There were some difficult questions in this quiz tonight and all the players who scored more than 20 out of 30 were doing really well I would say. The questions were meant to provoke thinking and to be stimulating for you rather than all being simple recall of facts. I want to draw your attention to a few of the main ideas.
1) Antigen is a difficult term to define and students often confuse it with the similar word antibody. Antigens are proteins on the surface of an invading pathogen that can trigger an immune response. (For the sake of completion, antibodies are proteins secreted by B lymphocytes/plasma cells that can bind to antigens and so help eliminate them from the body) Have a look at my blog post on immunity which can be found by searching using the tag cloud.
2) This blog post on immunity will also answer the question about why someone can never suffer from the disease measles more than once. Remember this cannot be due to antibodies remaining in the blood stream after the first exposure. I had measles as a 5 year old but all the antibodies produced in this primary response would have disappeared before my 6th birthday. But I will be protected from measles for the rest of my life because of the memory cells I made all those years ago.
3) Very few players knew that malaria was a disease caused by a protistan parasite. This is disappointing as it is a straightforward factual recall and the Plasmodium parasite for malaria is specifically mentioned in the specification in the section on Five Kingdom classification.
4) Almost everyone got almost all of the digestion questions correct so there is little to add here.
5) I put a few tricky questions on the menstrual cycle into the quiz. Now I do know that the hormones FSH and LH are not specifically mentioned and it is actually unlikely that you will be asked on them. But if you are to understand the menstrual cycle to an A* level, you cannot do this without an appreciation of the four hormones that regulate reproductive function: FSH, LH, oestrogen and progesterone.
I will try to write a post for you all on menstrual cycle just to top up your understanding. Keep your eyes on this blog during the week…..
6) The question about which molecules can be made by a plant in photosynthesis was a bit of a trick question – please accept my apologies. The thing I would like you to appreciate is that photosynthesis doesn’t just make glucose (or the storage polymer starch) but actually makes all the biomolecules in the plants’ cells. Glucose, starch, amino acids, proteins, fats, vitamins and DNA are all made by the plant in photosynthesis. (This is yet another reason why the equation that you have to learn for photosynthesis cannot be 100% correct)
7) There were then a few questions on the kidney. Remember if you are ever asked in any context about the movement of water into or out of cells, there is only mechanism by which this can happen. Water never moves by diffusion and is never pumped into or out of cells by active transport. The only mechanism ever for water movement across a cell membrane is via osmosis.
8) Nitrogen cycle often catches people out. It is a vital topic to revise and understand fully as often questions on it can be superb A* discriminator questions. Learn the four types of bacteria that are involved – my two blog posts on the subject should be a help.
Any more questions/comments/queries, please comment on this post and I will get back you asap.