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Edexcel GCE Biology Unit 4 6BI04 June 2013

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Reply 380
What are your predictions?
I made a list of all the possible topics and looked at the patterns...
Here is my prediction
-Structure of chloroplast
- Light dependant stage of photosynthesis
-how the products of photosynthesis are used
NPP/GPP
Carbon Cycle
Ecology prac
Niches/Succession
Cause of global warming and the effect of global warming
Evidence for global warming
Nature of the genetic code
Post transcriptional change
DNA profiling
Transcription
Bacteria vs Virus
Barriers to infection
TB
Specific immunity
Antibiotics prac
Hospital Acquired infections
Original post by Sravya
What are your predictions?
I made a list of all the possible topics and looked at the patterns...
Here is my prediction
-Structure of chloroplast
- Light dependant stage of photosynthesis
-how the products of photosynthesis are used
NPP/GPP
Carbon Cycle
Ecology prac
Niches/Succession
Cause of global warming and the effect of global warming
Evidence for global warming
Nature of the genetic code
Post transcriptional change
DNA profiling
Transcription
Bacteria vs Virus
Barriers to infection
TB
Specific immunity
Antibiotics prac
Hospital Acquired infections


lol wat is left?
Reply 382
Original post by hussaincute
lol wat is left?


Hydrogen and glucose
ATp used as energy
Trophic levels
biotic and abiotic factors affecting a population
Increase in temperature and development
Canges in allele frequency
Speciation
PCR
Translation
Gel electrophresis
Decomposition- Entemology. temp and rigor mitosis
HIV
Antiobiotic types
Original post by Sravya
Hydrogen and glucose
ATp used as energy
Trophic levels
biotic and abiotic factors affecting a population
Increase in temperature and development
Canges in allele frequency
Speciation
PCR
Translation
Gel electrophresis
Decomposition- Entemology. temp and rigor mitosis
HIV
Antiobiotic types



more or less they r linked to each other except gel electrophoresis n entemology stuff
Reply 384
A students! What's the secret to getting an A?
can somebody explain selection pressure?
Original post by Alia223
A students! What's the secret to getting an A?


Taking the Edexcel D
oh mah gawd,

I'm so nervous!

Buh good luck guys!
Reply 388
Original post by Sravya
Can someone name all the key core pracs?


Gram staining - identifying -ve and +ve bacteria
Brine shrimps - linked to global warming effects on animals and species
Antibiotics - effectiveness (greater the zone of inhibition the more effective it is)
Ecology - Random (usually with quadrat) and systematic sampling (usually with line transect)


Hope I helped!
Goodluck everyone for tomorrow!
Reply 389
Original post by nukethemaly
the official textbook is quite good for it, so have a look through that!


Yeah, thanks! The only thing I'm abit uncertain about is for which circumstances would we talk about the cell mediatiated or the humoral?
Reply 390
Original post by hussaincute
can somebody explain selection pressure?


Selection pressure occurs due to natural selection. So the environment changes due to natural reasons, and that has an impact on the species. Most favorable genes survive - get passed on.

Does that help?
(edited 10 years ago)
Reply 391
Original post by HQazi
Gram staining - identifying -ve and +ve bacteria
Brine shrimps - linked to global warming effects on animals and species
Antibiotics - effectiveness (greater the zone of inhibition the more effective it is)
Ecology - Random (usually with quadrat) and systematic sampling (usually with line transect)


Hope I helped!
Goodluck everyone for tomorrow!


Where does it say in the syllabus we need to knwo about gram stains i though that was old syllabus?
Cause i know zilch about it..could you summerise it for me?
Original post by HQazi
Selection pressure occurs due to natural selection. So the environment changes due to natural reasons, and that has an impact on the species. Most favorable genes survive - get passed on.

Does that helps?


oh ok thanks
Reply 393
Original post by hussaincute
can somebody explain selection pressure?


Selection pressures are changes in the environment like an introduction of new disease or predator which causes some species to adapt better to the change in the environment more than others for example some species may have the allele which is resistant to the new disease and hence are able to survive and reproduce to produce new offspring, they pass on this favourable allele to the next generation and the allele frequency of the allele increases the gene pool of the population of that species meaning more individuals in the population with possess the allele resistant the new disease.

Natural selection always selects for the individuals with traits that makes them easier to survive a change in the environment

So to summarise, selection pressure is basically a change in the environment
Reply 394
Original post by Sravya
Where does it say in the syllabus we need to knwo about gram stains i though that was old syllabus?
Cause i know zilch about it..could you summerise it for me?


Um, I know but we did in class just in case it comes up :smile:
Nothing great. Here it is
It's just another technique used for identifying the type of bacteria (besides the physical appearance, its toxicity + whether its aerobic or anaerobic.

The bacteria are stained - with two results;

Gram-positive bacteria - thick layer of peptidoglycan, which means a more teichoic acid - the acid binds to the crystal violet in the stain and the bacteria will appear blue/purple under a light microscope.

Gram-negative bacteria - thin layer of peptiglycan, which means no teichoic acid. The crystal violet in the stain is readily decolourised and replaced with red safarine, so the cells appears red under a light microscope.
Reply 395
Can someone please list the types of calculations that come up? Never seem to get them right! Thanks


Posted from TSR Mobile
Original post by Alia223
Selection pressures are changes in the environment like an introduction of new disease or predator which causes some species to adapt better to the change in the environment more than others for example some species may have the allele which is resistant to the new disease and hence are able to survive and reproduce to produce new offspring, they pass on this favourable allele to the next generation and the allele frequency of the allele increases the gene pool of the population of that species meaning more individuals in the population with possess the allele resistant the new disease.

Natural selection always selects for the individuals with traits that makes them easier to survive a change in the environment

So to summarise, selection pressure is basically a change in the environment


okay i have got it now thanks alia :smile:
Reply 397
Original post by hussaincute
oh ok thanks


No problem :smile:
Reply 398
Original post by Sravya
Where does it say in the syllabus we need to knwo about gram stains i though that was old syllabus?
Cause i know zilch about it..could you summerise it for me?


Hello, we only need to know about the following experiments:

11 Describe how to carry out a study on the ecology of a habitat to produce valid and reliable data (including the use of quadrats and transects to assess abundance and distribution of organisms and the measurement of abiotic factors, eg solar energy input, climate, topography, oxygen availability and edaphic factors).

17 Describe how to investigate the effects of temperature on the development of organisms (eg seedling growth rate, brine shrimp hatch rates).

18 Describe how to investigate the effect of different antibiotics on bacteria.

"From the Edexcel SNAB Specification"
okay guys please start asking some hard questions now

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