Human Biology 4HB1 | Paper 2 Mock 01 | Written Paper 2
Question 1 Report
Fig. 1 shows a simplified section through the surface of a human heart. A cardiologist has identified a narrowed coronary artery at P in a person who experiences chest pain when walking uphill.
(a) Name the type of blood vessel at P. [1]
(b) Describe how narrowing at P affects the blood supply to nearby heart muscle cells. [3]
(c) Explain how inserting a stent at P can reduce the person's symptoms. [2]
(d) Use the information in the question to explain why the chest pain is more likely during uphill walking than when resting. [2]
(a) P is an artery, specifically a coronary artery. [1]
(b) Narrowing reduces the amount of blood that can flow through the coronary artery. Consequently, less oxygen reaches nearby heart muscle cells. Less aerobic respiration can occur, so less energy is released for heart muscle contraction. [3]
(c) A stent holds the artery open and widens its lumen. This allows more blood, and therefore more oxygen, to reach the heart muscle, reducing symptoms caused by limited oxygen supply. [2]
(d) Uphill walking makes the heart work harder. Its muscle needs more oxygen, but the narrowed artery cannot provide enough blood and oxygen to meet the increased demand, causing chest pain. [2]
Answer Details
(a) P is an artery, specifically a coronary artery. [1]
(b) Narrowing reduces the amount of blood that can flow through the coronary artery. Consequently, less oxygen reaches nearby heart muscle cells. Less aerobic respiration can occur, so less energy is released for heart muscle contraction. [3]
(c) A stent holds the artery open and widens its lumen. This allows more blood, and therefore more oxygen, to reach the heart muscle, reducing symptoms caused by limited oxygen supply. [2]
(d) Uphill walking makes the heart work harder. Its muscle needs more oxygen, but the narrowed artery cannot provide enough blood and oxygen to meet the increased demand, causing chest pain. [2]
Question 2 Report
At a coastal education centre, visitors monitored a small brackish-water enclosure for 30 days. Fig. 1 shows one feeding route observed in the enclosure. An arrow points from the organism that is eaten to the organism that eats it. Table 1 gives the energy becoming new biomass at each stage during the survey. The centre is considering whether fish from similar ponds could be used as food for people.
Table 1
| Organism | Energy becoming new biomass in 30 days / kJ |
|---|---|
| algae | 48 000 |
| water fleas | 5 800 |
| sticklebacks | 620 |
| heron | 45 |
(a) Name the producer in Fig. 1. [1]
(b) Describe what the arrows in Fig. 1 show. [2]
(c) Use Table 1 to calculate the percentage of water-flea biomass energy transferred to stickleback biomass. Give your answer to the nearest whole number. [2]
(d) Explain why much of the energy in water fleas does not become stickleback biomass. [3]
(e) Suggest why growing edible algae for human food could provide more usable food energy per area than growing sticklebacks. [3]
(f) Describe the likely effect on the heron population if disease caused a large fall in the number of water fleas. [2]
(a) The producer is algae. Producers make biomass using energy from sunlight. [1]
(b) The arrows show feeding relationships, or transfer of food energy. Each arrow points from the organism that is eaten to the consumer that eats it. [2]
(c) \[\frac{620}{5800}\times100=10.69\ldots\%\] To the nearest whole number, the transfer is 11%. [2]
(d) Sticklebacks use energy in respiration, and energy is released as heat. Energy is also used for movement and maintaining body processes. Some food is not digested and is lost in faeces, while some is lost in excretion. Any three relevant losses explain why only a small fraction becomes biomass. [3]
(e) If people eat algae, fewer trophic transfers are needed than if they eat sticklebacks. Energy is lost through respiration and waste at every transfer. Therefore more original energy becomes available as human food, so less area is needed for the same usable food energy. [3]
(f) A large fall in water fleas reduces food available to sticklebacks, so stickleback numbers are likely to fall. Herons then have less stickleback food, reducing survival or reproduction, so the heron population is also likely to fall. [2]
Answer Details
(a) The producer is algae. Producers make biomass using energy from sunlight. [1]
(b) The arrows show feeding relationships, or transfer of food energy. Each arrow points from the organism that is eaten to the consumer that eats it. [2]
(c) \[\frac{620}{5800}\times100=10.69\ldots\%\] To the nearest whole number, the transfer is 11%. [2]
(d) Sticklebacks use energy in respiration, and energy is released as heat. Energy is also used for movement and maintaining body processes. Some food is not digested and is lost in faeces, while some is lost in excretion. Any three relevant losses explain why only a small fraction becomes biomass. [3]
(e) If people eat algae, fewer trophic transfers are needed than if they eat sticklebacks. Energy is lost through respiration and waste at every transfer. Therefore more original energy becomes available as human food, so less area is needed for the same usable food energy. [3]
(f) A large fall in water fleas reduces food available to sticklebacks, so stickleback numbers are likely to fall. Herons then have less stickleback food, reducing survival or reproduction, so the heron population is also likely to fall. [2]
Question 3 Report
The diagram shows how influenza can spread in a crowded clinic waiting room. An infected person coughs. Some droplets land on a chair arm, and other droplets are breathed in by a person sitting nearby.
(a) Name the type of pathogen that causes influenza. [1]
(b) Describe two routes by which the influenza virus shown in the diagram can enter another person's body. [2]
(c) Explain why antibiotics would not cure influenza. [2]
(d) Complete the sentence: Covering a cough can reduce the number of virus-containing __________ released into the air. [1]
(a) Influenza is caused by a virus [1].
(b) Virus-containing droplets can be breathed into the nose or mouth [1]. Droplets landing on the chair arm can transfer to hands and then enter through the mouth, nose or eyes [1].
(c) Antibiotics act against bacteria [1]. Influenza is caused by a virus, so antibiotics do not kill the influenza virus and would not cure the illness [1].
(d) The missing word is droplets [1].
Answer Details
(a) Influenza is caused by a virus [1].
(b) Virus-containing droplets can be breathed into the nose or mouth [1]. Droplets landing on the chair arm can transfer to hands and then enter through the mouth, nose or eyes [1].
(c) Antibiotics act against bacteria [1]. Influenza is caused by a virus, so antibiotics do not kill the influenza virus and would not cure the illness [1].
(d) The missing word is droplets [1].
Question 4 Report
Table 1 shows measurements made during an altitude-training assessment. Two healthy people cycled for 12 minutes at the same workload. One test was carried out at sea level and the other in a chamber where the air had a lower oxygen concentration. Blood samples were taken immediately after exercise. The body cells of each person need oxygen for aerobic respiration.
| Test condition | Oxygen concentration in inhaled air (%) | Breathing rate (breaths per minute) | Oxygen concentration in blood leaving lungs (%) |
|---|---|---|---|
| Sea level | 21.0 | 22 | 19.2 |
| Low-oxygen chamber | 15.0 | 31 | 16.8 |
(a) Use Table 1 to state the difference in breathing rate between the two tests. [1]
(b) Explain why the person in the low-oxygen chamber breathed faster. [3]
(c) Describe the effect of the lower oxygen concentration in inhaled air on the oxygen concentration in blood leaving the lungs. [2]
(d) Explain how reduced oxygen delivery to body cells could affect the person’s cycling performance. [3]
(e) Suggest one control used in this assessment that makes the comparison between the two people more valid. [2]
(a) \[31 - 22 = 9\] The breathing rate is 9 breaths per minute higher in the low-oxygen chamber. [1]
(b) The inhaled air in the chamber contains less oxygen. Therefore less oxygen diffuses into the blood and blood oxygen concentration falls. Faster breathing increases ventilation, bringing more air, and therefore more oxygen, to the air spaces each minute. [3]
(c) Lower oxygen concentration in inhaled air decreases the oxygen concentration in blood leaving the lungs, from \(19.2\%\) to \(16.8\%\). This is a decrease of \(2.4\) percentage points. [2]
(d) Less oxygen delivered to body cells reduces the rate of aerobic respiration. Less energy is released for muscle contraction, so muscles fatigue sooner or produce less force. Cycling performance is therefore reduced. [3]
(e) Valid controls include making both people cycle at the same workload and for the same time. Using the same equipment and taking blood samples at the same time after exercise are also acceptable. These controls mean oxygen concentration is the main intended difference. [2]
Answer Details
(a) \[31 - 22 = 9\] The breathing rate is 9 breaths per minute higher in the low-oxygen chamber. [1]
(b) The inhaled air in the chamber contains less oxygen. Therefore less oxygen diffuses into the blood and blood oxygen concentration falls. Faster breathing increases ventilation, bringing more air, and therefore more oxygen, to the air spaces each minute. [3]
(c) Lower oxygen concentration in inhaled air decreases the oxygen concentration in blood leaving the lungs, from \(19.2\%\) to \(16.8\%\). This is a decrease of \(2.4\) percentage points. [2]
(d) Less oxygen delivered to body cells reduces the rate of aerobic respiration. Less energy is released for muscle contraction, so muscles fatigue sooner or produce less force. Cycling performance is therefore reduced. [3]
(e) Valid controls include making both people cycle at the same workload and for the same time. Using the same equipment and taking blood samples at the same time after exercise are also acceptable. These controls mean oxygen concentration is the main intended difference. [2]
Question 5 Report
Fig. 1 shows the skin between the toes of a swimmer who has athlete's foot after using a changing-room floor without sandals. The condition is itchy and can spread in damp communal areas.
(a) Name the group of pathogens that causes athlete's foot. [1]
(b) Describe how the disease could spread from this swimmer to another person in the changing room. [2]
(c) Explain why drying feet thoroughly and wearing sandals could reduce spread of the disease. [2]
(a) Athlete's foot is caused by a fungus [1].
(b) Fungal cells or spores may be left on the damp changing-room floor by the swimmer [1]. Another person can acquire the fungus when their feet contact that contaminated floor [1].
(c) Drying feet removes the damp conditions needed for fungal growth [1]. Sandals prevent direct contact between feet and a contaminated floor [1], reducing transfer of fungal spores.
Answer Details
(a) Athlete's foot is caused by a fungus [1].
(b) Fungal cells or spores may be left on the damp changing-room floor by the swimmer [1]. Another person can acquire the fungus when their feet contact that contaminated floor [1].
(c) Drying feet removes the damp conditions needed for fungal growth [1]. Sandals prevent direct contact between feet and a contaminated floor [1], reducing transfer of fungal spores.
Question 6 Report
Read the information and study Fig. 1. A paramedic attends a music event where a person has taken an unknown drug and is showing signs of overheating, confusion and a rapid heart rate. The diagram shows the body's negative-feedback response when body temperature rises. The medical team must first assess the person's condition and identify the substance where possible.
(a) Name the body system that carries chemical messages in the blood. [1]
(b) Use Fig. 1 to explain how sweating lowers body temperature. [3]
(c) Explain why severe overheating can be dangerous to a person's cells. [3]
(d) Describe three actions a trained first aider should take while waiting for emergency medical help. [3]
(e) Explain why taking an unknown drug at a crowded event may increase both physical and mental health risks. [4]
(f) Suggest three pieces of information the paramedic should obtain from friends of the person. [3]
(a) The endocrine system carries chemical messages, called hormones, in the blood. [1]
(b) When temperature rises, sweating increases. Sweat evaporates from the skin, and evaporation transfers heat energy from the body to the surroundings. This lowers body temperature. [3]
(c) Severe overheating can denature enzymes. Enzyme-controlled reactions then slow down or stop, so cells and organs may be damaged or fail. [3]
(d) Appropriate actions include calling emergency services, moving the person to a cooler and less crowded place if safe, removing excess clothing or cooling with damp cloths, and monitoring breathing and level of response. If unconscious but breathing, place the person in the recovery position. Do not give more drugs or alcohol. Any three gain credit. [3]
(e) Unknown drugs have unpredictable contents and doses. They may increase body temperature or heart rate, while crowding and dancing increase heat production and dehydration. Confusion impairs judgement and increases injury risk; anxiety, panic or altered perception can affect mental health. Alcohol or other drugs can further increase risk. Any four points gain credit. [4]
(f) The paramedic should obtain any three of: the substance taken, amount taken, time taken, whether alcohol or other drugs were used, known medical conditions or medicines, and changes in symptoms or consciousness. [3]
Answer Details
(a) The endocrine system carries chemical messages, called hormones, in the blood. [1]
(b) When temperature rises, sweating increases. Sweat evaporates from the skin, and evaporation transfers heat energy from the body to the surroundings. This lowers body temperature. [3]
(c) Severe overheating can denature enzymes. Enzyme-controlled reactions then slow down or stop, so cells and organs may be damaged or fail. [3]
(d) Appropriate actions include calling emergency services, moving the person to a cooler and less crowded place if safe, removing excess clothing or cooling with damp cloths, and monitoring breathing and level of response. If unconscious but breathing, place the person in the recovery position. Do not give more drugs or alcohol. Any three gain credit. [3]
(e) Unknown drugs have unpredictable contents and doses. They may increase body temperature or heart rate, while crowding and dancing increase heat production and dehydration. Confusion impairs judgement and increases injury risk; anxiety, panic or altered perception can affect mental health. Alcohol or other drugs can further increase risk. Any four points gain credit. [4]
(f) The paramedic should obtain any three of: the substance taken, amount taken, time taken, whether alcohol or other drugs were used, known medical conditions or medicines, and changes in symptoms or consciousness. [3]
Question 7 Report
Fig. 1 shows a sports clinic image of the elbow joint of a person whose arm is bent to catch a ball. The labelled muscles work as an antagonistic pair. The humerus is the upper arm bone and the radius is one bone of the forearm.
(a) Name the muscles labelled X and Y. [2]
(b) Describe the movement of the forearm at the elbow when the person straightens their arm. [2]
(c) Explain how the muscles labelled X and Y cause the arm to bend at the elbow. [3]
(d) Complete the statements about this movement.
A muscle is attached to a bone by a __________. Muscles can only __________, so a second muscle is needed to pull the bone in the opposite direction. [2]
(e) Use Fig. 1 to name the type of joint at the elbow. [1]
(a) X is the biceps [1] and Y is the triceps [1].
(b) When the arm straightens, the forearm moves away from the upper arm and the angle at the elbow increases [1]. This movement is called extension [1].
(c) To bend the arm, the biceps contracts and shortens [1]. Its tendon pulls the radius, and therefore the forearm, upwards [1]. At the same time, the triceps relaxes and lengthens [1]. Antagonistic muscles work in opposite ways because muscles can pull but cannot push.
(d) A muscle is attached to a bone by a tendon [1]. Muscles can only contract or shorten [1].
(e) The elbow is a hinge joint [1], allowing movement mainly in one plane.
Answer Details
(a) X is the biceps [1] and Y is the triceps [1].
(b) When the arm straightens, the forearm moves away from the upper arm and the angle at the elbow increases [1]. This movement is called extension [1].
(c) To bend the arm, the biceps contracts and shortens [1]. Its tendon pulls the radius, and therefore the forearm, upwards [1]. At the same time, the triceps relaxes and lengthens [1]. Antagonistic muscles work in opposite ways because muscles can pull but cannot push.
(d) A muscle is attached to a bone by a tendon [1]. Muscles can only contract or shorten [1].
(e) The elbow is a hinge joint [1], allowing movement mainly in one plane.
Question 8 Report
Fig. 1 shows a section of human skin from a fingertip. A researcher compared the response of the fingertip with the response of skin on the upper arm when a person was touched with two fine points.
(a) Name the type of cell labelled sensory neurone in Fig. 1. [1]
(b) Describe the route of an impulse from a touch receptor in the skin until the person becomes aware of the touch. [3]
(c) Explain why fingertips can distinguish two close points more easily than skin on the upper arm. [3]
(d) Use Fig. 1 to explain why damage to a sensory neurone may reduce a person's ability to feel touch. [3]
(e) Draw a simple arrow on Fig. 1 to show the direction an impulse travels along the sensory neurone. [3]
(a) A sensory neurone is a nerve cell, or neurone. [1]
(b) A touch receptor is stimulated and produces an electrical impulse. The impulse travels along a sensory neurone or nerve to the brain. The brain interprets the impulse, making the person aware of touch. [3]
(c) Fingertips have more touch receptors per unit area, so their receptors are closer together. Two close points are more likely to stimulate separate receptors. The brain receives separate impulses and can identify two points rather than one. [3]
(d) A sensory neurone carries impulses from a receptor towards the central nervous system. If it is damaged, impulse transmission may be reduced or stopped. The brain receives less information, so touch may be felt less accurately or not at all. [3]
(e) The arrow must begin at a receptor, follow the sensory neurone, and point away from the receptor towards the central nervous system. [3]
Answer Details
(a) A sensory neurone is a nerve cell, or neurone. [1]
(b) A touch receptor is stimulated and produces an electrical impulse. The impulse travels along a sensory neurone or nerve to the brain. The brain interprets the impulse, making the person aware of touch. [3]
(c) Fingertips have more touch receptors per unit area, so their receptors are closer together. Two close points are more likely to stimulate separate receptors. The brain receives separate impulses and can identify two points rather than one. [3]
(d) A sensory neurone carries impulses from a receptor towards the central nervous system. If it is damaged, impulse transmission may be reduced or stopped. The brain receives less information, so touch may be felt less accurately or not at all. [3]
(e) The arrow must begin at a receptor, follow the sensory neurone, and point away from the receptor towards the central nervous system. [3]
Question 9 Report
The table below shows measurements made from a cyclist before and during a timed hill climb. Fig. 1 shows the double circulation of a human, with blood passing through the lungs before it returns to the left side of the heart.
| Condition | Heart rate / beats per minute | Stroke volume / cm3 per beat |
|---|---|---|
| Resting | 72 | 70 |
| Hill climb | 150 | 105 |
(a) Complete the calculation of cardiac output at rest.
cardiac output = heart rate × stroke volume
= 72 × 70 = ........ cm3 per minute [2]
(b) Use Table 1 to calculate the increase in cardiac output during the hill climb. [2]
(c) Describe the route of blood from the right ventricle to the left atrium. [3]
(d) Explain why cardiac output increases during the hill climb. [1]
(a)
\[72\times70=5040\text{ cm}^3\text{ per minute}\]
The cardiac output at rest is 5040 cm3 per minute. [2]
(b) During the hill climb:
\[150\times105=15\,750\text{ cm}^3\text{ per minute}\]
\[15\,750-5040=10\,710\text{ cm}^3\text{ per minute}\]
The increase in cardiac output is 10 710 cm3 per minute. [2]
(c) Blood travels from the right ventricle into the pulmonary artery, then to the lungs and capillaries around the alveoli. It returns by the pulmonary vein to the left atrium. [3]
(d) During the hill climb, working muscle cells need more oxygen and glucose and require carbon dioxide to be removed more rapidly. Increasing cardiac output increases blood flow to meet these demands. [1]
Answer Details
(a)
\[72\times70=5040\text{ cm}^3\text{ per minute}\]
The cardiac output at rest is 5040 cm3 per minute. [2]
(b) During the hill climb:
\[150\times105=15\,750\text{ cm}^3\text{ per minute}\]
\[15\,750-5040=10\,710\text{ cm}^3\text{ per minute}\]
The increase in cardiac output is 10 710 cm3 per minute. [2]
(c) Blood travels from the right ventricle into the pulmonary artery, then to the lungs and capillaries around the alveoli. It returns by the pulmonary vein to the left atrium. [3]
(d) During the hill climb, working muscle cells need more oxygen and glucose and require carbon dioxide to be removed more rapidly. Increasing cardiac output increases blood flow to meet these demands. [1]
