biology topic 2 organisation

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  • organisation
    • cell organisation
      • large multi- cellular organisms
        • made up of organ systems
        • have different systems for exchanging and transporting substances
      • tissues
        • a group of similar cells that work together to carry out a specific function.
      • organs
        • a group of different tissues that work together to perform a certain function.
      • organ systems
        • a group of organs working together to perform a particular function
      • plant cell organisation
        • structure of leaf
          • 1)epidermal tissue covered in waxy cuticle
          • 2)upper epidermis is transparent
          • 3)palisade layer has lots of chloroplasts
          • 4)xylem& phloem form network of vascular bonds
          • 5)tissues of leaves adapted to gas exchange
    • enzymes& digestion
      • enzymes
        • carbohydrases
          • convert carbohydrates into simple sugars
          • made in: salivary glands, pancreas, small intestine
        • proteases
          • convert proteins into amino acids
          • made in: stomach, pancreas, small intestine
        • lipases
          • convert lipids into glycerol and fatty acids
          • made in: pancreas, small intestine
      • digestive enzymes
        • break down big molecules eg: starch,proteins and fats
        • make smalller molecules like sugars, amino acids,glycerol& fatty acids.
      • bile
        • neutralises stomach acid & emulsifies fats
          • breaks fat into tiny droplets
      • digestion
        • salivary glands
          • produce amylase enzyme in saliva
        • gullet
          • oesophagus
        • pancreas
          • produces protease, amylase and lipase enzymes
        • stomach
          • produces protease enzyme, pepsin
        • gall bladder
          • bile stored here before being released into small intestine
        • liver
          • bile is produced here. which neutralises stomach acid and emulsifies fats
        • large intestine
          • excess water is absorbed from food here
        • rectum
          • faeces held here until released through anus
        • small intestine
          • 1)produces protease, amylase and lipase enzymes to complete digestion
          • 2)digested food absorbed here
    • the lungs
      • alveoli
        • 1) little air sacs in the lungs. gas exchange happens here
        • 2) blood passing to next alveoli has just returned to the lungs from rest of body.
        • 3) when blood reaches cells oxygen is released from RBC's and diffuses into cells
        • 4)at same time co2 diffuses out of cells into blood then carried back to lungs
      • breathing rate
        • =number of breaths/number of minuites
    • circulatory systems
      • the heart
        • double circulatory system
          • first, right ventricle pumps deoxygenated blood to lungs to take in oxygen
          • second, after blood returns to heart left ventricle pumps oxygenated blood around all other organs of body.
        • heart/pacemaker
          • 1) resting heart rate controlled by group of cells in right atrium acting as a pacemaker
          • 2) cells produce small electric impulses which spread to surrounding muscle cells
          • 3) artificial pacemaker is often used to control heartbeat if natural one doesn't work properly.
        • heart contracts to pump blood around the body
          • 1)blood flows into 2 atria from vena cava and pulmonary artery
          • 2)atria contract pushing blood into the ventricles
          • 3)ventricles contract forcing blood into pulmonary artery and aorta and out of heart
          • 4)blood flows to organs through arteries and returns through veins,
          • 5)atria fills again and cycle repeats
      • blood
        • white blood cells(WBC)
          • defend against infection
            • 1)some change shape and engulf microorganism called phagocytosis
            • 2)some produce antibodies to fight microorganisms as well as antitoxins
            • have a nucleus
        • red blood cells(RBC)
          • carry oxygen from lungs to cells in body
          • shape=biconcave giving large surface area
          • no nucleus
          • red pigment called haemoglobin
        • plasma
          • RBC&WBC are platelets
          • it carries things such as ...
            • carbon dioxide
            • urea
            • hormones
            • proteins
            • antibodies & antitoxins
        • platelets
          • small fragments of cell
          • no nucleus
          • help blood to clot at a wound
          • lack of them can cause excessive bleeding and bruising
      • blood vessels
        • capillaries
          • arteries branch into cappilaries
          • tiny
          • carry blood really close to every cell to exchange substances with them
          • permeable walls
          • supply foos and oxygen and take away waste like co2
          • usually one cell thick increasing rate of diffusion
        • veins
          • capillaries join to form veins.
          • have a bigger lumen then arteries helping blood flow
          • also have valves to help keep blood flowing in right direction
        • rate of blood flow
          • =volume of blood/number of minutes
        • arteries
          • 1) heart pumps blood at high pressure so artery walls are elastic and strong
          • 2) walls are thick compared to size of hole in middle called lumen
          • 3)contain thick layers of muscle to make them strong an elastic fibers to allow them to stretch and spring back
    • cardiovascular disease
      • stents
        • tubes inserted inside arteries keeping them open.
        • a way of lowering risk of heart attack  in people with CHD
        • risk of complication during operation risk of  infection in surgery
        • risk of blood clots developing near stent
          • called thrombosis
      • statins
        • reduce cholesterol in blood
        • advantage
          • reducing 'bad' cholesterol reduces risk of CHD and heart attacks
          • can also increae amount of beneficial type of cholesterol in bloodstream
        • disadvantage
          • long-term drug must be taken regularly
          • can have negative side-effects
          • effect is not instant
      • faulty heart valves
        • 1)valves in heart can be damaged or weakened
          • could cause valve to stiffen so it wont open properly
          • could cause valve to leak allowing blood to flow in both directions
        • 2)severe damage treated by replacing valve can be biological valves from other peopl/animals or mechanical valves
        • 3)replacing valve much less drastic procedure then a whole hesrt transplant.
        • 4)fitting artificial valves is still a major surgery and could cause blood clots
      • artificial blood
        • 1)when someone loses alot of blood heart still pumps remaining red blood cells around
        • 2)a blood substitute to replace the lost volume of blood
        • 3)it would replace the function of the lost RBC's so there should be no need for a blood transfusion.
    • health and disease
      • diseases
        • communicable
          • can spread from person to person or between animals and people
          • caused by bacteria, viruses, parasites and fungi
        • non-communicable
          • cannot spread  between people or animals
          • generally last for a long time and get worse over time
      • factors affecting health
        • whether or not you have a good/balanced diet
        • the amount of stress you are under
        • your life situation; the access you have to medicine and facilities
    • risk factors for non-communicable diseases
      • directly causing disease
        • smoking
          • during pregnancy as well as in general
        • obesity
        • excessive alcohol consumption
        • exposure to certain radiation
      • costly
        • human cost
          • millions of people die from these diseases per year
          • causes families to suffer as well as the individual
        • financial cost
          • NHS researching is very expensive
          • families may have to move to adapt their home to help family member with a disease
          • families income is reduced if the person with the disease worked or dies
            • can affect the country's economy
    • cancer
      • types of cancers
        • benign
          • 1)tumor grows until theres no more room
          • 2)it stays in one place instead of attacking other tissues
          • not normally dangerous or cancerous
        • malignant
          • 2)cells can break of & spread to other parts through the bloodstream
          • 1)tumor grows & spreads to other tissus
          • 3)they invade other tissues everywhere in body forming secondary tumors
          • dangerous and fatal-they are cancers
      • risk factors
        • increase chance of some cancers
        • lifestyle
          • smoking
          • obesity
          • UV exposure
          • viral infection
        • genetics
          • inherit faulty genes
          • mutations in BRCA linked to likelihood of breast and ovarian cancer
    • transpiration & translocation
      • phloem
        • transport food substances made in leaves to rest of plant
        • transport goes in both directions
          • called translocation
            • transport food substances made in leaves to rest of plant
        • made of elongated living cells in end walls
      • xylem
        • made of dead cells joined together
        • carry water&mineral ions from roots to stem&leaves
        • movement of water from roots through xylem and out the leaves
          • transpiration stream
      • transpiration
        • loss of water from plant
        • evaporaion creates slight shortage of water in leaf.
        • more water drawn up  from roots- constant transpiration stream
        • caused by evaporation& diffusion of water from plants surface
      • factors affecting transpiration rate
        • light intensity
          • bright light= greater rate
        • temperature
          • warmer= faster rate
        • air flow
          • better= greater rate
        • humidity
          • drier air= faster rate
      • guard cells
        • kidney shaped &open and close stomata
        • lots of water=turgid less water=flacid
        • adapted for gas exchange controlling water loss within leaf
  • malignant
    • 2)cells can break of & spread to other parts through the bloodstream
    • 1)tumor grows & spreads to other tissus
    • 3)they invade other tissues everywhere in body forming secondary tumors
    • dangerous and fatal-they are cancers

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