Biology - Unit B1

A Balanced Diet
1. You need to balance the amount of energy intake and energy uptake.
2. Components
  1. Carbohydrates = immediate supply of energy
  2. Proteins = growth and repair
  3. Fats = store of energy
  4. Vitamins and Minerals = shortage leads to deficiency diseases
  5. Fibre
  6. Water
3. BMI
  1. Gives an indication about a persons ideal body mass compared to their height.
  2. BMI = mass in Kg / (height in m)2
  3. Underweight = 18.8 - normal = 18.5 to 25 overweight = 25 to 30 obese = 30+
  4. Metabolic Rate
    1. The speed at which chemical reactions occur in the cells of your body.
    2. Affecting Factors = Inheritance - Proportion of muscle to fat in your body - Gender - Age
    3. Obesity
      1. Health Problems = Coronary heart disease - high blood pressure - type 2 diabetes - cancer
Disease
1. A pathogen is a micro-organism that carries disease around your body and makes you ill.
2. Bacteria make you feel ill by injecting toxins into your blood stream which are carried around your body.
3. Viruses inject DNA inot a cell which then creates small viruses, which causes the cell to burst releasing the virus.
4. Barriers to infection
  1. Nose - mucus lining preventing the passing of pathogens
  2. Mouth - mucus and acid in the stomach so are killed in the stomach
  3. Skin - glands create antiseptic and coats our skin in an oily substance
  4. Eyes - tears produce lysozyme which cleans our eyes.
  5. Second Line of Defence
    1. White blood cells called phagocytes engulf the white blood cells and destroy them.
    2. Third Line of Defence
      1. The Immune System
      2. The white blood cells produce different anti-bodies to lock onto the antigen.
      3. Every antigen needs its own special antibody.
      4. Antitoxins
        Neutralise toxins that bacteria dump in your body.
      5. Reproduction
        Sexual
        Occurs in both animals and plants
        Involves 2 parents and the joining of the gametes
        Results in variation in the offspring
        Asexual
        Involves only 1 parent
        Results in clones and are genetically identical
        There is no variation
  6. Vaccinations
    1. Endemics are the spread of disease in one country.
    2. Pandemics is the spread of disease across several countries.
    3. Involves injecting a small harmful amount of the pathogen into your immune system which then creates the antibodies needed to fight it, in preparation for the real disease.
    4. Genetically Engineered Insulin
      1. DNA is a universal code
      2. Transferring genes from ones species to another is genetic engineering
      3. The species that has had its DNA changed is known as genetically modified.
      4. GM bacteria are used to produce insulin for diabetes.
      5. GM Crops
        To improve there quality or resistance to insects or herbicides.
        Used to alter the rate of growth
        virus resistance
        Contamination, may be unsafe, takes years to come onto the market.
5. Antibiotic Resistance
  1. When bacteria are no longer killed by antibiotics.
  2. Happens when mutations occur in the dividing of bacteria.
Hormones and Fertility
1. A hormone is a chemical produced by a gland in one part of the body, released into your blood stream and carried to a target organ where it has an effect.
2. Hormone Glands include pituitary, thyroid, Adrenal, Pancreas, ovaries and testes.
3. Menstrual Cycle
  1. LH - produced in the pituitary - target organ are the ovaries and it causes egg release.
  2. FSH - produced in pituitary - target organ ovary - matures the eg and produces oestrogen.
  3. Increasing Fertilty
    1. Involves the giving of FSH and LH in a fertility drug to stimulate maturation of eggs which can be used in IVF.
  4. Decreasing Fertility
    1. Pills are taken containing oestrogen which prevents the release of FSH and prevents the eggs from maturing.
Tropisms
1. Plant responses are called tropisms, plants respond to light, gravity and water.
2. A response to light is phototropism
3. A response to gravity is geotropism
4. A response to water is hydrotropism
5. Positively tropic means plant grows towards a stimulus
6. Negatively tropic means plant grows away from the stimulus.
7. Growth in Plants
  1. The hormone auxin stimulates a plant to grow
  2. The auxin encourages the cells to elongate and it moves down the stem by diffusion.
  3. Plant Hormones
    1. Weed killers - the auxins cause rapid growth in plants which lead to plants growing them to death e.g. agent orange
    2. Rooting Powders - auxin causes the roots to grow
    3. Ethylene - Causes fruit to ripen converting starch into sugar.
Drugs
1. A drug is any chemical that alters the way the body works.
2. Stimulants - Ecstacy, Cocaine
3. Depressants - Heroin, Nicotine, Alcohol
4. Key Words
  1. Addiction = when a drug contains an addictive chemical that alters body chemistry and can cause withdrawal symptoms.
  2. Withdrawal = a range of symptoms such as sweating and tremors associated with stopping taking an addictive drug.
  3. Tolerance = requiring larger and larger doses to get the same effect with the risk of overdose.
  4. Gateway Drug = a drug that leads to more addictive drug use e.g. cannabis
  5. Drugs in Sport
    1. Beta Blockers = overcome nervousness
      1. Natural Selection and Evolution
        Evolution is a change over time
        1. many young are born - shortage of food
        Charles Darwins theory of how evolution happens is called natural selection.
        2. individuals show variation due to spontaneous mutation
        3. Genes allowing survival are passed to the next generation.
        4. individuals most suited to the environment survive and breed successfully.
    2. Lean Mass Builders = increases muscle growth
    3. Diuretics = removes excess water
    4. Stimulants = boosts physical activity
    5. Painkillers = treats pain
Competition in animals
1. Animals and plants have to compete for limited resources. The best adapted survive.
2. Compete for food, water, mate, territory.
3. Interspecies = compete outside of species
4. Intraspecies = compete within species
5. Adaptation
  1. Special feature or behaviour that makes an organism particularly suited to its habitat.
  2. Adaptations may be general or specific.
    1. General = legs to walk or fins to swim
    2. Specific = multiple rows of teeth for eating
    3. Specific = adaptation that makes the animal unique to others.
Competition in Plants
1. Compete for light, water, nutrients and minerals from the soil
2. Adaptation
  1. Plant adaptations include surface area of leaves, water storage and root systems.
3. Competition = the way plants compete with each other for their necessities.
Extremophiles
1. Hydrothermal Vents = extreme temperature, pressure, acidity, no light.
2. Chemosynthetic bacteria = Animals/plants use minerals out of black smokers for growth and food and they form the first steps of the food chain e.g. crab
Environmental Change
1. Changes in the environment affect the distribution of living organisms.
2. Non living factors = change in temperature, water availability, light levels, pH and amount of oxygen available.
3. Living factors = arrival of new competitor for food, arrival of new predator, arrival of a new disease.
4. A living indicator is any organism that is present in a certain place that can indicate whether it is polluted or not.
5. Cloning
  1. Taking a cutting
    1. You leave one leaf on the cutting and place it in a plastic bag for the water to evaporate. Put auxin on the end of the cutting which causes cell elongation and grows.
      1. DOLLY THE SHEEP
  2. Tissue Culture
    1. Hundreds of clones are made at the same time. The cutting is sterilised and broken down and grown in agar.
  3. Embryo Transplantation
    1. A fertilised egg divides and the cells are implanted into surrogates before implanted into the uterus, each cell divides into identical embryos.
      1. All offspring are genetically identical in all of these techniques

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Biology - Unit B1

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