As Ocr Biology A Study Guide Questions And Correct Answers

How is haemoglobinic acid formed? {Ans: Haemoglobin accepts the H+ ions produced when carbonic acid is broken down into H+ and HCO3-. Haemoglobinic acid acts as a pH buffer.}How do you interpret the t-test? {Ans: If the value of t is greater than the critical value, you can state that the difference is significant.}Describe the humoral specific response. {Ans: 1) B effector cells with complementary antibodies on their cell surface membrane bind to pathogens, engulf it, and become APCs. 2) T helper cells have CD4 receptors which make them bind to the APC (clonal selection). 3) The T helper cell releases interleukins to activate other B effector cells to divide into plasma cells and B memory cells (clonal expansion). This process is used for antigens found outside of cells, and produces antibodies that are soluble in blood.}Describe cofactors. {Ans: Inorganic. Help enzyme and substrate bind. Don't directly participate. Cl- is a cofactor for amylase. Minerals are sources.}What are aerenchyma cells? {Ans: Special parenchyma (packing) cells found in hydrophytes. Has large air spaces formed by apoptosis of parenchyma.}Describe the process of active transport. {Ans: 1) Molecule binds to receptors in carrier protein on outside 2)