Topic 2: Molecular biology

Describe the control for this experiment.

What are the type of reaction and the product(s) shown in this reaction?

Draw a molecular diagram of alpha-D-glucose.

With reference to the diagram, identify one example of catabolism.

Cells produce a large variety of proteins with different sequences of amino acids. Explain how this is done.

Explain the shape of the polypeptide chain at X.

Draw a circle on the diagram to enclose the carboxyl group.

Describe the control for this experiment.

Describe the control for this experiment.

What are the type of reaction and the product(s) shown in this reaction?

Draw a molecular diagram of alpha-D-glucose.

Draw a molecular diagram of alpha-D-glucose.

With reference to the diagram, identify one example of catabolism.

With reference to the diagram, identify one example of catabolism.

Cells produce a large variety of proteins with different sequences of amino acids. Explain how this is done.

Cells produce a large variety of proteins with different sequences of amino acids. Explain how this is done.

Explain the shape of the polypeptide chain at X.

Explain the shape of the polypeptide chain at X.

Draw a circle on the diagram to enclose the carboxyl group.

Draw a circle on the diagram to enclose the carboxyl group.

Water has important solvent properties. Explain these properties using an example to illustrate your answer.

Calculate the change in temperature in each cup after 20 minutes.

Uncovered:

Covered with wet tissue paper:

State two conditions that must be the same for each cup at the start of the experiment.

Explain, with reference to the thermal properties of water, how this experiment helps demonstrate how humans respond to overheating.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Water has a specific heat capacity of 4.2 J g^–1 K^–1 at room temperature, a latent heat of vaporization equal to 2257 J g^–1, and a boiling point of 100 °C. What are the specific heat capacity, latent heat of vaporization and boiling point of methane?

[Source: © International Baccalaureate Organization 2019]

Outline how the carbon dioxide could be removed from the water used to irrigate the plant.

Outline how hydrogen bonds form in water.

Outline how the properties of water make it an ideal transport medium in plants.

The activity of amylase from two bacterial species and a fungus was measured at different pH levels and constant temperature. The results are shown in the graph.

[Source: Held, P., 2012. Enzymatic Digestion of Polysaccharides. Part II: Optimization of Polymer Digestion and Glucose Production in Microplates. Available at: https://www.agilent.com/cs/library/applications/enzymatic-digestion-of-polysaccharides-part-II-5994-3304EN-agilent.pdf.]

Which statement about the effect of pH on amylase can be concluded?

A.  A. oryzae amylase has the highest optimum pH.

B.  A change in pH affects amylase most in B. licheniformis.

C.  The optimum pH is 6 in B. subtilis.

D.  Amylase activity at pH 8 is the lowest in B. licheniformis.

State how many water molecules are shown in the diagram. 

State how many water molecules are shown in the diagram. 

Outline how the carbon dioxide could be removed from the water used to irrigate the plant.

Outline how the carbon dioxide could be removed from the water used to irrigate the plant.

Outline how hydrogen bonds form in water.

Outline how hydrogen bonds form in water.

Outline how the properties of water make it an ideal transport medium in plants.

Outline how the properties of water make it an ideal transport medium in plants.

The activity of amylase from two bacterial species and a fungus was measured at different pH levels and constant temperature. The results are shown in the graph.

[Source: Held, P., 2012. Enzymatic Digestion of Polysaccharides. Part II: Optimization of Polymer Digestion and Glucose Production in Microplates. Available at: https://www.agilent.com/cs/library/applications/enzymatic-digestion-of-polysaccharides-part-II-5994-3304EN-agilent.pdf.]

Which statement about the effect of pH on amylase can be concluded?

A.  A. oryzae amylase has the highest optimum pH.

B.  A change in pH affects amylase most in B. licheniformis.

C.  The optimum pH is 6 in B. subtilis.

D.  Amylase activity at pH 8 is the lowest in B. licheniformis.

Water has important solvent properties. Explain these properties using an example to illustrate your answer.

Water has important solvent properties. Explain these properties using an example to illustrate your answer.

Calculate the change in temperature in each cup after 20 minutes.

Uncovered:

Covered with wet tissue paper:

State two conditions that must be the same for each cup at the start of the experiment.

Explain, with reference to the thermal properties of water, how this experiment helps demonstrate how humans respond to overheating.

Calculate the change in temperature in each cup after 20 minutes.

Uncovered:

Covered with wet tissue paper:

State two conditions that must be the same for each cup at the start of the experiment.

Explain, with reference to the thermal properties of water, how this experiment helps demonstrate how humans respond to overheating.

State how many water molecules are shown in the diagram. 

State how many water molecules are shown in the diagram. 

State how many water molecules are shown in the diagram. 

State how many water molecules are shown in the diagram. 

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Water has a specific heat capacity of 4.2 J g^–1 K^–1 at room temperature, a latent heat of vaporization equal to 2257 J g^–1, and a boiling point of 100 °C. What are the specific heat capacity, latent heat of vaporization and boiling point of methane?

[Source: © International Baccalaureate Organization 2019]

The Framingham heart study was an observational study that went on for 20 years. The following data were produced.

[Source: adapted from Gillman et al., Margarine intake and subsequent coronary heart disease in men.
Epidemiology, 1997 Mar; 8(2): 144–9]

Which conclusion can be drawn, based on these data?

A. It is better to eat margarine than to eat butter.

B. The more margarine consumed, the greater the incidence of coronary heart disease.

C. Butter is a natural product whereas margarine is hydrogenated vegetable oil that leads to coronary heart disease.

D. Margarine causes more heart related deaths than butter.

Which type(s) of fatty acid in the diet is/are positively correlated with an increased risk of coronary heart disease?

I.   Saturated

II.  Trans unsaturated

III. Cis unsaturated

A. I only 

B. I and II only

C. II only

D. II and III only

Which fatty acid would occur in a trans fat?

[Source: © International Baccalaureate Organization 2018]

Which molecule represents a lipid?

[Source: © International Baccalaureate Organization 2018]

The diagram shows two polysaccharides, formed from condensation of many glucose molecules.

[Source: © International Baccalaureate Organization 2019]

What are the names of X and Y?

Using the nomogram, what is the minimum mass at which a woman of height 165 cm would be considered overweight?

[Source: Copyright 1978, George A. Bray. Used by permission]

A. 72

B. 67

C. 64

D. 61

Explain how measurement of BMI could help to assess whether a person has an increased risk of type II diabetes.

The chart shows ranges of body mass index (BMI) for children and teenagers.

[Source: Centers for Disease Control and Prevention, About Child & Teen BMI. Available at:
https://www.cdc.gov/healthyweight/assessing/bmi/childrens_bmi/about_childrens_bmi.html.]

A 9-year-old boy has a height of 120 cm and weighs 28.8 kg. What weight category is he in according to his BMI?

A. Underweight

B. Healthy

C. Overweight

D. Obese

Comment on the total energy content of the two diets.

Distinguish between the two diets.

Calculate, showing your working, the percentage change in mean cholesterol level after one week on the study diet.

. . . . . . . . . . . . . . . . . . . .%

The hypothesis made before the study was that saturated fats in the diet affected the risk of coronary artery blockage and diabetes. Using all the data in question 1, evaluate whether this hypothesis is supported by the study.

Draw a molecular diagram of alpha-D-glucose.

The table shows the range and classification of body mass index (BMI) values, as shown in the nomogram.

[Source: © All rights reserved. Canadian Guidelines for Body Weight Classification in Adults. Health Canada, 2003. Adapted and reproduced with permission from the Minister of Health, 2021.]

What is the approximate reduction in body mass that a person of height 155cm and mass 95kg would have to lose to reach normal body mass?

A. 10kg

B. 22kg

C. 36kg

D. 54kg

Describe the structure of starch.

The chart classifies individuals according to their height and mass.

[Source: InvictaHOG, 2006. Body mass index chart. [chart online] Available at: <https://commons.wikimedia.org/w/index.php?curid=1208092> [Accessed: 4 April 2019].]

Based on the information provided, which individual is most at risk of diseases associated with the accumulation of excessive body fat?

Broad beans are rich in starch and cellulose. Compare and contrast the structure of starch and cellulose.

The diagrams show how monosaccharide molecules are joined to form chains in two polysaccharides.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

Using the nomogram, what is the minimum mass at which a woman of height 165 cm would be considered overweight?

[Source: Copyright 1978, George A. Bray. Used by permission]

A. 72

B. 67

C. 64

D. 61

Explain how measurement of BMI could help to assess whether a person has an increased risk of type II diabetes.

Explain how measurement of BMI could help to assess whether a person has an increased risk of type II diabetes.

The chart shows ranges of body mass index (BMI) for children and teenagers.

[Source: Centers for Disease Control and Prevention, About Child & Teen BMI. Available at:
https://www.cdc.gov/healthyweight/assessing/bmi/childrens_bmi/about_childrens_bmi.html.]

A 9-year-old boy has a height of 120 cm and weighs 28.8 kg. What weight category is he in according to his BMI?

A. Underweight

B. Healthy

C. Overweight

D. Obese

Comment on the total energy content of the two diets.

Distinguish between the two diets.

Calculate, showing your working, the percentage change in mean cholesterol level after one week on the study diet.

. . . . . . . . . . . . . . . . . . . .%

The hypothesis made before the study was that saturated fats in the diet affected the risk of coronary artery blockage and diabetes. Using all the data in question 1, evaluate whether this hypothesis is supported by the study.

Comment on the total energy content of the two diets.

Distinguish between the two diets.

Calculate, showing your working, the percentage change in mean cholesterol level after one week on the study diet.

. . . . . . . . . . . . . . . . . . . .%

The hypothesis made before the study was that saturated fats in the diet affected the risk of coronary artery blockage and diabetes. Using all the data in question 1, evaluate whether this hypothesis is supported by the study.

Draw a molecular diagram of alpha-D-glucose.

Draw a molecular diagram of alpha-D-glucose.

The table shows the range and classification of body mass index (BMI) values, as shown in the nomogram.

[Source: © All rights reserved. Canadian Guidelines for Body Weight Classification in Adults. Health Canada, 2003. Adapted and reproduced with permission from the Minister of Health, 2021.]

What is the approximate reduction in body mass that a person of height 155cm and mass 95kg would have to lose to reach normal body mass?

A. 10kg

B. 22kg

C. 36kg

D. 54kg

Describe the structure of starch.

Describe the structure of starch.

The chart classifies individuals according to their height and mass.

[Source: InvictaHOG, 2006. Body mass index chart. [chart online] Available at: <https://commons.wikimedia.org/w/index.php?curid=1208092> [Accessed: 4 April 2019].]

Based on the information provided, which individual is most at risk of diseases associated with the accumulation of excessive body fat?

Broad beans are rich in starch and cellulose. Compare and contrast the structure of starch and cellulose.

Broad beans are rich in starch and cellulose. Compare and contrast the structure of starch and cellulose.

The diagrams show how monosaccharide molecules are joined to form chains in two polysaccharides.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.

Suggest with a reason which P:L diet is closest to the normal diet of these bumblebees.

The Framingham heart study was an observational study that went on for 20 years. The following data were produced.

[Source: adapted from Gillman et al., Margarine intake and subsequent coronary heart disease in men.
Epidemiology, 1997 Mar; 8(2): 144–9]

Which conclusion can be drawn, based on these data?

A. It is better to eat margarine than to eat butter.

B. The more margarine consumed, the greater the incidence of coronary heart disease.

C. Butter is a natural product whereas margarine is hydrogenated vegetable oil that leads to coronary heart disease.

D. Margarine causes more heart related deaths than butter.

Which type(s) of fatty acid in the diet is/are positively correlated with an increased risk of coronary heart disease?

I.   Saturated

II.  Trans unsaturated

III. Cis unsaturated

A. I only 

B. I and II only

C. II only

D. II and III only

Which fatty acid would occur in a trans fat?

[Source: © International Baccalaureate Organization 2018]

Which molecule represents a lipid?

[Source: © International Baccalaureate Organization 2018]

The diagram shows two polysaccharides, formed from condensation of many glucose molecules.

[Source: © International Baccalaureate Organization 2019]

What are the names of X and Y?

Which protein has the highest tensile strength (ability to resist breaking when stretched)?

A. Cellulose

B. Actin

C. Spider silk

D. Albumin

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

The graph shows the results of an investigation into the activity of turnip peroxidase. The accumulation of the product of the reaction catalysed by the enzyme is shown at different pH values.

[Source: © International Baccalaureate Organization 2019]

Based on the data in the graph, what is most probably the optimum pH for turnip peroxidase?

A. Between 3 and 5

B. Between 10 and 11

C. Between 7 and 8

D. Between 9 and 10

Which statement correctly describes genome and proteome?

A. Only the genome but not the proteome can be analysed using gel electrophoresis.

B. The genome and the proteome are the same in all tissues in an organism.

C. In cells of different tissues, the genome is the same while the proteome varies.

D. Only mutations in the proteome but not in the genome cause any variability.

The graph shows the activity of an enzyme at different temperatures.

[Source: © International Baccalaureate Organization 2019]

What does the dashed line in the graph represent?

A. Increasing temperature increases substrate concentration.

B. Increasing temperature affects the active site.

C. Increasing temperature increases the rate of reaction.

D. Increasing temperature decreases the movement of particles.

Outline the range of functions of proteins in cells.

State one function of Rubisco.

State the genus of the plant where this Rubisco is found.

Outline one factor that could affect the activity of Rubisco.

The image shows the structure of the protein hemoglobin

Outline the process of protein denaturation.

Explain how denaturation affects the activity of an enzyme.

The diagram shows the structure of the protein CXCL12.

Describe the structure of proteins, including features that are common to all proteins and features that vary.

The table shows the approximate energy stores in a man with an average mass.

_{[Source: Reprinted from Clinics in Endocrinology and Metabolism, 5(2),
Cahill Jr., G.F., Starvation in Man, Copyright (1976), with permission from Elsevier.]}

What can be concluded from the data?

A.  The brain contains no short-term stored energy.

B.  The liver contains less long-term than short-term stored energy.

C.  The adipose tissue provides for most of the long-term energy storage.

D.  Carbohydrates provide more energy per gram than lipids or proteins.

The table shows the approximate energy stores in a man with an average mass.

_{[Source: Reprinted from Clinics in Endocrinology and Metabolism, 5(2),
Cahill Jr., G.F., Starvation in Man, Copyright (1976), with permission from Elsevier.]}

What can be concluded from the data?

A.  The brain contains no short-term stored energy.

B.  The liver contains less long-term than short-term stored energy.

C.  The adipose tissue provides for most of the long-term energy storage.

D.  Carbohydrates provide more energy per gram than lipids or proteins.

Outline the range of functions of proteins in cells.

Outline the range of functions of proteins in cells.

State one function of Rubisco.

State the genus of the plant where this Rubisco is found.

Outline one factor that could affect the activity of Rubisco.

State one function of Rubisco.

State the genus of the plant where this Rubisco is found.

Outline one factor that could affect the activity of Rubisco.

The image shows the structure of the protein hemoglobin

Outline the process of protein denaturation.

Outline the process of protein denaturation.

Explain how denaturation affects the activity of an enzyme.

Explain how denaturation affects the activity of an enzyme.

The diagram shows the structure of the protein CXCL12.

Which protein has the highest tensile strength (ability to resist breaking when stretched)?

A. Cellulose

B. Actin

C. Spider silk

D. Albumin

Describe the structure of proteins, including features that are common to all proteins and features that vary.

Describe the structure of proteins, including features that are common to all proteins and features that vary.

The table shows the approximate energy stores in a man with an average mass.

_{[Source: Reprinted from Clinics in Endocrinology and Metabolism, 5(2),
Cahill Jr., G.F., Starvation in Man, Copyright (1976), with permission from Elsevier.]}

What can be concluded from the data?

A.  The brain contains no short-term stored energy.

B.  The liver contains less long-term than short-term stored energy.

C.  The adipose tissue provides for most of the long-term energy storage.

D.  Carbohydrates provide more energy per gram than lipids or proteins.

The table shows the approximate energy stores in a man with an average mass.

_{[Source: Reprinted from Clinics in Endocrinology and Metabolism, 5(2),
Cahill Jr., G.F., Starvation in Man, Copyright (1976), with permission from Elsevier.]}

What can be concluded from the data?

A.  The brain contains no short-term stored energy.

B.  The liver contains less long-term than short-term stored energy.

C.  The adipose tissue provides for most of the long-term energy storage.

D.  Carbohydrates provide more energy per gram than lipids or proteins.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

The graph shows the results of an investigation into the activity of turnip peroxidase. The accumulation of the product of the reaction catalysed by the enzyme is shown at different pH values.

[Source: © International Baccalaureate Organization 2019]

Based on the data in the graph, what is most probably the optimum pH for turnip peroxidase?

A. Between 3 and 5

B. Between 10 and 11

C. Between 7 and 8

D. Between 9 and 10

Which statement correctly describes genome and proteome?

A. Only the genome but not the proteome can be analysed using gel electrophoresis.

B. The genome and the proteome are the same in all tissues in an organism.

C. In cells of different tissues, the genome is the same while the proteome varies.

D. Only mutations in the proteome but not in the genome cause any variability.

The graph shows the activity of an enzyme at different temperatures.

[Source: © International Baccalaureate Organization 2019]

What does the dashed line in the graph represent?

A. Increasing temperature increases substrate concentration.

B. Increasing temperature affects the active site.

C. Increasing temperature increases the rate of reaction.

D. Increasing temperature decreases the movement of particles.

Three flasks were prepared for an analysis of the activity of amylase. At time zero, each of the substances indicated in the diagrams was added.

Which flask(s) could provide support for the hypothesis that heat denatures enzymes?

A. Flasks I and II after 15 minutes

B. Flasks II and III after 15 minutes

C. Flasks I and III after 15 minutes

D. Flask III at time zero and again after 15 minutes

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Describe the relationship between increasing H₂O₂ concentration and catalase activity.

Evaluate the claim that, based on the data, the optimum H₂O₂ concentration for catalase is 70 mM.

Lactose intolerance occurs when the enzyme, lactase, that digests lactose is not produced after infancy in humans. The incidence of lactose intolerance varies in different racial groups. The graph shows the distribution of lactose intolerance in different human populations.

[Source: © International Baccalaureate Organization 2019]

What can be hypothesized from the graph?

A. Native American people produce most lactase after infancy.

B. Most Indian people do not produce lactase after infancy.

C. Lactase is not produced after infancy in most Caucasian people.

D. One quarter of Afro-Caribbean people will probably experience digestive problems when drinking milk.

The graph of the effect of pH on immobilized lipase activity does not allow for the determination of optimum pH precisely. Explain how a more exact value for the optimum pH could be determined.

Which enzyme is matched to its function?

State a role of the active site of an enzyme.

Explain what happens to an enzyme if there is a change of pH.

Explain the decrease in activity of the enzyme on either side of the optimum temperature.

In biotechnology, enzymes are used to transfer genes to bacteria. Outline how two specific enzymes are used for the transfer.

Outline, using graphs, the effect of different factors that influence enzyme activity.

Explain how enzymes are used in the preparation of milk suitable for individuals who are lactose intolerant.

Explain the role of lactose in the expression of the gene for lactase production.

Outline the role of ADH in osmoregulation.

State the effect that immobilizing the enzyme had on the relative activity of the enzyme.

Through a series of enzymatic reactions, the amino acid threonine is converted to isoleucine. The graph shows the rate of reaction of threonine deaminase according to the concentration of its substrate threonine, with and without the presence of isoleucine.

^{[Source: Calhoun, D.H., Rimernian, R.A. and Hatfield, G.W., 1973.
Threonine Deaminase from Escherichia coli.
I. Purification and Properties. The Journal Of Biological Chemistry,
248(10), pp. 3511–3516. Open Access.]}

What can be seen from these results?

A.  Threonine deaminase only works in the presence of isoleucine.

B.  Isoleucine inhibits threonine deaminase at low concentrations of threonine.

C.  Production of isoleucine is inhibited at high concentration of threonine.

D.  End-product inhibition controls the production of threonine deaminase.

In the grass plant Halopyrum mucronatum, the enzyme amylase breaks bonds in polysaccharides during germination. The graph shows how the activity of the enzyme varies with the concentration of polysaccharide.

_{[Source: Material from: Siddiqui, Z.S. and Khan, M.A., The role of enzyme amylase in two germinating seed morphs of
Halopyrum mucronatum (L.) Stapf. in saline and non-saline environment, published 2011, Acta Physiologiae
Plantarum, reproduced with permission of SNCSC.]}

What is the reason for the curve levelling off?

A.  There is insufficient substrate for the enzyme to act on.

B.  The product acts as an enzyme inhibitor.

C.  The enzymes have all been consumed in the reaction.

D.  All the enzyme active sites are occupied by substrate.

Explain how temperature affects enzymes.

In the grass plant Halopyrum mucronatum, the enzyme amylase breaks bonds in polysaccharides during germination. The graph shows how the activity of the enzyme varies with the concentration of polysaccharide.

_{[Source: Material from: Siddiqui, Z.S. and Khan, M.A., The role of enzyme amylase in two germinating seed morphs of
Halopyrum mucronatum (L.) Stapf. in saline and non-saline environment, published 2011, Acta Physiologiae
Plantarum, reproduced with permission of SNCSC.]}

What is the reason for the curve levelling off?

A.  There is insufficient substrate for the enzyme to act on.

B.  The product acts as an enzyme inhibitor.

C.  The enzymes have all been consumed in the reaction.

D.  All the enzyme active sites are occupied by substrate.

Which enzyme is matched to its function?

State a role of the active site of an enzyme.

State a role of the active site of an enzyme.

Explain what happens to an enzyme if there is a change of pH.

Explain what happens to an enzyme if there is a change of pH.

Explain the decrease in activity of the enzyme on either side of the optimum temperature.

In biotechnology, enzymes are used to transfer genes to bacteria. Outline how two specific enzymes are used for the transfer.

Explain the decrease in activity of the enzyme on either side of the optimum temperature.

In biotechnology, enzymes are used to transfer genes to bacteria. Outline how two specific enzymes are used for the transfer.

Outline, using graphs, the effect of different factors that influence enzyme activity.

Outline, using graphs, the effect of different factors that influence enzyme activity.

Explain how enzymes are used in the preparation of milk suitable for individuals who are lactose intolerant.

Explain how enzymes are used in the preparation of milk suitable for individuals who are lactose intolerant.

Explain the role of lactose in the expression of the gene for lactase production.

Explain the role of lactose in the expression of the gene for lactase production.

Three flasks were prepared for an analysis of the activity of amylase. At time zero, each of the substances indicated in the diagrams was added.

Which flask(s) could provide support for the hypothesis that heat denatures enzymes?

A. Flasks I and II after 15 minutes

B. Flasks II and III after 15 minutes

C. Flasks I and III after 15 minutes

D. Flask III at time zero and again after 15 minutes

Outline the role of ADH in osmoregulation.

Outline the role of ADH in osmoregulation.

State the effect that immobilizing the enzyme had on the relative activity of the enzyme.

State the effect that immobilizing the enzyme had on the relative activity of the enzyme.

Through a series of enzymatic reactions, the amino acid threonine is converted to isoleucine. The graph shows the rate of reaction of threonine deaminase according to the concentration of its substrate threonine, with and without the presence of isoleucine.

^{[Source: Calhoun, D.H., Rimernian, R.A. and Hatfield, G.W., 1973.
Threonine Deaminase from Escherichia coli.
I. Purification and Properties. The Journal Of Biological Chemistry,
248(10), pp. 3511–3516. Open Access.]}

What can be seen from these results?

A.  Threonine deaminase only works in the presence of isoleucine.

B.  Isoleucine inhibits threonine deaminase at low concentrations of threonine.

C.  Production of isoleucine is inhibited at high concentration of threonine.

D.  End-product inhibition controls the production of threonine deaminase.

In the grass plant Halopyrum mucronatum, the enzyme amylase breaks bonds in polysaccharides during germination. The graph shows how the activity of the enzyme varies with the concentration of polysaccharide.

_{[Source: Material from: Siddiqui, Z.S. and Khan, M.A., The role of enzyme amylase in two germinating seed morphs of
Halopyrum mucronatum (L.) Stapf. in saline and non-saline environment, published 2011, Acta Physiologiae
Plantarum, reproduced with permission of SNCSC.]}

What is the reason for the curve levelling off?

A.  There is insufficient substrate for the enzyme to act on.

B.  The product acts as an enzyme inhibitor.

C.  The enzymes have all been consumed in the reaction.

D.  All the enzyme active sites are occupied by substrate.

Explain how temperature affects enzymes.

Explain how temperature affects enzymes.

In the grass plant Halopyrum mucronatum, the enzyme amylase breaks bonds in polysaccharides during germination. The graph shows how the activity of the enzyme varies with the concentration of polysaccharide.

_{[Source: Material from: Siddiqui, Z.S. and Khan, M.A., The role of enzyme amylase in two germinating seed morphs of
Halopyrum mucronatum (L.) Stapf. in saline and non-saline environment, published 2011, Acta Physiologiae
Plantarum, reproduced with permission of SNCSC.]}

What is the reason for the curve levelling off?

A.  There is insufficient substrate for the enzyme to act on.

B.  The product acts as an enzyme inhibitor.

C.  The enzymes have all been consumed in the reaction.

D.  All the enzyme active sites are occupied by substrate.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Describe the relationship between increasing H₂O₂ concentration and catalase activity.

Evaluate the claim that, based on the data, the optimum H₂O₂ concentration for catalase is 70 mM.

Describe the relationship between increasing H₂O₂ concentration and catalase activity.

Evaluate the claim that, based on the data, the optimum H₂O₂ concentration for catalase is 70 mM.

Lactose intolerance occurs when the enzyme, lactase, that digests lactose is not produced after infancy in humans. The incidence of lactose intolerance varies in different racial groups. The graph shows the distribution of lactose intolerance in different human populations.

[Source: © International Baccalaureate Organization 2019]

What can be hypothesized from the graph?

A. Native American people produce most lactase after infancy.

B. Most Indian people do not produce lactase after infancy.

C. Lactase is not produced after infancy in most Caucasian people.

D. One quarter of Afro-Caribbean people will probably experience digestive problems when drinking milk.

The graph of the effect of pH on immobilized lipase activity does not allow for the determination of optimum pH precisely. Explain how a more exact value for the optimum pH could be determined.

The graph of the effect of pH on immobilized lipase activity does not allow for the determination of optimum pH precisely. Explain how a more exact value for the optimum pH could be determined.

State two structural features that differ between RNA and DNA.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Label the parts of the DNA diagram indicated by I, II, III and IV.

Sketch the complementary strand to complete the section of a DNA diagram.

Draw a molecular diagram of alpha-D-glucose.

Draw a labelled diagram to show the structure of a single nucleotide of RNA.

Draw a labelled diagram to show the structure of a single nucleotide of RNA.

Explain how the two strands of the DNA double helix are held together.

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

Sketch the complementary strand to complete the section of a DNA diagram.

Sketch the complementary strand to complete the section of a DNA diagram.

Draw a molecular diagram of alpha-D-glucose.

Draw a molecular diagram of alpha-D-glucose.

Draw a labelled diagram to show the structure of a single nucleotide of RNA.

Draw a labelled diagram to show the structure of a single nucleotide of RNA.

Draw a labelled diagram to show the structure of a single nucleotide of RNA.

Draw a labelled diagram to show the structure of a single nucleotide of RNA.

Explain how the two strands of the DNA double helix are held together.

Explain how the two strands of the DNA double helix are held together.

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

State two structural features that differ between RNA and DNA.

State two structural features that differ between RNA and DNA.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.

Label the parts of the DNA diagram indicated by I, II, III and IV.

Label the parts of the DNA diagram indicated by I, II, III and IV.

Nitrogen is part of many important substances in living organisms.

Distinguish between transcription and translation.

DNA codes for the amino acid sequence of polypeptides. List two other functions of DNA.

Outline the role of the enzyme helicase in replication.

Meselson and Stahl investigated DNA replication by first feeding bacteria with bases containing ¹⁵N (heavy), and then with bases containing ¹⁴N (light). The results are shown in the photographs.

[Source: © International Baccalaureate Organization 2018]

From this information, what would be the composition of the DNA in generation 3?

A. There will be a single ¹⁴N band.

B. There will be a single ¹⁵N band and a single ¹⁴N band.

C. There will be a darker ¹⁴N band and a lighter hybrid band.

D. There will be a single ¹⁵N band, a single hybrid band and a single ¹⁴N band.

Outline the function of Rubisco and of spider silk in relation to their three-dimensional conformation.

The diagram shows mRNA codons.

[Source: elementix / Alamy Stock Photo]

The mRNA sequence UGGAACGUA codes for what amino acid sequence?

A. Glycine-Glutamine-Methionine

B. Methionine-Glutamine-Glycine

C. Threonine-Valine-Histidine

D. Tryptophan-Asparagine-Valine

The diagram represents transcription and translation.

[Source: © International Baccalaureate Organization 2020.]

What structures do the letters X and Y represent?

What is the reason for Taq DNA polymerase being used in the polymerase chain reaction (PCR)?

A. It does not denature at high temperatures.

B. It produces Okazaki fragments more rapidly.

C. It allows translation to proceed rapidly.

D. It works efficiently with helicase in PCR.

Outline the role of DNA polymerase III in DNA replication.

Outline the role of three enzymes used in the replication of DNA.

Insulin is produced in β cells of the pancreas and not in other cells of the human body. Explain how differentiation of cells and regulation of gene expression allow proteins such as insulin to be produced in only certain types of body cell.

What are linked by hydrogen bonds?

A. Hydrogen and oxygen within a water molecule

B. Phosphate and sugar within a DNA molecule

C. Base and sugar between DNA nucleotides

D. Hydrogen and oxygen in different water molecules

Outline how a protein is made in a cell by the process of translation.

Describe the function of three named enzymes involved in DNA replication.

Cells were grown in heavy nitrogen (¹⁵N) for many generations and then grown in light nitrogen (¹⁴N) for two rounds of DNA replication. Which diagram shows the result of the centrifuged DNA?

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

Outline the function of Rubisco and of spider silk in relation to their three-dimensional conformation.

Outline the function of Rubisco and of spider silk in relation to their three-dimensional conformation.

The diagram shows mRNA codons.

[Source: elementix / Alamy Stock Photo]

The mRNA sequence UGGAACGUA codes for what amino acid sequence?

A. Glycine-Glutamine-Methionine

B. Methionine-Glutamine-Glycine

C. Threonine-Valine-Histidine

D. Tryptophan-Asparagine-Valine

The diagram represents transcription and translation.

[Source: © International Baccalaureate Organization 2020.]

What structures do the letters X and Y represent?

What is the reason for Taq DNA polymerase being used in the polymerase chain reaction (PCR)?

A. It does not denature at high temperatures.

B. It produces Okazaki fragments more rapidly.

C. It allows translation to proceed rapidly.

D. It works efficiently with helicase in PCR.

Outline the role of DNA polymerase III in DNA replication.

Outline the role of DNA polymerase III in DNA replication.

Outline the role of three enzymes used in the replication of DNA.

Insulin is produced in β cells of the pancreas and not in other cells of the human body. Explain how differentiation of cells and regulation of gene expression allow proteins such as insulin to be produced in only certain types of body cell.

Outline the role of three enzymes used in the replication of DNA.

Insulin is produced in β cells of the pancreas and not in other cells of the human body. Explain how differentiation of cells and regulation of gene expression allow proteins such as insulin to be produced in only certain types of body cell.

What are linked by hydrogen bonds?

A. Hydrogen and oxygen within a water molecule

B. Phosphate and sugar within a DNA molecule

C. Base and sugar between DNA nucleotides

D. Hydrogen and oxygen in different water molecules

Outline how a protein is made in a cell by the process of translation.

Outline how a protein is made in a cell by the process of translation.

Describe the function of three named enzymes involved in DNA replication.

Describe the function of three named enzymes involved in DNA replication.

Cells were grown in heavy nitrogen (¹⁵N) for many generations and then grown in light nitrogen (¹⁴N) for two rounds of DNA replication. Which diagram shows the result of the centrifuged DNA?

Nitrogen is part of many important substances in living organisms.

Distinguish between transcription and translation.

Nitrogen is part of many important substances in living organisms.

Distinguish between transcription and translation.

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

Dolly the sheep was the first mammal to be cloned from an adult somatic cell.

_{[Source: Squidonius, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Dolly_clone.svg.]}

Which DNA did Dolly inherit?

A.  Nuclear and mitochondrial DNA from the surrogate ewe

B.  Nuclear and mitochondrial DNA from the Finn-Dorset

C.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the Finn-Dorset

D.  Mitochondrial DNA from the Scottish Blackface and nuclear DNA from the surrogate ewe

DNA codes for the amino acid sequence of polypeptides. List two other functions of DNA.

DNA codes for the amino acid sequence of polypeptides. List two other functions of DNA.

Outline the role of the enzyme helicase in replication.

Outline the role of the enzyme helicase in replication.

Meselson and Stahl investigated DNA replication by first feeding bacteria with bases containing ¹⁵N (heavy), and then with bases containing ¹⁴N (light). The results are shown in the photographs.

[Source: © International Baccalaureate Organization 2018]

From this information, what would be the composition of the DNA in generation 3?

A. There will be a single ¹⁴N band.

B. There will be a single ¹⁵N band and a single ¹⁴N band.

C. There will be a darker ¹⁴N band and a lighter hybrid band.

D. There will be a single ¹⁵N band, a single hybrid band and a single ¹⁴N band.

A cricket was placed in a respirometer at constant temperature for ten minutes. The soap bubble moved along the pipette.

[Source: © International Baccalaureate Organization 2017]

What was measured by the movement of the soap bubble?

A. Production of carbon dioxide

B. Volume of excretory products

C. Oxygen consumption

D. Release of heat

Describe the role of oxygen in aerobic cell respiration.

Yeast cells, Saccharomyces cerevisiae, were incubated with and without glucose at three different temperatures for a period of four minutes, during which the rate of CO₂ production was measured with a CO₂ sensor.

[Source: © International Baccalaureate Organization 2019]

What conclusion can be drawn from the results of this experiment?

A. Yeast uses lipids rather than glucose in respiration at low temperatures.

B. Addition of glucose has a greater impact on rates of cell respiration at lower temperatures.

C. Rates of cell respiration increase with temperature.

D. More glucose is produced at higher temperatures.

Using the following table, compare and contrast anaerobic cell respiration in yeasts and in humans. The first row has been completed as an example.

The diagram shows a respirometer used to measure respiration rate in germinating seeds.

[Source: used with the kind permission of the Nuffield Foundation and the Royal Society of Biology]

What is the expected direction of movement of the fluid at X and the function of the fluid at Y?

The diagram shows a respirometer.

[Source: Courtesy The Royal Society of Biology.]

What solution should be in the bottom of each tube and in which direction will the manometer fluid move?

The graph shows the results of an experimental investigation that compared the rates at which lactose, glucose and galactose are broken down in the process of anaerobic cellular respiration by the yeast Torulopsis cremoris.

A respirometer is used to measure the oxygen consumption of germinating seeds. The distance that the oil drop moves is measured at 15-minute intervals.

[Source: © The Royal Society of Biology.]

What is the function of chemical X?

A. Absorbs carbon dioxide so the oxygen released by the seeds can be measured

B. Absorbs carbon dioxide so the oxygen absorbed by the seeds can be measured

C. Absorbs oxygen so the carbon dioxide released by the seeds can be measured

D. Absorbs oxygen so the carbon dioxide absorbed by the seeds can be measured

State one process that produces ATP.

Outline the use of ATP. 

Describe anaerobic respiration in humans and in yeast.

Describe how plants transport organic compounds from where they are made to where they are stored.

Describe the organelles and other structures in animal cells that are visible in electron micrographs.

Using the following table, compare and contrast anaerobic cell respiration in yeasts and in humans. The first row has been completed as an example.

Using the following table, compare and contrast anaerobic cell respiration in yeasts and in humans. The first row has been completed as an example.

The diagram shows a respirometer used to measure respiration rate in germinating seeds.

[Source: used with the kind permission of the Nuffield Foundation and the Royal Society of Biology]

What is the expected direction of movement of the fluid at X and the function of the fluid at Y?

The diagram shows a respirometer.

[Source: Courtesy The Royal Society of Biology.]

What solution should be in the bottom of each tube and in which direction will the manometer fluid move?

The graph shows the results of an experimental investigation that compared the rates at which lactose, glucose and galactose are broken down in the process of anaerobic cellular respiration by the yeast Torulopsis cremoris.

A respirometer is used to measure the oxygen consumption of germinating seeds. The distance that the oil drop moves is measured at 15-minute intervals.

[Source: © The Royal Society of Biology.]

What is the function of chemical X?

A. Absorbs carbon dioxide so the oxygen released by the seeds can be measured

B. Absorbs carbon dioxide so the oxygen absorbed by the seeds can be measured

C. Absorbs oxygen so the carbon dioxide released by the seeds can be measured

D. Absorbs oxygen so the carbon dioxide absorbed by the seeds can be measured

State one process that produces ATP.

Outline the use of ATP. 

State one process that produces ATP.

Outline the use of ATP. 

Describe anaerobic respiration in humans and in yeast.

Describe anaerobic respiration in humans and in yeast.

Describe how plants transport organic compounds from where they are made to where they are stored.

Describe how plants transport organic compounds from where they are made to where they are stored.

A cricket was placed in a respirometer at constant temperature for ten minutes. The soap bubble moved along the pipette.

[Source: © International Baccalaureate Organization 2017]

What was measured by the movement of the soap bubble?

A. Production of carbon dioxide

B. Volume of excretory products

C. Oxygen consumption

D. Release of heat

Describe the organelles and other structures in animal cells that are visible in electron micrographs.

Describe the organelles and other structures in animal cells that are visible in electron micrographs.

Describe the role of oxygen in aerobic cell respiration.

Describe the role of oxygen in aerobic cell respiration.

Yeast cells, Saccharomyces cerevisiae, were incubated with and without glucose at three different temperatures for a period of four minutes, during which the rate of CO₂ production was measured with a CO₂ sensor.

[Source: © International Baccalaureate Organization 2019]

What conclusion can be drawn from the results of this experiment?

A. Yeast uses lipids rather than glucose in respiration at low temperatures.

B. Addition of glucose has a greater impact on rates of cell respiration at lower temperatures.

C. Rates of cell respiration increase with temperature.

D. More glucose is produced at higher temperatures.

Explain the process of photosynthesis.

State a suitable solvent for extracting photosynthetic pigments from plant tissue.

Explain how the pigments in the chromatogram of spinach are identified.

Outline what happens when spinach extract is spotted on a TLC plate and placed into a container of solvent.

Explain what the R_f values represent in chromatography.

State two photosynthetic pigments that could be identified using chromatography.

Discuss briefly whether the detection of starch in this experiment was proof that photosynthesis had occurred in the leaf.

The graph shows the effect of increasing light intensity on the rate of CO₂ uptake by a species of green plant maintained in conditions of constant temperature and CO₂ concentration.

[Source: © International Baccalaureate Organization 2019]

Which statement is consistent with the graph?

A. Photosynthesis stops at high light intensity.

B. Rates of photosynthesis increase with temperature.

C. Cell respiration leads to net production of CO₂ at low light intensity.

D. There is a negative correlation between CO₂ uptake and light intensity.

The graph shows the absorption spectra of chlorophyll a and chlorophyll b.

[Source: adapted from F. P. Zscheile and C. L. Comar, 'Influence of Preparative Procedure on the Purity of Chlorophyll
Components as Shown by Absorption Spectra.' Int. J. Plant Sciences, Volume 102, Number 3, Mar., 1941, pp. 463–481.
Used with the kind permission of University of Chicago Press.]

What can be concluded from the graph?

A. Both chlorophyll a and chlorophyll b absorb a large amount of green light

B. Chlorophyll b absorbs red light more efficiently than blue light

C. Other pigments must absorb light between blue and red in the spectrum

D. Chlorophyll a and chlorophyll b have different absorption peaks

Outline how photosynthesis produces glucose.

Suggest how a plastic bag placed around the plant pot prevents carbon dioxide from reaching the plant’s leaves.

A chromatograph was made of the photosynthetic pigments of a leaf of the plant.

[Source: Adapted from “Diversity of Photosynthetic Pigments” by Alexander F. Motten in Tested Studies for
Laboratory Teaching, Volume 16 of the Association for Biology Laboratory Education and used by permission of the
author.]

Outline what measurements would be taken to identify pigment X.

In 1882, Engelmann investigated photosynthesis by shining light of varying wavelength on a green alga. He observed where aerobic bacteria accumulated.

[Source: Republished with permission of Oxford University Press, from Plant Physiology and Development, Sixth Edition by
Lincoln Taiz, Eduardo Zeiger, Ian M. Møller, and Angus Murphy, 2015. Permission conveyed through Copyright
Clearance Center, Inc.]

What can be deduced from this experiment?

A. Only parts of the chloroplast contained chlorophyll.

B. The distribution of bacteria indicates the action spectrum of photosynthesis.

C. Most oxygen is released from the algae in green light.

D. Chloroplasts reflect blue and red light.

The amount of food passing into food chains can be affected by the rate of photosynthesis. Explain the effect of one limiting factor on photosynthesis.

Explain the effect of temperature on the rate of photosynthesis in this mesocosm.

Describe how leaf cells make use of light energy.

The apparatus shown was used to investigate the effect of varying carbon dioxide concentration on the rate of photosynthesis. Carbon dioxide concentrations were varied by adding different amounts of sodium hydrogen carbonate (NaHCO₃) to water.

What is the dependent variable in this investigation?

A. Temperature

B. Light intensity

C. Amount of NaHCO₃ added

D. Volume of oxygen produced

Describe how plants affect the amount of carbon dioxide in the atmosphere.

The micrograph shows part of a chloroplast.

_{[Source: Newcomb, E., n.d. [Detail of a chloroplast]. [image online] Available at: https://search.library.wisc.edu/digital/
AHDTZ7JMHZ5VSU8C [Accessed 1 October 2021] © Board of Regents of the University of Wisconsin System.
Licensed under the Creative Commons Attribution 4.0 International. https://creativecommons.org/licenses/by/4.0/
deed.en.]}

What reaction takes place in region P?

A.  Carboxylation of ribulose bisphosphate

B.  Photolysis of water molecules

C.  Generation of ATP by ATP synthase

D.  Reduction of NAD in Photosystem I

Suggest how a plastic bag placed around the plant pot prevents carbon dioxide from reaching the plant’s leaves.

A chromatograph was made of the photosynthetic pigments of a leaf of the plant.

[Source: Adapted from “Diversity of Photosynthetic Pigments” by Alexander F. Motten in Tested Studies for
Laboratory Teaching, Volume 16 of the Association for Biology Laboratory Education and used by permission of the
author.]

Outline what measurements would be taken to identify pigment X.

Suggest how a plastic bag placed around the plant pot prevents carbon dioxide from reaching the plant’s leaves.

A chromatograph was made of the photosynthetic pigments of a leaf of the plant.

[Source: Adapted from “Diversity of Photosynthetic Pigments” by Alexander F. Motten in Tested Studies for
Laboratory Teaching, Volume 16 of the Association for Biology Laboratory Education and used by permission of the
author.]

Outline what measurements would be taken to identify pigment X.

In 1882, Engelmann investigated photosynthesis by shining light of varying wavelength on a green alga. He observed where aerobic bacteria accumulated.

[Source: Republished with permission of Oxford University Press, from Plant Physiology and Development, Sixth Edition by
Lincoln Taiz, Eduardo Zeiger, Ian M. Møller, and Angus Murphy, 2015. Permission conveyed through Copyright
Clearance Center, Inc.]

What can be deduced from this experiment?

A. Only parts of the chloroplast contained chlorophyll.

B. The distribution of bacteria indicates the action spectrum of photosynthesis.

C. Most oxygen is released from the algae in green light.

D. Chloroplasts reflect blue and red light.

The amount of food passing into food chains can be affected by the rate of photosynthesis. Explain the effect of one limiting factor on photosynthesis.

The amount of food passing into food chains can be affected by the rate of photosynthesis. Explain the effect of one limiting factor on photosynthesis.

Explain the effect of temperature on the rate of photosynthesis in this mesocosm.

Explain the effect of temperature on the rate of photosynthesis in this mesocosm.

Describe how leaf cells make use of light energy.

Describe how leaf cells make use of light energy.

The apparatus shown was used to investigate the effect of varying carbon dioxide concentration on the rate of photosynthesis. Carbon dioxide concentrations were varied by adding different amounts of sodium hydrogen carbonate (NaHCO₃) to water.

What is the dependent variable in this investigation?

A. Temperature

B. Light intensity

C. Amount of NaHCO₃ added

D. Volume of oxygen produced

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Describe how plants affect the amount of carbon dioxide in the atmosphere.

Explain the process of photosynthesis.

Explain the process of photosynthesis.

State a suitable solvent for extracting photosynthetic pigments from plant tissue.

Explain how the pigments in the chromatogram of spinach are identified.

State a suitable solvent for extracting photosynthetic pigments from plant tissue.

Explain how the pigments in the chromatogram of spinach are identified.

Outline what happens when spinach extract is spotted on a TLC plate and placed into a container of solvent.

Explain what the R_f values represent in chromatography.

State two photosynthetic pigments that could be identified using chromatography.

Outline what happens when spinach extract is spotted on a TLC plate and placed into a container of solvent.

Explain what the R_f values represent in chromatography.

State two photosynthetic pigments that could be identified using chromatography.

The micrograph shows part of a chloroplast.

_{[Source: Newcomb, E., n.d. [Detail of a chloroplast]. [image online] Available at: https://search.library.wisc.edu/digital/
AHDTZ7JMHZ5VSU8C [Accessed 1 October 2021] © Board of Regents of the University of Wisconsin System.
Licensed under the Creative Commons Attribution 4.0 International. https://creativecommons.org/licenses/by/4.0/
deed.en.]}

What reaction takes place in region P?

A.  Carboxylation of ribulose bisphosphate

B.  Photolysis of water molecules

C.  Generation of ATP by ATP synthase

D.  Reduction of NAD in Photosystem I

Discuss briefly whether the detection of starch in this experiment was proof that photosynthesis had occurred in the leaf.

Discuss briefly whether the detection of starch in this experiment was proof that photosynthesis had occurred in the leaf.

The graph shows the effect of increasing light intensity on the rate of CO₂ uptake by a species of green plant maintained in conditions of constant temperature and CO₂ concentration.

[Source: © International Baccalaureate Organization 2019]

Which statement is consistent with the graph?

A. Photosynthesis stops at high light intensity.

B. Rates of photosynthesis increase with temperature.

C. Cell respiration leads to net production of CO₂ at low light intensity.

D. There is a negative correlation between CO₂ uptake and light intensity.

The graph shows the absorption spectra of chlorophyll a and chlorophyll b.

[Source: adapted from F. P. Zscheile and C. L. Comar, 'Influence of Preparative Procedure on the Purity of Chlorophyll
Components as Shown by Absorption Spectra.' Int. J. Plant Sciences, Volume 102, Number 3, Mar., 1941, pp. 463–481.
Used with the kind permission of University of Chicago Press.]

What can be concluded from the graph?

A. Both chlorophyll a and chlorophyll b absorb a large amount of green light

B. Chlorophyll b absorbs red light more efficiently than blue light

C. Other pigments must absorb light between blue and red in the spectrum

D. Chlorophyll a and chlorophyll b have different absorption peaks

Outline how photosynthesis produces glucose.

Outline how photosynthesis produces glucose.