Biology Paper 1

• what is aerobic respiration? Process of producing energy from glucose in the presence of oxygen.
• 2 functions that immune system has?

  • destroys pathogens and any toxins they produced
  • the immune system protects us incase the same type of pathogen invades us again
• 3 functions that white blood cells have?

  1. phagocytosis
  2. antibodies
  3. antitoxins
• Process in Phagocytosis?

  1. white blood cell detects chemicals released from pathogen and moves towards it
  2. white blood cell ingests (takes in) the pathogen
  3. uses enzymes to destroy the pathogen
• What are antibodies?

  • = protein molecules produced by white blood cells
  • very specific -> will only protect against specific pathogens
  • can remain in the blood for a long time -> can protect us if the same pathogen infects us again
• Antibodies process?

  1. white blood cells release the antibodies
  2. antibodies stick to the pathogen
  3. trigger the pathogen and destroy it
• Antitoxins process?

  1. White Blood Cell produces antitoxins
  2. Antitoxins stick to toxin molecules and prevent them from damaging cells
• Bacteria - Gonorrhea

  • An STD
  • sexual contact
  • thick yellow or green discharge from vagina or penis
  • pain when urinating
  • prevent - condoms, having unsafe sex
  • treatment - penicillin (lots of types of gonorrhea so they become resistant to penicillin) but now theres more expensive antiobiotics
• Bacteria - Salmonella

  • food poisoning
  • alive chicken and contaminated food
  • fever ,stomach cramps, affect intestines, vomiting and diarrhoea
• Bacteria?

  • bad and helpful bacteria (e.g digest our food)
  • 100x smaller
  • can reproduce by themselves
  • might produce toxins and make us ill by damaging cells/tissues
• Viruses - TMV (tobacco Mosaic virus)

  • affects tobacco and tomato plants
  • patches of leaves get discoloured
  • therefore photosynthesis can't take place and can't produce enough sugar - can't grow properly
• Viruses - HIV (human immunodeficiency virus)

  • spread by sexual contact and changing body fluids
  • fever, tiredness, aches, inadequate immune system
  • treatment - antiretroviral drugs which prevent cells from replicating
• Viruses - Measles

  • passes through coughs and sneezes
  • red rashes, fever
  • can be fatal
• Viruses

  • not made of cells
  • nonliving organism
  • can't reproduce by themselves
  • 10,000x smaller than animal and plant cells
• Virus - process to make us ill

  • enter one of our cells
  • create multiple copies of itself
  • virus makes cell burst , making us ill
• Vaccinations - benefits?

  • protect us from diseases
  • controls common diseases
  • prevents outbreaks
• Vaccinations - negatives?

  • don't always work
  • don't grant full immunity
  • can have bad reactions - swelling etc
• How do vaccinations work?

  • small amount of dead, inactive pathogens are injected into the body
  • this stimulates the lymphocyte to produce the correct antibodies to destroy the antigens
  • therefore memory cells remain and can produce antibodies quicker
• When are new vaccinations needed?

  when some viruses mutate into new strains
• Example of a vaccination?


  MMR (measles , mumps and rubella) vaccine
• Fungi

  • eukaryotic
  • multi and unicellular
  • E.G - mushrooms (have hyphae producing spores which can penetrate skin and cause diseases) and yeast (makes bread rises) and penicillium
• Fungi - Rose Black Spot

  • causes purple/black spots to form in leaves or roses
  • this reduces ability to photosynthesis and therefore don't grow so well
  • it spreads in water and in wind
  • treatment : chop infected leaves and spray with fungicides
• Protists

  • eukaryotes
  • multi and uni cellular
  • transported by vectors
• Protists - Malaria

  • caused by a parasitic protists so it needs a host to survive
  • transported by mosquitoes as they suck up parasites
  • fever, headache and can be fatal
  • treatment - use insecticide/repellent sprays, use mosquito nets and kill them
• Why can't antibiotics treat viruses?

  • they are specifically made to kill bacteria
  • this is because viruses live in cells so you would have to destroy your own cell to destroy the virus
  • therefore making us more ill
• Why do antibiotics become less useful?

  • the bacteria develops resistance to the antibiotic
• Drugs - Thalidomide

  • it cures morning sickness
  • however it causes deformity
  • used to treat leprosy now
• What can drugs do ?

  • treat the disease (e.g antibiotics - penicillin from penicillium moulds)
  • Relieve the symptoms (e.g painkillers - paracetamol and aspirin from willow trees which lower fevers)
• Cancer - Malignant Cancer?

  • it is cancer
  • fatal
  • spreads to different parts of the body quickly
  • can create secondary tumours
• Cancer - Benign

  • not cancer
  • spreads slowly
  • stays in one area
• Cancer?

  • a abnormal mass of cells
• Cancer - risk factors?

  • Obesity - bowel, liver and kidney
  • UV light - skin (from sun, UV radiation damages skin cells)
  • Smoking - lung, cervical, mouth, stomach
  • Genes - BRCA Gene - increases risk of ovarian and breast
  • Alcohol - liver
• What is the job of the non specific defence system ?

  to prevent pathogens from entering the body
• Non specific defence systems - skin

  • outer layer of skin consists of dead cells - make it difficult for pathogens to penetrate
  • produces an oily substance called sebum which can kill bacteria
  • forms a scab when damaged to prevent pathogens from entering into the skin
• Non specific defence system - nose

  • hairs and mucus trap pathogens
  • cilia wafts the mucus upwards to the throat when its swallowed into the stomach (tiny hairs covered in mucus)
• Non specific defence system - stomach

  • contains hydrochloric - kills pathogens
• Pathogens

  • = microorganisms that cause infectious disease
  • spread - through direct contact , contaminated water and food and air (carried in tiny droplets that expel when we cough or sneeze)
  • how to stop spreading - be hygienic, kill the vectors (mosquitos), vaccine everyone and isolate/quarantine
• Communicable diseases

  • diseases that are infectious and spread from person to person
  • causes by pathogens
  • e.g cold, malaria, meningitis
• Non communicable diseases

  • diseases that aren
• Non communicable diseases

  • diseases that aren't infectious and don't spread between people
  • e.g - asthma, cancer, diabetes, coronary heart disease