AQA GCSE BIOLOGY PAPER 1 EXAM. QUESTIONS WITH 100% CORRECT ANSWERS.

What are antibiotics? Drugs that kill or prevent the growth of bacteria without killing healthy body cells What is the problems with antibiotics? Bacteria can mutate and become resistant to an antibiotic How do bacteria make us feel ill? Producing toxins that damage cells and tissues Digitalis Used to treat heart conditions Developed from a chemical found in foxgloves What are monoclonal antibodies? Produced from lots of clones of a single white blood cell They're all identical & will only target one specific protein antigen What is a hybridoma cell? The fusion of a mouse B-lymphocyte with a tumor cell They can be cloned lots to get lots of identical cells - these cells all produce the same (monoclonal) antibodies which can be collected & purified How are monoclonal antibodies used to treat cancer? They're attached to an anti-cancer drug which is given to the patient via a drip. The antibodies target the specific cancer cells as they only bind to tumor markers. The cancer cells are killed but the normal body cells are left untouched What can monoclonal antibodies be used for? 1) Binding to hormones & other chemicals in blood to measure their levels 2) Testing blood samples in laboratories for certain pathogens 3) Locating specific molecules on a cell or in a tissue How are monoclonal antibodies used to locate specific molecules on a cell or in a tissue? 1) Monoclonal antibodies are made that will bind to the specific molecule 2) The antibodies are then bound to a fluorescent dye 3) If the molecules are present in the sample being analyzed, the monoclonal antibodies will attach to them - they can be detected using the dye Problems of Monoclonal Antibodies 1) They have side effects e.g. fever, vomiting & low blood pressure 2) They're not as widely used as treatments due to the many side effects they have Anaerobic respiration - animals Respiration without oxygen Incomplete breakdown of glucose Happens when your body can't supply enough oxygen to your muscles during vigorous exercise Doesn't transfer as much energy as aerobic respiration - glucose isn't fully oxidized Anaerobic respiration equation - animals Glucose --> lactic acid What does anaerobic respiration lead to? Oxygen debt - the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from the cells What forms when oxygen reacts with lactic acid? Carbon dioxide and water How else does the body cope with a high level of lactic acid? The blood that enters your muscles transports the lactic acid to the liver. Here, the lactic acid is converted back to glucose What is muscle fatigue? When over long periods of exercise, the muscles get tired & stop contracting efficiently