Question 1
1
Tufted ducks (Aythya fuligula) are found in lakes and lagoons throughout Europe. They eat molluscs, insects and plants, sometimes from the surface but mostly by diving under the water. The graph shows how the heart rate of a tufted duck changes when diving under the water. \footnotetext{ R. Stephenson, P. J. Butler and A. J. Woakes, "Diving behaviour and heart rate in tufted ducks (Aythya fuligula)", J Exp Biol (1986) 126:341359. Reproduced with permission. }
12 marks
Question 1(a)
1(a)
State the length of time the tufted duck was under the water.
Easystructured1 marks
Answer
\(40 \mathrm{~s} /\) seconds (units required)
Question 1(b)
1(b)
Outline the changes in the heart rate during the dive.
Mediumstructured2 marks
Answer
initially the heart rate decreases rapidly; heart rate increases over the next seconds; heart rate falls to its lowest level / reaches lowest level after \(55 \mathrm{~s} /\) seconds \(/ 35 \mathrm{~s} /\) seconds after start of dive; in the last seconds before the dive ends, the heart rate increases;
Question 1(d)
1(d)
Calculate the percentage increase in blood flow to the leg muscles when the tufted duck changes from swimming at normal speed to swimming at maximum speed.
Mediumstructured1 marks
Answer
200 (\%)
Question 1(e)
1(e)
Compare the blood flow to the heart muscles with the blood flow to the flight muscles when changing from swimming at normal speed to swimming at maximum speed.
Mediumstructured2 marks
Answer
Award [1] for each correct row. Answers do not need to be shown in a table format, but must be comparative statements.
Question 1(f)
1(f)
Explain the changes in blood flow that occur when swimming at maximum speed.
Hardstructured2 marks
Answer
legs/leg muscles need more energy/ATP for fast swimming; legs/leg muscles need more blood to provide oxygen/glucose for energy; (the legs need more blood) to remove carbon dioxide; the heart needs more blood to pump faster; intestines/kidneys/flight muscles have less blood to allow for increased flow to heart/legs;
Question 1(g)
1(g)
Predict, with reference to both graphs, what would happen to the blood flow to the heart muscles when the tufted duck is diving.
Hardstructured2 marks
Answer
blood flow decreases; as heart rate is seen to decrease in the first graph; as lower heart rate means less requirement for oxygen/nutrients/blood/removal of waste;
Question 1
1
Hypertension (blood pressure exceeding 140 mmHg ) affects millions of people worldwide. Many modern societies consume more sodium in the form of salt (NaCl) than is required for normal physiology. The effect of changing the levels of dietary sodium has been studied in various organisms. Scientists recorded the blood pressure changes in chimpanzees (Pan troglodytes) fed a diet without added sodium (control) or a sodium supplemented diet (experimental) as follows - 5 grams of salt per day from December 1991 until May 1992 - 10 grams of salt per day until June 1992 - 15 grams of salt per day until August 1993 after which no more salt was added to the diet until the experiment ended.
14 marks
Question 1(a)
1(a)
Outline the effect shown in the graph of increasing the sodium in the diet of chimpanzees.
Mediumdata_response2 marks
Answer
sodium in diet/experiment increased blood pressure (in chimpanzees); b. after treatment the chimpanzees showed hypertension/high blood pressure; c. after treatment ended blood pressure returned to normal;
Question 1(c)
1(c)
Blood pressure is measured in the arteries. Explain how arteries are adapted to withstand increases in blood pressure.
Mediumshort_answer2 marks
Answer
thick outer layer of collagen fibres/thick muscle wall (give it strength); thick layers of circular/elastic muscle fibres gives it (thick alone not sufficient, flexibility to support changes in blood pressure; (must be qualified)
Question 1
1
Consumption of dark chocolate has been shown to have health benefits. A study was undertaken to see the effects of epicatechin (Epi), a substance in dark chocolate, on the aerobic capacity of leg muscles of mice. A group of adult mice was used to measure the effects of a low dose of Epi given over 15 days. The mice were divided into four groups and given either water or Epi and were either kept idle (no exercise) or made to exercise on a treadmill. After 15 days, the results were analysed. The blood capillary density in leg muscle was measured under the light microscope.
10 marks
Question 1(a)
1(a)
0 marks
Question 1(a)(ii)
1(a)(ii)
Outline the trends in capillary density in the results of this experiment.
Mediumstructured2 marks
Answer
ii a. exercise «significantly» increased the density with both water and Epi b. Epi «significantly» increased the density with and without exercise c. Epi-exercise had the greatest increase in the density OR Epi increases the density more than exercise alone "both" or OWTTE must be mentioned 2 max
Question 1(b)
1(b)
Describe how increased capillary density could affect the aerobic capacity of muscle.
Mediumstructured2 marks
Answer
a. increases amount of blood taken to the muscle b. increases the delivery of oxygen/glucose/nutrients for aerobic respiration c. increases the removal of carbon dioxide/wastes OR increased gas exchange 2 max
Question 1
1
Phytoremediation is the use of plants to extract and remove contaminants or lower their bioavailability (amount available to organisms) in soil. Tree species are used because they have deep root systems and fast growth rates that enable them to take up contaminants in larger amounts than plants such as grasses. The diagram shows the steps in phytoremediation in plants. A study in North Carolina, USA, used different tree species for phytoremediation of groundwater contaminated by leaked petrochemicals. Four types of hybrid poplar clones (Populus sp.), loblolly pine (Pinus taeda) and willow (Salix sp.) were planted from 2006 to 2008, and measurements were made of trees in 2010 and 2012. The graph shows percent survival of hybrid poplar clones, loblolly pine and willow trees on the phytoremediation site.
structured15 marks
Question 1(e)
1(e)
Removal of excess soil water increases oxygen levels in the soil. Suggest how this may be beneficial in soil phytoremediation. In the same study, the levels of TPH (total petroleum hydrocarbons) and BTEX (benzene, toluene, ethylbenzene and xylene) present in the soil of contaminated areas were measured each winter and summer from 2007 to 2013 before and after planting trees.
Mediumstructured1 marks
Answer
a. (roots need oxygen) for aerobic respiration/for energy supply/for ATP production; b. less anaerobic respiration / less production of (toxic) ethanol/alcohol; c. increase in bacteria/decomposers that can metabolize contaminants; 1 max
Question 2
2
In an investigation to compare the elasticity of arteries and veins, rings of the same diameter \((20 \mathrm{~mm})\) of artery and vein tissue were cut from blood vessels obtained from a mammal. Each ring was attached to a clamp. Multiple masses of 10 g were added and removed. The vertical diameter of the artery and the vein was measured, both with the mass and once the mass had been removed. The results are shown in the table.
0 marks
Question 2(a)
2(a)
State the independent and dependent variables in this experiment. Independent: Dependent:
Easystructured2 marks
Answer
a. Independent: mass; b. Dependent: (vertical) diameter/length; Do not accept elasticity
Question 2(b)
2(b)
State one feature of the rings that has to be kept constant apart from their initial diameter.
Easystructured1 marks
Answer
a. width/section depth/slice of the ring; b. same animal/age/freshness/temperature; Don't accept thickness or diameter[图片] 肚 Any wording referring to the longitudinal section. 1 max
Question 2(c)
2(c)
Explain the differences between the results shown for vein and artery.
Mediumstructured3 marks
Answer
a. veins have thinner walls (than arteries); b. veins sustain lower (blood) pressure (than arteries); c. when stretched, veins become longer (than arteries); d. veins have less muscle/elastic (fibre in their) walls (than arteries); e. veins have lower elasticity/recover less/remain more stretched (than arteries after weights removed); Accept inverse for arteries in all cases Do not accept a listing of numerical values without explanation 3 max
Question 2
2
In an investigation to compare the elasticity of arteries and veins, rings of the same diameter \((20 \mathrm{~mm})\) of artery and vein tissue were cut from blood vessels obtained from a mammal. Each ring was attached to a clamp. Multiple masses of 10 g were added and removed. The vertical diameter of the artery and the vein was measured, both with the mass and once the mass had been removed. The results are shown in the table.
0 marks
Question 2(a)
2(a)
State the independent and dependent variables in this experiment. Independent: Dependent:
Easystructured2 marks
Answer
Independent: mass; Dependent: (vertical) diameter; Do not accept elasticity.
Question 2(b)
2(b)
State one feature of the rings that has to be kept constant apart from their initial diameter.
Easystructured1 marks
Answer
a. width/depth of section/slice (of the ring); b. same animal/age/freshness/temperature; Do not accept thickness or diameter.[图片] 1 max
Question 2(c)
2(c)
Explain the differences between the results shown for vein and artery.
Mediumstructured3 marks
Answer
a. veins have thinner walls (than arteries); b. veins sustain lower (blood) pressure (than arteries); c. when stretched, veins become longer (than arteries); d. veins have less muscle/elastic (fibre in their) walls (than arteries); e. veins have lower elasticity/recover less/remain more stretched (than arteries after weights removed); Accept inverse for arteries in all cases. Do not accept a listing of numerical values without explanation. 3 max
Question A2
A2
4 marks
Question A2(c)
A2(c)
Evaluate the benefits of reducing dietary cholesterol in lowering the risk of coronary heart disease.
Mediumstructured2 marks
Answer
dietary cholesterol correlated to blood cholesterol/fatty acids; high blood cholesterol is an important risk factor (but not the only cause); some cholesterol required for normal synthesis of body molecules; genetic factors play an important role in determining cholesterol levels; other environmental factors (smoking) play a role in determining cholesterol levels;
Question 2
2
The micrograph shows a section of an organ in the human body.
0 marks
Question 2(d)
2(d)
One of the functions of this organ is absorption. On the micrograph, draw an arrow showing the direction of absorption.
Mediumstructured1 marks
Answer
[图片]
Question 2
2
The image shows a severed aphid stylet embedded in plant tissue.
5 marks
Question 2(a)
2(a)
Identify the tissue labelled II.
Mediumstructured1 marks
Answer
xylem
Question 2(b)
2(b)
Outline one piece of evidence that the tissue labelled I is phloem tissue.
Mediumstructured1 marks
Answer
a. it has a stylet embedded in it OR aphids insert their stylets into phloem b. is closer to the surface/exterior/outside the xylem c. cells smaller than xylem tissue «below it» d. smaller «companion» cells are adjacent to larger «sieve tube» cells 1 max
Question 2
2
A leafy shoot was cut from a plant and connected to a potometer to measure the transpiration rate. The length of the air column in the glass tube was measured using the ruler.
0 marks
Question 2(b)
2(b)
Describe how the apparatus could be used to demonstrate that the transpiration rate is affected by air movement.
Mediumpractical3 marks
Answer
a. a fan is placed so that air blows on the leaves «and the experiment is repeated» b. a control with no air blowing «in still air/no fan» c. distance moved by the bubble in a given time is measured OR time is recorded for the bubble to move a given distance d. the bubble is reset to the beginning «with the tap» e. greater distance moved by bubble over time = higher transpiration rate \(\) f. repeat experiment at same temperature g. use different speeds of fan to determine effect of a range of air movement Do not accept "place plant in wind" Accept different distances from fan for mpg 3 max
Question 2(c)
2(c)
One criticism of the experiment is that it only measured the rate of transpiration indirectly. Explain how the experiment is an indirect measurement of transpiration.
Mediumstructured2 marks
Answer
a. transpiration is water evaporating from «the leaves of» a plant b. what is being measured is water uptake to the plant c. assumes no water used for other processes/photosynthesis This is not about water loss from apparatus 2 max
Question 2(d)
2(d)
Red dye was added to the water in the potometer. A cross section of the stem was observed under the light microscope.
0 marks
Question 2(d)(i)
2(d)(i)
Label with an R the tissue where the red dye would appear.
Easystructured1 marks
Answer
[图片] Award [1] for correct labeling of R
Question 2(d)(ii)
2(d)(ii)
Label with a C the tissue where organic compounds are transported.
Easystructured1 marks
Answer
[图片] Award [1] for correct labeling of C