AQA BIOL2 ~ 21 May 2012 ~ AS Biology

Has anyone got any basic notes/mark scheme answers on 'how antibiotics work' and 'antibiotic resistance'?
Text book notes are confusing me, and my notes talk about 'transcription and translation' =/

Antibiotics basically:
- prevent the formation of bacterial cell walls
- some bind to bacterial ribosomes which inhibit protein synthesis.
- some disrupt DNA synthesis during DNA replication.
- some disrupt cell membranes.

All you need to know for antibiotic resitance:
A mutation is present for antibitotic resistance.
This produces an allele for antibiotic resistance.
Non resistant bacteria die.
Bacteria containing resistant bacteria survive and reproduce.
This process is called vertical gene transmission.
This increases the frequency of alleles for bacteria to be passed on to future generations.

Reply 1181

EffKayy

16

Original post by britash

x

Antibiotic resistance
- Mutation for the resistance allele
- Antibiotics kill bacteria which are not resistant, resistant bacteria survives, reproduces, without competition passes allele onto next generation/offspring via horizontal gene transmission (conjugation, plasmid is transferred through pilus, is replicated - through different species) or vertical (down the same species, asexual reproduction so the plasmid replicated - passed onto daughter cells)
- Over time the frequency of the allele for resistance is increased.

Reply 1182

Mocking_bird

11

Not sure if stupid idea or not but... would anyone find it useful to do like a group skype call so we can do the Q&A outloud? (obviously still use this thread too for those who arent able to use skype) :smile:

Reply 1183

EffKayy

16

Original post by Mocking_bird

Not sure if stupid idea or not but... would anyone find it useful to do like a group skype call so we can do the Q&A outloud? (obviously still use this thread too for those who arent able to use skype) :smile:

Don't have a mic =/
What about scriblink ? An online white board where you can draw/type stuff with other users.. etc

Reply 1184

dongonaeatu

Original post by Mocking_bird

Not sure if stupid idea or not but... would anyone find it useful to do like a group skype call so we can do the Q&A outloud? (obviously still use this thread too for those who arent able to use skype) :smile:

whats your skype

Reply 1185

Mocking_bird

11

Original post by EffKayy

Don't have a mic =/
What about scriblink ? An online white board where you can draw/type stuff with other users.. etc

Awh

& Thats just the same as doing it on here really :tongue:

Reply 1186

AtomicMan

13

do we have to know the pressure changes that occur in the mouth of fish that lead to water flow over the gills, and the various structures that play a role in the process?

Reply 1187

WizKidd

2

I'm struggling to understand something...
How is glycogen more compact than starch if it has 1,6 glycosidic bonds which are alot more frequent than the 1,6 bonds in amylopectin. Surely it should be less compact?

Reply 1188

EffKayy

16

Original post by Mocking_bird

Awh

& Thats just the same as doing it on here really :tongue:

But its more fun and interactive! hahaahhhhhhhhhh i want to do itttt :'(

Reply 1189

Dunclr

2

Original post by AtomicMan

do we have to know the pressure changes that occur in the mouth of fish that lead to water flow over the gills, and the various structures that play a role in the process?

NO! Don't do this, my teacher taught us this but its not in the spec its because he hasn't done new power points from old spec.

Also the antibiotic resistance thing, we only need to know the effect of osmotic lysis on weakened cell walls (cross linkages inhibited from forming in growing bacteria, weakened cell wall lower wp in bacteria water moves in by osmosis, no resistance to expansion and can't withstand pressure ——> lysis/bursts). Does my head in when teachers give a load of old questions that include other stuff...

Reply 1190

Mocking_bird

11

Original post by EffKayy

But its more fun and interactive! hahaahhhhhhhhhh i want to do itttt :'(

Lets then!

Reply 1191

roro_tu

Original post by AtomicMan

do we have to know the pressure changes that occur in the mouth of fish that lead to water flow over the gills, and the various structures that play a role in the process?

You don't have to know the pressure changes, that was in the old syllabus. All you have to know is that water passes over the gills, and you have to know the stucture of the gills (fillaments, lamallae etc) :smile:

Reply 1192

username890104

2

Original post by Mocking_bird

Not sure if stupid idea or not but... would anyone find it useful to do like a group skype call so we can do the Q&A outloud? (obviously still use this thread too for those who arent able to use skype) :smile: