B5 - Communicatible diseases

Question 1

What is a pathogen?

Answer 1

A micro organism that can cause illness or disease

Question 2

What is the process called how bacteria grow and how does it work?

Answer 2

Binary fission

1) cell replicates its genetic material
2) cell then splits into two

Question 3

List 6 ways is which diseases can be spread.

Answer 3

• airborne
• direct contact
• waterborne
• vector
• std’s
• breaks in the skin

Question 4

What is the method for growing bacteria?

Answer 4

1) sterilise the inoculating loop by heating it until red hot and then leaving to cool
2) dip the sterilised loop into a suspension of bacteria you want to grow
3) then use it to make zig zig streaks across the surface of the agar
4) place the lid immediately on the Petri dish to avoid contamination
5) tape the edges shut (but not all the way round as to not cause anaerobic bacteria) to prevent movement of micro organisms in or out of the Petri dish.
6) incubate the culture at around 25 degrees (never above as you don’t want to grow human pathogens) for several days
7) observe your findings

Question 5

Name three safety issues that must be kept in mind when growing bacteria?

Answer 5

• never culture plates at no more than 25 degrees to stop human antigens from growing
• keep Petri dishes closed once bacteria has grown
• avoid contamination as much as possible

Question 6

What is mean division time?

Answer 6

The average time needed by species of bacteria to divided by binary fission

Question 7

How to work out mean division time?

Answer 7

1) calculate how many times the bacteria divides in the time given - must have the same units
2) calculate the number of bacteria in the population using the equation ( bacteria at beginning x 2^number of divisions)

Question 8

When testing the effects of disinfectants and antibiotics, what shows how effective the antibiotic/ disinfectant was?

Answer 8

The zone of inhibition ( the size of the circle where it has killed bacteria )

Question 9

What were the discoveries of Dr Semmelweis?

Answer 9

-realised that dead bodies and sick people could spread diseases
-he introduced simple hygiene to hospitals in Vienna and death rate fell.

Question 10

Why is nitrogen needed in plants?

Answer 10

Helps growth/ produced proteins

Question 11

Why is phosphorus needed in plants?

Answer 11

Healthy roots

Question 12

Why is magnesium needed in plants?

Answer 12

Chlorophyll production

Question 13

How can you prevent bacterial growth?

Answer 13

Low temp, high temp, disinfectant, antisceptic, anitbiotic

Question 14

Name a few types of viruses and how they’re transmitted.

Answer 14

-measles - airborne
-HIV/aids - bodily fluids in sex
-tobacco mosaic(plants) - physical contact

Question 15

Name some bacteria and how their transmitted?

Answer 15

Salmonella- passed through food chain
Gonorrhoea- transmitted during sex
Malaria - spread by mosquitos

Question 16

Name some types of funguses and how their transmitted?

Answer 16

Athletes foot- direct contact
Rose black spot- airborne in moisture

Question 17

Describe what happens in malaria?

Answer 17

-mosquito bites a human and releases malaria-causing parasites into the human.
-They travelled the liver and damage liver cells
-they also infect the human’s blood cells.
-they make lots of copies of themselves which causes the red blood cells to burst releasing them into the blood.
-the mosquito then bites the human again, taking the parasite into its body to reinfect someone else.

Question 18

What treatment Is there for malaria?

Answer 18

-If diagnosed quickly can be treated with lots of drugs.
-however not always effective as some mosquitoes have become resistant to medicines
-also many drugs aren’t available in countries most effective
-most techniques focus on prevention

Question 19

What are some of the human defences?

Answer 19

Earwax, mucus, tears, hydrochloric acid in stomach, skin, platelets.

Question 20

What is the name of the process when white blood cells ingest microbes and kill them?

Answer 20

Phagocytosis

Question 21

Describe phagocytosis?

Answer 21

1) phagocyte detects bacterium toxins
2) phagocyte extends its cytoplasm around the bacterium
3)phagocyte engulfs bacterium
4) enzymes released to digest bacterium
5) white blood cell gets rid of it to be used or destroyed

Question 22

What is an antibody?

Answer 22

• white blood cells can release
  Chemicals called antibodies which stick to microbes and help to kill them.
• antibodies are very specific for a particular antigen(little lumps on a pathogen).
  -they look like big Ys with a weird shape at the tips

Question 23

Describe how white blood cells ability to make antibodies help them to kill pathogens.

Answer 23

1) the antibodies collide with and bind with the antigens to form a pathogen anitbody complex.
2) the phagocyte is drawn to the pathogen
3) the phagocyte ingest the pathogen-antibody complex

Question 24

What are anti toxins and what do they do?

Answer 24

-An anti-toxin is a chemical that white blood cells release to stop toxins from working.
-like antibodies different antitoxins are needed to deal with different toxins.

Question 25

What are the symptoms and treatment for measles?

Answer 25

Symptoms = Cough, red eyes, runny nose, white spots inside cheek
Treatment = no treatment but there are vaccines.

Question 26

Symptoms and treatment for HIV / aids.

Answer 26

Symptoms = fever, headache, rash, sore throat, will progressively weaken immune system
Treatment = no cure but can be prevented

Question 27

Tobacco mosaic symptoms and treatment.

Answer 27

Symptoms = discoloured leaves
Treatment = no cure

Question 28

Salmonella symptoms and treatment.

Answer 28

Symptoms = diarrhoea, nausea, stomach cramps
Treatment = electrolyte replacement and rehydration

Question 29

Gonorrhoea symptoms and treatment

Answer 29

Symptoms = pain urinating, discharge from genitals
Treatment = antibiotics or preventation

Question 30

Athletes foot symptoms and treatment.

Answer 30

Symptoms = Rashes, itchy patches
Treatment = creams and sprays

Question 31

Rose black spot symptoms and treatment.

Answer 31

Symptoms = black marking on leaves
Treatment = remove infected leaves

Question 32

Malaria symptoms and treatment

Answer 32

Symptoms = headaches, fever
Treatment = medicine or prevent getting bitten by mosquitoes

Question 33

How does the number of antibodies differ between the first and second exposure to an antigen (1st one is a vaccine)

Answer 33

• for second one the gradient at start is steeper
• more antibodies are produced (higher peak)
• second one decreases slower (shallower gradient)