Topic 5 - Health, Diseases and the development of medicines

• World health Organisation define health as a state of complete physical, mental and social well-being.
• Communicable disease: A disease that can be spread from one person to another and is cause by a pathogen
• Non-communicable diseases: diseases that cannot be passed from person to person it is not caused by pathogens but could be from genetics
• Virus have a protein coat with genetic material

  • not cells
  • infect living things to reproduce
• When virus attach to the host cell and inject genetic material:

  1. lytic pathway: normal one and replicate
  2. Lysogenic pathway: replicate the genes, eventually enter the lytic pathway
• Lytic pathway:

  1. virus attach to host cell and inject genetic material
  2. virus use proteins and enxyme in the host cell to replicate it's genetic material and produce component of new viruses
  3. The viral component assemble
  4. host cell splits, releasing viruses and infect more cell
• Lysogenic pathway::

  1. The injected genetic material is incorporated into the genome (DNA) of host cell
  2. The viral DNA replicate when host cell divides = no new virus + inactive
  3. trigger (e.g. a chemiscal) causes the viral genetic material to leave the genome and enter the lytic pathway
• Pathogens: organisms that cause communicable diseases.
• Sxually transmitted infections: infection spread through sexual contact
• Human defences physical:

  • skin: blood clots and seal cut prevent pathogen in
  • Hairs and mucus in nose: trap particles containing pathogens
  • Mucus in trchea and bronchi trap pathogens and cilia wraft mucus up the throat so it can be swallowed
• HUman defence ( chemical) :

  • hydrochloric acid: kills most of the pathogen swallowed
  • Lysozymes kills bacteria on the surface of the eye
• Specific immune respond: the immune response to a specific pathogen

  1. Every pathogen has antigens (unique )
  2. B-lymphocytes produce protein call antibodies. It blind in the pathogens and can be later destroyed by other white blood cells
  3. Antibodies are produced rapidly and flow around to find similar pathogens
  4. Meomory lymphocytes is also produced
• Secondary immunse resond:

  • faster and stronger than the first one
  • trigger fast production of antibodies
  • often get rid of a pathogen before have any symptoms
• Immunisation: process that makes an individual resistant to become ill from a specific communicable disease

  Injection:

  1. dead or inactive pathogens
  2. antibodies produce by B-lymphocytes
  3. If live pathogen attacks, memory lymphocytes recognise them and quickly produce anti-bodies
• Advantage of immunisation:

  • prevent individual from getting ill
  • create herd immunity ( high percentage of population is immunised so spread of diseases is limited = less outbreak of diseases
  • wiped out diseases e.g. small pox
• Disadvantge of immunisation:

  • don't always work
  • Bad reaction to vaccination e.g. sweling / fever
• Plant defences (physical):

  • waxy cuticle on leave: barrier to pest and pathogen + water collecting
  • Cellulose cell wall: barrier
• Plant defence (chemical):

  • Antiseptic chemicals kill bacterial and fungal pathogen
  • Plant produce chemicals to deter pest from feeding on them
  • used to treat human e.g. aspirin = pain and fever, quinine = malaria
• Ways t detect or identify plant diseases:

  1. observation: look at plant's symptoms and identify the diseases
  2. Experimentation: alter plant's environmental conditions and observe any changes to see if environment is causing plant symptoms or a pathogen
  3. analysing distribution: identifying the disease by looking at distribution of affected plant (e.g. random distribution suggest airbone pathogen)
  4. Diagonstic testing: test sample of plat tissue in lab for presence of particular pathogen
• DIagonostic testing:

  • use monoclonal antibodies to detect antigens from the pathogens
  • test for pathogens DNA to check is there pathogen DNA in it
• Monoclonal antibodies: produced from lots of clones of a single white cell (B-lymphocytes)

  • all identicle
  • specific to one protein antigen
• Pregnancy test:

  • If pregnant, produce hormone called HCG
  • your wee has antibodies to that hormone attach to blue head and the strip aso have antibodies to the hormone
  • If pregnant, the hormones bind to the antibodies on blue bead
  • urine move up the stick and bead and hormone bind to the antibodies of the strip = get stuck = blue
  • If not pregnant = doesn't stick = nothing happen
• Detecting cancer cells and blood clot:

  radioactive element attach to the monoclonal antibodies that bind to tumour markerss or rpoteins in clot. Location of radioactivity then found with a special camera
• treating cancer:

  • anti-cancer drug attached to monoclonal antibodies
  • antibody blind to tumour markers as tumout marker is unique to cancer cells
  • substance is deliver to the cancer cell
  • this drug doesn't kill any normal body cell
• Antibiotics:

  • only kill bacteria
  • They inhibit processes in bacteria cells, but not in host organism
• Developing new medicine:

  • scientist use knowledge of how diseases work to identify molecule used to treat it. New drug is then developed through testing
  • Preclinical tesing: test on human cell and tissue --> live animal
  • Clinical testing: test on healthy volunteers, dosage gradually increase from a very low initial does --> test on ill patients, finding optimum dose
  • New drug approved by medical agency when test show it's safe and effective
• Clinical trials are double - blind (doctors and patients)

  • some are given placebo: substance that are like the drug but don't do anything
• Risk factor for non-communicable diseases

  • lack of exercise: linked to cardiovascular diseases and obesity
  • poor diet: malnutrition e.g. obesity, scurvy ( lact of vitamin C)
  • drinking too much alcohol: liver diseases and cardiovascular disease
  • smokng: cardiovascular disease, lung disease and cancer
  • These factor interact
• Effects of non-communicable diseases:

  • local: high level of disease put pressure on local hospitals
  • national: expensive for NHS to treat everyone and reduce number of people who can work (affect economy)
  • Global: cost associae with high level of diseases can hold back a country development
• BMI = mass(kg) / (height(m))^2
• Waist to hip ratio = waist circumference (cm) / hip circumference (cm)

  ratio above 1.0 for men and 0.85 for woman indicate abdominal obseity
• Cardiovascular diseases:

  1. Too much blood cholesterol cause fatty deposits to build up in arteries
  2. lead to blood clot and block of blood flow
  3. cause a heart attack oor stroke
• Treatment for CVD:

  • LIfestyle change: + reduce risk
  • Statins: +reduce cholesterol, slowing down the formation of fatty deposits - liver damage
  • Anticoagulants: + blood clot less likely - excessive bleeding
  • Antihypertensive: + reduce blood pressure, limiting damage to blood vessels - headache, fainting
• Treatment for CVD (surgical procedures) :

  • Stent (tube put in artery): + keep artery open so blood flow isn't blocked -scar tissue may form + take drugs to stop blood cloting
  • Coronary bypass (healthy blood vessel bypass the blocked section): + reduce risk of heart attack - risk of bleeding, clot, infection
  • Donour heart: +treat heart failure - risk from surgery + drugs taken to stop body rejecting it
• Prepare an aseptic culture of bacteria:

  1. A Petri dish and some agar jelly are sterilised in an autoclave to kill any unwanted microorganisms in them
  2. Hot agar jelly is poured into the Petri dish and allow to cool and set
  3. An inoculating loop is passed through a hot flame to sterilise it
  4. The loop is used to transfer bacteria to the agar jelly
  5. The Petri diish is taped shut to stop microorganism in the air getting in. It is stored at 25 and upside down to stop drops of condensation falling on the agar surface.
• Experiment:

  • prepared agar plate with even covering of bacteria
  • paper disc soaked with different types or concentration of antibiotics, antiseptics or plant extracts (independant variable)
  • inhibitation zone - no bacteria growing (dependant variable)
  • measure the diameter of inhibition zone
• More effective antibiotic (independant variable) = wider inhibition zone
• How does cancer develops:

  • mutations in DNA, cell division is uncontrolled
• Name for the tips of the root which many cell divide by mitosis

  meristem
• Plant root cells contain an enzyme that joins glucose molecules together to make starch.

  Devise a plan to investigate the effect of pH on the activity of this enzyme.

  • independant variables
  • test for presence of starch
  • test at set intervals