A level biology AQA

In the markscheme when talking about T cell it say that T cells stimulate B cell. However I thought that T cell activated B cell in some marksheme it also says that. in the exam what should I say.

Reply 1

macpatgh-Sheldon

20

Hi it depends what the Q is asking EXACTLY.
Helper T cells aid B cell function in that they make it easier for B cells to identify the specific antigen and to produce antibodies against it.

Indirectly B cells also aid T cells cos the antibodies produced by the B cells [after B cells transform into a clone of plasma cells] make phagocytosis easier - this is called opsonization.

If you are struggluing with any specific exam Qs, post them here and I shall guide you.
M [specialist biology tutor]

Reply 2

nnn121337

OP

8

Original post by macpatgh-Sheldon

Hi it depends what the Q is asking EXACTLY.
Helper T cells aid B cell function in that they make it easier for B cells to identify the specific antigen and to produce antibodies against it.

Indirectly B cells also aid T cells cos the antibodies produced by the B cells [after B cells transform into a clone of plasma cells] make phagocytosis easier - this is called opsonization.

If you are struggluing with any specific exam Qs, post them here and I shall guide you.
M [specialist biology tutor]

Thanks for the help I have one question what do I need to do get A* in Biology currently I do all the topic question on PMT and just revision in general however I feel like it not enough what should I do.

Reply 3

macpatgh-Sheldon

20

Original post by nnn121337

Thanks for the help I have one question what do I need to do get A* in Biology currently I do all the topic question on PMT and just revision in general however I feel like it not enough what should I do.

PMT is a single "disease"/topic - my advice would be to do past papers on entire syllabus [whole ones]: first read the Qs, then study the relevant topics from books/websites, then sit yourself down to do the paper in near-exam conditions: no more books etc. get mum or dad to time you. Then use mark scheme to mark the paper and keep on doing papers until u r scoring 90+ %.

Check out my numerous posts herein on exam technique, too.

Best of luck - go for it - it is achievable!

Reply 4

nnn121337

OP

8

Original post by macpatgh-Sheldon

PMT is a single "disease"/topic - my advice would be to do past papers on entire syllabus [whole ones]: first read the Qs, then study the relevant topics from books/websites, then sit yourself down to do the paper in near-exam conditions: no more books etc. get mum or dad to time you. Then use mark scheme to mark the paper and keep on doing papers until u r scoring 90+ %.

Check out my numerous posts herein on exam technique, too.

Best of luck - go for it - it is achievable!

You have been a big help i currently in year 12 and i have one more question sometimes i can't see the link between the mark scheme and question asked for e.g A group of scientists investigated the effect of grassy strips on the biodiversity of soil animals.
• They divided a field into plots measuring 25 m × 5 m, with a 5-metre-wide grassy strip of land between each plot. • Each year, they planted wheat in each of the plots. • In the fifth year, they removed samples of soil from each plot where wheat was growing and from the grassy strips around them. • They sorted each soil sample by hand for 40 minutes to collect the soil animals within the sample.(b)

The scientists decided to collect animals from the soil samples for 40 minutes. Suggest how the scientists decided that 40 minutes was an appropriate time.

mark scheme says 1. Repeat soil sorting for different times and record number of species collected;
find optimum time / time beyond which further sorting does not lead to increase in animal species found

Reply 5

macpatgh-Sheldon

20

Original post by nnn121337

You have been a big help i currently in year 12 and i have one more question sometimes i can't see the link between the mark scheme and question asked for e.g A group of scientists investigated the effect of grassy strips on the biodiversity of soil animals.
• They divided a field into plots measuring 25 m × 5 m, with a 5-metre-wide grassy strip of land between each plot. • Each year, they planted wheat in each of the plots. • In the fifth year, they removed samples of soil from each plot where wheat was growing and from the grassy strips around them. • They sorted each soil sample by hand for 40 minutes to collect the soil animals within the sample.(b)

The scientists decided to collect animals from the soil samples for 40 minutes. Suggest how the scientists decided that 40 minutes was an appropriate time.

mark scheme says 1. Repeat soil sorting for different times and record number of species collected;
find optimum time / time beyond which further sorting does not lead to increase in animal species found

DW - you are not the only one struggling with this issue: it can be difficult to predict what the examiner is looking for, esp. with Edexcel board who are sometimes blatantly incorrect! - count yourself v lucky that your school has chosen AQA [the easiest board to score v highly in!].

With this Q, the job is hard I must admit, esp. when you are under pressure in the exam hall. When measuring biodiversity, the greater the number of different species collected, the greater the value of biodiversity, yeah? So, if the scientists collected the highest number of species in 40 minutes, that is the optimal time to use [first point in mark scheme]; if no more species are collected after 40 minutes, then it is conceivable to deduce that as there is no further increase in no. of species thereafter, then this is the time to use. [you are absolutely right - it is easier to work out the link after seeing the mark scheme]!

Let me cite a different example:-
You are given a diagram of a pancreatic exocrine cell, yeah? The ER is labelled X and the Golgi is labelled Y. The Q asks you why X and Y are well-developed/extensive in this cell, OK? [3 mark Q]

Your line of thought should be [and our answer should fiollow this logic]:-

1.

What does ER do? Yes, well done, protein synthesis!

2.

What does Golgi do? Again brilliant: packages secretions [one function]

3.

What is the function of this pancreatic cell? Secretion of digestive enzymes [e.g. amylase + trypsin]

4.

What are enzymes chemically? Yes oc proteins.

Now just say these 3 points to earn full marks i.e. ER makes enzymes; enzymes are proteins; Golgi prepares the enzymes for secretion [into the duodenum].

[you do not need the last 3 words [in sq brackets] or the enzyme names to earn your 3 marks, with me?

Always also try to work out what section(s) of the syllabus is the Q testing your knowledge of e.g. a detailed description is given of a specific enzyme such as e.g. malate dehydrogenase [you do not need to know the full details of the Kreb's cycle these days], and then asks you why this enzyme binds specifically only to malate. DO NOT get thrown by this material outside the syllabus: the Q is testing your knowledge of enzyme action in general, so all you need to do [v briefly] is to mention the binding site + lock and key theory or glove and hand theory: YOU GOT YOUR MARK [dw if you have never heard of malate dehydrogenase, yeah?]

Hope this further boosts your confidence, and enjoy your weekend: you must have heard the song: "Work hard, play hard" lol! :lol: