paper 2

Question 1

how are alveoli adapted to their function

Answer 1

-thin walls
-large surface area

Question 2

what is the shape of red blood cells

Answer 2

-biconcave to give a large surface area (curved)

Question 3

what is the function of red blood cells

Answer 3

-have the pigment called haemoglobin which binds to oxygen to make oxyhaemoglobin
-no nucleus to carry more oxygen
-also called erythrocytes

Question 4

how do white blood cells fight against infection

Answer 4

phagocytes-engulf unwelcomed microorganisms
lymphocytes-produce antibodies against the microorganism
-multiply to fight off infection os a blood test will show high white blood cell count

Question 5

what are platelets

Answer 5

small fragments of cell that have no nucleus
-help the blood clot to stop microorganisms fro coming in
-without it can cause excessive bleeding

Question 6

what is plasma

Answer 6

a pale liquid that carries everything:
-red,white blood cells and platelets
-glucose and amino acids
-carbon dioxide,urea,hormones,proteins,antibodies