Edexcel GCE Biology Unit 4 6BI04 June 2013

Though phagocytes are responsible for the 'non-specific' response, labeling a pathogen results in quicker detection. Also, labeling helps T-killer cells detect harmful pathogens and kill them.
Labeling can be done by antibodies produced by B cells, or by synthetic antibodies (that are injected into the body - i.e artificial passive immunity), provided they match the shape of the antigen.

ok, so labelling is only enabled by free antibodies , either secreted by b cells and specific to a previously encountered antigen. or injected (vaccin) right? and thanks for the answer!

Reply 101

Trinitybabe

Original post by TheUsername42

A vacuole is basically just many fused vesicles. If you really wanted to impress the markers - if you were answering a vesicle question you could include the fact there are different types of vesicles such as clathrin coated or COP I/II coated vesicles (this is something you will learn at uni if you do a bio-related degree). You may also find it useful to use www.thestudentsolutions.co.uk , may provide a good resource for your exams.

thanks, but i don t think the marking scheme implied that difference < i dont get what they mean. is there a difference in terms of permanent or temporary life in cytoplasm?

Reply 102

SKK94

1

Original post by Trinitybabe

thanks, but i don t think the marking scheme implied that difference < i dont get what they mean. is there a difference in terms of permanent or temporary life in cytoplasm?

Well, in general terms, a vesicle is mainly responsible for transporting substances within a cell, and a vacuole is for temporary storage(except in plant cells, where the vacuole is for storage but, is alsopermanent).
So, considering lifetime in the cytoplasm, we could say a vesicle exists for a shorter time than a temporary vacuole in the cytoplasm.

(edited 10 years ago)

Reply 103

SKK94

1

Original post by Trinitybabe

ok, so labelling is only enabled by free antibodies , either secreted by b cells and specific to a previously encountered antigen. or injected (vaccin) right? and thanks for the answer!

Yup

Reply 104

SKK94

1

Could someone please explain the concept behind peat bogs, and how they are used?

Reply 105

sapna09

What synoptic topics should we definitely revise?

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Reply 106

AHarris

Could some give an ordered list of the specific immune response
Thanks

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Reply 107

username1054067

2

Urgh, this is such a **** module.

I love Photosynthesis and Immunity
But the actual exam is bull, full of graphs, data etc sdfgsdg dh fdgh.

That's not even biology!!!!!!!! :angry:

sooooo wish it was actual biology.

Reply 108

Obtas

12

Original post by sapna09

What synoptic topics should we definitely revise?

Posted from TSR Mobile

Plant fibres - xylem and sclerenchyma, structure of cellulose, natural selection, structure of a chloroplast, structure of DNA and proteins (ie primary, secondary and tertiary). Erm sorry thats all I can think of for now

Reply 109

hannahhannah1

Hey guys quick question, in one of the papers there was a true/false table thing and one of the statements was 'I added nitrate fertiliser so that the microorganisms could synthesise nucleic acids.' which was in fact 'True.' Idk i'm probably being oblivious, but it seems so random! How does it fit into our course? Is there a topic i'm missing or something? :s-smilie:

Reply 110

Volltorb

1

Original post by Trinitybabe

ok, so labelling is only enabled by free antibodies , either secreted by b cells and specific to a previously encountered antigen. or injected (vaccin) right? and thanks for the answer!

Basically, B cells dont directly make antibodies, its the plasma cells. Each antigen corresponds to a specific B cell,with the specific receptor. So essentially specific antibodies are made that label specific (corresponding) antigen on the bacterium/Pathogen.
Macrophages contain receptors that are complementary to these antiboides that label the pathogen; they can easily engulf them

And remember each B cell produce only one type of antibody :smile:

(edited 10 years ago)

Reply 111

SKK94

1

Original post by hannahhannah1

Hey guys quick question, in one of the papers there was a true/false table thing and one of the statements was 'I added nitrate fertiliser so that the microorganisms could synthesise nucleic acids.' which was in fact 'True.' Idk i'm probably being oblivious, but it seems so random! How does it fit into our course? Is there a topic i'm missing or something? :s-smilie:

I think it's from Unit 2, the topic on minerals and plants, you know, where we had to learn the uses of different minerals in plants?
Like nitrates for making nucleic acids/proteins, magnesium for chlorophyll and so on :smile:

(edited 10 years ago)

Reply 112

Volltorb

1

Original post by hannahhannah1

Hey guys quick question, in one of the papers there was a true/false table thing and one of the statements was 'I added nitrate fertiliser so that the microorganisms could synthesise nucleic acids.' which was in fact 'True.' Idk i'm probably being oblivious, but it seems so random! How does it fit into our course? Is there a topic i'm missing or something? :s-smilie:

Plants use nitrate to make nitrogen for the production of nucleic acids (DNA RNA) and this involves protein synthesis and other fundamental reactions to take place. Its from unit 2; to do with mineral ions and how they affect the plants.
Correct me if im wrong guys.

Reply 113

AHarris

Could some give an ordered list of the events in the specific immune response

Thanksss

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Reply 114

SKK94

1

Original post by AHarris

Could some give an ordered list of the events in the specific immune response

Thanksss

Posted from TSR Mobile

See post #49 (page 3) :smile:

Reply 115

Huntx

****ing hell I have a clash between bio 4 and Eco 4. Mother****

Reply 116

Volltorb

1

Original post by SKK94

Could someone please explain the concept behind peat bogs, and how they are used?

Its the pollen in the peat bogs, the pollen comes form a certain species that live however long ago...By estimating the time it was released using carbon dating, it tell us how old it is and from which species it comes from. This specific species has certain ecological conditions that it grows in, which tells us what the weather may have been back then; all this helps determine what the weather was like.

The pollen
-outer coating is very resistant to decay
-Dosnt grow/decay much if not at all in anaerobic and acidic conditions
-Is abundant (in the ground/peat bogs), therfore easily obtained

(edited 10 years ago)

Reply 117

HQazi

9

Original post by murtz14

Did anyone take this in January? Possibly the worst paper I've ever seen, pure dirt

It was awful. Dirt is the right word :frown:

Reply 118

SKK94

1

Original post by Volltorb

Its the pollen in the peat bogs, the pollen comes form a certain species that live however long ago...By estimating the time it was released using carbon dating, it tell us how old it is and from which species it comes from. This specific species has certain ecological conditions that it grows in, which tells us what the weather may have been back then; all this helps determine what the weather was like.

The pollen
-outer coating is very resistant to decay
-Dosnt grow/decay much if not at all in anaerobic and acidic conditions
-Is abundant (in the ground/peat bogs), therfore easily obtained