6 Microbiology And Pathogens

Question 1

Give examples of aseptic techniques

Answer 1

Aseptic technique - culturing microorganisms
• to be able to grow a particular strain of bacteria without the growth of unwanted microorganism.
Flame the inoculating loop and streak the culture 3 times while turning
culture = growing
incubating = conditions for growth
flaming the loop - on a blue flame and hold the neck of the broth at an angle dip incoulating loop in alcohol etc? disinfectant used to sterilise surfaces
autpclave- a machine that uses steam under pressure to kill harmful bacteria only tape 2 sides - oxygen still goes on
Wear protective clothing

Question 2

Difference between spread plate and streak

Answer 2

Spread distributes microorganisms evenly with a sterile spreader, streak obtains single colonies by rotating the plate by building layers on 3 separate streaks.

Question 3

What are the ways of culturing microorgnism

Answer 3

• broth cultures - liquid- can grow a large volume of bacteria
• agar cultures - solid - single discrete colony for study
• slective medium - contains a specific mix of chemicals

Broth
adv - can grow large volumes of microorganisms, can provide differing levels of oxygen/nutrients
disadv - can’t view a single colony of bacteria
Agar
adv - solid, so easy to store less likely to spill, easy to identift microorganisms on the plate
disadv - cant add more nutrients for continued growth
batch culture
* bacteria inoculated into growth medium, in fixed volume container - growth rate decreases
* one batch only affected by contamination
continuous culture
* bacteria inoculated into growth medium in container that has culture removed and replace by new medium
* one contamination will contaminate entire container

Question 4

Why is antibiotic resistance happening

Answer 4

1. wrong prescription
2. prescription of antibiotics for viral infections
3. low doses of antibiotics in agriculturel

ways to prevent antibiotic resistence
* not prescribing antibiotics for viral diseases(coughs,colds)
* prescribing the correct ntibiotics
* ensure patients take the full course of antibiotics
* prescribing antibiotics for serious bacterial infections

Question 5

What are the problems for crop farmers

Answer 5

• digesting the stem tissue
  weakens stem, cant harves
• use of nutrients that would usually be stored in seeds
  reduced yield/harvest
• damage to the outer eperdermis of the stem
  increases water loss and makes more susceptible to infections by pathogens

Question 6

Describe b cells and t cells

Answer 6

t cells
shape of receptors are different(specific)
dont produce antibodies

b cells
    have antibodies 
    t cell activates b cell
    t cell releases cytokines that activate b cell
    once b cell is activated it divides by mitosis to form cloned b cells
    all have the same antibodies 
    divide into 2 cells a plasma b cell releasing antibodies
memory cell keeps antibodies on the surface and remains in the blood stream

Question 7

Influenza

Answer 7

• antiviral medication
• antibiotics treat secondary bacteria infection
• painkillers

Question 8

Humoral immune response - release of antibodies into blood

Answer 8

• pathogen collides with b cell that has complementary antigen receptors
• B cells engulf the pathogen
• b cell presents the antigen
• macrophages present antigens on mhc proteins
• macrophages activates T helper cell by binding
• t helper cell activates B cell by releasing cytokinin
• B cell divides to form plasma cell and memory cells