Transport of oxygen and carbon dioxide

Which factors would assist a person in adapting from living at a low altitude to living at a high altitude?

Feb/March 2018

Tobacco smoke contains substances that influence the functioning of the human body. Which option correctly matches the substances with their effects?

Feb/March 2019

The diagram illustrates a network of blood vessels that delivers blood to muscle tissue in the human body. When the muscle tissue is at rest, which statement correctly compares the blood at X with the blood at Y?

Feb/March 2023

What effect does a higher concentration of carbon dioxide in the blood have?

Feb/March 2023

Carbon dioxide travels in the blood in several different forms.

May/June 2011

Explain how the structure of red blood cells is adapted for the transport of oxygen to body tissues.

May/June 2011

In mammals, haemoglobin transports oxygen, while myoglobin stores oxygen in muscles. Fig. 4.1 gives the oxygen dissociation curves for myoglobin, fetal haemoglobin and adult haemoglobin.

May/June 2011

Haemoglobinopathies are inherited disorders associated with the structure and function of haemoglobin. Sickle cell anaemia is one such condition, in which oxygen is transported to and delivered to tissues less effectively than normal. An investigation was done to find out how sickle cell anaemia affects the capacity of blood to carry oxygen. Blood samples were collected from two people: person L without sickle cell anaemia and person M with sickle cell anaemia. The percentage saturation of haemoglobin with oxygen was measured across a range of oxygen partial pressures. Fig. 3.1 shows oxygen haemoglobin dissociation curves for the two blood samples.

May/June 2012

Which process can take place in a mature red blood cell?

May/June 2014

The diagram presents an enlarged view of part of the lungs that contains specialised tissues. In which location would a high proportion of carbonic anhydrase, $\text{HCO}_3^-$ ions and lysosomes be present?

May/June 2014

Which row correctly shows the effects of carbon monoxide, nicotine and tar?

May/June 2014

The graph presents the findings of a study designed to find out whether a relationship exists between the number of cigarettes smoked by a mother and the birth weight of her baby. Which conclusions may be made from this graph? 1 As the number of cigarettes smoked rises, the baby's weight always falls. 2 Other factors besides smoking influence a baby's birth weight. 3 Nicotine, tar and carbon monoxide reduce the growth of an unborn baby. 4 Most smokers smoke between 10 and 35 cigarettes per day.

May/June 2015

Within an ecosystem, during which stage is the greatest amount of energy lost?

May/June 2015

From the prey eaten by the lion, which box receives the greatest amount of energy?

May/June 2015

Which short-term effects of smoking result from carbon monoxide?

May/June 2016

The photograph depicts one kind of blood cell. Which of the following statements about these cells are correct?

May/June 2016

Fig. 5.1 shows part of an animal cell during a stage of mitosis.

May/June 2016

When humans are kept at high altitudes, their red blood cell count rises. What causes this to happen?

May/June 2017

At high altitudes, the oxygen content of the air can be one third of the level at sea level. As a person climbs a mountain, the body slowly adapts to the altitude. What increases during this adjustment period?

May/June 2018

Fig. 4.1 shows a ribbon diagram of a haemoglobin molecule.

May/June 2018

Oxygen diffuses from the alveoli in the lungs into the blood stream, while carbon dioxide diffuses out of the blood stream into the alveoli. Most oxygen is transported by haemoglobin in red blood cells to the body tissues.

May/June 2018

Athletes sometimes travel from low altitude to high altitude when preparing for a race. Which of the following statements about the effects of high-altitude training are correct?

May/June 2019

Fig. 5.1 is a photomicrograph showing human blood cells that have been suspended in a sodium chloride solution.

May/June 2019

What accurately describes the importance of the rise in the red blood cell count of humans who move from living at low altitude to high altitude?

May/June 2020

Cigarette smoke includes carbon monoxide, nicotine and tar. Which row gives the correct description of how these substances affect the body?

May/June 2020

At high altitudes, the oxygen content of the air can be only a third of the amount at sea level. As a person makes a gradual climb up a mountain, the body slowly adapts to the high altitude. What is increased during this time of adjustment?

May/June 2021

The enzyme carbonic anhydrase has been identified in a wide variety of organisms and functions as a catalyst in many tissues. Research has shown that the protein structure of the enzyme differs, and that the number and arrangement of introns and exons in the gene coding for the enzyme also differ. All carbonic anhydrase enzymes catalyse the same reversible reaction, shown in Fig. 4.1: $\text{CO}_2 + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3 \rightleftharpoons \text{H}^+ + \text{HCO}_3^-$

May/June 2022

What substance is found in the blood inside human veins?

May/June 2023

Fig. 5.1 shows a longitudinal section of a capillary in muscle tissue, as seen with a transmission electron microscope.

May/June 2023

Blood includes red blood cells as well as white blood cells.

May/June 2023

State which part of the haemoglobin molecule is labelled X.

May/June 2025

Respiratory gases are carried by both blood plasma and red blood cells. The globular protein found in red blood cells is haemoglobin.

May/June 2025

A number of babies are born with an opening between the right and left atria. These newborn babies are discovered to have a larger number of red blood cells. Why does this happen?

Oct/Nov 2010

Which of the effects in the list occur as a result of breathing in both carbon monoxide and nicotine from cigarette smoke?

Oct/Nov 2010

Red blood cells are kept in plasma, and this plasma has a concentration equal to a 0.9\% sodium chloride (NaCl) solution. A student investigated the changes to red blood cells when they were placed in sodium chloride solutions of different concentrations. A small drop of blood was added to $10\text{ cm}^3$ of each sodium chloride solution. Samples were then taken from each mixture and viewed under the microscope. The number of red blood cells still present in each sample was worked out as a percentage of the number in the 0.9\% solution. The results are shown in Fig. 3.1.

Oct/Nov 2010

The photograph depicts a kind of blood cell. Which of these statements about the cells is correct?

Oct/Nov 2012

A mature human body contains about $5\,\text{dm}^3$ of blood, and this blood makes one complete circulation roughly every minute. Each $100\,\text{cm}^3$ of arterial blood contains $19\,\text{cm}^3$ of oxygen. Each $100\,\text{cm}^3$ of venous blood contains $12.5\,\text{cm}^3$ of oxygen. What is the approximate volume in $\text{cm}^3$ of oxygen absorbed per minute in the lungs?

Oct/Nov 2012

An insect ingests $180\ \text{J}$ of plant material. From this, $95\ \text{J}$ of energy leaves in the insect’s faeces and $58\ \text{J}$ is released in respiration. What percentage of the energy in the original plant material absorbed by the insect is turned into biomass?

Oct/Nov 2013

People have a higher red blood cell count when they live at high altitudes. What causes this?

Oct/Nov 2013

Table 2.1 lists eight ions of biological significance: ammonium ($\text{NH}_4^{+}$), hydrogen ($\text{H}^{+}$), hydrogen carbonate ($\text{HCO}_3^{-}$), iron ($\text{Fe}^{2+}$), magnesium ($\text{Mg}^{2+}$), nitrate ($\text{NO}_3^{-}$), phosphate ($\text{PO}_4^{3-}$), sulfate ($\text{SO}_4^{2-}$). For each statement below, select the ion that fits it. In every case, write one letter from Table 2.1. Any letter from A to H may be used once, repeatedly, or not used at all.

Oct/Nov 2013

In mammals, oxygen is carried by red blood cells within a system called double circulation. Most oxygen molecules travel as oxyhaemoglobin. In respiring tissues, oxygen leaves haemoglobin and diffuses into nearby cells.

Oct/Nov 2014

Which process takes place in a mature red blood cell?

Oct/Nov 2015

Which of the following effects are brought about by inhaling both carbon monoxide and nicotine in cigarette smoke?

Oct/Nov 2015

What substance is found in the blood within human veins?

Oct/Nov 2015

Complete Table 4.1 by naming the transport mechanism shown in each example.

Oct/Nov 2015

The table gives some of the consequences of smoking. Which row indicates the effect of nicotine and carbon monoxide?

Oct/Nov 2016

A study determined the volume of oxygen that combined with haemoglobin at a range of different partial pressures of oxygen. The findings are shown in Fig. 5.1.

Oct/Nov 2016

Which process is able to be carried out by a mature red blood cell?

Oct/Nov 2018

Which reactions occur in blood as it flows through active tissues?

Oct/Nov 2018

The graph illustrates the percentage saturation of haemoglobin with oxygen over a range of partial pressures of oxygen, with two different partial pressures of carbon dioxide shown. One curve is drawn for the partial pressure of carbon dioxide in the lungs, and the other curve is drawn for the partial pressure of carbon dioxide in the liver. Which points on the curves represent the percentage saturation of haemoglobin in the lungs and in the liver?

Oct/Nov 2018

A person relocates from sea level to live at a high altitude. After spending three months at high altitude, which change would be present in this person while at rest?

Oct/Nov 2018

Haemoglobin is a globular protein that can carry oxygen and is soluble in water.

Oct/Nov 2018

As a red blood cell reaches maturity, its organelles are removed from the cell. This leaves extra room for the haemoglobin molecules that have been synthesised.

Oct/Nov 2018

People who smoke tobacco are at a higher risk of developing non-infectious diseases of the gas exchange system and the cardiovascular system. In 2004, a survey was carried out on the most popular filter cigarette brands from each of the six World Health Organization (WHO) regions. During this survey, the smoke drawn through the filter was tested for tar, nicotine and carbon monoxide (CO) content for every cigarette brand. For each WHO region, the mean tar, nicotine and carbon monoxide content of the different cigarette brands was calculated. The results are shown in Fig. 2.1.

Oct/Nov 2019

Fig. 1.1 shows a diagram of a haemoglobin molecule.

Oct/Nov 2019

Fig. 6.1 illustrates the oxygen dissociation curve of adult human haemoglobin. When the partial pressure of carbon dioxide $(p\text{CO}_2)$ rises in respiring tissue, the Bohr effect occurs.

Oct/Nov 2020

When active tissues contain a high concentration of carbon dioxide, oxyhaemoglobin must release oxygen to the tissues. In what form is carbon dioxide carried away from the tissues in the blood?

Oct/Nov 2021

Fig. 3.1 shows a transmission electron micrograph of red blood cells inside a capillary from a healthy adult. The image magnification is $\times 4000$.

Oct/Nov 2021

Fig. 6.1 illustrates several of the changes that happen as a red blood cell passes through a capillary in the lungs. The diagram shows the reactions $\text{CO}_2 + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3 \rightleftharpoons \text{HCO}_3^- + \text{H}^+$ and $X + \text{O}_2 \rightarrow \text{HbO}_2 + \text{H}^+$, and the movement of $\text{HCO}_3^-$ and $\text{Cl}^-$ between the red blood cell and plasma.

Oct/Nov 2022

Researchers measured the concentrations of sodium ions and potassium ions in red blood cells and in blood plasma from a group of people. Table 1.1 presents the results, with mean concentrations expressed in $\text{mmol dm}^{-3}$.

Oct/Nov 2023

Haemoglobin is a large, complex protein made up of four separate subunits, as shown in Fig. 3.1.

Oct/Nov 2023

Some babies are born with an opening between the right atrium and the left atrium. In these babies, a larger number of red blood cells is found. What is the cause of this rise in red blood cells in these babies?

Oct/Nov 2024

The photomicrograph shows a kind of blood cell. Which statements about these cells are correct?

Oct/Nov 2024

In the mammalian circulatory system, red blood cells move through several kinds of blood vessel as they leave the heart for respiring tissues and then return to the heart. Fig. 2.1 shows the kinds of blood vessels through which red blood cells move in the circulatory system.

Oct/Nov 2024

Haemoglobin is a globular protein that contains haem groups. Explain how the presence of haem groups enables the haemoglobin molecule to transport oxygen.

Oct/Nov 2025