BMAT - Biology

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BMAT - Biology
2015-11-02 16:58:43
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  1. What is the structure of a bacterium?
    • Single celled
    • Cytoplasm
    • Cell membrane, surrounded by cell wall
    • Strand of DNA (no nucleus)
  2. What are the four types of pathogens?
    • Fungi
    • Protozoa
    • Viruses
    • Bacteria
  3. Bacteria
    • Reproduce by asexual reproduction (binary fission)
    • Can damage cells
    • Can release toxins
  4. Producing antibodies
    • Every invading cell has antigens
    • When foreign antigen is encountered →
    • antibodies produced
    • After infection, memory cells produced = immunity
  5. Antibiotic resistance
    • Bacteria can mutate= resistance
    • Resistance=natural selection, those that are resistant survive
    • Resistant strains can't be treated by antibiotics, e.g. MRSA (causes wound infections), resistant to methicillin
    • Overuse of antibiotics=more resistance.
    • Resistance is becoming more common
  6. What is a catalyst?
    A substance that increases the rate of reaction without undergoing any permanent change itself.
  7. What is respiration?
    • Involves many reactions, all of which are catalysed by enzymes.
    • Process of releasing energy form glucose, which goes on in every cell.
    • Aerobic= with oxygen
    • Anaerobic=without oxygen
    • Respiration used to build larger molecules, to keep body temp steady.
    • Anaerobic is incomplete breakdown of glucose
    • Produces lactic acid, does not release as much energy
    • Glycogen converted back to glucose during exercise
  8. Active transport in gut
    • When high conc. of nutrients in gut, they diffuse naturally into blood.
    • When low conc. of nutrients in gut but high in blood, active transport is used.
    • This stops us from starving.
  9. Cell organisation
    • Cell-tissue-organ-system
    • Tissues can include more than one type of cell
    • Organs can include more than one type of tissue
  10. Enzymes and digestion
    • Amylase breaks down starch into maltose (saliva, pancreas, small intestine)
    • Protease breaks down proteins into A.A (made in stomach -pepsin-, pancreas, small intestine)  
    • Lipase breaks down lipids into fatty acids and glycerol (made in pancreas and small intestine)
  11. Digestive system
    • Stomach: breaks down food
    • Liver: produces bile (neutralises acidic stomach acid and emulsifies fats)
    • Gall bladder: stores bile
    • Small intestine: Where nutrients are absorbed
    • Large intestine: water is absorbed
    • rectum: stores faeces
  12. Thorax
  13. Ventilation
    • Breathing in: Diaphragm and intercostal muscles contract, ribs move up and out, pressure decreases
    • Breathing out: Diaphragm and intercostal muscles relax, ribs move down and in, pressure increases
    • Ventilators: help people to breathe, work by pumping air into lungs, can destroy alveoli.
  14. Heart blood flow
  15. Blood clotting
    • Too much clotting can cause stroke and deep vein thrombosis.
    • Haemophilia is a genetic disease where blood doesnt clot because clotting factor is missing. This can be injected.
  16. Blood transfusions
    • You need to match the blood groups to transfuse.
    • A, B, AB, O - refer to antigens on surface of RBC's.
    • RBC's have A or B antigens (or neither, or both)
    • If anti-A/B antibody meets A/B antigen, agglutination occurs.
    • O has no antigens - can donate to anyone.
  17. Heart rate
    • Adrenaline affects heart rate (fight or flight mode)
    • A group of cells called pacemakers produce small electric currents, which cause heart to contract.
    • Sino atrial node stimulates the atria
    • Atrio ventricular node stimulates ventricles
    • SAN stimulates AVN.
    • Artificial pacemakers used if cells don't work.
    • Electrocardiograms (ECG) used to show electrical activity of heart.
    • Echocardiogram are ultrasounds of heart.
  18. Sense organs and receptors
    • Eyes (SO): Light receptors
    • Ears: sound receptors
    • Nose: smell receptors
    • Tongue: taste receptors
    • Skin: touch receptors
    • Messages from CNS (brain and spinal chord) are sent to effectors (muscles)
    • Sensory neurons: send signals from receptors to CNS
    • Relay neurons: carry signals from sensory neutrons to motor neurone
    • Motor neurons: carry signal from CNS to effector
  19. Neurons
    • Electrical impulses pass along axon.
    • Myelin sheaths increase speed of signals.
    • Have branched endings - dendrites
    • Sensory neurons: One long dendrite carries signal from receptors to cell body.

    • Short axon carries signal from cell body to CNS.
    • Relay neuron: Short dendrites carry signal from sensory neutron to cell body.
    • Short axons carry signal form cell body to motor neurons.
    • Motor neurons: Short dendrites carry signal from CNS to cell body
    • Long axon carries signal from cell body to effector cell.
  20. Reflex arc
    • Pain receptors are stimulated
    • Impulses travel along sensory neutron
    • Impulses pass through relay neutron via synapse
    • Impulse travels through motor neuron via synapse.
    • When impulse reaches muscle, it contracts.
    • Reflexes improve chance of survival.
    • Drugs (like ecstasy) block serotonin receptors.
    • Serotonin conc increases - mood enhancer.
  21. Hormones vs nerves
    • Hormones travel in blood stream
    • Hormones are slow nerves are fast
    • Hormones have long lasting effects, nervous do not
    • Nerves act on specific area, hormones more general
  22. Homeostasis
    • Homeostasis is about maintaining a constant internal environment
    • Negative feedback is used to bring levels back to normal e.g. water.
  23. General hormones
    • Adrenaline: released from adrenal glands. Responsible for fight or flight mode. Triggers glycolysis in liver and muscles.
    • Insulin: Released from beta cells in pancreas. Reduces glucose levels.
    • Glucagon: Increases blood glucose, released from alpha cells.
    • ADH: released from pituitary gland. Inhibits loss of water. Acs on lower parts of nephron.
    • Testosterone: growth, puberty, hair growth.
  24. Menstrual cycle hormones
    • Oestrogen: Produced in ovaries. Inhibits FHS, overrides progesterone at the end of pregnancy. Buildup of uterus.
    • Progesterone: maintains the lining of the uterus. Inhibits FSH and LH. Causes breast development
    • FSH: Released by pituitary gland at start of menstrual cycle. Stimulates development of primary follicles which secrete oestrogen.
    • LH: Produced by pituitary gland at around day 12 of cycle. Causes release of egg cell.