B3 - Infection and response

Question 1

what are pathogens?

Answer 1

microorganisms that enter the body and cause disease

Question 2

what is a communicable disease?

Answer 2

an infectious disease that can be easily spread

Question 3

how do bacteria make you feel ill?

Answer 3

by producing toxins that damage your cells and tissues

Question 4

which is bigger - bacteria or viruses?

Answer 4

bacteria are about 100 times bigger

Question 5

what is a vector

Answer 5

an organism that carries and spreads a disease without getting ill itself

Question 6

name two bacterial diseases

Answer 6

salmonella and gonorrhoea

Question 7

what are some symptoms of salmonella?

Answer 7

fever, stomach cramps, vomiting and diarrhoea

Question 8

what are the symptoms of salmonella caused by?

Answer 8

the toxins that the bacteria produce

Question 9

how can you get salmonella food poisoning?

Answer 9

by eating food that’s been contaminated with salmonella bacteria

Question 10

how is gonorrhoea passed on?

Answer 10

it is a sexually transmitted disease (STD) so it is passed on by sexual contact

Question 11

what are some symptoms of gonorrhoea?

Answer 11

pain while urinating, a thick yellow or green discharge from the vagina or penis

Question 12

what was gonorrhoea originally treated with, and why is this no long as effective?

Answer 12

it used to be treated with penicillin, but this has become trickier now because strains of the bacteria have become resistant to it

Question 13

how can the spread of gonorrhoea be prevented?

Answer 13

people can be treated with antibiotics and should use barrier methods of contraception, such as condoms

Question 14

what are 4 things we can do to reduce or prevent the spread of a disease?

Answer 14

1. being hygienic
2. destroying vectors
3. isolating infected individuals
4. vaccination

Question 15

how does being hygienic help to reduce the spread of a disease?

Answer 15

using simple hygiene measures can prevent the spread of a disease. For example, doing things like washing your hands thoroughly before preparing food or after you’ve sneezed can stop you infecting another person

Question 16

how can isolating infected individuals help to reduce the spread of a disease?

Answer 16

if you isolate someone who has a communicable disease, it prevents them from passing it on to anyone else

Question 17

how can vaccination help to prevent the spread of a disease

Answer 17

vaccinating people and animals against communicable diseases means that they can’t develop the infection and then pass it on to someone else.

Question 18

how do vaccinations work?

Answer 18

vaccinations involve injecting small amounts of dead or inactive pathogens. These carry antigens, which cause your body to produce antibodies to attack them - even though the pathogen is harmless (since it’s dead or inactive). If live pathogens of the same type appear after that, the white blood cells can rapidly mass-produce antibodies to kill off the pathogen

Question 19

what does the MMR vaccine contain?

Answer 19

weakened versions of the viruses that cause measles, mumps and rubella

Question 20

what are the pros of vaccination?

Answer 20

• vaccines have helped control lots of communicable diseases that were once common in the UK. Smallpox no longer occurs at all, and polio infections have fallen by 99%
• epidemics can be prevented if a large percentage of the populations is vaccinated. That way, even the people who aren’t vaccinated are unlikely to catch the disease because there are fewer people able to pass it on. But if a significant number of people aren’t vaccinated, the disease can spread quickly through them and lots of people will be ill at the same time

Question 21

what are the cons of vaccination?

Answer 21

• vaccines don’t always work - sometimes they don’t give you immunity
• you can sometimes have a bad reaction to a vaccine, but this is very rare

Question 22

how do we slow down the rate of development of strains of bacteria that are resistant to antibiotics?

Answer 22

to slow down the rate of development of resistant strains, it’s important for doctors to avoid over-prescribing antibiotics, and that you finish the whole course of antibiotics and don’t just stop once you feel better

Question 23

where was aspirin developed from?

Answer 23

a chemical found in willow

Question 24

what is digitalis used to treat?

Answer 24

heart conditions

Question 25

what was digitalis developed from?

Answer 25

a chemical found in foxgloves

Question 26

what happens in the first stage of drug testing?

Answer 26

1. in preclinical testing, drugs are tested on human cells and tissues in the lab
2. however, you can’t use human cells and tissues to test drugs that affect whole or multiple body systems

Question 27

what happens in the second stage of drug testing

Answer 27

1. they test the drug on live animals. This is to test efficacy, toxicity, and to find the best dosage
2. the law in britain states that any new drug must be tested on two different life mammals. Some people thinl it’s cruel to test on animals, but others believe this is the safest way to make sure a drug isn’t dangerous before it’s given to humans

Question 28

what happens in the third stage of drug testing?

Answer 28

1. the drug is tested on human volunteers in a clinical trial
2. first, it’s tested on healthy volunteers to make sure that it doesn’t have any harmful side affects when the body is working normally
3. if the results are good, the drug is tested on people suffering from the illness. The optimum dose is found
4. the drug is tested against a placebo in a blind, or often double-blind trial
5. the results of drug testing and drug trials aren’t published until they’ve been through peer review. this helps to prevent false claims

Question 29

what are double-blind trials?

Answer 29

trials where neither the patient nor the doctor knows whether the patient is receiving a real drug or a placebo