AQA AS LEVEL BIOLOGY LATEST ACTUAL EXAMA

AQA AS LEVEL BIOLOGY LATEST ACTUAL EXAMA ALREADY GRADED A+ 2024 The infected person will show symptoms of the disease while the body produces enough of the right antibody to overcome the infection. T-cells and B-cells produce memory cells. Memory T-cells remember the specific antigen and will recognise it second time round. Memory B-cells record the specific antibodies needed to bind the antigen. The body is now immune. Explain what is meant by the secondary response. - ANSWER-If the same pathogen enters the body again, the immune system will produce a quicker, stronger immune response. Memory B-cells divide into plasma cells that produce the right antibody to the antigen. Memory T-cells divide into the correct type of T cells to kill the cell carrying the antigen. The secondary response often gets rid of the pathogen before you begin to show any symptoms. Explain how monoclonal antibodies target cancer - ANSWER-1) Cancer cells have antigens called tumour markers that are not found on body cells. 2) Monoclonal antibodies can be made that will bind to the tumour markers. 3) You can also attach anti-cancer drugs to the antibodies 4) Antibodies come into contact with the cancer cells and bind to the tumour markers 5) This means the drug will acuumulate in the body where there are cancer cells. 6) side effects of an antibody based drug are lower than other drugs because they accumulate near specific cells What are the three ways a pathogen can damage hosts cells? - ANSWER-1) rupturing them to release nutrients inside them 2) breaking down nutrients inside the cell for their own use. This starves and eventually kills the cell. 3) replicating inside the cells and bursting them when they're released What are the two ways pathogens cause disease? - ANSWER-1) production of toxins 2) cell damage