2024 AQA A LEVEL BIOLOGY
IMMUNITY UNIT 1, AQA AS LEVEL
BIOLOGY EXAM QUESTIONS WITH
CORRECT ANSWERS
What are the three surfaces of contact- where pathogens enter our body?
and how do they get in? - CORRECT-ANSWERS1) gas-exchange system = if
you breathe in air that contains pathogens, most of them will be trapped in
mucus lining the lung epithelium. Some pathogens are able to reach the
alveoli where they can invade cells and cause damage.
2) Skin = if you damage your skin, pathogens on the surface can enter your
bloodstream. blood clots prevent pathogens from entering.
3) Digestive system = if you eat or drink food that contains pathogens. Some
will survive from the acidic conditions of the stomach, and invade cells of the
gut wall and cause disease.
Explain the process of phagocytosis. - CORRECT-ANSWERS1) A phagocyte
recognises the antigens on a pathogene
2) The cytoplasm of the phagocyte moves round the pathogen, engulfing it.
3) The pathogen is now contained in a vacuole or a vesicle in the cytoplasm
of the phagocyte.
4) A lysosome fuses with the phagocytic vacuole and the lytic enzymes break
down with the pathogen
5) The phagocyte presents the pathogens antigens, it sticks the antigens on
its surface to activate other immune system cells.
What is the cellular and humoral response? - CORRECT-ANSWERSCellular =
The T-cells and other immune system cells that they interact with e.g
phagocytes , form the cellular response
Humoral - B cells and the production of antibodies form the humoral
response.
Explain what is meant by a primary response. - CORRECT-ANSWERSThe
primary response is slow because there aren't many B-cells that can make
the antibody needed to bind to it.
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 Elitaa. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.99. You're not tied to anything after your purchase.
