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Biology Summer HW - Coggle Diagram

- - - - Theory of evolution: Variation exists within a species as a result of mutations in DNA. Organisms with characteristics most suited to the environment are more likely to survive to reproduce successfully, known as survival of the fittest. The beneficial characteristics are then passed on to the next generation. Over many generations, the frequency of alleles for this advantageous characteristic increases within the population, leading the species to eventually evolve.
  - - - Three domain system: Archaea (primitive bacteria which live in extreme environments such as hot springs), Bacteria (true bacteria) and eukaryote (organisms which have a nucleus enclosed in a membrane)
- - - - Bacteria are also small pathogens that multiply very quickly through a process called binary fission. They produce toxins which can damage cells.
        
        Fungi can be single celled or made up of thread-like structures (hyphae). They can produce spores which can be spread to other organisms.
        
        Protists can be parasitic which means that they can use humans and animals as their hosts.
  - - - Hydrochloric acid - used to kill bacteria in food reaching the stomach to prevent infection.
      - Lysozymes - found in white blood cells, used to kill and digest bacteria.
  - - - During this process, the antigens also trigger production of memory lymphocytes. If you become infected again with the same pathogen, the specific complementary antibodies will be produced at a faster rate. The individual will not feel the symptoms of the illness.
  - - - Clinical testing - the drug is tested on patients/volunteers. First, they are tested on healthy volunteers with a low dose to ensure there are no harmful side effects. They are then tested on patients to find out the most effective dose
        
        To test how well it works, patients are split into two groups with one group receiving the drug and one receiving a placebo. (does not contain the active ingredient).
        
        These can be single blind (only the doctor knows which one is real or which is fake) or double blind (patient and doctor both don't know which is the placebo and which is the real drug to eliminate any bias in the results).
- - - - Where a capital G is demonstrated, that is the genotype of the banana. (and phenotype as it is the dominant colour)
  - - - Mutations are a change of base in DNA. They can have either small or large effects on any living organism.
  - - - 2) Peel the skin of Kiwi, chop into small pieces.
        
        3) Add solution from step 1 to Kiwi.
        
        Filter the solution
        
        Add 10ml of pineapple juice and wait a few minutes.
        
        6) Add 2 teaspoons of ethanol and wait around 10 minutes, you should be able to see the DNA from the fruit.
- - - - Sperm cells - specialised to carry the male's DNA to the egg cell (ovum) for reproduction.
        
        Its adaptations are: streamlined head and long body, lots of mitochondria for swimming, acrosome contains digestive enzymes used to penetrate the egg cell and it is haploid.
        
        Egg cell - specialised to accept only a single sperm cell to develop into an embryo.
        
        Its adaptations are: surrounded by a special membrane which only accepts a single sperm cell during fertilisation.
        
        Ciliated epithelial cells are specialised to waft bacteria (trapped by mucus) to the stomach. They are killed by stomach acid and it is one of the ways our body protects against illnesses.
  - - - As substrate concentration increases, a saturation point is met where increasing the concentration of substrates will have no effect on the rate of reaction because all of the active sites are full.
        
        An optimum temperature and pH are required so that enzymes do not denature (lose the shape of their active site, when this happens an enzyme-substrate complex can no longer be formed so a chemical reaction cannot be sped up)
  - - - Centi x 0.01 || Milli x 0.001 || Micro x 0.000001 || Nano x 0.000000001
- - - - Adult stem cells - found in bone marrow, they can form many types of cells e.g blood cells, but are unable to form every type of cell.
      - Meristem in plants - Found in shoots/root tips. They can differentiate into any type of cell and the plant can use them throughout its entire life.
      - Embryonic stem cells - formed when a zygote is created. Can differentiate into any type of cell in the body.
  - - - Prophase: The DNA in chromosomes and their copies condense and the membrane around the nucleus begins to break down.
        
        Metaphase: Chromosomes line up in the middle of the cell.
        
        Anaphase: Chromosomes are pulled to polar opposite ends of the cell
        
        Telophase: New membrane forms around the chromosomes at each end of the cell.
        
        Cytokinesis: Cell membrane pinches and divides into two daughter cells.
  - - - Effectors carry out a response by contracting muscles or glands secreting hormones in response to a stimulus.
        
        A synapse is a gap between two neurons. When an impulse reaches the first neuron, a neurotransmitter is released and it diffuses across the gap. Once it reaches the second neuron, a new impulse is generated and the signal carries on, repeating the process if any more synapses are present.