Topic 2 Microbes And Defense Against Disease Flashcards
Communicable diseases meaning
Those that can be transferred from one person to another, or from one organism to another
Non-communicable diseases meaning
One that cannot be transferred between people or other orgasims
6 examples of communicable diseases
Measles
HIV
Influenza
Athlete’s foot
Hepatitis
Small pox
Non-communicable diseases
Depression
Cancer
Alzheimer’s
Diabetes
Asthma
Heart disease
3 types of microbe
Fungi
Viruses
Bacteria
Description of structure.
Fungi
Network of threads
Why are fungi dangerous
Responsible for athletes foot infection as well as ringworm and thrush. They can also mould bread and other food
Why are fungi useful
Yeast is the best known fungi it is used in the baking and brewing industries. Fungi is also used for cheese think of blue cheese.
Virus structure
There is a head capsule with DNA with a long tale with an end plate attached
Why is virus dangerous
Make people sick, contagious, spread from one person to another and antibiotics don’t work on viruses
How can a virus be useful
Humans can use them to genetic engineer
Bacteria structure
Cocci are spherical in shape, bacilli are rod shaped, spirochètes are spiral shaped.
How can bacteria be dangerous
Cause food to go off, responsible for diseases like MRSA, salmonella and tuberculosis
How can bacteria be useful
Production of yogurt, treating sewage and genetic engineering.
What is a pathogen
A pathogen is a microbe that causes sickness and disease
Four ways pathogens spread
Airborne eg: breath in infected air (Covid, cold and tuberculosis
Water (drink infected water) cholera and typhoid
Direct contact (touch) chicken pox
Indirect contact (eat infected food) eg:salmonella
Why is it important to wash your hands
So diseases don’t spread as easily (if you don’t use soap bacteria will go on food and everything you touch.)
What aseptic technique
To minimise risk of contamination. When working with agar/ biological samples
Method of aseptic technique
Bunsen setup
Pétri dish on mat close to Bunsen
Using chinagraph pencil, draw cross on outside of base of dish to divide base into 4 quarters
Unscrew lid of agar
Flame mouth of the air bottle in a blue Bunsen flame
Lift up the lid of pétri dish just enough to pour agar in
Close lid as quickly as possible
Gently move dish to make sure the bottom of dish is completely covered in agar
Allow 5-10 mins to set
Decide on 4 sited where to obtain microbes
Use cotton bud to obtain microbes of chosen surface
Return to work area, lift lid and stroke the cotton bud over the surface of the agar
Replace lid on dish
Seal dish with sello tape and label initials, he date and source of microbes
Place in incubator upside down
What do you call a group of bacteria
Colonies
Give an example of where the aseptic technique may be used
Dressing wounds in a environmental health lab
Give 3 measures that are taken when working under aseptic conditions
Bunsen burner on heat proof mat
Sterilise all equipment
Keep lid on as much as possible
Wash hands
Wear gloves and masks
Why is it recommended to work close to a Bunsen when making growth plates
The heat from Bunsen will kill microbes which will stop your results from getting contaminated. And upward flow of air reduces the chance of microbes falling onto plate and contaminating it
Why do you incubate your pétri dish upside down
So condensation falls to the bottom and doesn’t affect resukts
Why would it be dangerous to incubate the growth plates at 37 degrees
Cause you would grow microbes that would be able to survive in the human body (as 37 degrees is body heat) which could make us sick.
Defences against pathogens
Skin forms a protective barrier to prevent microbe entry. Skin secretions are acidic
Microbes on food enter stomach and acid will kill bacteria
Cilia in lungs produce mucus in lungs to trap bacteria. They waft this back to the stomach
Tears have anti septic fluid and kills microbes
Platelets in blood clot and form a scab if skin is broken
White blood cells (phagocytes and lymphocytes) in blood destroy microbes
What happens during phagocytosis
- The phagocyte identifies pathogen
- Migration the phagocyte changes shape and moves towards the bacteria
- Pathogen becomes engulfed by the cytoplasm
- Bacteria is digested by enzymes
What is a outbreak
A sudden rise in the number of cases of a disease
May occur in community or geographical area, or may affect several countries
It may last a few days, weeks or several years
What is a epidemic
Occurs when infectious diseases spread rapidly to many people
What is a pandemic
A global outbreak
It affects wider geographical area, often world wide
What does SARS STAND FOR
Severe Acute respiratory syndrome
How many hundreds of known corona viruses can infect humans
7
What is the virus that cause Covid 19
SARS- Cov -2
Where do viruses spread best
Enclosed spaces
What is the proper name for mistakes that the virus makes when it replicates
Mutations
Why are virus mutations dangerous
They can be better suited in a new environment and won’t die
What disease did milk maids get from the cows they worked with
Cow pox
Jenner seemed to notice milk maids never got small pox why was this
Cow pox made them immune to small pox
Who did Jenner choose to carry out his experiments on and what age was he
James ribs who was 8 3/4
How did Jenner treat the boy
Took puss from a women with cow pox and rubbed the puss onto one of James scratches then infected the boy with small pox and it didn’t make James sick as his plan worked.
