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.
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.
