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A Level Biology B (Advancing Biology) H422/03 Practical skills in biology
Practice paper – Set 1 Time allowed: 1 hour 30 minutes
INSTRUCTIONS
• Use black ink. You may use an HB pencil for graphs and diagrams.
• Complete the boxes above with your name, centre number and candidate number.
• Answer all the questions.
• Write your answer to each question in the space provided. If additional space is
required, use the lined page(s) at the end of this booklet. The question number(s)
must be clearly shown.
• Do not write in the barcodes.
INFORMATION
• The total mark for this paper is 60.
• The marks for each question are shown in brackets [ ].
• Quality of extended responses will be assessed in questions marked with an
1 (a) A farmer with an orchard produces cider using the juice from the apples.
An advisor from the Government visits the farm and suggests that the farmer could grazesheep on the grass in the orchard to qualify for additional grant payments. The advisorsays that the productivity figures for the sheep will not be as good as the figures for theapples.
Table 1.1 shows some of the energy content and transfer efficiencies for the food chain:
Grass Sheep Human
Table 1.1
(i) Calculate the percentage efficiency of the conversion of photosynthetic wavelengthsinto above ground primary production.
Show your working. Give your answer to two decimal places.
(ii) The advisor calculates the efficiency of energy conversion for grass (primaryproduction) and sheep (secondary production) in the food chain.
Using your knowledge of food chains, explain why the percentage efficiency figuresfor primary (0.50%) and secondary (0.002%) production are so different.
(ii) At the time it is bottled the optimum number of live yeast cells is between 250 000 to500 000 cells per cm3 of cider. This ensures the finished cider will contain just theright volume of CO2.
Using this information and your answer to (c)(i) would this cider be ready forbottling?
(b) The vet discovers that two different species of bacteria are present which may be causingthe pneumonia.
Once suitably prepared and stained using the Gram staining technique, a sample of thebacteria are observed using the high power lens of a light microscope.
In one of the bacterial species, the cells are seen to be stained red/pink.
(i) Why must a high power lens be used to view the bacteria?
Fig. 2.2 shows the results of a test carried out using the Klebsiella pneumoniae bacteria cultured from the horse. The bacterial culture was spread on an agar plate and discs containing antibiotics A to D were placed on the agar as shown. The plate was then incubated overnight.
Fig. 2.2
Table 2.1 shows information about the 4 antibiotics used in the test.
Antibiotic Mode of Action Notes
A Inhibits the synthesis of protein by bacteria, leading to cell death
Family of over 20 antibiotics
B Inhibits bacterial cell wall synthesis
Most widely used antibiotics
C Inhibits bacterial cell wall synthesis
Resistance evolves rapidly
D Interferes with bacterial DNA replication and transcription
Common ‘drug of last resort’ used with resistant strains
Table 2.1
(d) The vet chooses to use antibiotic A. Using Fig 2.2 and Table 2.1, justify this decision.
(c) Apart from using Benedict’s solution and a colorimeter, suggest two alternativequantitative methods for measuring the concentration of glucose in blood plasma.
4 Maize plants can be grown commercially in greenhouses.
The greenhouses have lighting systems but are unheated. The lighting systems used are controlled electronically and will be turned off when temperatures inside the greenhouses fall below 10oC.
Fig. 4.1 shows a graph of the rate of photosynthesis of maize at different temperatures.
Fig. 4.1
(a) (i) Indicate, with an arrow, a compensation point on this graph.
The answer to this question must be written on Fig. 4.1. [1]
(ii) Suggest why the control system for the lights is programmed to switch them off atlow temperatures.
(b) Some varieties of maize plants have smooth kernels (seeds), whereas others havewrinkled kernels. This is a genetic trait.
Varieties with smooth kernels are rich in starch and useful for making flour.
A farmer has been given some smooth seeds all of the same unknown genotype. Thefarmer carries out a cross-breeding experiment using these seeds and some known to beheterozygous for this trait.
The results are shown in Table 4.1.
F1 phenotype Observed results Expected results
Smooth 547
Wrinkled 185
Total 732
Table 4.1
The 2statistic is calculated in the following way:
22( )
observed expected
expected
(i) Calculate the value of 2 for the above data. Show your working.
................................................................................................................................ [2] (iii) Describe the genotype of the seed the farmer was given. Give a reason for your
(b) Higher VO2 max is associated with better race performance. An athlete has a VO2 max of38 cm3 kg-1
min-1. The athlete’s trainer suggests experimenting with carbohydrate-loadingto find out if carbohydrate-loading improves VO2 max.
During the experiment, the athlete raced once a week and each time the VO2 max was measured. For the first 8 weeks, the athlete ate a normal diet. For weeks 9 to 20, the athlete followed a carbohydrate-loading diet plan.
The athlete’s VO2 max was measured every week during the investigation.
The results are shown in Table 5.1.
Week Treatment VO2 max (cm3 kg-1 min-1)
1 Normal diet 38
2 37
3 37
4 39
5 41
6 41
7 40
8 38
Mean VO2 max (cm3 kg-1 min-1)
39
9 Carbohydrate-loading 39
10 40
11 39
12 42
13 43
14 39
15 44
16 40
17 40
18 41
19 43
20 42
Mean VO2 max (cm3 kg-1 min-1)
41
Table 5.1
(i) Plot a graph, on the grid provided, to show the mean values of the data shown inTable 5.1 in the most appropriate way.
Add range bars to show the highest and lowest VO2 max values in each of the two treatments.
(ii)* If the results of the investigation show that the carbohydrate-loading improves VO2 max the trainer would recommend it for all the athletes they coach.
Evaluate the investigation the trainer carried out. Your account should include a consideration of:
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