Experimental Data Analysis Part 1 exam pro qs PDF

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Experimental Data AnalysisPart 1Name: ________________________Class: ________________________Date: ________________________Time: 395 minutesMarks: 273 marksComments:Q1.A student investigated the effect of chewing on the digestion of starch in cooked wheat. He devised a laboratory model of starch dig...

Description

Experimental Data Analysis Part 1

Time:

395 minutes

Marks:

273 marks

Comments:

Name:

________________________

Class:

________________________

Date:

________________________

Q1. A student investigated the effect of chewing on the digestion of starch in cooked wheat. He devised a laboratory model of starch digestion in the human gut. This is the method he used. 1. 2. 3. 4. 5.

(a)

Volunteers chewed cooked wheat for a set time. The wheat had been cooked in boiling water. This chewed wheat was mixed with water, hydrochloric acid and a protein-digesting enzyme and left at 37 °C for 30 minutes. A buffer was then added to bring the pH to 6.0 and pancreatic amylase was added. This mixture was then left at 37 °C for 120 minutes. Samples of the mixture were removed at 0, 10, 20, 40, 60 and 120 minutes, and the concentration of reducing sugar in each sample was measured. Control experiments were carried out using cooked wheat that had been chopped up in a blender, not chewed. What reducing sugar, or sugars, would you expect to be produced during chewing? Give a reason for your answer. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2)

(b)

In this model of digestion in the human gut, what other enzyme is required for the complete digestion of starch? ___________________________________________________________________ (1)

(c)

What was the purpose of step 2, in which samples were mixed with water, hydrochloric acid and pepsin? ___________________________________________________________________ ___________________________________________________________________ (1)

(d)

In the control experiments, cooked wheat was chopped up to copy the effect of chewing. Suggest a more appropriate control experiment. Explain your suggestion. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2)

(e)

The figure below shows the student’s results.

Incubation time / minutes Explain what these results suggest about the effect of chewing on the digestion of starch in wheat. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (3) (Total 9 marks)

Q2. A student investigated the glucose concentration in five different drinks. His results are shown below.

(a)

Using the data, calculate how many grams of glucose would be in 220 cm3 of drink F.

Answer = ____________________________ g (1)

(b)

Calculate how much more glucose is in drink C than in drink F. Show your answer as a percentage.

Answer = ____________________________ % (1) (Total 2 marks)

Q3. (a)

The letters A, B, C, D and E represent stages in mitosis. • • • • •

A – anaphase B – interphase C – metaphase D – prophase E – telophase

Write one of the letters, A to E, in the box to complete the following statement.

Chromosomes line up on the equator of the mitotic spindle in (1)

(b)

Scientists looking for treatments for cancer are investigating the use of substances called kinesin inhibitors (KI). These inhibitors prevent successful mitosis. Some kinesin inhibitors cause the development of a monopolar spindle in mitosis. The diagram below shows chromosomes attached to a normal mitotic spindle and to a monopolar mitotic spindle.

Suggest why the development of a monopolar mitotic spindle would prevent successful mitosis. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2)

(c)

Scientists investigated the effect of different concentrations of a kinesin inhibitor (KI) on mitosis of human bone-cancer cells grown in a culture. The following table shows the scientists’ results.

Concentration of kinesin inhibitor / nmol dm−3

Percentage of dividing human bone-cancer cells showing a monopolar mitotic spindle

0

0

1

0

10

8

100

93

1000

100

10 000

100

A student who saw these results concluded that in any future trials of this kinesin inhibitor with people, a concentration of 100 nmol dm−3 would be most appropriate to use. Do these data support the student’s conclusion? Give reasons for your answer. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (4)

(d)

At the start of their investigation, the scientists made a solution of kinesin inhibitor (KI) with a concentration of 10 000 nmol dm−3. They used this to make the other concentrations by a series of dilutions with water. Describe how they made 100 cm3 of 1000 nmol dm−3 solution of kinesin inhibitor. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2) (Total 9 marks)

Q4. The blink reflex can be affected by anaesthetics. Local anaesthetics are used to stop people feeling pain but do not make them unconscious. General anaesthetics make

people unconscious and stop them feeling pain. Doctors investigated two ways of measuring the effect of general anaesthetics. They gave: • •

anaesthetic S to 18 people anaesthetic Q to 29 people

They recorded how long it took for the people to stop blinking. The doctors then repeated the investigation. This time, they used a machine that measures brain activity to decide when a person was unconscious, rather than when blinking stopped. For each person, they recorded how long it took for the machine’s readings to show that the person was unconscious. Their results are shown in the table. A value of ±2 × SD from the mean includes over 95% of the data.

Anaesthetic

Mean time taken to stop blinking / minutes (±2 × SD)

Mean time taken for machine to show that person was unconscious / minutes (±2 × SD)

S

0.24 (±0.01)

0.48 (±0.11)

Q

0.28 (±0.02)

0.44 (±0.07)

(a)

Blinking involves cholinergic synapses. Anaesthetic S is a similar shape to acetylcholine. Suggest how anaesthetic S stops the transmission across the synapse. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (3)

(b)

Should time taken to stop blinking be used as an indicator of when to start surgery? Explain your answer. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________

(2)

(c)

Each person was given the same volume of anaesthetic per kg of body mass. Suggest why. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (1) (Total 6 marks)

Q5. Apple farmers want to harvest their fruit when it is ripe enough for eating but also when it can be stored to sell later. One method apple farmers use to decide when to harvest their fruit is to determine the starch content. As apples ripen, starch in the apple is converted into soluble sugars that make them taste sweet. Scientists investigated the best time to harvest apples for storage before being sold. To determine the starch content, they picked samples of apples. They cut each apple in half and covered the cut surface with iodine solution. They left it for 1 minute and then compared it with the diagram below to give it a starch index score between 1 and 10.

They collected samples of apples at 5 different days during the ripening period and tested them for starch content. These results are shown in the table below. When apples were collected / day during ripening period

Mean starch index

117

3.7

124

4.4

131

6.3

138

7.7

145

8.2

The scientists stored samples of apples from each collection day for 180 days. They then determined the percentage of apples that were rotten. These results are shown in the graph below.

(a)

The cut surface of the apple covered with iodine solution is left for 1 minute before being compared to Figure 1. Explain why each apple must be left for the same length of time. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2)

(b)

Describe and explain the change in appearance of the cut surface of the apple when treated with iodine solution from underripe (starch index 1) to overripe (starch index 10). ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________

___________________________________________________________________ ___________________________________________________________________ (3) (Total 5 marks)

Q6. Iodine has many uses. One use is as an antiseptic to kill bacteria and another is helping apple farmers decide when to harvest their apples. Iodine solution has been used as an antiseptic on wounds for over 150 years. At first, its use in hospitals was limited because it irritated people’s skin. In the 1950s, iodine solution was made into providone iodine that caused less skin irritation. A surgeon investigated how effective providone iodine was at killing bacteria on skin. The surgeon treated the forearms of 25 people in 4 ways. Treatment A − no washing Treatment B − washed with soap and water only Treatment C − washed with soap and water then rubbed with Hex scrub for 5 minutes (Hex scrub was the treatment the surgeon used at that time to wash a patient’s skin before surgery) Treatment D − washed with soap and water then rubbed with providone iodine for 5 minutes After each treatment, the surgeon collected bacteria by rubbing each person’s skin with a sterile cotton swab. He put the swab into sterile liquid agar. He then poured the agar into a Petri dish and allowed it to set. He incubated the Petri dish and when bacterial colonies had grown, he counted them. The surgeon’s results are shown in the table below.

(a)

Treatment

Mean number of bacterial colonies (± standard deviation)

A

401.6 (±96.4)

B

191.4 (±63.7)

C

25.9 (±15.6)

D

0.7 (±1.5)

Suggest three factors the surgeon kept constant when sampling from the skin and growing the bacterial colonies. 1. _________________________________________________________________ ___________________________________________________________________ 2. _________________________________________________________________ ___________________________________________________________________ 3. _________________________________________________________________ ___________________________________________________________________

(3)

(b)

Calculate the percentage difference in mean number of bacterial colonies for Treatment D compared with Treatment A. Show your working.

Answer ________________________________________ % (2)

(c)

Treatment D produced a mean of 0.7 colonies and a standard deviation of ±1.5. What does this suggest about the number of colonies on the Petri dish? ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (1)

(d)

After this investigation, the surgeon wanted to test the effectiveness of providone iodine when used on patients who were about to have surgery. In this new investigation, the test group was given Treatment D. Suggest and explain the treatment that he should give to the control group to ensure that this is an ethical investigation. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2) (Total 8 marks)

Q7. A student investigated the effect of body position on pulse rate. The table below shows her processed results. Pulse rate / beats per minute

Body position

Reading 1

Reading 2

Reading 3

Mean

Sitting

80

76

76

77

Standing

84

88

92

88

Lying down

68

72

68

69

The way the student recorded her pulse produced pulse rates per minute with even

numbers. Other than by chance, suggest why. _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ (Total 1 mark)

Q8. The artery leaving the left ventricle is the aorta. One form of heart disease is aortic valve disease (AVD). In this disease, the valve (the aortic valve) between the left ventricle and the aorta opens normally but only partly closes. This means that when the ventricle relaxes some blood flows back into the ventricle from the aorta. Severe AVD can be treated by replacing the aortic valve. A surgeon investigated the effect of this treatment, • He replaced the aortic valves of 19 patients with valves removed from donors who had recently died. • The valves from donors were stored in an isotonic antibiotic solution before use. • He recorded the maximum pressure reached in an artery (as the ventricles contract) and minimum pressure in the artery (as the ventricles relax) in each patient before and after valve replacement surgery. His results are shown in Table 1. Table 1 Mean maximum pressure reached in the artery / kPa (± standard deviation)

Mean minimum pressure reached in the artery / kPa (± standard deviation)

Before surgery

21.7 (±3.5)

4.8 (±2.5)

After surgery

18.2 (±2.2)

11.0 (±1.1)

This investigation involved 19 patients. •

The mean age was 36 years (standard deviation ±17 years).

•

The mean time after surgery that pressure readings were taken was 7 months (standard deviation ±5 months).

Table 2 shows the normal range of values of pressure in this artery in the UK. Table 2 Pressure

Range of pressures / kPa

Maximum

12.0 to 18.5

Minimum

8.0 to 11.9

Aortic valves removed from donors were stored in isotonic solution containing an antibiotic

before being used in valve replacement surgery. (a)

Explain why the valves were stored in an isotonic solution. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2)

(b)

Explain why the valves were stored in a solution containing an antibiotic. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (1)

(c)

There was a significant increase in the minimum blood pressure in the artery after valve replacement surgery. Explain why the valve replacement surgery had this effect. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (1)

(d)

The surgeon concluded that there was sufficient evidence for him to continue using this treatment. How does the information above support his conclusion? ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ____________________________________________________...