Summary AQA A Level Biology- Cell Recognition and the Immune System
35 views 0 purchase
Course
Unit 2 - Cells
Institution
AQA
Book
AQA A Level Biology Year 1 Revision Guide
Comprehensive active recall-style questions that cover the immune system of the new AQA A Level Biology specification. Great for spaced repetition as the questions can be converted to flashcards.
AQA A Level Biology- Transport Across Cell Membranes
AS/A LEVEL NOTES SECTION 1
All for this textbook (9)
Written for
A/AS Level
AQA
A Level Biology
Unit 2 - Cells
All documents for this subject (281)
Seller
Follow
anjalibhambra
Content preview
1. What do lymphocytes do?
Identify and kill pathogens
2. What do lymphocytes recognise?
Antigens
3. What can the different surface molecules enable lymphocytes to identify?
Toxins, pathogens, cells from other organisms of the same species, abnormal body
cells
4. How are lymphocytes prevented from attacking self cells?
The lymphocytes that are complementary to self-cells die
5. What are the remaining lymphocytes complementary to?
Non-self cells
6. What are antigens?
Proteins on the cell surface membrane that trigger an immune response
7. What is antigen variability?
When the pathogen’s DNA mutates and the shape of the antigen changes
1. What is the first line of defence?
Physical barriers like skin
2. What is the second line of defence?
White blood cells
3. What type of responses does the second line of defence have?
Phagocytosis: non-specific
Lymphocytes: specific
4. What is a phagocyte?
Macrophage that carries out phagocytosis
5. Describe the process of phagocytosis
The phagocyte is attracted to the chemical products released by the pathogen, so it
moves towards it along a concentration gradient. The receptors on the phagocyte
bind to the antigen of the pathogen. The phagosome engulfs the pathogen and the
lysosomes move and fuse with the pathogen to form a phagolysosome. The
lysosome contains lysozyme enzymes, which hydrolyse the pathogen and kill it. The
hydrolysis products are absorbed by the cytoplasm.
1. Where do T cells mature?
Thymus
2. What type of response involves T cells?
Cell-mediated response
3. What is an antigen-presenting cell?
A cell that has antigens of a non-self cell
4. Why is the response called cell-mediated?
T cells will only respond to the antigens that are on the antigen-presenting cells
rather than antigens in the blood
5. Describe the process of the cell-mediated response
The phagocyte engulfs and destroys the pathogen. The antigens from the pathogen
present themselves on the surface of the cell to form an antigen-presenting cell. The
T-helper cells have receptors which bind to the antigens on the APC. This stimulates
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anjalibhambra. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.34. You're not tied to anything after your purchase.
