biology topic 3

• Having the risk factor of non-communicable disease (NCD)

  Increases the chance of getting NCD, but it is not certain that you will get it
• Risk factors that increase disease

  • Lifestyle
  • Substance in environment
  • Substance in bodies
• Risk factors that cause NCD and the diseases they cause

  • Smoking - lung cancer, lung disease, cardiovascular disease
  • Obesity - diabetes
  • Alcohol - liver disease, deteriorating brain function
  • Alcohol and smoking during pregnancy - NCD
• Cancer can be caused by radiation
• How NCD is costly


  • Millions of people suffer from NCD and die every year
  • People with NCD have a low life expectancy which can affect family
  • The cost for NHS for researching and treating NCD is expensive
  • Family may move houses to make the member with NCD more comfortable and easier for them
  • If the member with NCD dies or stops working the family income will decrease
  • If lots of people have NCD there will be a decrease of people working which will decrease the country's economy
• Types of cancer


  • Benign tumour
  • Malignant tumour
• Benign tumour


  Growth of abnormal cells which stay in one place usually the thin membrane and does not invade other tissues, not cancerous nor dangerous
• Malignant tumour


  Grows and spreads in neighbouring healthy tissues, cells break off and spread into bloodstream which allows the tumour to invade healthy parts of body, it is fatal and very cancerous
• Risks of getting cancer

  • Smoking - lung cancer
  • Obesity - kidney cancer, liver cancer
  • UV exposure - skin cancer
  • Viral infection like hepatitis - liver cancer
• Genetics with faulty genes can increase the risk of getting cancer
• Plant cell organisation


  • Epidermis layer
  • Palisade layer
  • Xylem and phloem
  • Spongy mesophyll tissue layer
  • Meristem tissue
  • Guard cell
• Epidermis layer


  Covers the whole plant, is transparent so light can enter, has a waxy cuticle to reduce water loss from evaporation
• Palisade layer


  Contains a lot of chloroplast so photosynthesis mainly takes place here
• Xylem and phloem


  Vascular bundle that delivers nutrients and water to leaves and rest of plant
• Spongy mesophyll tissue layer

  Has lots of air gaps to allow gases to diffuse in and out of cell
• Meristem tissue


  Stores stem cell
• Guard cell


  If plant loses water the guard cell loses water and becomes flaccid, making the stomata close and reducing water vapour from escaping. If plant has lots of water the guard cell fills up until it becomes plump and turgid, making stomata open and water vapour leave
• Phloem


  Columns of long cells with pores to allow cell sap to flow through, transport food made in leaves to other regions or storage region, deliver food in both directions (translocation)
• Xylem


  Made of dead cells with hole in middle and strengthened by lignin, transport water and mineral ions from root to stem and leaves (transpiration)
• Translocation


  Movement of food molecules in phloem tissue
• Transpiration


  Loss of water from the plant
• Factors affecting transpiration


  • Light intensity
  • Temperature
  • Air flow
  • Humidity
• Light intensity


  The brighter = higher rate of transpiration
• Temperature


  The higher the temp = faster rate of transpiration
• Air flow


  The better the air flow around leaves the greater the transpiration rate
• Humidity


  The drier the leaves the higher the rate of transpiration
• Communicable disease


  Where it spreads quickly (affects animals and plants)
• Main communicable diseases


  • Bacterial
  • Viral
  • Protist
  • Fungal
• Bacteria


  Very small cells, reproduce rapidly, produce toxins which damage cells and tissues causing illness
• Virus

  Very small, not a cell, reproduce rapidly by living in host cells and using their machinery to produce copies that burst the cell
• Protist


  Single-celled, mainly parasites that live on other organisms to cause damage, often transferred by vectors
• Fungus


  Single-celled, grow and penetrate human skin and plant surfaces to cause disease
• Pathogen spread methods


  • Air
  • Water (contaminated)
  • Direct contact
• Viral diseases


  • Measles
  • HIV
  • Tobacco mosaic virus
• Measles


  Spread by inhaling droplets from infected people, symptoms include red rash and fever, can lead to pneumonia and brain infection, prevented by vaccine
• HIV


  Spread by sexual contact or exchanging fluids like blood e.g drug share needles, attacks immune cells, leads to AIDS which makes the body prone to infections and cancer
• Tobacco mosaic virus


  Affects tomato plants, causes mosaic pattern and discoloration on leaves, reduces photosynthesis
• symptom of hiv


  flu like symptoms
• what happens during hiv

  -virus attack immune cell, damage to immune system

  – unable to defend the body against disease

  -Prone to cancer and infections

  -This stage body is at last stage HIV infection / aids
• how to prevent HIV

  antiretroviral drugs