Biology Y9 Medicines

Question 1

6 external defences for humans

Answer 1

tears, nose and ear hairs, urinary tract, cilia and mucus in trachea, skin, stomach

Question 2

tears

Answer 2

they are antimicrobial lysozyme chemicals

Question 3

nose and ear hairs

Answer 3

the wax/mucus catch airborne pathogens

Question 4

urinary tract

Answer 4

regular urination helps keep the urethra clear of pathogens

Question 5

trachea (2 external defences)

Answer 5

mucus catches pathogens and cilia are hair-like structures that waft mucus up

Question 6

skin (3 ways of external defending)

Answer 6

antimicrobial secretions (sebum), acts as a barrier, commensal bacteria

Question 7

stomach protect you

Answer 7

hydrochloric acid destroys pathogens

Question 8

scabs protect you

Answer 8

platelets found in blood form a ‘clotting cascade’ whe they detect damage to skin/blood vessel where the platelets, red blood cells and a type of protein form clots/scabs.

Question 9

internal defence

Answer 9

a defence which only plays a role when pathogens/.foreign material gets into healthy tissues

Question 10

internal defence against pathogens (WBCs)

Answer 10

WBC need to recognise there is an infected cell/pathogen:
- do this by recognising foreign antigens (markers on the outside of cells that tell the immune system whether it is local or foreign) - specific and complementary WBC will activate

then：
phagocytes engulf/phagocytose the pathogen (and enzymes are released to digest and destroy it)

lymphocytes produces antitoxins which bind to the toxins produced by the pathogen and neutralise them
lymphocytes also produce antibodies, released into the blood, that target and destroy some pathogens by binding to antigens - kill pathogens, stick pathogens together, mark pathogens for destruction

Question 11

antibodies and antibody production

Answer 11

(a Y-shaped protein that sticks to pathogens to target them for destruction - UNIQUE FOR EACH TYPE OF PATHOGEN)

specialised WBCs take in unique antigens and produce a specific chemical called an antibody in response
the cell clones itself many time so lots of identical cells produce the antibody - concentration within the blood increases

antibodies:
kill pathogens, stick pathogens together, mark pathogens for destruction

Question 12

memory cell

Answer 12

copies of the plasma cell stored for later

remembers the antigen and recognises it faster, for a bigger and quicker response (antibody production)

Question 13

plasma cell (B-lymphocyte)

Answer 13

produce millions of antibodies

Question 14

immune memory (graph of antibody production upon first and second immune response + explanation)

Answer 14

upon 1st exposure to a pathogen, antibody production increases.
at peak antibody production, the pathogen is gone and the antibodies stop being produced
but antibody concentration never reaches 0, memory cells store the antibody
and on 2nd exposure, response / concentration can increase to a greater level and much faster

Question 15

how does vaccination work

Answer 15

a dead or inactive version of a pathogen is injected into the body to stimulate a safe immune response (producing correct antibodies) - then when same pathogen re-enters, they can be produced more and faster to prevent infection (THIS IS IMMUNITY)

Question 16

what is herd immunity

Answer 16

if a large proportion of a population is immune to a disease, the ability for the pathogen to spread is greatly reduced

Question 17

why should you vaccinate (3 reasons)

Answer 17

1) protect yourself from serious diseases
2) cheaper to vaccinate than to treat disease
3) less of a societal burden

Question 18

how to treat bacterial,fungal,viral infection

Answer 18

antibiotics
antifungals
antivirals

Question 19

what do painkiller

Answer 19

relieve the symptoms - dont affect pathogen

Question 20

disinfectants

Answer 20

onto objects and surfaces - destroy most biological tissue/cells including human cells

Question 21

antiseptics

Answer 21

applied to wounds help remove infectious pathogens before they infect the tissue around the wound
means many patients can survivefrom surgery without infection
first attempted by Joseph Lister in late 1800s
only target infective pathogens

Question 22

antibiotics

Answer 22

specifically damage bacteria and not human cells - kills pathogens (bacteria) or stops them reproducing

Question 23

zone of inhibition

Answer 23

area with no microorganism growth
the antibiotic/antiseptic is more effective the larger the ZOI is

Question 24

2 drugs that come from plants

Answer 24

digitalis - foxgloves (strengthens heart in heart failure)
aspirin - willow trees (antiinflamatory,painkiller)

Question 25

what is a good medicine (5 things)

Answer 25

efficient (efficacious), safe, stable, easy to administer, successfully taken and removed from the body

Question 26

what are drugs researched on (in order)

Answer 26

1) cells/tissue cultures 2) small animals e.g. rats, mice, rabbits 3) larger animals e.g. horses, dogs 4) humans

Question 27

stages of clinical trials

Answer 27

1) healthy humans - test for side-effects/toxicity 2) patients with disease - test for efficacy and safety 3) bigger groups of patients - test efficacy and safety 4) peer review

Question 28

peer review

Answer 28

other scientists reviewing the data - to remove bias from the trial

Question 29

double blind trials

Answer 29

there are two groups - one gets the drug and one gets a placebo - people administering the drug dont know which is which - to remove the psychological effect

Question 30

aseptic technique (and examples of it)

Answer 30

the laboratory procedures carried out to prevent the contamination of pure cultures of microorganisms. * disinfect hands / work surface * sterilise Petri dish or culture medium (before use) * pass inoculating loop / forceps through a flame (before use) * work near a flame or work in a fume cupboard * tilt lid (of Petri dish) when placing discs on agar (to minimise contact with air / breath) * secure lid of Petri dish with adhesive tape