A level Bio 3.4 Mass transport in Animals

Give the pathway a red blood cell takes when travelling in the human circulatory system from a kidney to the lungs. Do not include descriptions of pressure changes in the heart or the role of heart valves in your answer. (3)

Renal vein (1)

Vena cava to right atrium (1)

Right ventricle to pulmonary artery (1)

Tissue fluid is formed from blood at the arteriole end of a capillary bed. Explain how water from tissue fluid is returned to the circulatory system. (3)

(Plasma) proteins remain (1)

(creates) water potential gradient (1)

Water moves (to blood) by lymphatic system (1)

A student dissected an organ from a mammal to observe blood vessels. He dissected a slice of the organ and identified two blood vessels. Figure 1 shows a photograph of his dissection.

Describe two precautions the student should take when clearing away after the dissection. (2)

Put organ/gloves/paper towels in a (separate) bag/bin/tray to dispose (1)

Disinfect instruments/surfaces (1)

Explain how an arteriole can reduce the blood flow into capillaries. (2)

Muscle contracts (1)

Constricts arteriole/lumen (1)

The image below shows heart valves during one stage of a cardiac cycle. Ventricles are visible through the open valves.

What can you conclude from the appearance of valves in the image above about heart muscle activity and blood movement between:

1. ventricles and arteries? (2)

2. atria and ventricles? (2)

(Ventricles and arteries)

Ventricle (muscle) relaxed (1)

No (blood) backflow (into ventricles) (1)

(Atria and ventricles)

Atria (muscle) contracted (1)

Blood movement from atria (into ventricles (1)

Which blood vessel carries blood at the lowest blood pressure

A Capillary

B Pulmonary vein

C Renal vein

D Vena cava (1)

D - Vena cava is a large vein returning blood to the heart (1)

The diagram below shows pressure and blood flow during the cardiac cycle in a dog.

At P on the diagram above, the pressure in the left ventricle is increasing. At this time, the rate of blood flow has not yet started to increase in the aorta. Use evidence from diagram above to explain why (2)

Aortic/semi-lunar valves is closed (1)

Because pressure in aorta higher than in ventricle (1)

The diagram below shows pressure and blood flow during the cardiac cycle in a dog.

At Q on the diagram above there is a small increase in pressure and in rate of blood flow in the aorta. Explain how this happens and its importance (2)

Elastic recoil (of the aorta wall/tissue) (1)

Smooths the blood flow (1)

A student correctly plotted the right ventricle pressure on the same grid as the left ventricle pressure in diagram above.

Describe one way in which the student’s curve would be similar to and one way it would be different from the curve shown in the diagram above. (2)

Peaks/contractions at the same/similar time (1)

Lower pressure (1)

Figure 3 shows pressure and blood flow during the cardiac cycle in a dog.
Use information from Figure 3 to calculate the heart rate of this dog. (1)

Time of one cycle =0.36s=0.006 min

beats per minute =1/0.006=166.67 beats minute^-1(1)

Describe the advantage of the Bohr effect during intense exercise. (2)

Increases dissociation of oxygen (1)

For aerobic respiration at the tissues/muscles/cells (1)

An increase in the intensity of exercise produces an increase in the volume of carbon dioxide produced.

However, the graph above shows that the pCO₂ in air breathed out did not show a large increase during the exercise. Suggest one physiological change that would cause this result. Explain how the physiological change would allow for the removal of the increase in the volume of carbon dioxide produced (2)

Increase in breathing (rate) (1)

Similar/same pCO₂ per breath, but increased volume per breath (1)

EPO is another performance-enhancing drug. It can increase the haematocrit (the percentage of red blood cells in blood).

A heart attack is caused by a lack of glucose and oxygen being delivered to cardiac muscle via the coronary arteries. The overuse of EPO can increase the risk of a heart attack. Suggest how. (2)

EPO causes blood to thicken (1)

(The thickened blood) could block the coronary arteries (1)

The normal haematocrit for human males is 47(±5)%. For professional male cyclists, the maximum haematocrit allowed is 50%. A student suggested that professional male cyclists should be allowed to use EPO until their haematocrit is 50%. Give two reasons why this suggestion is not valid. (2)

Some cyclists will gain a bigger advantage (1)

there are health risks associated with taking EPO (1)

Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin. (2)

More dissociation of oxygen (1)

by decreasing blood pH (1)

Seals are diving mammals. They fill their lungs with air before they dive and hold their breath during the dive.

The graph shows the dissociation curves for seal oxyhaemoglobin and seal myoglobin. Myoglobin is an oxygen-carrying protein found in muscles.

Use information in the graph to explain how the seal’s myoglobin dissociation curve shows the seal is adapted for diving. (2)

High(er) affinity for O₂ (than haemoglobin) (1)

Allows aerobic respiration when diving/at lower pO₂ (1)

Explain how valve A in Figure 1 maintains a undirectional flow of blood. (2)

(When) pressure above valve is higher than below valve it opens (1)

Pressure in (left) ventricle/B is higher than in atrium causing valve to close (1)

A research scientist investigated the effect of caffeine on heart rate in human

volunteers.

The scientist divided volunteers into three groups. Each group was given the same volume of fluid.

• Each member of Group I was given a sports drink containing caffeine and sugar.

• Each member of Group J was given a sports drink containing caffeine and

no sugar.

• Each member of Group K was given water.

The scientist recorded the volunteers’ heart rate before the drink was given and

for 120 minutes after the drink was given.

Her results can be seen in Figure 2.

The increase seen in Group I could be due to the combination of caffeine and sugar. Suggest one drink to be given to an additional group that should be investigated to find out if this is true. Give a reason for your answer. (2)

Sugar solution (only) (1)

To show sugar alone is not causing the increases in HR (1)

Binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind.

Explain why (2)

Binding of first oxygen changes tertiary / quaternary (structure) of haemoglobin (1)

Uncovers another binding site (1)

Explain the role of the heart in the formation of tissue fluid (2)

Contraction of ventricle(s) produces high blood / hydrostatic pressure (1)

(This) forces water (and some dissolved substances) out (of blood capillaries) (1)

Lymphoedema is a swelling in the legs which may be caused by a blockage in the lymphatic system. Suggest how a blockage in the lymphatic system could cause lymphoedema. (1)

Excess tissue fluid cannot be (re)absorbed / builds up (1)

The graph shows the oxyhaemoglobin dissociation curves for fetal haemoglobin (HbF) and adult haemoglobin (HbA).

At birth 98% of the haemoglobin is HbF. By the age of 6 months, the HbF has usually completely disappeared from the baby’s blood and been replaced by HbA.

Use the graph above to explain why this change is an advantage for the baby (2)

(HbA has) lower affinity for O₂ at low partial pressures (1)

Easier unloading of O₂ for (aerobic) respiration (1)

Sickle cell disease (SCD) is caused by production of faulty HbA. This results in a reduced ability to transport oxygen to tissues. Scientists investigated the use of a substance called hydroxyurea to treat babies with SCD.

Hydroxyurea changes the concentration of HbF in the blood. The scientists carried out an investigation with 122 babies who had SCD. Each baby was given hydroxyurea for 41 months. The scientists then found the mean change in the concentration of HbF in the babies’ blood. Their results are shown in the table

The scientists concluded that treatment with hydroxyurea would increase the concentration of oxygen in the blood of babies with SCD. Suggest how the graph and table above support this conclusion (3)

A large/significant increase in HbF (1)

(HbF has) higher affinity for O₂ (than faulty HbA) (1)

Higher proportion of HbF in blood so more oxygen carried (1)

This question is about the flow of blood into and through the heart.

Add the numbers 1 to 6 to the table below to give the order of structures through which blood will pass as it enters the heart and flows through the left ventricle.

Use each number only once. Number 4 has been done for you. (2)

(2)

Name the type of blood vessel that controls blood flow to muscles and explain how these blood vessels change blood flow during exercise. (3)

Arteriole (1)

(Circular/smooth) muscle relaxes (1)

vasodilation increases blood flow (1)

Blood donation involves healthy donors giving blood that can be used to

treat hospital patients.

When donors arrive, the haemoglobin concentration of their blood is tested.

A sample of each donor’s blood is added to a copper sulfate solution to

determine whether the haemoglobin concentration is high enough to donate.

Errors sometimes occur with this test.

Tom has a concentration of haemoglobin high enough to donate.

Lucy has a concentration of haemoglobin too low to donate.

Evaluate the consequences of errors occurring when Tom’s and Lucy’s blood samples are tested. (3)

(Tom)

Healthy donor not allowed to donate (1)

(lucy)

her blood may not help patients (1)

Her (missed) low haemoglobin goes untreated (1)

Lugworms create tubes in the sand on seashores. The tubes are filled with seawater.

A scientist measured the partial pressure of dissolved oxygen (pO₂) in seawater at different places in a tube with a lugworm inside.

Figure 1 shows her results.

The pO₂ of dissolved oxygen in lugworm blood is < 2.7 kPa Using the data in Figure 1, what can you conclude about the uptake of oxygen over the entire body of the lugworm? (4)

Enters by diffusion (1)

Down a concentration gradient (1)

More across parts of body with gills (1)

Gills provide a larger surface area for absorption (1)

The intensity of the red colour in blood is affected by the pO₂ of the blood.

The intensity of the colour in a solution is measured using a colorimeter.

The scientist used a colorimeter to measure the intensity of red colour in

samples of lugworm blood with different pO₂ values. She prepared a

calibration curve with this information.

Describe how the scientist will use information from the colorimeter and her

calibration curve to determine the pO₂ in a sample of lugworm blood.(2)

(Measure light) absorption/transmission (1)

Interpolate/draw line to curve (1)

A student dissected a sheep’s heart. He prepared a risk assessment on:

• carrying a scalpel

• using a scalpel.

Complete the table below by giving three control measures the student

must use to reduce the risks associated with carrying and using a scalpel.(2)

Cut onto hard surface

Cut away from body

Disinfect used scalpel as instructed (2)

In a separate investigation, a doctor measured the effect of blood pressure medicines on treating a large number of patients with a mean blood pressure of

22 kPa

The doctor used two different treatments.

• Treatment 1 contained one blood pressure medicine.

• Treatment 2 contained three blood pressure medicines.

He measured the change in the mean blood pressure after each treatment in these patients.

Figure 3 shows his results.

Using information in Figure 2 and Figure 3, evaluate the effect of these treatments on reducing the risk of developing cardiovascular disease in patients with a mean blood pressure of 22 kPa (4)

Treatment 2 is more effective (than treatment 1) (1)

Neither treatment achieves low(est) risk (1)

No statistics test so do not know if changes/differences (in bp) are due to chance/are significant (1)

Unknown side effects of treatments (1)