Transport (Humans)

Question 1

How do vaccines work?

Answer 1

• A dead version of the virus is injected into the bloodstream
• Lymphocytes will recognise the antigens on the dead pathogen, and the lymphocyte specific to it will divide, producing many antibodies and leaving memory cells
• If a live version of the virus enters the body, the memory cells will provide a faster and greater immune response and the infection should be dealt with before symptoms are exhibited

Question 2

What are platelets?

Answer 2

Fragments of cells found in the blood plasma

Question 3

What are platelets for and how do they work?

Answer 3

• They are involved in blood clotting and forming scabs where the skin has been cut/punctured
• They collect at the site of the wound and clump together, as well as release chemicals which cause soluble fibrinogen proteins to convert into insoluble fibrin which forms an insoluble mesh across the wound, trapping red blood cells and forming a clot
• The clot dries into a scab, which remains until new skin has grown underneath it

Question 4

What are the purposes of clotting?

Answer 4

• It prevents continued blood loss from wounds
• Scab formation prevents the entry of pathogens into the bloodstream which could cause infection