Biology 1A

Biology 1A

Diet/Metabolic rate + Factors affecting health
1. Carbohydrates= Release Energy Fats= to keep warm and release energy Protein= Growth, Cell, repair and Cell replacement Fibre= Smooth running of digestive system
2. Excess carbohydrate or fat in the diet can lead to obesity (bad diet, overeating and lack of exercise)
3. Lack of food (malnourishment) leads to slow growth, fatigue, poor resistance to infection and irregular periods
4. Metabolic rate: Speed at which chemical reactions happen in your body
Food, Lifestyle and Diet
1. Sodium (salt) in food can lead to health problems such as high blood pressure
2. Saturated fats can raise your chlorestal level
3. Energy from food is measured in kJ/Calories/Kcal
4. Eating less fat/carbohydrate (less energy taken in) and doing more exercise (using more energy) will allow weight to be lost
Fighting Disease
1. Vaccination
  1. Vaccination involves Injecting small amount of dead/inactive microorganisms
  2. These carry antigens causing the body to produce antibodies (attack them)
  3. Live microorganisms of same type appear = White blood cells producing antibodies to kill pathogen
2. Drugs
  1. Painkillers= Reduce Symptons of disease Antibiotics= Kill/prevent growth of bacteria without killing body cells. Antibiotics dont kill viruses. Viruses reproduce using your own body cells.
  2. Bacteria mutates (causing them to be resistant to antibiotic) Treat infection= non-resistant strains of bacteria
  3. Individual resistant bacteria survive+reproduce. Population of resistant strain will increase (serious infection)
3. Past + Future
  1. Ignaz Semmelweis
    1. Saw that women were dying (huge numbers) after childbirth from puerperal fever
    2. Disease spread on unwashed hands
    3. Told doctors to wash hands in antiseptic solution (death rate fell)
    4. Solution= Killed bacteria. Semmelweis could find out why it worked so death rate rose
4. Bacteria are small cells they can reproduce rapidly inside your body. They make you feel ill by damaging your cells and producing toxins
5. Viruses replicate themeselves by invading cells using the cell to produce copies of themeselves, bursting them to release new viruses
6. White blood cells travel around your body engulfing foreign cells and digesting them
7. Antibodies are produced by white blood cells and lock onto + kill invading cells. They are produced rapidly and carried around the body
The Nervous System
1. Stimulus=Change in your environment Receptors=Groups of cells sensitive to a stimulus Stimulus= Light, Sound, touch, pressure or temperature
2. Eyes: Light receptors= Sensitive to light, contain a nucleus, cytoplasm and cell membrane
3. Ears: Sound Receptors= Sensitive to sound "Balance Receptors"= Sensitive to changes in postion
4. Nose: Smell Receptors= Sensitive to chemical stimuli
5. Tongue: Taste Receptors= Sensitive to sweet, salt, bitter, savoury
6. Skin: Sensitive to touch, pressure, pain and temperature change
7. Neurones
  1. Sensory: Nerve cells which carry signals (electrical impulses) from receptors in sense organs to the central nervous system
  2. Relay: Nerve cells which carry signals from sensory neurone to motor neurone
  3. Motor Neurone: Nerve cells that carry signals from central nervous system to the effector muscle/gland
  4. Effectors: Muscle + Glands which respond in different ways. Muscles contract in responce to impulse from nervous system. Glands secrete hormones
Hormones
1. Hormones: Chemical messengers which travel in the blood, activating target cells
2. Nerves: Fast actions, short time, precise area
3. Hormones: Slower action, long time, general area
The Menstrual Cycle
1. FSH: Produced by pituitary gland. Causes egg to mature in ovaries and stimulates ovaries to produce oestrogen
2. OESTROGEN: Produced in the ovaries. Causes pituitary to produce LH and inhibits the further release of FSH
3. LH (LUTEINISING HORMONE): Produced in the pituitary gland. It stimulates the release of a egg at the middle of the menstrual cycle
4. PROGESTERONE: Hormone produced by ovaries
Synapse + Reflexes
1. Reflex Arc
  1. Stimulus Detected
  2. Stimulation of pain receptor
  3. Impulses travel along sensory neurone
  4. Impulses pass along a relay neurone (synapse)
  5. Impulses travel along a motor neurone (synapse)
  6. Impulse reaches muscle, contracting. Moving hand away from stimulus
Plant Hormones
1. Auxin : Controls growth near tips of shoots and roots
  1. Controls its response to light (phototropism), gravity (geotrophism) and moisture
  2. Auxin is produced in the tips, it moves backwards stimulating cell elongation process which occurs in the cells behind the tips. If no auxin is available it may stop growing
2. Shoot grows towards light= grow faster on shaded side bending towards light. Shoot grows away from gravity= lower side growing faster, bending shoot upwards. Roots grow towards gravity= cells on top elongate faster, root bends downwards. Roots grow towards moisture= Inhibits growth on that side causing root to bend in that direction
Homeostasis
1. Bodily levels that need to be controlled. Ion, water, sugar content and temperature
2. Ions are taken into the body in food and absorbed into the blood. Some ions are lost in sweat and kidneys remove the excess from the blood, then got rid of in urine.
3. Water is lost through skin as sweat, via lungs in breath and via the kidneys as urine
4. On a hot day (more sweat) you produce less urine, but it will be more concentrated. Also when you lose more water through your breath when you exercise because you breathe faster
5. Enzymes work best at 37°c so your body trys to remain this temperature.
6. A hormone (insulin) helps maintain the right level of glucose in your blood so your cells get a constant supply of energy
Drugs
1. Drugs cause chemical changes leading the body to become addicted if the drug isnt taken a addict can suffer physical withdrawal symptons which are unpleasant
2. Medical drugs are medically useful some that do require prescriptions can be dangerous if misused. Recreational drugs are used for fun and performance enhancing drugs can improve a person's performance in sport.
3. Medical testing of drugs
  1. 1. tested on human cells and tissues in a lab (only drugs that dont affect the whole/multiple body systems
  2. 2. Test the drug on live animals. This is to see if it works, find out its toxicity and best dosage. Any new drug must be tested on two different live mammals.
  3. 3. If the drug passes it is tested on human volunteers in a clincal trial. First on healthy volunteers (low dose to start of and gradually increased)
  4. 4. Next it is tested on people with the illness and the optimum dose is found. Patients are put into two groups, one with the new drugs and the other with a placebo so the doctor can see the actual difference the drug is making.
  5. Clincal trials are blind, neither the doctor nor the patient know untill results are gathered
Controlling Fertility

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