Biology Hormonal Communication Exam Questions And Correctly Well Defined Answers.

The following terms relate to the metabolism of carbohydrates in the human body: 1 gluconeogenesis 2 glycogenesis 3 glycolysis Which of these processes will be stimulated when glucagon is released into the bloodstream? - correct answer 1 gluconeogenesis Studies on the effects of hCG in humans have revealed the following information: Many different tissues are affected by hCG. Susceptible cells have glycoprotein receptors on their cell surface. These receptors are complementary to the shape of hCG molecules. What can be concluded from this information? - correct answer (hCG is a) peptide hormone / hCG is not a lipid-based hormone (1) (hCG) binds to cell surface receptor (1) idea that cell signalling is involved in action of hCG (1) (hCG) uses cAMP / second messenger, to bring about response in cell (1) Another hormone produced during pregnancy is oestrogen. Oestrogen is lipid soluble. Which molecule does oestrogen interact with when it changes cell activity? - correct answer DNA A hydatidiform mole is a rare complication of pregnancy that can occur after implantation of the fertilised egg in the uterus. It results in excessive production of hCG and damage to the lining of the womb, leading to miscarriage. Suggest how a hydatidiform mole could increase hCG above normal levels. - correct answer idea that (hydatidiform mole) cells produce more hCG than normal (1) (due to) expression / up regulation, of genes (1) synthesising more, hCG / protein(s) (1) idea that other tissues could be stimulated to produce more hCG than normal (1) Growth hormone (GH) is a peptide hormone that stimulates cell reproduction and regeneration in humans and other animals. It is produced during development to increase muscle mass and increase bone size and density. GH can also be used in farming to enhance yields from different animals. Design an experiment to investigate the following hypothesis: "Varying the concentration of GH injected affects the yield of meat from farmed chickens" You must explain how you would obtain valid data. - correct answer Independent variable - concentration of GH injected Dependent variable - rate of growth Control variables - animal species, foodstuff, (named) conditions Trial populations over several months Control group to ensure validity of conclusions Method for assessing growth - e.g. % mass change or growth rate to allow comparability Different species of chickens should be investigated Ensure food is consistent across all trial groups Sample size needs to be large enough to reduce effect of anomalies Ethical concerns - chickens should be reared in humane conditions Consideration of potential negative effects on chickens, e.g. larger muscle mass, so may be unable to move as easily Heart rate can be increased by the hormone adrenaline, which binds to cardiac cells. Describe how adrenaline binds to cardiac cells - correct answer (binds to) receptor in, cell surface / plasma, membrane (1) glycoprotein (1) The published Glycaemic Index value (GI) of a carbohydrate-containing food, rates the food on a scale from 0 to 100 according to how much it raises blood glucose concentration after it is eaten. To determine the GI value of a test food: 10 healthy people fast overnight the test food containing 50 g of carbohydrate is eaten blood samples are taken every 15 minutes for the next two hours and blood glucose concentrations are measured a value known as the iAUC is obtained from these measurements the GI value is calculated by dividing the iAUC for the test food by the iAUC for glucose and multiplying by 100 the mean of the GI values from all 10 people is the published GI value for that food Why is it necessary for the people to fast overnight before the start of the test? - correct answer to ensure that the (blood) glucose, is at its, base (level) / low (level) / normal (level); The iAUC for glucose is used to calculate the GI value of the test food. For this calculation to be valid, a number of variables must be controlled when determining the iAUC for glucose. Suggest two variables and how they may be controlled. - correct answer 1 50 g of glucose must be used; 2 the data for glucose should be obtained for the same (ten) people (to eliminate differences between individuals); 3 same age / same age range (as people in original test); 4 same gender balance (as in original test); 5 have the same level of activity (during the test); 6 be at the same temperature; 7 don't eat or drink anything else (during the test); 8 same, body mass / BMI; Why does the procedure use the mean of the GI values to obtain the published GI value for the food? - correct answer it reduces the effect of, outliers / anomalous values; A common misapprehension was that by calculating a mean it would identify or eliminate any anomalous results rather than reducing the effect of an atypical