Topic 6: Human physiology

Discuss the roles of the enzymes secreted by the pancreas during digestion.

The photomicrograph drawing shows a longitudinal section of the small intestine.

[Source: Henry Gray (1918) Anatomy of the Human Body]

What is the function of the tissue layers labelled X and Y?

A. Secretion of digestive enzymes

B. Absorption of digested food

C. Transport of absorbed foods

D. Movement of food in the intestine

Distinguish between the amino acid contents of yellow mealworms and cattle.

Predict, with a reason, whether the amino acid composition of yellow mealworms or cattle is more suitable for a human diet.

Birds and mammals maintain constant body temperature despite considerable losses of body heat to the environment. In insects such as mealworms, body temperature is variable and is often the same as the temperature of the environment or only slightly above it. Analyse the data in the bar charts, using this information.

Describe the processes involved in absorbing different nutrients across the cell membrane of villus epithelium cells lining the small intestine.

The diagram shows the human digestive system. Which organ is responsible for the majority of the absorption of digested food?

[Source: BruceBlaus/Wikimedia. File licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/)]

The micrograph shows part of a cell.

The diagram shows the human digestive system. Where are lipids digested?

[Source: BruceBlaus/Wikimedia. File licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/)]

What are these structures?

[Source: Burgstedt | Dreamstime.com]

A. Fatty acids in the small intestine

B. Bacteria in the large intestine

C. Villi in the small intestine

D. Feces egested from the large intestine 

Explain the action of enzymes in digestion and the different roles of at least two named enzymes that are produced in the pancreas.

The micrograph is of a longitudinal section through the small intestine. Which letter represents the circular muscle layer?

[Source: Henry Gray (1918) Anatomy of the Human Body]

The photomicrograph shows a section through a human small intestine.

[Source: Chiodini RJ, Dowd SE, Chamberlin WM, Galandiuk S, Davis B,
Glassing A (2015) Microbial Population Differentials between Mucosal and Submucosal Intestinal Tissues in
Advanced Crohn’s Disease of the Ileum. PLoS ONE 10(7): e0134382. https://doi.org/10.1371/journal.pone.0134382.]

Which statement corresponds to the labelled structures?

A. X moves food along the intestine.

B. Y is the mucosa.

C. Y contains lacteals.

D. Z causes peristalsis

Outline how proteins are digested and the products of protein digestion absorbed in humans.

A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken?

A. Mouth

B. Stomach

C. Small intestine

D. Gall bladder

Outline the functions of the villi in the small intestine.

Explain the consequences of celiac disease for absorption of digested nutrients.

Wheat, barley and rye all contain gluten. Outline how a protein such as gluten is digested.

Explain how amino acids in casein could reach the liver, starting from the moment when the person takes a bite of pastry cream pie.

Congenital lactase deficiency is a type of lactose intolerance that occurs in infants. It is inherited in an autosomal recessive pattern. Calculate the chance of congenital lactose intolerance in a child whose parents are both carriers for the disorder, showing fully how you reached your answer.

A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken?

A. Mouth

B. Stomach

C. Small intestine

D. Gall bladder

The diagram shows some of the organs associated with the digestion of starch. Which organ produces amylase?

The diagram shows a cross section through the small intestine of a mammal. Which label points to the mucosa?

[Source: JOSE LUIS CALVO MARTIN & JOSE ENRIQUE GARCIA-MAURIÑO MUZQUIZ / www.istockphoto.com.]

Outline the significance of surface area to volume ratio in the limitation of cell size.

Explain the adaptations of the small intestine to its function.

Where in the digestive system are lipids broken down?

[Source: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health. The Digestive System
[online] Available at: https://www.niddk.nih.gov/news/media-library/11172. Source adapted.]

Humans rely on carbohydrates for much of their energy. Outline the process of digestion and absorption of starch in the human digestive system.

Outline how starch in the diet is modified for absorption in humans.

Describe how the small intestine is adapted for efficient absorption of nutrients.

The digestive system hydrolyses macromolecules into monomers for absorption. Which chemical(s) produced by humans can perform hydrolysis?

I.   Cellulase

II.  Glycogen

III. Amylase

A.  I and III only

B.  II and III only

C.  III only

D.  I, II and III

The micrograph is of a longitudinal section through the small intestine. Which letter represents the circular muscle layer?

[Source: Henry Gray (1918) Anatomy of the Human Body]

The photomicrograph shows a section through a human small intestine.

[Source: Chiodini RJ, Dowd SE, Chamberlin WM, Galandiuk S, Davis B,
Glassing A (2015) Microbial Population Differentials between Mucosal and Submucosal Intestinal Tissues in
Advanced Crohn’s Disease of the Ileum. PLoS ONE 10(7): e0134382. https://doi.org/10.1371/journal.pone.0134382.]

Which statement corresponds to the labelled structures?

A. X moves food along the intestine.

B. Y is the mucosa.

C. Y contains lacteals.

D. Z causes peristalsis

Outline how proteins are digested and the products of protein digestion absorbed in humans.

Outline how proteins are digested and the products of protein digestion absorbed in humans.

A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken?

A. Mouth

B. Stomach

C. Small intestine

D. Gall bladder

Outline the functions of the villi in the small intestine.

Explain the consequences of celiac disease for absorption of digested nutrients.

Wheat, barley and rye all contain gluten. Outline how a protein such as gluten is digested.

Outline the functions of the villi in the small intestine.

Explain the consequences of celiac disease for absorption of digested nutrients.

Wheat, barley and rye all contain gluten. Outline how a protein such as gluten is digested.

Explain how amino acids in casein could reach the liver, starting from the moment when the person takes a bite of pastry cream pie.

Congenital lactase deficiency is a type of lactose intolerance that occurs in infants. It is inherited in an autosomal recessive pattern. Calculate the chance of congenital lactose intolerance in a child whose parents are both carriers for the disorder, showing fully how you reached your answer.

Explain how amino acids in casein could reach the liver, starting from the moment when the person takes a bite of pastry cream pie.

Congenital lactase deficiency is a type of lactose intolerance that occurs in infants. It is inherited in an autosomal recessive pattern. Calculate the chance of congenital lactose intolerance in a child whose parents are both carriers for the disorder, showing fully how you reached your answer.

A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken?

A. Mouth

B. Stomach

C. Small intestine

D. Gall bladder

The diagram shows some of the organs associated with the digestion of starch. Which organ produces amylase?

The diagram shows a cross section through the small intestine of a mammal. Which label points to the mucosa?

[Source: JOSE LUIS CALVO MARTIN & JOSE ENRIQUE GARCIA-MAURIÑO MUZQUIZ / www.istockphoto.com.]

Outline the significance of surface area to volume ratio in the limitation of cell size.

Explain the adaptations of the small intestine to its function.

Outline the significance of surface area to volume ratio in the limitation of cell size.

Explain the adaptations of the small intestine to its function.

Where in the digestive system are lipids broken down?

[Source: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health. The Digestive System
[online] Available at: https://www.niddk.nih.gov/news/media-library/11172. Source adapted.]

Humans rely on carbohydrates for much of their energy. Outline the process of digestion and absorption of starch in the human digestive system.

Humans rely on carbohydrates for much of their energy. Outline the process of digestion and absorption of starch in the human digestive system.

Outline how starch in the diet is modified for absorption in humans.

Describe how the small intestine is adapted for efficient absorption of nutrients.

Outline how starch in the diet is modified for absorption in humans.

Describe how the small intestine is adapted for efficient absorption of nutrients.

The digestive system hydrolyses macromolecules into monomers for absorption. Which chemical(s) produced by humans can perform hydrolysis?

I.   Cellulase

II.  Glycogen

III. Amylase

A.  I and III only

B.  II and III only

C.  III only

D.  I, II and III

Discuss the roles of the enzymes secreted by the pancreas during digestion.

Discuss the roles of the enzymes secreted by the pancreas during digestion.

The photomicrograph drawing shows a longitudinal section of the small intestine.

[Source: Henry Gray (1918) Anatomy of the Human Body]

What is the function of the tissue layers labelled X and Y?

A. Secretion of digestive enzymes

B. Absorption of digested food

C. Transport of absorbed foods

D. Movement of food in the intestine

Distinguish between the amino acid contents of yellow mealworms and cattle.

Predict, with a reason, whether the amino acid composition of yellow mealworms or cattle is more suitable for a human diet.

Birds and mammals maintain constant body temperature despite considerable losses of body heat to the environment. In insects such as mealworms, body temperature is variable and is often the same as the temperature of the environment or only slightly above it. Analyse the data in the bar charts, using this information.

Distinguish between the amino acid contents of yellow mealworms and cattle.

Predict, with a reason, whether the amino acid composition of yellow mealworms or cattle is more suitable for a human diet.

Birds and mammals maintain constant body temperature despite considerable losses of body heat to the environment. In insects such as mealworms, body temperature is variable and is often the same as the temperature of the environment or only slightly above it. Analyse the data in the bar charts, using this information.

Describe the processes involved in absorbing different nutrients across the cell membrane of villus epithelium cells lining the small intestine.

Describe the processes involved in absorbing different nutrients across the cell membrane of villus epithelium cells lining the small intestine.

The diagram shows the human digestive system. Which organ is responsible for the majority of the absorption of digested food?

[Source: BruceBlaus/Wikimedia. File licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/)]

The micrograph shows part of a cell.

The diagram shows the human digestive system. Where are lipids digested?

[Source: BruceBlaus/Wikimedia. File licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/)]

What are these structures?

[Source: Burgstedt | Dreamstime.com]

A. Fatty acids in the small intestine

B. Bacteria in the large intestine

C. Villi in the small intestine

D. Feces egested from the large intestine 

Explain the action of enzymes in digestion and the different roles of at least two named enzymes that are produced in the pancreas.

Explain the action of enzymes in digestion and the different roles of at least two named enzymes that are produced in the pancreas.

The diagram shows red blood cells and undifferentiated tissue cells.

[Source: © International Baccalaureate Organization 2017]

Diffusion of oxygen from blood cells to tissue cells is represented by arrow 3 in the diagram.
What molecules are shown diffusing by arrow 1 and arrow 2?

Distinguish between the vein and the artery with reference to structures visible in the micrograph.

Distinguish between the structure of arteries and the structure of veins.

Which diagram represents blood flow through the mammalian heart?

[Source: © International Baccalaureate Organization 2019]

On the diagram, label the aorta.

On the diagram, label the right atrium. 

The graph shows blood pressure changes on the left side of the heart during one heartbeat. Identify the two parts of the circulatory system that produce traces I and II on the graph.

[Source: © International Baccalaureate Organization 2019]

The diagram shows the human heart.

State the independent and dependent variables in this experiment.

Independent: 

Dependent: 

State one feature of the rings that has to be kept constant apart from their initial diameter.

Explain the differences between the results shown for vein and artery.

The image shows the four chambers of the mammalian heart viewed from the ventral side. The sinoatrial node is located in the wall of one of these chambers. Which chamber is it?

This micrograph shows a transverse section of an artery.

State one function of epinephrine in the human body.

The light micrograph shows two blood vessels, an artery and a vein, in transverse section.

[Source: Columbia Center for New Media Teaching and Learning, n.d. Epithelium: Simple Squamous Epithelium. [image online] Available at: http://www.columbia.edu/itc/hs/medical/sbpm_histology_old/lab/lab02_squamous.html [Accessed 29 November 2019].]

What explains the different shapes of these blood vessels?

A. Arteries do not have valves.

B. Muscle cells are found only in the walls of veins.

C. Arteries have a larger lumen-to-wall thickness ratio.

D. There are fewer elastic fibres in the walls of veins.

The image shows the changes in heart rate of an athlete during exercise.

[Source: Liddle, P.F., 2010. Heart Rate Variability (HRV) during exercise. [online] Available at: https://canute1.wordpress.com/2010/07/ [Accessed 1 August 2019].]

What is likely to have occurred between 0 and 4 minutes and between 24 and 28 minutes?

Explain the change in heart rate during the period of hibernation.

Blood transports nutrients to all tissues of the body. Explain the initiation of the heartbeat and how blood flow is controlled in the heart.

The diagram shows a staggered transverse section (cut across rather than down) through the heart.

[Source: Oregon State University, n.d. Heart Anatomy. [diagram online] Available at:
https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/ [Accessed 28 October 2021].]

In what state are the valves when the ventricles are contracting?

The diagram shows the human heart.

State the independent and dependent variables in this experiment.

Independent: 

Dependent: 

State one feature of the rings that has to be kept constant apart from their initial diameter.

Explain the differences between the results shown for vein and artery.

State the independent and dependent variables in this experiment.

Independent: 

Dependent: 

State one feature of the rings that has to be kept constant apart from their initial diameter.

Explain the differences between the results shown for vein and artery.

The image shows the four chambers of the mammalian heart viewed from the ventral side. The sinoatrial node is located in the wall of one of these chambers. Which chamber is it?

This micrograph shows a transverse section of an artery.

State one function of epinephrine in the human body.

This micrograph shows a transverse section of an artery.

State one function of epinephrine in the human body.

The light micrograph shows two blood vessels, an artery and a vein, in transverse section.

[Source: Columbia Center for New Media Teaching and Learning, n.d. Epithelium: Simple Squamous Epithelium. [image online] Available at: http://www.columbia.edu/itc/hs/medical/sbpm_histology_old/lab/lab02_squamous.html [Accessed 29 November 2019].]

What explains the different shapes of these blood vessels?

A. Arteries do not have valves.

B. Muscle cells are found only in the walls of veins.

C. Arteries have a larger lumen-to-wall thickness ratio.

D. There are fewer elastic fibres in the walls of veins.

The image shows the changes in heart rate of an athlete during exercise.

[Source: Liddle, P.F., 2010. Heart Rate Variability (HRV) during exercise. [online] Available at: https://canute1.wordpress.com/2010/07/ [Accessed 1 August 2019].]

What is likely to have occurred between 0 and 4 minutes and between 24 and 28 minutes?

Explain the change in heart rate during the period of hibernation.

Explain the change in heart rate during the period of hibernation.

Blood transports nutrients to all tissues of the body. Explain the initiation of the heartbeat and how blood flow is controlled in the heart.

Blood transports nutrients to all tissues of the body. Explain the initiation of the heartbeat and how blood flow is controlled in the heart.

The diagram shows a staggered transverse section (cut across rather than down) through the heart.

[Source: Oregon State University, n.d. Heart Anatomy. [diagram online] Available at:
https://open.oregonstate.education/aandp/chapter/19-1-heart-anatomy/ [Accessed 28 October 2021].]

In what state are the valves when the ventricles are contracting?

The diagram shows red blood cells and undifferentiated tissue cells.

[Source: © International Baccalaureate Organization 2017]

Diffusion of oxygen from blood cells to tissue cells is represented by arrow 3 in the diagram.
What molecules are shown diffusing by arrow 1 and arrow 2?

Distinguish between the vein and the artery with reference to structures visible in the micrograph.

Distinguish between the vein and the artery with reference to structures visible in the micrograph.

Distinguish between the structure of arteries and the structure of veins.

Distinguish between the structure of arteries and the structure of veins.

Which diagram represents blood flow through the mammalian heart?

[Source: © International Baccalaureate Organization 2019]

On the diagram, label the aorta.

On the diagram, label the right atrium. 

On the diagram, label the aorta.

On the diagram, label the right atrium. 

The graph shows blood pressure changes on the left side of the heart during one heartbeat. Identify the two parts of the circulatory system that produce traces I and II on the graph.

[Source: © International Baccalaureate Organization 2019]

The graph shows blood pressure changes on the left side of the heart during one heartbeat. Identify the two parts of the circulatory system that produce traces I and II on the graph.

[Source: © International Baccalaureate Organization 2019]

Rotavirus causes diarrhea and vomiting. Explain why viral diseases cannot be treated using antibiotics.

Explain how antibiotic resistance can evolve in bacteria, such as those causing pneumonia.

Many diseases are caused by bacteria and other pathogens. Explain, using examples, how other factors can lead to disease in humans.

Calculate the total number of M. lucifugus flights that were recorded in the summer of 2007

Suggest one limitation of this recording method in determining the accurate mean number of individual bats flying.

Calculate the percentage decline in the mean number of M. lucifugus flights for 2009 when compared to 2008.

Evaluate the conclusion that the decline in the population of M. lucifugus is due to infection by the fungus.

Distinguish between the patterns of hibernation of the uninfected and infected bats.

Based on the data and your biological knowledge, suggest how the infection could lead to premature death in a bat.

Outline the relationship between date of death and the mean interval between hibernation emergence periods.

Discuss whether the data in the graph show that there is a causal link between the date of death and the interval between hibernation emergence periods.

Suggest one reason, other than the interval between hibernation emergence periods, for some infected bats surviving longer than others.

Using all of the data, predict the effect of WNS on bat populations.

The diagram shows the major events involved in the formation of a blood clot.

[Source: © International Baccalaureate Organization 2019]

What is Factor Y?

A. Fibrin

B. Prothrombin

C. Fibrinogen

D. Thrombin

Identify the country with the largest number of Ebola cases.

The blood of two men was tested and the results are shown. Anti-D refers to the rhesus blood group. Clotting indicates that antigens associated with a particular factor or blood group are present in a blood sample.

[Source: © International Baccalaureate Organization 2019]

The man who tested positive for anti-D was then tested for ABO blood group. These results were obtained.

[Source: © International Baccalaureate Organization 2019]

What ABO blood group does the man testing positive for anti-D have?

A. A

B. B

C. AB

D. O

The graph shows the results of measuring two factors in the blood of patients with HIV/AIDS.

[Source: Courtesy ACRIA.]

What do X and Y represent?

Explain the role of cells in the defence against infectious disease.

Deduce the concentration of ZDV that would cause a 50 % reduction in root growth compared to the control.

Identify the root length, as a percentage of the control, resulting from a ZDV concentration of $400 \text{μmol}$.

Compare and contrast the effect of ZDV and NVP on the growth of Allium roots.

Based on the information, suggest with a reason which of the labelled cell types will become more common in Allium root tips treated with ZDV.

Allium root tips continue to show some growth even at high concentrations of NVP. Suggest a possible reason for the growth seen in root tips with 800μmol NVP.

Explain the production of antibodies when a patient is infected with the TB bacterium.

Explain how cells and cell components in the blood defend the body against infectious disease.

Explain how blood clotting occurs and the consequence for a person who has hemophilia.

Explain how cells in the bloodstream cause a specific immune response.

Despite continuous scientific research into the control of pathogens, it has proved very difficult to eliminate them. What is/are the reason(s) for this?

I.   Development of antibiotic resistance in viruses

II.  Development of antibiotic resistance in bacteria

III. Mutations of pathogens

A.  II only

B.  I and II only

C.  II and III only

D.  I, II and III

Explain how natural selection could increase the prevalence of an antibiotic resistance gene in a species of soil bacterium.

Using the data in the stacked column graph, describe the features that characterize the B2 enterotype.

The graph shows the results of measuring two factors in the blood of patients with HIV/AIDS.

[Source: Courtesy ACRIA.]

What do X and Y represent?

Explain the role of cells in the defence against infectious disease.

Explain the role of cells in the defence against infectious disease.

Deduce the concentration of ZDV that would cause a 50 % reduction in root growth compared to the control.

Identify the root length, as a percentage of the control, resulting from a ZDV concentration of $400 \text{μmol}$.

Compare and contrast the effect of ZDV and NVP on the growth of Allium roots.

Based on the information, suggest with a reason which of the labelled cell types will become more common in Allium root tips treated with ZDV.

Allium root tips continue to show some growth even at high concentrations of NVP. Suggest a possible reason for the growth seen in root tips with 800μmol NVP.

Deduce the concentration of ZDV that would cause a 50 % reduction in root growth compared to the control.

Identify the root length, as a percentage of the control, resulting from a ZDV concentration of $400 \text{μmol}$.

Compare and contrast the effect of ZDV and NVP on the growth of Allium roots.

Based on the information, suggest with a reason which of the labelled cell types will become more common in Allium root tips treated with ZDV.

Allium root tips continue to show some growth even at high concentrations of NVP. Suggest a possible reason for the growth seen in root tips with 800μmol NVP.

Explain the production of antibodies when a patient is infected with the TB bacterium.

Explain the production of antibodies when a patient is infected with the TB bacterium.

Explain how cells and cell components in the blood defend the body against infectious disease.

Explain how cells and cell components in the blood defend the body against infectious disease.

Explain how blood clotting occurs and the consequence for a person who has hemophilia.

Explain how blood clotting occurs and the consequence for a person who has hemophilia.

Explain how cells in the bloodstream cause a specific immune response.

Explain how cells in the bloodstream cause a specific immune response.

Despite continuous scientific research into the control of pathogens, it has proved very difficult to eliminate them. What is/are the reason(s) for this?

I.   Development of antibiotic resistance in viruses

II.  Development of antibiotic resistance in bacteria

III. Mutations of pathogens

A.  II only

B.  I and II only

C.  II and III only

D.  I, II and III

Rotavirus causes diarrhea and vomiting. Explain why viral diseases cannot be treated using antibiotics.

Rotavirus causes diarrhea and vomiting. Explain why viral diseases cannot be treated using antibiotics.

Explain how natural selection could increase the prevalence of an antibiotic resistance gene in a species of soil bacterium.

Explain how natural selection could increase the prevalence of an antibiotic resistance gene in a species of soil bacterium.

Using the data in the stacked column graph, describe the features that characterize the B2 enterotype.

Using the data in the stacked column graph, describe the features that characterize the B2 enterotype.

Explain how antibiotic resistance can evolve in bacteria, such as those causing pneumonia.

Many diseases are caused by bacteria and other pathogens. Explain, using examples, how other factors can lead to disease in humans.

Explain how antibiotic resistance can evolve in bacteria, such as those causing pneumonia.

Many diseases are caused by bacteria and other pathogens. Explain, using examples, how other factors can lead to disease in humans.

Calculate the total number of M. lucifugus flights that were recorded in the summer of 2007

Suggest one limitation of this recording method in determining the accurate mean number of individual bats flying.

Calculate the percentage decline in the mean number of M. lucifugus flights for 2009 when compared to 2008.

Evaluate the conclusion that the decline in the population of M. lucifugus is due to infection by the fungus.

Distinguish between the patterns of hibernation of the uninfected and infected bats.

Based on the data and your biological knowledge, suggest how the infection could lead to premature death in a bat.

Outline the relationship between date of death and the mean interval between hibernation emergence periods.

Discuss whether the data in the graph show that there is a causal link between the date of death and the interval between hibernation emergence periods.

Suggest one reason, other than the interval between hibernation emergence periods, for some infected bats surviving longer than others.

Using all of the data, predict the effect of WNS on bat populations.

Calculate the total number of M. lucifugus flights that were recorded in the summer of 2007

Suggest one limitation of this recording method in determining the accurate mean number of individual bats flying.

Calculate the percentage decline in the mean number of M. lucifugus flights for 2009 when compared to 2008.

Evaluate the conclusion that the decline in the population of M. lucifugus is due to infection by the fungus.

Distinguish between the patterns of hibernation of the uninfected and infected bats.

Based on the data and your biological knowledge, suggest how the infection could lead to premature death in a bat.

Outline the relationship between date of death and the mean interval between hibernation emergence periods.

Discuss whether the data in the graph show that there is a causal link between the date of death and the interval between hibernation emergence periods.

Suggest one reason, other than the interval between hibernation emergence periods, for some infected bats surviving longer than others.

Using all of the data, predict the effect of WNS on bat populations.

The diagram shows the major events involved in the formation of a blood clot.

[Source: © International Baccalaureate Organization 2019]

What is Factor Y?

A. Fibrin

B. Prothrombin

C. Fibrinogen

D. Thrombin

Identify the country with the largest number of Ebola cases.

Identify the country with the largest number of Ebola cases.

The blood of two men was tested and the results are shown. Anti-D refers to the rhesus blood group. Clotting indicates that antigens associated with a particular factor or blood group are present in a blood sample.

[Source: © International Baccalaureate Organization 2019]

The man who tested positive for anti-D was then tested for ABO blood group. These results were obtained.

[Source: © International Baccalaureate Organization 2019]

What ABO blood group does the man testing positive for anti-D have?

A. A

B. B

C. AB

D. O

Explain how a low FEV can be used to indicate emphysema.

Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.

Elastin is also an important component of other tissues such as arteries and ligaments. Evaluate how these other sources of elastin could affect the interpretation of the biomarker as an indicator of COPD.

Other studies on pulmonary diseases have shown a wide variety of results. Apart from age, sex and severity of COPD, list two other factors that may explain the inconsistent results between studies.

Discuss whether measurements of desmosine concentration would be useful for monitoring changes in the health of a patient.

Using the data in the graph, deduce whether hypoxia increases or decreases the endurance of the rats’ diaphragm muscle.

Using the data presented in this question, explain the effect of hypoxia on the body.

Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.

Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.

Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.

Using all relevant data in the question, evaluate the effectiveness of the rats’ adaptation to hypoxia.

Discuss the advantages and disadvantages of using rats as models in this investigation.

Outline the role of the parts of an alveolus in a human lung.

Calculate the total volume of air inhaled during one minute during the highest velocity of the treadmill in this test, giving the units.

Outline how ventilation rate could have been monitored in this study.

The graph shows a spirometer trace of oxygen consumption when breathing at rest and during exercise.

[Source: Courtesy of Dr. Dafang Wang for his work at University of Utah.]

What explains the difference between the traces at regions X and Y on the graph?

A. At X, the internal intercostal muscles contract more than the external intercostal muscles.

B. At Y, the ribcage moves up and out more than at X.

C. At X, the diaphragm flattens more per breath than at Y.

D. At Y, the intercostal muscles contract more slowly than at X.

Outline the process of inhalation.

Explain the process of gas exchange taking place in the alveoli.

The graph shows the concentration of the lipid lecithin in the amniotic fluid surrounding the fetus during normal gestation. This lipid is produced in the lungs of the fetus and acts as a surfactant.

[Source: Gluck, L. and Kulovich, M., n.d. [Concentrations of phospholipids]. [graph online] Available at:
http://www.columbia.edu/itc/hs/medical/humandev/2004/Chpt12-LungDev.pdf [Accessed 28 October 2021].]

What problem may occur in a baby born before 34 weeks gestation?

A.  Type I pneumocytes do not produce sufficient surfactant for lungs to inflate.

B.  There are no type II pneumocytes.

C.  The alveolar walls stick together.

D.  The alveoli are too large.

The diagram shows a section through an alveolus.

[Source: Bergman, Ronald A., Ph.D., and D'Alessandro, Michael P., M.D. Pulmonary alveoli, “Anatomy Atlases”. Available online: http://www.anatomyatlases.org/ [Accessed 02/01/2023].]

What are the functions of the following labelled structures?

Explain how breathing is controlled by the brain.

The graph shows a spirometer trace of oxygen consumption when breathing at rest and during exercise.

[Source: Courtesy of Dr. Dafang Wang for his work at University of Utah.]

What explains the difference between the traces at regions X and Y on the graph?

A. At X, the internal intercostal muscles contract more than the external intercostal muscles.

B. At Y, the ribcage moves up and out more than at X.

C. At X, the diaphragm flattens more per breath than at Y.

D. At Y, the intercostal muscles contract more slowly than at X.

Outline the process of inhalation.

Explain the process of gas exchange taking place in the alveoli.

Outline the process of inhalation.

Explain the process of gas exchange taking place in the alveoli.

The graph shows the concentration of the lipid lecithin in the amniotic fluid surrounding the fetus during normal gestation. This lipid is produced in the lungs of the fetus and acts as a surfactant.

[Source: Gluck, L. and Kulovich, M., n.d. [Concentrations of phospholipids]. [graph online] Available at:
http://www.columbia.edu/itc/hs/medical/humandev/2004/Chpt12-LungDev.pdf [Accessed 28 October 2021].]

What problem may occur in a baby born before 34 weeks gestation?

A.  Type I pneumocytes do not produce sufficient surfactant for lungs to inflate.

B.  There are no type II pneumocytes.

C.  The alveolar walls stick together.

D.  The alveoli are too large.

The diagram shows a section through an alveolus.

[Source: Bergman, Ronald A., Ph.D., and D'Alessandro, Michael P., M.D. Pulmonary alveoli, “Anatomy Atlases”. Available online: http://www.anatomyatlases.org/ [Accessed 02/01/2023].]

What are the functions of the following labelled structures?

Explain how a low FEV can be used to indicate emphysema.

Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.

Elastin is also an important component of other tissues such as arteries and ligaments. Evaluate how these other sources of elastin could affect the interpretation of the biomarker as an indicator of COPD.

Other studies on pulmonary diseases have shown a wide variety of results. Apart from age, sex and severity of COPD, list two other factors that may explain the inconsistent results between studies.

Discuss whether measurements of desmosine concentration would be useful for monitoring changes in the health of a patient.

Explain how a low FEV can be used to indicate emphysema.

Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.

Elastin is also an important component of other tissues such as arteries and ligaments. Evaluate how these other sources of elastin could affect the interpretation of the biomarker as an indicator of COPD.

Other studies on pulmonary diseases have shown a wide variety of results. Apart from age, sex and severity of COPD, list two other factors that may explain the inconsistent results between studies.

Discuss whether measurements of desmosine concentration would be useful for monitoring changes in the health of a patient.

Using the data in the graph, deduce whether hypoxia increases or decreases the endurance of the rats’ diaphragm muscle.

Using the data presented in this question, explain the effect of hypoxia on the body.

Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.

Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.

Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.

Using all relevant data in the question, evaluate the effectiveness of the rats’ adaptation to hypoxia.

Discuss the advantages and disadvantages of using rats as models in this investigation.

Using the data in the graph, deduce whether hypoxia increases or decreases the endurance of the rats’ diaphragm muscle.

Using the data presented in this question, explain the effect of hypoxia on the body.

Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.

Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.

Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.

Using all relevant data in the question, evaluate the effectiveness of the rats’ adaptation to hypoxia.

Discuss the advantages and disadvantages of using rats as models in this investigation.

Explain how breathing is controlled by the brain.

Outline the role of the parts of an alveolus in a human lung.

Outline the role of the parts of an alveolus in a human lung.

Calculate the total volume of air inhaled during one minute during the highest velocity of the treadmill in this test, giving the units.

Calculate the total volume of air inhaled during one minute during the highest velocity of the treadmill in this test, giving the units.

Outline how ventilation rate could have been monitored in this study.

Outline how ventilation rate could have been monitored in this study.

Which structure in the motor neuron is required for saltatory conduction?

Common pesticides used by gardeners contain neonicotinoids.

[Source: © International Baccalaureate Organization 2018]

What is the effect of a neonicotinoid pesticide on the transmission of a nerve impulse between neurons in an insect?

A. It prevents the release of acetylcholine from the presynaptic membrane.

B. It widens the synaptic cleft so diffusion of acetylcholine across the gap is slower.

C. It irreversibly binds with acetylcholine receptors on the postsynaptic membrane.

D. It interferes with the enzymatic breakdown of acetylcholine by acetylcholinesterase.

Outline how neurons generate a resting potential.

The diagram shows a graph of an action potential.

The diagram shows a neural synapse in the central nervous system of a honey bee (Apis mellifera).

[Source: © International Baccalaureate Organization 2019]

How do neonicotinoid pesticides cause paralysis and death of honey bees?

A. They destroy I.

B. They bind to II.

C. They inhibit the release of III.

D. They block the activity of IV.

The diagram shows a motor neuron.

[Source: © International Baccalaureate Organization 2019]

What are the biochemical nature and function of the myelin sheath?

A. The myelin sheath is mainly protein which allows growth of the axon.

B. The myelin sheath is mainly protein which acts as membrane carriers.

C. The myelin sheath is mainly lipid which allows saltatory conduction.

D. The myelin sheath is mainly lipid which provides an energy source.

Using evidence from the chart, identify, giving a reason, which group of neurons responded most to the chemicals.

Compare and contrast hormonal and nervous communication.

Explain how neonicotinoids affect synaptic transmission in insects.

Companies that manufacture neonicotinoid pesticides have argued that they do not cause significant harm to honeybees. Construct an argument, based on the data in this question, for serious concern about the manufacture and use of neonicotinoid pesticides.

Outline how depolarization of the membrane of an axon occurs.

Explain how acetylcholine initiates an action potential in a postsynaptic membrane.

State the action of the enzyme acetylcholinesterase.

The electron micrograph shows a transverse section through a myelinated neuron.

Explain the propagation of nerve impulses along the membrane of a neuron.

State the approximate value of the membrane potential at X.

Y is the threshold potential. State what happens when the threshold potential is reached.

Describe the movements in ions that occur during time t.

Explain how a nerve impulse is passed on to other neurons.

Describe the effect of neonicotinoid pesticides on the nervous system of insects.

Compare and contrast the cumulative increase in mass of the three groups of colonies once they were placed in the field.

Using the data in the graph, predict how the use of neonicotinoid pesticides will affect bumblebee populations.

Describe the overall effects of low and high doses of neonicotinoid on the egg lengths of all four species.

Deduce, based on the data presented, whether the levels of neonicotinoids used in agriculture cause direct harm to B. terrestris.

The diagram shows the synaptic transmission of nerve impulses by the neurotransmitter acetylcholine. 

[Source: Zhang, X. A Mathematical Model of a Neuron with Synapses based on Physiology. Nat Prec (2008).
https://doi.org/10.1038/npre.2008.1703.1 available at https://www.nature.com/articles/npre.2008.1703.1
Source adapted.]

What is the fate of acetylcholine immediately after binding to the receptor?

A. It is pumped into the postsynaptic neuron.

B. It diffuses into the presynaptic neuron.

C. It is broken down in the synaptic cleft.

D. It binds to another receptor in the postsynaptic neuron.

Identify the structure labelled X.

Outline how the neuron is stimulated to release the neurotransmitter.

Explain the action of neonicotinoid pesticides in insects.

Describe what occurs in a neuron when an action potential is propagated along the axon.

Compare and contrast hormonal and nervous communication.

Compare and contrast hormonal and nervous communication.

Explain how neonicotinoids affect synaptic transmission in insects.

Companies that manufacture neonicotinoid pesticides have argued that they do not cause significant harm to honeybees. Construct an argument, based on the data in this question, for serious concern about the manufacture and use of neonicotinoid pesticides.

Explain how neonicotinoids affect synaptic transmission in insects.

Companies that manufacture neonicotinoid pesticides have argued that they do not cause significant harm to honeybees. Construct an argument, based on the data in this question, for serious concern about the manufacture and use of neonicotinoid pesticides.

Outline how depolarization of the membrane of an axon occurs.

Explain how acetylcholine initiates an action potential in a postsynaptic membrane.

State the action of the enzyme acetylcholinesterase.

Outline how depolarization of the membrane of an axon occurs.

Explain how acetylcholine initiates an action potential in a postsynaptic membrane.

State the action of the enzyme acetylcholinesterase.

The electron micrograph shows a transverse section through a myelinated neuron.

Explain the propagation of nerve impulses along the membrane of a neuron.

Explain the propagation of nerve impulses along the membrane of a neuron.

State the approximate value of the membrane potential at X.

Y is the threshold potential. State what happens when the threshold potential is reached.

Describe the movements in ions that occur during time t.

Explain how a nerve impulse is passed on to other neurons.

State the approximate value of the membrane potential at X.

Y is the threshold potential. State what happens when the threshold potential is reached.

Describe the movements in ions that occur during time t.

Explain how a nerve impulse is passed on to other neurons.

Describe the effect of neonicotinoid pesticides on the nervous system of insects.

Compare and contrast the cumulative increase in mass of the three groups of colonies once they were placed in the field.

Using the data in the graph, predict how the use of neonicotinoid pesticides will affect bumblebee populations.

Describe the overall effects of low and high doses of neonicotinoid on the egg lengths of all four species.

Deduce, based on the data presented, whether the levels of neonicotinoids used in agriculture cause direct harm to B. terrestris.

Describe the effect of neonicotinoid pesticides on the nervous system of insects.

Compare and contrast the cumulative increase in mass of the three groups of colonies once they were placed in the field.

Using the data in the graph, predict how the use of neonicotinoid pesticides will affect bumblebee populations.

Describe the overall effects of low and high doses of neonicotinoid on the egg lengths of all four species.

Deduce, based on the data presented, whether the levels of neonicotinoids used in agriculture cause direct harm to B. terrestris.

The diagram shows the synaptic transmission of nerve impulses by the neurotransmitter acetylcholine. 

[Source: Zhang, X. A Mathematical Model of a Neuron with Synapses based on Physiology. Nat Prec (2008).
https://doi.org/10.1038/npre.2008.1703.1 available at https://www.nature.com/articles/npre.2008.1703.1
Source adapted.]

What is the fate of acetylcholine immediately after binding to the receptor?

A. It is pumped into the postsynaptic neuron.

B. It diffuses into the presynaptic neuron.

C. It is broken down in the synaptic cleft.

D. It binds to another receptor in the postsynaptic neuron.

Identify the structure labelled X.

Outline how the neuron is stimulated to release the neurotransmitter.

Explain the action of neonicotinoid pesticides in insects.

Identify the structure labelled X.

Outline how the neuron is stimulated to release the neurotransmitter.

Explain the action of neonicotinoid pesticides in insects.

Describe what occurs in a neuron when an action potential is propagated along the axon.

Describe what occurs in a neuron when an action potential is propagated along the axon.

Which structure in the motor neuron is required for saltatory conduction?

Common pesticides used by gardeners contain neonicotinoids.

[Source: © International Baccalaureate Organization 2018]

What is the effect of a neonicotinoid pesticide on the transmission of a nerve impulse between neurons in an insect?

A. It prevents the release of acetylcholine from the presynaptic membrane.

B. It widens the synaptic cleft so diffusion of acetylcholine across the gap is slower.

C. It irreversibly binds with acetylcholine receptors on the postsynaptic membrane.

D. It interferes with the enzymatic breakdown of acetylcholine by acetylcholinesterase.

Outline how neurons generate a resting potential.

Outline how neurons generate a resting potential.

The diagram shows a graph of an action potential.

The diagram shows a neural synapse in the central nervous system of a honey bee (Apis mellifera).

[Source: © International Baccalaureate Organization 2019]

How do neonicotinoid pesticides cause paralysis and death of honey bees?

A. They destroy I.

B. They bind to II.

C. They inhibit the release of III.

D. They block the activity of IV.

The diagram shows a motor neuron.

[Source: © International Baccalaureate Organization 2019]

What are the biochemical nature and function of the myelin sheath?

A. The myelin sheath is mainly protein which allows growth of the axon.

B. The myelin sheath is mainly protein which acts as membrane carriers.

C. The myelin sheath is mainly lipid which allows saltatory conduction.

D. The myelin sheath is mainly lipid which provides an energy source.

Using evidence from the chart, identify, giving a reason, which group of neurons responded most to the chemicals.

Using evidence from the chart, identify, giving a reason, which group of neurons responded most to the chemicals.

Explain how hormones are used to control the human menstrual cycle.

The diagram shows the human female reproductive system.

[Source: © International Baccalaureate Organization 2019]

What is produced by structure X?

A. FSH

B. X chromosomes

C. Fertilized eggs

D. Estrogen and progesterone

The diagram shows the human female reproductive system

[Source: © International Baccalaureate Organization 2019]

Which labels indicate where fertilization occurs and where luteinizing hormone (LH) acts?

Discuss the control of blood glucose levels and the consequences if they are not maintained.

The diagram shows the human male reproductive system.

[Source: logika600/Shutterstock]

Which numbers indicate a gland providing fluid for sperm and a tube that transports sperm only?

Compare the data for plasma insulin levels before and after the study diet.

State which cells secrete insulin.

Outline one aspect of how P. caudatum carries out homeostasis.

The graph shows the blood levels of hormones associated with the menstrual cycle.

The graph showing blood levels of hormones associated with the menstrual cycle.

Describe the genetic and hormonal control of male sexual characteristics in a human.

Compare and contrast hormonal and nervous communication.

What is a function of luteinizing hormone (LH) in the female menstrual cycle?

A. To promote secondary sexual characteristics

B. To inhibit progesterone secretion

C. To stimulate the follicle to release estrogen

D. To trigger ovulation

Leptin helps to regulate body mass in humans and mice. The image shows an obese mouse (O) and a normal mouse (N).

[Source: [Obesity in mice]. [image online] Available at: https://commons.wikimedia.org/wiki/File:Fatmouse.jpg Oak Ridge National Laboratory, U.S. Department of Energy.]

What hypothesis could account for the differences between the mice?

A. The hypothalamus of mouse O stopped producing leptin.

B. Adipose cells of mouse O are continuously producing leptin.

C. Mouse N has a defective leptin receptor.

D. Leptin binds to receptors in the hypothalamus of mouse N.

Describe what is happening to the bone during hibernation.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Discuss how helpful these studies of bears can be in developing an understanding of osteoporosis in humans.

Explain what happens in a person when they develop type I diabetes.

The diagram shows organs that produce hormones in a female human. Which organ is the source of the hormone used in IVF treatment to produce many ova?

Melatonin controls circadian rhythms and is involved in the sleep-wake cycle. The pineal gland, which secretes melatonin, is inhibited by light. The graph shows a normal cycle where bedtime is around 10pm.

Using data from the graph, what might be the effect(s) of screen light from a laptop, tablet or phone at bedtime?

I.   Delay in melatonin production

II.  Lower peak concentration of melatonin

III. Peak of melatonin earlier in the evening

A.  I only

B.  III only

C.  II and III only

D.  I, II and III

State how many water molecules are shown in the diagram. 

Outline the role of ADH in osmoregulation.

Merriam’s kangaroo rat (Dipodomys merriami) is a small mammal found in desert biomes in the southwestern USA and Mexico. What would help these kangaroo rats to conserve water in order to survive high temperatures in desert biomes?

A.  Increased sweating

B.  A long loop of Henle

C.  Decreased secretion of ADH

D.  Decreased reabsorption from the collecting duct

State how many chromosomes there would be in male or female gametes of L. purpureus.

State how many water molecules are shown in the diagram. 

Compare the data for plasma insulin levels before and after the study diet.

State which cells secrete insulin.

Compare the data for plasma insulin levels before and after the study diet.

State which cells secrete insulin.

Outline one aspect of how P. caudatum carries out homeostasis.

Outline one aspect of how P. caudatum carries out homeostasis.

The graph shows the blood levels of hormones associated with the menstrual cycle.

The graph showing blood levels of hormones associated with the menstrual cycle.

Describe the genetic and hormonal control of male sexual characteristics in a human.

Compare and contrast hormonal and nervous communication.

Describe the genetic and hormonal control of male sexual characteristics in a human.

Compare and contrast hormonal and nervous communication.

What is a function of luteinizing hormone (LH) in the female menstrual cycle?

A. To promote secondary sexual characteristics

B. To inhibit progesterone secretion

C. To stimulate the follicle to release estrogen

D. To trigger ovulation

Leptin helps to regulate body mass in humans and mice. The image shows an obese mouse (O) and a normal mouse (N).

[Source: [Obesity in mice]. [image online] Available at: https://commons.wikimedia.org/wiki/File:Fatmouse.jpg Oak Ridge National Laboratory, U.S. Department of Energy.]

What hypothesis could account for the differences between the mice?

A. The hypothalamus of mouse O stopped producing leptin.

B. Adipose cells of mouse O are continuously producing leptin.

C. Mouse N has a defective leptin receptor.

D. Leptin binds to receptors in the hypothalamus of mouse N.

Describe what is happening to the bone during hibernation.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Discuss how helpful these studies of bears can be in developing an understanding of osteoporosis in humans.

Describe what is happening to the bone during hibernation.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Discuss how helpful these studies of bears can be in developing an understanding of osteoporosis in humans.

Explain what happens in a person when they develop type I diabetes.

Explain what happens in a person when they develop type I diabetes.

The diagram shows organs that produce hormones in a female human. Which organ is the source of the hormone used in IVF treatment to produce many ova?

Melatonin controls circadian rhythms and is involved in the sleep-wake cycle. The pineal gland, which secretes melatonin, is inhibited by light. The graph shows a normal cycle where bedtime is around 10pm.

Using data from the graph, what might be the effect(s) of screen light from a laptop, tablet or phone at bedtime?

I.   Delay in melatonin production

II.  Lower peak concentration of melatonin

III. Peak of melatonin earlier in the evening

A.  I only

B.  III only

C.  II and III only

D.  I, II and III

Explain how hormones are used to control the human menstrual cycle.

Explain how hormones are used to control the human menstrual cycle.

State how many water molecules are shown in the diagram. 

State how many water molecules are shown in the diagram. 

Outline the role of ADH in osmoregulation.

Outline the role of ADH in osmoregulation.

Merriam’s kangaroo rat (Dipodomys merriami) is a small mammal found in desert biomes in the southwestern USA and Mexico. What would help these kangaroo rats to conserve water in order to survive high temperatures in desert biomes?

A.  Increased sweating

B.  A long loop of Henle

C.  Decreased secretion of ADH

D.  Decreased reabsorption from the collecting duct

State how many chromosomes there would be in male or female gametes of L. purpureus.

State how many chromosomes there would be in male or female gametes of L. purpureus.

State how many water molecules are shown in the diagram. 

State how many water molecules are shown in the diagram. 

The diagram shows the human female reproductive system.

[Source: © International Baccalaureate Organization 2019]

What is produced by structure X?

A. FSH

B. X chromosomes

C. Fertilized eggs

D. Estrogen and progesterone

The diagram shows the human female reproductive system

[Source: © International Baccalaureate Organization 2019]

Which labels indicate where fertilization occurs and where luteinizing hormone (LH) acts?

Discuss the control of blood glucose levels and the consequences if they are not maintained.

Discuss the control of blood glucose levels and the consequences if they are not maintained.

The diagram shows the human male reproductive system.

[Source: logika600/Shutterstock]

Which numbers indicate a gland providing fluid for sperm and a tube that transports sperm only?