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A level Biology: Post your doubts here!
- Thread starter XPFMember
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our mircoscope was faulty..there was no epg scale given to measure ratios..and i also did not draw vascular bundles in the plan diagram
Same.Our microscopes were faulty too...
Complain to your center then. They will make contact with CIE. This matter isn't something to be taken lightly.
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The Practical was really tough but just escaped Q1 part b(i).... but else Q2 was very easy... Wish get B
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Want Some important guide for AS structure paper on 22 Oct... Kindly do
reply..
reply..
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I did..they did want to accept their fault first..then at last they agreed to a written complaint from me..lets see what happens.
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by the way did any one draw vascular bundles in the plan diagram??
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Okhay so people,
I heard that there's this summary of all the bio chapters, here somewhere on the community. I was unable to find it .. So if someone could please direct me towards that or somehow u know like get me there, it'd be WELL APPRECIATED.
Thank you
I heard that there's this summary of all the bio chapters, here somewhere on the community. I was unable to find it .. So if someone could please direct me towards that or somehow u know like get me there, it'd be WELL APPRECIATED.
Thank you
Okhay so people,
I heard that there's this summary of all the bio chapters, here somewhere on the community. I was unable to find it .. So if someone could please direct me towards that or somehow u know like get me there, it'd be WELL APPRECIATED.
Thank you
Okhay so people,
I heard that there's this summary of all the bio chapters, here somewhere on the community. I was unable to find it .. So if someone could please direct me towards that or somehow u know like get me there, it'd be WELL APPRECIATED.
Thank you
- Messages
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- 1,241
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- 153
THAAAAANK YOUUUU SOO MUCH
- Messages
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- 1,241
- Points
- 153
Can someone please explain me .. That as the pathogen or the antigen develops resistance against an antibiotic .. How is it related to the change in DNA structure .. Or like mutation .. Of that pathogen ?
Help would be really appreciated .. Detail answer please .. Thank you
Help would be really appreciated .. Detail answer please .. Thank you
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Phagocytosis is the process of ingestion by the phagocytes of any foreign material that is recognised by the body as 'antigens'.
A usual past paper question would be about asking how it actually works and 'cell membrane' fusion to form vesicles definitely needs to be mentioned.
http://papers.xtremepapers.com/CIE/...and AS Level/Biology (9700)/9700_s05_qp_2.pdf
Q2 (a)(i) is the one with dots the phloem sieve tube?
Q2 (a)(i) is the one with dots the phloem sieve tube?
Yes!
The process of phagocytosis:
1. In the tissues attacked by pathogens mast cells produce histamine which causes inflammation and attract neutrophils.
2. Iflammation means that blood vessels dilate so more blood reaches site of attack and making capillaries leaky so phagocytes can ne squeezed out.
3. Neutrophils attracted towards the antigens by chemotaxis
4. Bacteria may be attracted directly to the membrane of neutrophil or marked by an antibody or plasma protein as the surface of neutrophil contains receptors for antibodies and plasma protein where they can be fiitted to stimulate the process of phagocytosis. (plasma protein used in marking antigen in known as complement or opsonin protein)
5. Pathogen is engulfed and taken in a vesicle by endocytosis.
6. Lysosomes fuse with the phagocytotic vesicle where bacteria are killed by free radicals, H2O2 and digested by enzymes.