteurise
        Heat for a few seconds.
        Don't boil
        Put in barrels
      2. Amylase is produced and digests the starch into maltose
4. cloning
  1. Take a body cell from animal A
    1. The donor
    2. Take an egg cell from animal B
      1. Haploid number
      2. Take the nucleus out of the egg
        enucleated egg
        Use a pipet to transfer somatic cell
        OR use an electric shock to fuse the two together
        Wait until the cell has divided
        Transfer the embryo into surrogate mothers uterus
        You have a clone of animal A
    3. Diploid number
  2. Making genetically identical copies
    1. Asexual reproduction
5. Genetic modification
  1. Some people cannot make insulin
    1. A protein made in the pancreas
    2. So they must inject it
      1. So we get bacteria to make insulin
        Take a chromosome from a non-diabetic
        Cut out the gene that makes insulin
        Using a restriction enzyme
        Cut a plasmid
        Using a restriction enzyme
        Join the plasmid and the gene
        With ligase
        Makes a recombinant DNA
        Insert the plasmid into a host cell
        usually bacteria
        not animal because
        No vet bills
        Less space needed
        Continuous + rapid reproduction
        plasmid replictates
        A vector
Classification
1. Kingdoms
  1. Bacteria
    1. Single celled
    2. No nucleus
      1. But do have a large circular chromosome
    3. Example: Lactobacillus bulgaricus
  2. Protoctists
    1. Single celled
    2. Not animals as they have no embryo stage
    3. Example: Amoeba
  3. Fungi
    1. Have a nucleus
    2. Can be single celled or form hyphae
      1. long threads of joined cells with many nuclei
    3. Cell wall made by chitin
    4. Feed by extra cellular digestion
      1. They are saprophytes
    5. Example yeast
  4. Plants
    1. Have a nucleus
    2. Are multicelluar
    3. Have a cellulose cell wall
    4. Have chloroplasts
    5. Store carbohydrates as starch
  5. Animals
    1. Have no cell wall
    2. Eat other organisms
    3. Store carbohydrates as glycogen
  6. Viruses
    1. Not cells
    2. No nucleus
      1. DO have DNA
    3. Protein coat
    4. Reproduce inside living cells
    5. Example: influenza virus
Ecology
1. Deforestation
  1. Why
    1. To make room for buildings
    2. Wood for furniture
    3. Fuel
    4. Paper
    5. Room for crops
  2. consequences
    1. Draught
      1. Because of no transpiration
    2. Loss of habitat
    3. Loss of food for animals
    4. Soil erosion/Leaching
    5. Oxygen levels decrease
      1. No photosynthesis
      2. Green house effect
2. Global warming
  1. Caused by the increase of greenhouse gases
    1. Short wave heat radiation in
      1. Long reflects off the earth
        Not all can escape our atmosphere

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