The image shows the male reproduction system.
Where is prostate cancer likely to start developing?
Aerobic capacity is a function of both VO2 max and heart beat rate. A study was conducted to see the effect of regular endurance exercise on maximal aerobic capacity in women. The scatter graphs show the effect of age on VO2 max and maximal heart rate for two groups of women. The endurance-trained group had been competing in long distance races for at least the past two years. The sedentary group performed no regular physical exercise but were healthy and non-obese.
Key: - - endurance-trained - - sedentary
Deduce, with a reason from the data, the age range over which exercise is likely to have beneficial effects.
Compare the effect of age on VO2 max in endurance-trained and sedentary women.
Predict, with a reason, the effect of a programme of regular endurance exercise on maximal heart rate.
State the effect of age on the maximal heart rate shown in this study.
Which of the following parts of the digestive system secrete proteases?
Stomach | Small Intestine | Large Intestine | |
---|---|---|---|
A. | Yes | Yes | Yes |
B. | Yes | No | Yes |
C. | Yes | No | No |
D. | No | No | No |
The equation below shows the production of glucose and galactose from lactose.
Glucose and galactose are examples of monosaccharides. State one other example of a monosaccharide.
There are several different types of carbohydrate. State which type of carbohydrate lactose is.
State the type of chemical reaction that occurs when lactose is digested into glucose and galactose.
Lactase is widely used in food processing. Explain three reasons for converting lactose to glucose and galactose during food processing.
Simple laboratory experiments show that when the enzyme lactase is mixed with lactose, the initial rate of reaction is highest at 48°C. In food processing, lactase is used at a much lower temperature, often at 5°C. Suggest reasons for using lactase at relatively low temperatures.
The graph below shows the levels of hormones during the menstrual cycle.
Identify hormones I and II.
Outline the roles of FSH in the menstrual cycle.
FSH is secreted by the pituitary gland. During pregnancy, FSH secretion is inhibited. Suggest how FSH secretion could be inhibited during pregnancy.
Draw a labelled diagram of the human heart showing the attached blood vessels.
Describe the action of the heart in pumping blood.
Nerves connecting the brain and heart contain neurons that control heart rate. Explain how a nerve message passes from one neuron to another neuron.
The structure of part of the digestive system is shown in the diagram below. [Source: https://wccyusoueahdpdicsyrg.supabase.co/storage/v1/object/public/question-images/images/69c87bb4-31dd-4a17-a292-cd2edda2d48f.jpg Created by Wikipedia user: Madhero88.]
Label the diagram to show the structure that is involved in digestion of proteins in acid conditions (using the letter A).
Label the diagram to show the structure where most absorption of water to prevent dehydration occurs (using the letter B).
Label the diagram to show the structure where most absorption of nutrients occurs (using the letter C).
Explain how the structure of veins is adapted to their function.
Cells defend the body against pathogens. Outline how some of these cells ingest pathogens in the blood and in body tissues.
Type II diabetes is commonly observed in obese humans. Munc18c is a protein related to insulin-mediated glucose transport in skeletal muscle. A group of lean (BMI < 25) and obese (BMI > 30) individuals, all non-diabetic, fasted (had no food) for either 12 hours or 48 hours. Blood glucose concentration and skeletal muscle Munc18c protein content were measured at the end of the fasting period in each individual. The results are shown in the graph. Skeletal muscle Munc 18 c protein content / arbitrary units Key:
State how body mass index is calculated.
Identify the lowest Munc18c protein content in a lean individual after 48 hours of fasting.
Outline the relationship between blood glucose concentration and Munc18c protein content in obese individuals after 12 hours of fasting.
Compare the overall effects of fasting for 12 hours and 48 hours on the blood glucose concentration.
Discuss the hypothesis that obesity is associated with reduced Munc18c protein content.
The following shows an electron micrograph of a liver cell. The electron micrograph is a higher magnification of a liver cell.
Calculate the magnification of the liver cell.
Calculate the actual diameter of the nucleus as marked on the electron micrograph.
State the name of the organelle labelled X.
State its main function.
Outline the significance of the relationship between the surface area and volume of a cell.
Liver cells store extra glucose as glycogen. Explain two steps that have to occur to release energy from glycogen during aerobic respiration.
Skeletal muscle fibres normally respond to insulin by absorbing glucose. Failure of skeletal muscle to respond to insulin is a major factor in the development of type II diabetes. A study was undertaken to investigate the effect of plasma lipids on the process of glucose absorption in response to insulin by muscle fibers. Muscle was bathed in a lipid solution for 5 hours. The lipid was then washed out over the next 3 hours. The graph shows the level of plasma fatty acids and the activity of an enzyme involved in glucose absorption in response to insulin over the period of the study. (Values are means ± standard error) Key: -o- plasma fatty acid → enzyme activity A further study was undertaken to look at the effect of increasing the concentration of insulin on glucose absorption in muscle bathed in lipids. A wide range of insulin concentrations were used in the same type of muscle. Glucose absorption was then measured after 5 hours. Key: □ control muscle with no lipid ■ muscle bathed in lipid [Source: Chunli Yu, et al. (2002), The Journal of Biological Chemistry, 277, pages 50 230-50 236]
Distinguish between type I and type II diabetes.
State the relationship between plasma fatty acid level and enzyme activity.
Calculate the percentage change of enzyme activity after 5 hours exposure to lipids.
Discuss, using the data, whether the effect of lipids on this enzyme is reversible.
Calculate the increase in glucose absorption when insulin is increased from 0 to 10³ μUml⁻¹ for the muscle bathed in lipid.
% of absorption with no insulin
Comment on the effect of increased insulin concentration on glucose absorption in the muscle bathed in lipid.
Some investigators suggest that there is a strong relationship between high lipid diet and the body's response to insulin. Using the data provided, evaluate this hypothesis.