bio b1 part 1

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  • Biology B1 part 1
    • Diet and Energy
      • Take in more energy than you use and your body uses it as fat, if you use less then your body raids its body fat stores
      • Carbohydrates are for energy
      • Fats are for energy and making cell membranes
      • proteins are for growth, making new cells, repair and energy
      • vitamins and minerals are needed in small amounts to be healthy
      • fibre helps the digestive system healthy
      • water is to keep the body hydrated and transport other nutrients
      • unbalanced diet leads to malnourishment (obesity, underweight, deficiency diseases.
      • Metabolic rate is the rate at which chemical reactions take place in cells.
        • affected by gender, age, proportion of muscle to fat and genes
    • Diet, Exercise and health
      • Cholestrol
        • Made by liver
        • needed to make cell membranes
        • Too much causes build up of plaque in the arteries which blocks them and causes clots. If an artery or blood vessel gets completely blocked a heart attack happens
        • low density lipoprotein are bad cholesterols found in animal fats/saturated fats.
        • High density lipoproteins are good cholesterols found in plant fats/unsaturated fats and decrease cholesterol levels by removing plaque from arteries.
        • affected by inheritance and lifestyle
      • Diabetes
        • increases risks of heart attacks
        • in type 2, blood sugar levels rise because certain cells in the body do not properly respond to insulin
        • healthy lifestyle reduces risk of diabetes
      • Receptors
        • Receptors detect stimuli and send information to the CNS
          • Stimuli is a change in the environment
            • Effectors do something in response to a stimulus
              • Nerve cells and neurones carry information around the CNS
                • Sensory neurones go from the receptor to the CNS
                  • Motor neurones go from the CNS to the effector
    • Pathogens and infections
      • Microorganisms are organisms too small to see without a microscope.
        • Microorganisms that cause disease are pathogens
      • Bacteria can reproduce rapidly inside the body and produce toxins.
      • Viruses reproduce in the cells and burst out of them.
      • an epidemic is when a wide range of people have a disease
      • A pandemic is when a disease effects a whole country or spreads world wide
      • Semmelweiss
        • there were two wards, one for medical students and one for midwives, the mothers giving birth died of pueperal fever a few days after giving birth normally.
        • When a professor cut himself by accident with a knife he died with similar symptoms to the mothers, this is when he realised diseases spread through contact
          • He got medical students to wash their hands and this reduced the deaths
    • Fighting infection
      • Part of the immune system are white blood cells
        • Phagocytes
          • surround bacteria and engulf them - they take the bacteria into their cytoplasm and kill them
        • Lymphocytes
          • Make antibodies and antitoxins to match specific pathogens, it can take the body a while to find the right lymphocyte
    • Drugs against disease
      • Painkillers don't cure disease but relieve side effects
      • antibiotics kill bacteria without killing your body's cells
      • Antivirals kill viruses.
    • Antibiotic resistance
      • Happens by chance if one bacterium mutates so its different to all other bacteria, Antibiotics are used and kill all bacteria except the mutated bacterium, this gives it an advantage and it reproduces and the bacteria are all resistant,
      • To prevent resistance: overprescribing which gives the bacteria an advantage, when you use antibiotics make sure you complete the whole course, dont use antibiotics for viruses
    • Vaccination
      • small amounts of dead or inactive pathogens are injected and your immune system kills them, next time the pathogen returns into your body, it knows which white blood cells to use and so the pathogen is killed very quickly
        • This is active immunity. Temporary immunity like anti venom is passive immunity
    • The MMR controversy
      • In 1998, some scientists released an article linking the MMR jab to autism
        • Parents didnt let their kids get the vaccinaton
        • They later said there was no link but less kids having the vaccine meant the measles mumps and rubella cases rose
      • The more people that have a vaccine, the less the pathogens can spread
    • Nerves and Hormones
      • information travels through nerves as electrical impulses
        • To and from the brain and the spinal cord/the central nervous system
      • Hormones carry information between organs,
        • The organs they effect are called target organs
      • Hormones are chemicals made by glands and are carried round the bloodstream. Hormones dissolve in the blood plasma and is carried inside blood vessels.
    • Reflex actions
      • Receptor detects stimuli
        • Receptor sends an electrical impulse down a sensory neurone to the CNS
          • There are gaps between each neurone called synapses which when the electrical impulses get to it, they release a chemical which diffuses across the gap
            • Relay Neurone
              • Motor Neurone
                • Effector
    • Controlling the body
      • Sweat
        • enzymes work best at 37 degrees
        • Cools you down because sweat is water and ions and water evaporates which takes heat
      • Food and drink
      • Urine
      • kidneys balance water and salt content by varying amount of water and salt excreted
    • Menstrual Cycle
      • Day 1: The uterus lining breaks down and is lost through a period. Pituitary gland releases FSH.
        • Week 1: Egg maturation daused by FSH. FSH causes oestrogen release which causes uterus lining to thicken
          • Week 2: LH causes egg release. Oestrogen reduces amount of FSH released
            • Week 3: low amounts of FSH stops oestrogen being released. egg has almost reached uterus and if it isnt fertilised it dies.
      • FSH is follicle stimulating hormone
      • LH is luteinising hormone
    • Fertility Drugs
      • Help women get pregnant using FSH and LH
      • IVF
        • Give woman fertility drugs to increase amount of eggs
          • eggs are taken and fertilised in a lab
            • Eggs are put back into womans ovaries
    • Control in plants
      • Phototropism: growth response to light
      • gravitropism: response to gravity
      • hydrotropism: growth response to water
      • Auxins
        • hormone that makes the cells shoot longer. They build up on the shady side of the plant and make it face the ight
      • Week 3: low amounts of FSH stops oestrogen being released. egg has almost reached uterus and if it isnt fertilised it dies.
      • Weedkiller makes plant grow too quickly so it dies
      • Rooting powder makes cuttings grow roots
    • Drugs
      • Changes chemical processes in the body
      • if someone gets addicted they get withdrawal symptoms
    • Developing new drugs
      • Tested in lab, then on volunteers, given to people with target illness
      • double blind trials are one group given placebo pill and other given real
      • Thalidomide was a sleeping pill but gave babies of pregnant woman defects
    • Legal and Illegal drugs
      • cannabis is an illegal 'gateway' drug that makes users relaxed and increases chance of getting schizophrenia
      • Make athletes perform better with steroids beta blockers and stimulants

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