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Sixth Form Entrance 2019
BIOLOGY
1 hour
ANSWER ALL THE QUESTIONS ON THE PAPER
You are advised to take note of the information and equations given at the start of each question.
Use of a calculator is permitted.
Name (Capital Letters): ..................................................................... Present School: ………………………………………………………
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1. A student wanted to investigate the effect of the drug caffeine on heart rate. He decided to look at how the heart of a tiny water animal called Daphnia responds to caffeine.
He put a single Daphnia on a microscope slide in a drop of water.
He looked at the Daphnia under low power and counted the number of heartbeats in 15 seconds
He repeated this procedure for 9 more Daphnia, to ensure he had collected 10 data samples.
He then tested the same 10 Daphnia in a weak caffeine solution.
His results are shown in the table
Daphnia Number of heartbeats in 15 seconds
Water Caffeine solution
1 23 36
2 27 37
3 25 29
4 24 40
5 23 38
6 25 37
7 26 39
8 23 36
9 26 39
10 23 28
a. Name the dependent variable in this investigation. (1)
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b. Name two variables that the student should control in his experiment. (2)
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c. Which would give more accurate results, counting the heartbeats for a period of 15 seconds or a period of 60 seconds? Explain your answer. (1)
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d. Why should the student put the Daphnia in the test solution for 60 seconds before starting to record the heart rate? (1)
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(Total for Question 1 = 5 marks)
Exam continues on the next page
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2. A pyramid of numbers can be used to show the number of organisms at each trophic level within an ecosystem. Data was collected from a British woodland habitat during May.
Organism Number found in woodland sample
Example
Nettle 800 Plants
photosynthesise
Robins 18 Robins feed on
caterpillars
Caterpillars 200 Caterpillars
feed on nettles
Hawk 2 Hawks feed on
robins
a. Draw this woodland food chain. (1)
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b. Draw, to scale, and label a pyramid of numbers for this data (3)
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c. This data was collected during the summer months. If the investigation was repeated during the
cold winter months what would you expect to happen to the number of caterpillars? Explain your
answer. (2)
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d. Suggest how the robins find enough to eat during the winter. (2)
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e. If one of the hawks was killed, what might happen to the number of caterpillars in the wood?
Explain your answer. (1)
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f. The total mass of the organisms at each level in the pyramid decreases as you move up the pyramid
from producer to tertiary carnivore. Explain why. (2)
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(Total for Question 2 = 11 marks)
Exam continues on the next page
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3. Fish open their mouths to allow water to pass over their gills. This is shown in the diagram below.
a. Which gas is absorbed from into the water from the fish’s blood? (1)
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b. If the fish lives in seawater, will water molecules move into or out of the fish’s blood? Explain
your answer. (1)
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c. Fish use their gills as a gas exchange surface. Suggest three ways in which fish gills are adapted
for efficient gas exchange. (3)
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ii. ………………………………………………………………………………………
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iii. ………………………………………………………………………………………
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Students investigated the effect of temperature on the breathing rate of fish. They put fish of
the same size in tanks of water at different temperatures. They measured the breathing rate by
counting the number of times the fish opened their mouths in a minute. The results are shown
in the table.
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Water temperature
in 0C
Ventilation movements of the fish mouth per minute
Trial 1 Trial 2 Trial3 Trial4 Average
2 2 3 3 4 3
8 30 33 27 30 30
14 54 52 53 53
20 80 75 81 84
26 101 98 102 101 101
d. Complete the table by calculating the missing average breathing rates. (1)
e. Plot a line graph to show the effect of water temperature on the average breathing rate of the fish.
Join the points with straight lines. (5)
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f. How is the fish’s ventilation rate linked to its respiration rate? (1)
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g. Explain why increasing the water temperature would result in a higher respiration rate for the
fish. (3)
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(Total for Question 3 = 15 marks)
4. A student wanted to investigate the effect of secretions (juices) made by the pancreas on the
digestion of protein.
The white of an egg was put into 15 capillary tubes, each tube was 50mm long. The tubes were
placed in boiling water for 10 minutes until the egg white was cooked and had become solid.
The 15 capillary tubes were split into 4 different groups.
5 tubes were placed into a beaker of distilled water
5 tubes were placed into a beaker with juice from the pancreas
5 tubes were placed into a beaker with juice from a pancreas that had been boiled
5 tubes were placed into a beaker with juice from a pancreas of a person suffering with cystic
fibrosis
After 3 hours the length of solid egg white within each tube was measured in mm. The results are
shown in the table.
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Length of solid boiled egg white left inside the tubes after 3 hours / mm
Distilled water Juice from the pancreas Boiled juice from the
pancreas
Juice from the
pancreas of a person
with cystic fibrosis
50 14 50 35
50 12 50 31
50 13 50 27
50 14 50 29
50 14 50 28
a. Describe the difference in the four sets of results. (1)
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b. Explain the difference seen in the results obtained in the pancreas juice compared to the distilled
water. (2)
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c. Explain the difference seen in the results obtained in the pancreas juice compared to the boiled
pancreas juice. (2)
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d. Does the person with cystic fibrosis make functional enzyme, trypsin, to digest the egg white? Give
evidence to support your answer. (1)
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e. If the tubes places in beakers of juice from the pancreas of a person with cystic fibrosis were left for
another three hours, six hours in total, what would you expect to happen to the length of solid egg
white within the tube? Give reasons for your answer. (2)
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(Total for Question 4 = 8 marks)
5. The drawing shows a foetus developing in the uterus of a woman.
a. What is the function of part B? (1)
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b. Name two molecules that will pass through A from the foetus into the mother by diffusion. (1)
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c. After the child is born, stem cells can be extracted from the umbilical cord. Describe how a stem
cell is different from one of the child’s normal body cells. (1)
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d. Scientists can take cells from part A and use them to find out if the foetus has a genetic condition.
This is called a chorionic villus sampling (CVS) test. How many chromosomes would the scientists
find in a placenta cell from a normal foetus? (1)
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e. Give one reason why a pregnant woman might decide not to have a CVS test. (1)
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f. Complete the table by ticking the box that shows the correct sex chromosomes the scientists would
find in a body cell from a male foetus. (1)
Sex Chromosomes Tick
XX
X
XY
Y
YY
(Total for Question 5 = 6 marks)
Exam continues on the next page
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6. Water in lakes can become polluted if too much phosphate is drained into the soil dissolved in
rainwater. The polluted water becomes very cloudy because of the growth of many microscopic
plants called algae.
It is possible to find out how polluted water is by using a black and white disc called a Secchi disc.
The following technique is used.
The disc is lowered into the water using a rope
The disk is lowered into the water until it can no longer be seen
The depth when the disk is no longer seen is measured.
The diagrams show a Secchi disk and the way in which it is used.
Scientists used Secchi disks to test the pollution levels of four lakes. The table shows the results
Lake Depth at which Secchi disk can no longer be seen / m
A 3.5
B 3.0
C 3.7
D 3.1
a. Which lake is most polluted? (1)
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b. Suggest one feature of the Secchi disk that must be kept the same each time a lake is tested. (1)
i. ………………………………………………………………………………………
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The graphs show changes in the level of phosphates and the Secchi depth measurements for one of the
lakes over a period of 25 years.
c. Using both graphs, describe the relationship between phosphate levels and Secchi depth. (2)
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d. Seawater is sometimes polluted by untreated human sewage. This water also becomes cloudy and is
not safe for humans to swim in. A scientist used Secchi disks to measure the pollution in seawater
at a beach for 12 months. The graph below shows the depth at which she could no longer see the
Secchi disk.
Exam continues on the next page
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e. How many times during the year was the Secchi disk used to measure pollution? (1)
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f. In which month were most depth measurements taken? (1)
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g. The scientist concluded that the only month when water was not safe for swimming was April.
i. Give a reason to support this conclusion (1)
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ii. Give a reason to reject this conclusion. (1)
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(Total for Question 6 = 8 marks)
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7. Flowering plants can respond to their environment through hormone controlled tropic responses.
These involve the root or shoot tips growing toward or away from a stimulus. An experiment to
investigate how shoots respond to gravity. A growing plant was placed on its side and its growth
was recorded, see the diagram below.
Growth after 5 days Growth after 10 days
a. On day 5 the pot was placed back on its base and the plant was left to grow for another 5 days. In the table above draw the appearance of the plant on day 10. (2)
b. Plant shoots will grow away from gravity, they will also grow towards light. How could you adapt this procedure to see which environmental stimulus, light or gravity, had the stronger effect on plant growth? (3)
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c. If germinating seeds are pinned to a rotating clinostat their shoots grow horizontally in a straight
line.
Explain how the hormone levels inside the shoot make this possible. (1)
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d. If the rotation speed of the clinostat was decreased, but not stopped, describe or draw the shoot growth pattern you would expect to see. (1)
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(Total for Question 7 = 7 marks)
END OF TEST Total 60 marks
Sixth Form Entrance 2018
BIOLOGY
1 hour
ANSWER ALL THE QUESTIONS ON THE PAPER
You are advised to take note of the information and equations given at the start of each question. Use of a calculator is permitted. Name (Capital Letters): .......................................................... Present School: ..…………………………………..................
1. Bacteria are found in a wide range of habitats including on humans. (a) A student took a small sample of bacteria from her mouth and placed the sample on a sterile agar plate. The student then brushed her teeth with toothpaste. She then took another sample from a different part of her mouth and placed it on a second sterile agar plate. 24 hours later, she repeated the experiment but used a different toothpaste. She repeated this four times. Each agar plate was left for two days and then the diameter of the colony of bacteria was measured and recorded. The table shows her results.
Condition Mean diameter of bacterial colony after two days in mm
Toothpaste A Toothpaste B Toothpaste C Toothpaste D
Before brushing 4.5 4.4 4.6 4.4
After brushing 2.2 1.5 1.6 1.8
(a) (i) State which toothpaste appears to be the best at reducing bacterial numbers in the mouth. Give a reason for your answer.
(2)
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………………………………………………………………………………………………….. (a) (ii) Using the table, what evidence is there that shows the student was consistent in the way she removed bacteria from her mouth?
(1)
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………………………………………………………………………………………………….. (a) (iii) Suggest two variables, other than the way she removed bacteria from her mouth, that she needed to keep constant.
(2)
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(b) A species of bacterium has been found that breaks down oil. A sample of these bacteria was placed on some oil and the numbers of bacteria present was estimated each day for three weeks. The graph below shows the results.
Using the graph, explain the change in numbers of these bacteria.
(3)
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time
number of bacteria
2. In a survey, people of different ages were asked if they thought that animal cloning is a good idea or a bad idea. The table shows the results of the survey.
Age group Percentage (%) of age group
Good idea Bad idea
under 24 10.6 89.4
25 to 34 14.2 85.8
35 to 44 13.8 86.2
45 to 54 15.0 85.0
over 55 23.5 76.5
(a) Plot a bar graph to show the data in the table.
(5)
(b) Describe the relationship between age and what people think about animal cloning. (1)
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………………………………………………………………………………………………….. (c) In the 45 to 54 age group, 18 people think that cloning is a good idea. Calculate the total number of people surveyed in this age group. Show your working.
(2)
total number of people = ………………………………….. (d) When animals are cloned, they are genetically identical to each other. Suggest two reasons why cloning cows may be a good idea.
(2)
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Exam continues on the next page
3. A student uses this apparatus to investigate the effect of nitrate ions on the growth of plants.
A young plant is grown in a sterile solution containing all the mineral ions needed for growth.
The student repeats the experiment with other young plants.
The student also carries out the experiment with young plants grown in a sterile solution that contains all the mineral ions except nitrate.
The student measures the length of the stem of each plant every five days.
Some of the student’s results are shown in the table.
Time in days
Mean (average) length of stem in mm
Solution containing all mineral ions
Solution without nitrate ions
0 23 23
5 30 25
15 45 30
25 98 38
35 145 38
45 160 37
55 163 37
(a) Describe the growth of plants in each solution.
(2)
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(b) Suggest why young plants absorb more mineral ions when air is bubbled through the solutions. (3)
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………………………………………………………………………………………………….. (c) (i) Suggest why each solution is sterilized at the start of this investigation.
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………………………………………………………………………………………………….. (c) (ii) Suggest why the glass jar is surrounded by cardboard during this investigation.
(2)
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………………………………………………………………………………………………….. (d) Identify the dependent variable in this investigation.
(1)
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Exam continues on the next page
4. The diagram shows the distribution of two plant species in a small area of a field.
A student uses a square metal frame to help count all the plants in the area. (a) (i) The student counts the number of plants in all of the squares marked out in the field. Complete the table to show the number of plants of each species and the mean (average) number of plants per m2.
(2)
Species Number of plants Mean number of plants per m2
bunchgrass 7 0.19
plantain
(a) (ii) Frequency is another measure that can be used to study distribution. Frequency is the number of squares that contain at least one plant of the species being counted. This value is expressed as a percentage of the total number of squares sampled. Complete the table by giving the frequency and percentage of the total number of squares sampled for the bunchgrass.
(2)
Species Frequency Precentage (%)
bunchgrass
plantain 8 22
(b) Suggest how the student could estimate the population size of plantain in a very large field. (4)
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(Total for Question 4 = 8 marks)
Exam continues on the next page
5. A student carries out an experiment to investigate the effect of different concentrations of a food dye on diffusion. (a) Describe what is meant by the term diffusion.
(1)
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(b) The student adds a different concentration of coloured food dye to each of five wells (holes) in an agar plate. The diagram shows the agar plate at the beginning of the experiment and after 24 hours.
The student does the experiment using three plates. For each plate the student measures the diameter of each circle to see how far the food dye has diffused. The table shows the results.
Concentration of food dye in
well (%)
Diameter of circle in mm
plate 1 plate 2 plate 3 mean (average)
0.1 0.7 0.6 0.7 0.7
0.2 1.5 1.4 1.4 ?
0.3 1.7 1.6 1.7 1.7
0.4 1.9 1.8 1.9 1.9
0.5 1.9 2.0 2.0 2.0
(b) (i) Calculate the mean diameter for the 0.2% concentration of food dye. (2)
mean diameter = …………………… cm (b) (ii) Describe the effect of food dye concentration on diffusion.
(2)
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………………………………………………………………………………………………….. (b) (iii) Explain the relationship between food dye concentration and diffusion.
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………………………………………………………………………………………………….. (c) State two variables that the student should control in this experiment to ensure that the results are valid.
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Exam continues on the next page
6. A group of students investigate the effect of exercise on breathing rate. They measure their breathing rate at rest by counting breaths per minute. They then exercise by running on the spot. After exercise they measure their breathing rate again. These are their results.
(a) Display these results in a table. (2)
(b) Explain how the students could improve their investigation.
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(c) Suggest why an increased breathing rate occurs during exercise. (3)
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(Total for Question 6 = 7 marks)
Exam continues on the next page
7. The graph shows the blood sugar (glucose) level of a diabetic person and a non-diabetic person for two hours after ingestion (eating) of a sugary food.
(a) Compare the blood glucose of the non-diabetic person with the diabetic person over the first 90 minutes.
(3)
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………………………………………………………………………………………………….. (b) Suggest why the blood sugar level of the diabetic person changes between 90 minutes and 120 minutes.
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diabetic
non-diabetic
(c) Suggest why the blood glucose level for the non-diabetic person at 120 minutes is different to the level at the start of the investigation.
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………………………………………………………………………………………………….. (d) The table shows the expected percentage of people, in two different areas of Wales, with diabetes.
Area Percentage of people expected to have diabetes
2010 2020
Hywel Dda 5.2 7.3
Powys 5.0 7.1
Suggest how the figures for 2020 have been calculated.
(1)
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………………………………………………………………………………………………….. (e) Give two functions of blood in the human body.
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END OF TEST Total 60 marks
