Help! Biology

Help I don’t get this question the answers in Green are correct but I don’t get he logic/ working out behind them plz help me

(edited 1 year ago)

Reply 1

Alonepast

For the first question, the smaller zones are the samples that are bacteria resistant and therefore not effective against MRSA
For the last question, the answer is disc E because it has the largest zone, meaning it would be more effective treating MRSA

Hope this helps
Good luck!

Reply 2

Alevelhelp.1

Original post by Alonepast

Thank you so much you explained so well!
btw what about part ii (the second Q)
I’m stuck I don’t get what methicillins are and the q hasn’t mentioned it

Reply 3

Alonepast

Original post by Alevelhelp.1

Thank you so much you explained so well!
btw what about part ii (the second Q)
I’m stuck I don’t get what methicillins are and the q hasn’t mentioned it

Methicillin is used to treat bacterial infections which are immune to penicillin such as MRSA

Reply 4

Emmmaaaa...

Just to add, for q1 you are comparing the zone of inhibition in the diagram with what the table says
The smaller zones mean less bacteria are killed, So they are more likely to be resistant to that antibiotic

(edited 1 year ago)

Reply 5

Emmmaaaa...

Original post by Alevelhelp.1

Thank you so much you explained so well!
btw what about part ii (the second Q)
I’m stuck I don’t get what methicillins are and the q hasn’t mentioned it

Methicillins are a type of antibiotic.
Mrsa stands for methicillin resistant bacteria, so the bacteria are resistant to the antibiotic, which you need to know before using it.
I guess you need to know what Mrsa stands for

Reply 6

covidiot

the antibiotics diffuse out from the disc through the agar. the further from the agar the lower the concentration of antibiotic there is. bacteria that are resistant to that antibiotic are able to grow at higher concentrations, and so can grow closer to the disc. because antibiotics are different sized chemicals etc they diffuse out differently and so the distances that make it resistant vary by the antibiotic. MRSA stands for methicillin resistant Staph aureus - technically to diagnosis it you would need to know that the bacteria was a Staph aureus and that the zone around the methicillin disc was smaller than the diameter the table suggests makes it resistant.