Labeling paghogens and phagocytosis

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Leah.J
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#1
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#1
When a pathogen enters a body , do the B cells have to produce antibodies to bind to the receptors of these pathogens so that they could be labeled and destroyed by macrophages or can the pathogen be engulfed right away ?
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MARYAM1234567
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#2
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when a b cell produces antibodies to kill a pathogen ...its a humoral response..ie specific immune response
in this one however initially the pathogen is taken into the cell by endocytosis..by lysozymes the all the toxins etc are neutralized except the antigens which are presented on the MHCs
when however the macrophage engulfs the pathogen..its a non-specific immune response
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MARYAM1234567
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#3
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hope this helps!
also antibodies are produces speed up phagocytosis by for example
agglutination
immobilization
opsonisation
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MARYAM1234567
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#4
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#4
antibodies are produced to speed up phagoctosis..****
(Original post by MARYAM1234567)
hope this helps!
also antibodies are produces speed up phagocytosis by for example
agglutination
immobilization
opsonisation
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macpatgh-Sheldon
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#5
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#5
Hi just a clarification to Maryam's input:-

Agglutination, precipitation and immobilization are mechanisms that are used by antibodies to destroy/inactivate antigens and the organisms that display them on their surface.

Opsonisation is a term that describes the facilitation or making easier of the process of phagocytosis by phagocytes [these include not only macrophages [of which the version in the blood are known as monocytes], but also neutrophils, killer T lymphocytes and dendritic cells [the last are also powerful antigen-recognition cells].

Also, primed [kinda activated] T-helper cells, release cytokines that can help B-cells to make antibody [after transforming into plasma cells] or activate macrophages and enable them to kill parasites.

There is also a group of substances called [collectively] complement, which consists of a series of proteins starting with C1q that work in a cascade fashion [rather like the blood clotting factors] to produce a massive number of final molecules. Complement causes mast cells to release chemicals that increase vascular permeability; this allows neutrophils to exit the circulation and phagocytose organisms coated with complement.

M
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Leah.J
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(Original post by macpatgh-Sheldon)
Hi just a clarification to Maryam's input:-

Agglutination, precipitation and immobilization are mechanisms that are used by antibodies to destroy/inactivate antigens and the organisms that display them on their surface.

Opsonisation is a term that describes the facilitation or making easier of the process of phagocytosis by phagocytes [these include not only macrophages [of which the version in the blood are known as monocytes], but also neutrophils, killer T lymphocytes and dendritic cells [the last are also powerful antigen-recognition cells].

Also, primed [kinda activated] T-helper cells, release cytokines that can help B-cells to make antibody [after transforming into plasma cells] or activate macrophages and enable them to kill parasites.

There is also a group of substances called [collectively] complement, which consists of a series of proteins starting with C1q that work in a cascade fashion [rather like the blood clotting factors] to produce a massive number of final molecules. Complement causes mast cells to release chemicals that increase vascular permeability; this allows neutrophils to exit the circulation and phagocytose organisms coated with complement.

M
Alright by my question is , is there a case where the antigen that enters the body is engulfed by phagocytes without being labelled with antibodies ?
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macpatgh-Sheldon
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#7
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#7
Hi Leah,

To address your Q directly, the answer is Yes. (thank you for reiterating your precise difficuilty - you are highlighting a basic inquiry, which we can overlook in the process of investigating highly detailed information).

Although recognition cells will precisely identify the nature of the antigen on the pathogen, for the process of phagocytosis to ensue identification is not required, but just a signal that the pathogen is foreign rather than self. Although the humoral response [mediated by B cells] and the cell-mediated response [mediated by T cells] are inter-related and facilitate each other, phagocytes including T cells, macrophages, and neutrophils ARE EQUIPPED TO ENGULF PATHOGENS without assistance from B cells [these latter cells are, of course, the ones that transform into plasma cells, which then synthesize monoclonal Abs].

If you still have any further problems, please feel free to ask again or PM me.

M
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Leah.J
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#8
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#8
(Original post by macpatgh-Sheldon)
Hi Leah,

To address your Q directly, the answer is Yes. (thank you for reiterating your precise difficuilty - you are highlighting a basic inquiry, which we can overlook in the process of investigating highly detailed information).

Although recognition cells will precisely identify the nature of the antigen on the pathogen, for the process of phagocytosis to ensue identification is not required, but just a signal that the pathogen is foreign rather than self. Although the humoral response [mediated by B cells] and the cell-mediated response [mediated by T cells] are inter-related and facilitate each other, phagocytes including T cells, macrophages, and neutrophils ARE EQUIPPED TO ENGULF PATHOGENS without assistance from B cells [these latter cells are, of course, the ones that transform into plasma cells, which then synthesize monoclonal Abs].

If you still have any further problems, please feel free to ask again or PM me.

M
I do have a few more questions if you don't mind. Why do some cells need labelling and others don't ? And how do I know which is which ? Below is a link to the question paper which started my questions .
https://qualifications.pearson.com/c...e_20110124.pdf Q4 , I answered this using the phagocytosis approach only , and not including anything about labelling

In question 4 , part b , the question says ''stages of phagocytosis" . I don't understand how
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macpatgh-Sheldon
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Hi again,
On looking at the paper in the link you sent, it seems you are referring to Q4 (a)(iii) [which has reference to macrophages] rather than Q4(b) [the latter is a graph Q on prevalence of TB]. However, even that part does not mention "stages of phagocytosis" anywhere! [are you referring to this phrase in the mark scheme?].

Assuming it is in the mark scheme, the stages of phagocytosis would include, (AND KEEP IT SIMPLE):-
1. Identification as foreign matter. (probs NOT in mark scheme because it is strictly BEFORE phagocytosis NOT part of it).
2. formation of outpouches on phagocyte [here macrophage].
3. outpouches [loosely, pseudopodia [Greek pseudo = false; pod = feet]] surround mycobacterium.
4. pseudopodia ends unite to enclose bacterium by endocytosis [Greek endo = inside; cytos = container [here cell]].
5. bacterium engulfed into "bubble" named a phagosome.
6. phagosome ---> phagolysosome ---> lysosome
7. enzymes in lysosome [protease + nuclease] kill and digest bacterium.

TIPS:
1. Put down at least as many points/factors/reasons/ideas as number of marks assigned to Q (part).
2. You do not need much detail ON EACH POINT at A level to earn max marks RATHER THE NUMBER OF SEPARATE POINTS [except in synopsis Q].
3. Read Q carefully twice and say EXACTLY WHAT THE EXAMINER IS LOOKING FOR: Try to read his/her mind, say what they want, as if you are saying "Hi examiner, this is what you were looking for - that is EXACTLY what I have written - can I have a mark pls - THANK you!" [remember these guys are like the fat man/woman in quiz "Chaser" on TV - either you thrash them or they thrash you - MAKE SURE IT IS THE FORMER!!
4. Check out my attached article and practice applying the tips therein with past papers - especially for synoptic Q.
AND
look at my numerous posts over last 2 years.
5. (EDEXCEL are i**ots, as proven time and again (sorry that your teachers could not work this out and did not go for AQA) - their mark schemes are sometimes not only unpredictable but DOWNRIGHT INCORRECT - sorry!)
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Leah.J
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#10
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#10
(Original post by macpatgh-Sheldon)
Hi again,
On looking at the paper in the link you sent, it seems you are referring to Q4 (a)(iii) [which has reference to macrophages] rather than Q4(b) [the latter is a graph Q on prevalence of TB]. However, even that part does not mention "stages of phagocytosis" anywhere! [are you referring to this phrase in the mark scheme?].

Assuming it is in the mark scheme, the stages of phagocytosis would include, (AND KEEP IT SIMPLE):-
1. Identification as foreign matter. (probs NOT in mark scheme because it is strictly BEFORE phagocytosis NOT part of it).
2. formation of outpouches on phagocyte [here macrophage].
3. outpouches [loosely, pseudopodia [Greek pseudo = false; pod = feet]] surround mycobacterium.
4. pseudopodia ends unite to enclose bacterium by endocytosis [Greek endo = inside; cytos = container [here cell]].
5. bacterium engulfed into "bubble" named a phagosome.
6. phagosome ---> phagolysosome ---> lysosome
7. enzymes in lysosome [protease + nuclease] kill and digest bacterium.

TIPS:
1. Put down at least as many points/factors/reasons/ideas as number of marks assigned to Q (part).
2. You do not need much detail ON EACH POINT at A level to earn max marks RATHER THE NUMBER OF SEPARATE POINTS [except in synopsis Q].
3. Read Q carefully twice and say EXACTLY WHAT THE EXAMINER IS LOOKING FOR: Try to read his/her mind, say what they want, as if you are saying "Hi examiner, this is what you were looking for - that is EXACTLY what I have written - can I have a mark pls - THANK you!" [remember these guys are like the fat man/woman in quiz "Chaser" on TV - either you thrash them or they thrash you - MAKE SURE IT IS THE FORMER!!
4. Check out my attached article and practice applying the tips therein with past papers - especially for synoptic Q.
AND
look at my numerous posts over last 2 years.
5. (EDEXCEL are i**ots, as proven time and again (sorry that your teachers could not work this out and did not go for AQA) - their mark schemes are sometimes not only unpredictable but DOWNRIGHT INCORRECT - sorry!)
Ah sorry ! I have mixed 2 questions ,"the stages of phagocytosis" part is in the question linked below
https://qualifications.pearson.com/c...e_20100616.pdf
Q4 part b . I agree about edexcel , in fact everybody agrees , their mark schemes are ridiculous and they change their answers every year *cries Anyways , this is the question that says stages of phagocytosis , and I didn't know how to answer it because I didn't know labelling was part of phagocytosis . Here's the link to the mark scheme for the 1st paper I linked , and yes I was referring to part iii
https://qualifications.pearson.com/c...s_20110309.pdf
I started my answer from the macrophages binding to the pathogen , but the answer in the mark scheme says the bacteria gets labelled first . How do I know when the bacteria gets labelled and when it doesn't ?
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macpatgh-Sheldon
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#11
Firstly, stop sobbing young lady! There is always a solution to any problem. I have seen the Q you need help with - I have had a tough hockey match this evening - I need to go to bed - promise I will help you out in the morning.

Since it is past 10 pm, you take some rest too - Good Night!!
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Leah.J
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#12
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#12
(Original post by macpatgh-Sheldon)
Firstly, stop sobbing young lady! There is always a solution to any problem. I have seen the Q you need help with - I have had a tough hockey match this evening - I need to go to bed - promise I will help you out in the morning.

Since it is past 10 pm, you take some rest too - Good Night!!
alrighty , Thank you
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macpatgh-Sheldon
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Good morning Leah!
("What?" she goes, "This guy is not even going to let me have my sausage, egg and bacon that mum just put on the table!" ).

It's OK - I have had broken shoes a few times, but never knew how to repair them - RE: old saying: "Promise breaker, shoe-maker!". (Just keeping my word of last night).

Let us take it step by step:
The Q on your new link needs some items identified: I would answer as below (KEEP IT SIMPLE)
Name:  Answers 2011 Q4 b Edexcel.jpg
Views: 221
Size:  53.4 KB

SOME MORE INFO, but don't worry if you can't remember this:
(Bacteria have "clever" ways of avoiding phagocytosis e.g. producing a capsule around themselves to prevent phagocyte binding to bacterium (this is singular; plural is bacteria - even BBC TV do not know the difference!), changing enzymes that synthesize the structure of the lipopolysaccharide on its surface to "confuse" phagocyte [e.g. by a bacterium called Campylobacter], producing toxins to poison the phagocyte, etc.

BUT WE ARE NOT "thick" EITHER!
We
1. can neutralize the toxins;
2. we have mechanisms of detecting pathogen-associated molecular patterns (PAMPs) present on bacteria BUT NOT ON HOST TISSUES e.g. endotoxin, peptidoglycan, double-stranded RNA [ALERT: do not let this confuse you on Q asking for differences between DNA and RNA - for A level RNA is single-stranded - sorry!] using pattern recognition receptors (PRRs), and then dealing with the bacteria.
etc etc)

FINALLY, regarding your exact Q (how to tell which cells "label" bacteria) - to be honest, I would struggle to remember, MY ADVICE: don't worry about it (it is highly complex) - what matters in hockey (do you play?) is to get the ball in the net [whether you do it by deflecting a powerful cross creamed across the 'D' by your right wing OR by dribbling past 4 oppo players and flicking the ball into the top right corner of the net is not important!] - it's goals that count!
SIMILARLY:
In A level biology, what matters is, AS I KEEP REITERATING TO MY STUDENTS; mark, mark, mark! Every mark counts - it can mean the difference between 89% (A) and 90% (A*).

BEST OF LUCK!
And you can have your breakfast now (stick it in the microwave first) - it must be freezing after all this - especially in UK weather!

M (specialist biology tutor)
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macpatgh-Sheldon
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@Leah.J

Hi just to let you know, I have answered your Q (kinda!) above.
You have suddenly gone all quiet - are you OK? Or is it that you were offended by my jokes?

M
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Leah.J
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#15
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#15
(Original post by macpatgh-Sheldon)
@Leah.J

Hi just to let you know, I have answered your Q (kinda!) above.
You have suddenly gone all quiet - are you OK? Or is it that you were offended by my jokes?

M
Ahahaha , I forgot about the question . I am in fact Ok , and while I do not get some of your jokes , I appreciate the help , thank you
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