Biology 1.1 & 1.2

Balanced Diet
1. A balanced diet it necessary to stay healthy
  1. It provides the right balance of different you need and the right amount of energy
2. What makes up a healthy diet?
  1. Fats and carbohydrates
    1. Provide energy for your body chemistry to function correctly
    2. Keep your body temperature at 37 degrees
    3. Excessive fats and carbohydrates can lead to obesity
      1. A common disorder in developed countries
      2. Having a mass of at least 20% greater than the max recommended body mass
      3. Overeating, lack of sufficient exercise, bad diet and hormonal problems
      4. Can lead to arthritis, type 2 diabetes, high blood pressure, and heart disease
  2. Protein
    1. Build cells, grow new tissue, repair & replace cells
  3. Mineral ions and vitamins
    1. Small amounts
    2. Healthy functioning of the body
    3. Mineral salts containing things like sodium, calcium, potassium and chloride ions
      1. Too much salt (sodium chloride) can cause high blood pressure & heart problems
  4. Fibre
    1. keeps everything running smoothly in your digestive system
3. Malnourishment
  1. When a person's diet is not balanced
  2. A malnourished person is not necessarily thin - an obese person could be malnourished if they only ate junk food as this is not providing them a balanced diet.
  3. MALNOURISHMENT AND STARVATION ARE NOT THE SAME THING!!!!!!
4. Losing weight
  1. A person loses mass when the energy content of the food taken in is lower than the amount of energy used by the body
5. Energy
  1. Metabolism/Metabolic rate
    1. How fast the chemical reactions in your body take place
      1. This is your metabolism
      2. These reactions are fuelled by energy
    2. The amount of exercise you do makes your metabolism vary
  2. Energy used by your body
    1. Exercise increases the amount of energy used by your body
      1. Athletes or people doing heavy manual labour need a higher energy (calorie) intake
        The amount of fat and carbohydrates you eat should be adjusted
Defence against disease
1. Pathogens
  1. Microorganisms that cause infectious disease
  2. Bacteria
    1. What they do
      1. Very small cells
      2. Rapidly reproduce
        Cell division
      3. Produce toxins
        What makes you feel ill
    2. Antibiotics
      1. Help cure bacterial disease
        Kill infectious bacteria
      2. CAN'T TREAT VIRUSES
        VIRUSES LIVE & REPRODUCE INSIDE THE CELLS
        CAN'T TREAT THEM WITHOUT DAMAGING THE CELLS
      3. Antibiotics like penicillin kill or prevent the growth of harmful pathogens
        They kill the bacteria but not your own body cells
      4. Different antibiotics target different bacteria
        Specific bacteria should be treated by specific antibiotics
    3. Antibiotic resistant strains
      1. Overuse and inappropriate use has increased the rate of development of antibiotic resistant strains
        Important not to over use antibiotics
      2. Many strains mutate which causes stronger, more resilient strains of bacteria to survive as a result of natural selection
      3. If infections are treated with antibiotics then resistant bacteria will survive
        This means resistant bacteria can survive and reproduce to infect other people
        This will then spread rapidly as people are not immune to it and there is no treatment
  3. Viruses
    1. NOT cells
      1. Smaller than bacteria
      2. They damage the cells in which they reproduce
        They replicate by invading a cell and then using the cell's genetic machinery they reproduce themselves as copies of the original virus
        The invaded cell then bursts releasing lots of new viruses
        The cell damage is what makes you feel ill as your body fights back to make new 'good' cells to replace those destroyed by the virus
    2. Can't be treated by antibiotics
  4. Fungi
    1. Biggest microorganisms
    2. Live in colonies
    3. Digest material externally
      1. Absorb the nutrients from outside their cells
    4. Can be useful or harmful
  5. How our body deals with it
    1. Has defense systems
      1. Skin, hair, mucus stop pathogens entering the body
      2. Skin helps as when you get a cut you get a scab over it (small sections of cells called platelets help the blood to clot
      3. Tears contain a chemical which kills bacteria on the surface of the eyes
      4. The stomach contains HCl acid which kills pathogenic bacteria
    2. WHITE BLOOD CELLS
      1. Ingesting
        WBCs surround invasive microorganisms and break them up and ingest them
      2. Produce antibodies
        An antibody is created by WBCs when they encounter a 'foreign' antigen on a pathogen they don't recognise. They produce antibodies which lock onto the antigens of the pathogen
        The antibodies produced are specific to that type of antigen - they will not lock onto any other type of antigen
        ANTIGEN
        All invading cells have unique molecules on their surface - these are antigens
      3. One of the most important parts of the IMMUNE SYSTEM
        Immune system
        Kicks in when a pathogen gets inside your body
        Produces specific antibodies to kill a particular pathogen
        Does this quicker if you have been vaccinated
        Injected into you with a inactive or weakened form of a pathogen
        The body starts an immune response
        Lymphocytes produce antibodies to fight the pathogen
        The body remembers how to fight the infection so if you do get infected you can fight it off quicker
        CULTURING MICROORGANISMS
        You should sterilise everything - petri dish, innocullating loop (by passing through a flame) and agar jelly
        The lid of the petri dish should be secured by tape
        It should not be incubated over 25 degrees to stop harmful pathogens growing
      4. Present throughout your body and always to hand
        If your WBC count is low you are more susceptible to disease & infection
    3. Produces antitoxins
      1. These counteract the toxic effect of the toxins released by the pathogen. They are very specific chemicals
Nervous system
1. any changes in your surroundings is potentially a detectable stimulus for your sensory organs
  1. sensory organs contain receptors that are sensitive to stimuli
  2. The nervous system controls our REFLEXES
    1. Receptor: sensitive to changes in conditions - stimulated by a stimulus
    2. Sensory neurone: the nerve cell connected to the receptor - a message is sent down it by the receptor cell
    3. Synapse: the junction between two neurones to keep the signal strong by diffusing chemicals - a message is passed onto it by the sensory neurone
    4. Relay neurone: the nerve cell found in the spinal chord - a message is passed down the relay neurone by the synapse
    5. Motor neurone: the nerve cell that sends the impulse to the effector - the relay neurone passes the message down the motor neurone
    6. Effector: the organ affected by a nerve impulse as a response to a stimulus - the message is passed by the motor neurone to the effector
Internal conditions
1. Water content
  1. lungs when we breathe out
  2. skin when we sweat
  3. kidneys in the urine
2. Ion content
  1. skin when we sweat
  2. kidneys in urine
3. Temperature
  1. brain keeps our body at 37 degrees
4. Blood sugar levels
  1. via insulin
    1. diabetes
      1. when your body cannot produce enough insulin to tell your body to reduce glucose
        Pancreas - controls the use of 2 hormones
        Insulin - hormone secreted by the pancreas
        Causes liver to remove any glucose not needed after digestion
        Glycogen - the liver converts soluble glucose into glycogen to store
        Glucagon - second hormone secreted by the pancreas
        tells the liver to convert glycogen back into glucose for use in respiration
Hormones
1. Menstrual cycle
2. Plant hormones
3. a hormone is a chemical messenger secreted by a gland carried to the effector cell by the blood

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Biology 1.1 & 1.2

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	Created by Ellen Hepburn over 9 years ago