1, alloster1.bmp
"The graph shows the activity of an allosteric enzyme (A) in the absence and (B) the presence of an allosteric effector. The allosteric effector is an inhibitor."
"T"
"Curve B has been shifted to the right by the allosteric effector, so that the enzyme now requires a higher concentration of substrate to achieve the same activity as in the absence of the effector. This is inhibition."
"The graph shows the activity of an allosteric enzyme (A) in the absence and (B) the presence of an allosteric effector. The allosteric effector is an activator."
"F"
"Curve B has been shifted to the right by the allosteric effector, so that the enzyme now requires a higher concentration of substrate to achieve the same activity as in the absence of the effector. This is inhibition."
2, fuels.bmp
"In the fed state muscle can take up glucose for use as a metabolic fuel because glucose transport in muscle is stimulated in response to insulin."
"T"
"Insulin acts to recruit glucose transporters to the cell surface in muscle and adipose tissue, so that in the presence of insulin they can take up and metabolize glucose."
"In the fed state muscle can take up glucose for use as a metabolic fuel because glucose transport in muscle is stimulated in response to glucagon."
"F"
"Glucagon is secreted in the fasting state. Insulin is secreted in the fed state and acts to recruit glucose transporters to the cell surface in muscle and adipose tissue, so that in the presence of insulin they can take up and metabolize glucose." 
3, DRV1.bmp
"The diagram shows the distribution of requirements for a nutrient. C marks the Reference Nutrient Intake (or Recommended Daily Amount)."
"F"
"C marks the average requirement."
"The diagram shows the distribution of requirements for a nutrient. A marks the Reference Nutrient Intake (or Recommended Daily Amount)."
"F"
"A marks the lower threshold intake."
4, DRV2.bmp
"The figure shows the cumulative distribution of requirements for a nutrient. A marks lower reference nutrient intake."
"T"
"A marks the lower reference nutrient intake."
"The figure shows the cumulative distribution of requirements for a nutrient. B marks the Reference Nutrient Intake (or Recommended Daily Amount)."
"F"
"At B the requirements of 50% of the population have been met - this is the average requirement."
5, pyrdh.bmp
"Pyruvate dehydrogenase is a thiamin (vitamin B1) dependent enzyme."
"T"
"This is why thiamin (vitamin B1) deficiency results in impaired carbohydrate metabolism."
"In thiamin (vitamin B1) deficiency pyruvate accumulates in muscle and there is acidosis."
"T"
"As a result of impaired pyruvate dehydrogenase activity there is a considerable increase in plasma concentrations of both pyruvate and lactate, leading to significant acidosis." 
6, retinoic.bmp
"The retinoic acid receptor (RAR) with all-trans-retinoic acid bound can dimerize with the retinoid X receptor with 9-cis-retinoic acid bound."
"T"
"The retinoic acid receptor (RAR) with all-trans-retinoic acid bound can indeed form heterodimers with the retinoid X receptor with 9-cis-retinoic acid bound."
"The retinoid X receptor (RXR) with 9-cis-retinoic acid bound can dimerize with the retinoic acid receptor with all-trans-retinoic acid bound."
"T"
"The retinoid X receptor (RXR) with 9-cis-retinoic acid bound can indeed form heterodimers with the retinoic acid receptor with all-trans-retinoic acid bound."
7, svplot1.bmp
"The graph shows the rate of reaction for an enzyme-catalysed reaction with increasing concentration of substrate (the s/v curve). There is a linear increase in the formation of product as the concentration of substrate increases." 
"F"
"Although at low concentrations of substrate the increase in rate is almost linear with increasing [substrate], this is a hyperbolic curve, and no part is linear."
"The point marked C is the Vmax of the enzyme." 
"T"
"The graph shows the rate of reaction for an enzyme-catalysed reaction with increasing concentration of substrate (the s/v curve). This is the (extrapolated) maximum rate at which the enzyme can act when it is saturated with substrate."
8, lbplot2.bmp
"The graph shows the Lineweaver-Burk double reciprocal plot (1 / v against 1 / [S]) for an enzyme catalysed reaction in the presence of varying concentrations of an inhibitor. Line Q represents incubation in the presence of the highest concentration of inhibitor." 
"F"
"Line Q shows the lowest values for 1 / rate of reaction, and therefore the highest values for rate of reaction. This must be the line in the presence of no inhibitor."
"The graph shows the Lineweaver-Burk double reciprocal plot (1 / v against 1 / [S]) for an enzyme catalysed reaction in the presence of varying concentrations of an inhibitor. Line P represents incubation in the presence of the highest concentration of inhibitor." 
"T"
"Line P shows the highest values for 1 / rate of reaction, and therefore the lowest values for rate of reaction. This must be the line in the presence of the highest concentration of inhibitor."
9, ATPase.bmp
"Endothermic (exergonic) reactions are commonly linked to the phosphorylation of ADP."
"F"
"The phosphorylation of ADP to ATP is itself an endothermic reaction, and is commonly linked (indirectly) to a variety of exothermic reactions."
"Exothermic (endergonic reactions) are commonly linked to the phosphorylation of ADP."
"T"
"The phosphorylation of ADP to ATP is an endothermic reaction, and is commonly linked (indirectly) to a variety of exothermic reactions."
10, muscle.bmp
"Binding of ATP to myosin causes a conformational change so that it no longer binds tightly to actin."
"T"
"Myosin with ADP bound to the head region is tightly bound to actin. When the ADP is replaced by ATP, myosin undergoes a conformational change, so that it is less tightly bound to actin."
"Binding of ATP to myosin causes a conformational change so that binds tightly to actin."
"F"
"Myosin with ADP bound to the head region is tightly bound to actin. When the ADP is replaced by ATP, myosin undergoes a conformational change, so that it is less tightly bound to actin."
11, oxeltrace3.bmp
"The ratio of ATP formed : oxygen consumed (the P : O ratio) for substrates that reduce flavoproteins is approximately 3."
"F"
"One of the protons that is expelled into the inter-membrane space arises in the series of reactions between NAD and ubiquinone; by contrast, flavins reduce ubiquinone directly. This means that there is an additional site for generation of the proton gradient when substrates reduce NAD, and hence more ATP is produced per mol of oxygen consumed. The P : O ratio is approximately 3 when substrates reduce NAD, and approximately 2 when they reduce a flavin."
"If electron transport has been inhibited by cyanide, addition of an uncoupler such as dinitrophenol permits more or less complete consumption of all the oxygen available regardless of the amount of ADP present."
"F"
"If electron transport has been inhibited then regardless of whether or not an uncoupler is present it is not possible to utilize oxygen."
12, git.bmp
"Gastric acid is important in the denaturation of proteins."
"T"
"Denaturation is important to permit proteolytic enzymes to gain access to peptide bonds in proteins, and gastric acid is important in denaturing proteins."
"Gastric acid activates pepsinogen to pepsin."
"T"
"Pepsin is secreted as an inactive precursor (a zymogen) and is activated by either gastric acid or pre-existing pepsin."
13,villus.bmp
"The diagram shows a small intestinal villus. Mucosal cells are proliferating in region A."
"F"
"The mucosal cells proliferate in the crypts (region E), and undergo apoptosis (programmed cell death) and are shed at the tip of the villus (region A)."
"The diagram shows a small intestinal villus. Mucosal cells are proliferating in region E."
"T"
"The mucosal cells proliferate in the crypts (region E), and undergo apoptosis (programmed cell death) and are shed at the tip of the villus (region A)."
14, starch.bmp
"The diagram shows part of a molecule of starch. Amylase catalyses sequential hydrolysis and release of single glucose units (as shown in region A)."
"F"
"Amylase catalyses random hydrolysis of glycoside bonds in starch, leading to formation of glucose, maltose (as in region C) and isomaltose (as in region B)."
"The diagram shows part of a molecule of starch. Amylase catalyses random hydrolysis of glycoside bonds in starch."
"T"
"Amylase catalyses random hydrolysis of glycoside bonds in starch, leading to formation of glucose (as in region A), maltose (as in region C) and isomaltose (as in region B)."
15, blank.bmp
"The glycaemic index is the increase in blood glucose after a test dose of a carbohydrate compared with that after an equivalent amount of glucose."
"T"
"It therefore provides an index of the extent of digestion and absorption of the carbohydrate."
"The term 'resistant starch' is used to describe starch that has a glycaemic index >1."
"F"
"A glycaemic index > 1 is impossible, since the glycaemic index is the increase in blood sugar following a test dose of a carbohydrate compared with that after an equivalent amount of glucose. Resistant starch has a glycaemic index < 1, since it is (partially) resistant to amylase action."
16, glucox.bmp
"Glucose oxidase will give a false positive result for glucose in the presence of vitamin C."
"F"
"Vitamin C will reduce the oxidized dyestuff back to its colourless form, so the glucose oxidase assay will give a false negative result in the presence of vitamin C."
"Alkaline copper reagents will give a false positive result for glucose in the presence of vitamin C."
"T"
"Alkaline copper reagents will react with any reducing compound, and this includes vitamin C."
17, blank.bmp
"The energy cost of physical activity can be determined by measuring carbon dioxide production during the activity."
"F"
"There is a constant amount of energy expenditure per L of oxygen consumed, but the amount of carbon dioxide produced per L of oxygen consumed depends on the mixture of fuels being oxidized. Simple measurement of carbon dioxide production will not permit estimation of energy expenditure over a short time."
"The energy cost of physical activity can be determined by measuring respiratory quotient (RQ) production during the activity."
"F"
"There is a constant amount of energy expenditure per L of oxygen consumed, but the RQ (the amount of carbon dioxide produced per L of oxygen consumed) depends on the mixture of fuels being oxidized. Simple measurement of RQ will not permit estimation of energy expenditure over a short time." 
18, wtloss.bmp
"The blue line shows the theoretical weight loss for a subject whose energy intake is less than energy expenditure. This subject will be in negative energy balance."
"T"
"Energy balance is the difference between energy intake in food and energy expenditure; a negative balance means that intake is less than expenditure - this subject is indeed in negative balance and is losing body weight."
"The blue line shows the theoretical weight loss for a subject whose energy intake is less than energy expenditure. This subject will be in positive energy balance."
"F"
"Energy balance is the difference between energy intake in food and energy expenditure; a negative balance means that intake is less than expenditure - this subject is in negative balance and is losing body weight." 
19, fed.bmp
"In the fed state there is increased secretion of insulin in response to increased glucose in the portal blood."
"T"
"Insulin is the hormone of the fed state. It is secreted in response to an increased concentration of glucose in the hepatic portal vein, coming from the gastro-intestinal tract."
"In the fed state there is decreased secretion of insulin in response to increased glucose in the portal blood."
"F"
"Insulin is the hormone of the fed state. It is secreted in response to an increased concentration of glucose in the hepatic portal vein, coming from the gastro-intestinal tract." 
20, glycol2.bmp
"If phosphofructokinase and fructose 1,6-bisphosphatase are both equally active at the same time there is a nett formation of ATP from ADP and phosphate."
"F"
"With both enzymes equally active at the same time there will be nett hydrolysis of ATP to yield ADP and phosphate."
"If phosphofructokinase and fructose 1,6-bisphosphatase are both equally active at the same time there is a nett loss of ATP and in increase in heat output from the body."
"T"
"This is a so-called 'futile cycle' or substrate cycle, and these two enzymes are regulated in such a way that only one has significant activity at any time. However, there is always some cycling between the two enzymes, both to maintain body temperature and also to permit rapid metabolic regulation." 
21, cori.bmp
"Oxygen debt is caused by the need to exhale carbon dioxide produced in response to acidosis."
"F"
"Oxygen debt represents the increased metabolic activity to provide the ATP required for gluconeogenesis from lactate after vigorous exercise."
"Oxygen debt reflects the need to replace oxygen that has been used in muscle during vigorous exercise."
"F"
"Oxygen debt represents the increased metabolic activity to provide the ATP required for gluconeogenesis from lactate after vigorous exercise." 
22, GSHpx.bmp
 "The drugs and toxins that lead to a haemolytic crisis in favism (genetic defect of glucose 6-phosphate dehydrogenase) all require NADPH for their metabolism."
"F"
"The various compounds that precipitate a haemolytic crisis in favism all undergo redox cycling, producing oxygen radicals that lyse the red cell membrane - but this does not involve NADPH. The role of NADPH is in the activity of glutathione reductase, which is involved in the protection of cell membranes from oxidative damage and lysis."
"Glutathione is a tripeptide."
"T"
"Glutathione is gamma-glutamyl-cysteinyl-glycine, a tripeptide." 
23, blank.bmp
"The Physical Activity Ratio (PAR) for a given activity depends on the subject's body weight."
"T"
"The energy cost of moving a heavier body is greater, so the energy cost of physical activity increases with body weight. Although Basal Metabolic Rate (BMR) also increases with increasing body weight, this is a smaller increase than the increase in the energy cost of activity. PAR is the energy cost of activity expressed as a multiple of BMR, so PAR for a given activity increases with increasing body weight."
"The Physical Activity Ratio (PAR) for a given activity does not depend on the subject's body weight."
"F"
"The energy cost of moving a heavier body is greater, so the energy cost of physical activity increases with body weight. Although Basal Metabolic Rate (BMR) also increases with increasing body weight, this is a smaller increase than the increase in the energy cost of activity. PAR is the energy cost of activity expressed as a multiple of BMR, so PAR for a given activity increases with increasing body weight." 
24, obmort.bmp
"The graph shows the considerable increase in premature mortality from all causes with obesity. Obese people are about twice as likely to die from coronary heart disease as lean people."
"T"
"In the study that produced the graph shown here, people who were 40% over the average weight of the group at the start of the study had a relative mortality from coronary heart disease of 2.1 compared with those between 90 - 110 percent of the average weight of the group."
"The graph shows the considerable increase in premature mortality from all causes with obesity. However, obese people are only about half as likely to die from coronary heart disease as lean people."
"F"
"In the study that produced the graph shown here, people who were 40% over the average weight of the group at the start of the study had a relative mortality from coronary heart disease of 2.1 compared with those between 90 - 110 percent of the average weight of the group."
25, blank.bmp
"One way of gathering evidence linking diet and diseases of affluence is to perform an intervention study. In such a study the effect of giving a nutritional supplement to one group of people is compared with a control group given a placebo."
"T"
"In an intervention study two groups of people, matched as closely as possible for other factors are treated with either placebo or the nutrient (or other intervention) of interest, then followed for 5 - 10 years in order to see whether the treatment has any effect on disease incidence."
"One way of gathering evidence linking diet and diseases of affluence is to perform an intervention study. In such a study people with and without the disease of interest are matched for as many factors as possible, and their diets compared."
"F"
"This would be a case-control study. In an intervention study two groups of people, matched as closely as possible for other factors are treated with either placebo or the nutrient (or other intervention) of interest, then followed for 5 - 10 years in order to see whether the treatment has any effect on disease incidence."
26, wales2.bmp
"The diagram shows changes in diet in rural Wales between 1870 (in blue on the left of each chart) and 1970 (in red on the right of each chart). This is an example of a case-control study."
"F"
"This is a secular study. In a case-control study the aim is to match people with and without the disease of interest as closely as possible, then see what dietary (or other) factors differ between the two groups, and so might give information about factors that may be important."
"The diagram shows changes in diet in rural Wales between 1870 (in blue on the left of each chart) and 1970 (in red on the right of each chart). This is an example of an intervention study."
"F"
"This is a secular study. In an intervention study two groups of people, matched as closely as possible for other factors are treated with either placebo or the nutrient (or other intervention) of interest, then followed for 5 - 10 years in order to see whether the treatment has any effect on disease incidence."
27, cholCHD.bmp
"The diagram shows the relationship between death from coronary heart disease and serum cholesterol. A serum cholesterol concentration < 5 mmol /L is considered to indicate a high risk of developing coronary heart disease."
"F"
"Below 5 mmol /L serum cholesterol is associated with the lowest risk of developing coronary heart disease, and can be considered to be desirable."
"The diagram shows the relationship between death from coronary heart disease and serum cholesterol. A serum cholesterol concentration < 5 mmol /L is considered to be desirable."
"T"
"Below 5 mmol /L serum cholesterol is associated with the lowest risk of developing coronary heart disease, and can be considered to be desirable."
28, cori2.bmp
"The diagram shows glucose oxidation and cycling between glycolysis and gluconeogenesis in three groups of patients with advanced cancer. There is no increase in total glucose oxidation, therefore there must be an increase in fatty acid oxidation in the hypermetabolic patients."
"T"
"There is a very considerable increase in cycling between glycolysis and gluconeogenesis in the hypermetabolic patients. This requires a significant amount of ATP. If glucose oxidation is not increased, the ATP must be coming from fatty acid oxidation. This will result in considerably reduced adipose tissue reserves, leading to significant wasting."
"The diagram shows glucose oxidation and cycling between glycolysis and gluconeogenesis in three groups of patients with advanced cancer. There is no increase in total glucose oxidation, and fatty acid oxidation will be normal in the hypermetabolic patients."
"F"
"There is a very considerable increase in cycling between glycolysis and gluconeogenesis in the hypermetabolic patients. This requires a significant amount of ATP. If glucose oxidation is not increased, the ATP must be coming from fatty acid oxidation. This will result in considerably reduced adipose tissue reserves, leading to significant wasting."
29, stunting.bmp
"Malnourished children may suffer from marasmus, kwashiorkor or marasmic kwashiorkor. Kwashiorkor is defined as weight < 60% of that expected, with oedema."
"F"
"This would be marasmic kwashiorkor, the most serious form of malnutrition. Kwashiorkor is defined as weight 60 - 80% of that expected, with oedema."
"Malnourished children may suffer from marasmus, kwashiorkor or marasmic kwashiorkor. Kwashiorkor is defined as weight 60 - 80% of that expected, with oedema."
"T"
"Kwashiorkor is defined as weight 60 - 80% of that expected, with oedema. Weight < 60% of that expected, with oedema, is marasmic kwashiorkor."
30, Nover.bmp
"Nitrogen balance is the difference between the intake of nitrogenous compounds in the diet and the output of nitrogenous metabolites from the body."
"T"
"This is the definition of nitrogen balance: the simple difference between intake and output. Balance = intake - excretion."
"Nitrogen balance is the ratio of intake of nitrogenous compounds / output of nitrogenous metabolites from the body."
"F"
"Nitrogen balance is the difference between the intake of nitrogenous compounds in the diet and the output of nitrogenous metabolites from the body. Balance = intake - excretion."
31, transam1.bmp
"The diagram shows the reaction of a transaminase. If substrate A is labelled with [14C], the label will be found in product D."
"F"
"Product D is the amino acid formed by transfer of the amino group from substrate A onto substrate C. The carbon skeleton of amino acid A is product B, so this is where the label would be found."
"The diagram shows the reaction of a transaminase. If substrate A is labelled with [14C], the label will be found in product B."
"T"
"Product B is the keto- acid formed when substrate C accepts the amino group from substrate A, so this is where the label would from substrate A will be found."
32, nbal.bmp
"The diagram shows daily nitrogen balance in a group of subjects who were fed mixtures of amino acids designed to provide an adequate amount of total protein, but whose composition was changed each week. In week B the mixture could have contained no glutamate."
"F"
"Glutamate is a non-essential amino acid, and can be synthesized in adequate amounts from the common metabolic intermediate ketoglutarate. Therefore it would still be possible to maintain nitrogen balance on a glutamate-free diet."
"The diagram shows daily nitrogen balance in a group of subjects who were fed mixtures of amino acids designed to provide an adequate amount of total protein, but whose composition was changed each week. In week B the mixture could have contained no aspartate."
"F"
"Aspartate is a non-essential amino acid, and can be synthesized in adequate amounts from the common metabolic intermediate oxaloacetate. Therefore it would still be possible to maintain nitrogen balance on an aspartate-free diet."
-999
Copyright David A Bender 2002

