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Mark KULLEĠĠ SAN BENEDITTU Secondary School, Kirkop

HALF YEARLY EXAMINATION – 2015/2016

Form 4 BIOLOGY TIME: 1h 30min

Question no:

Section A

1 2 3 4 5 6 7 Section

B 1 2 3 4 5

Global Mark

Mark Q1 + any

other two

Maximum Mark 4 10 8 4 9 8 12 15 15 15 15 15 100

DO NOT WRITE ABOVE THIS LINE

Name: __________________________________ Class: ___________

Section A

Answer ALL questions in this section. This section carries a maximum of 55 marks.

1. In some parts of the world, plants produce biomass very quickly, taking carbon dioxide

from the air and converting it into plant material by photosynthesis. For example,

sugar cane grows very rapidly and has a juice that is very high in carbohydrates,

particularly sucrose. Similarly, sweet corn is another fast grower. When the starch in

the sweet corn is treated with the enzyme amylase, it is finally broken down into

glucose. (3 marks)

From the information given above, name:

a) ONE food group: _______________________________________________________________ (1)

b) ONE monosaccharide: _______________________________________________________________ (1)

c) ONE disaccharide: _______________________________________________________________ (1)

d) ONE polysaccharide: _______________________________________________________________ (1)

(Total: 4 marks)


2. Four types of food were tested for starch, glucose, protein and lipids. The results

were recorded in the table below.

Food Test for Starch Test for glucose Test for protein Test for lipids

Bread Blue black Orange precipitate No change No change

Potato Blue black No change No change No change

Almonds No change No change Purple Cloudy white

Oil No change No change No change Cloudy white

Using the information above, answer the following questions:

a) Briefly describe the test for starch.

________________________________________________________________________________________________________

____________________________________________________________________________________________________ (2)

b) Name ONE food that contains starch. _______________________________________________ (1)

c) What colour change occurred when Benedict’s solution was added to food that

contained glucose?

____________________________________________________________________________________________________ (1)

d) Name ONE food that contains glucose. _______________________________________________ (1)

e) Name ONE food that contains protein. _______________________________________________ (1)

f) Explain why ethanol was used when conducting the test for lipids.

____________________________________________________________________________________________________ (1)

g) Name ONE food that contains lipids. _______________________________________________ (1)


h) State why having a control is important when conducting an experiment.

____________________________________________________________________________________________________ (1)

i) Describe a control which could have been used for this experiment.

____________________________________________________________________________________________________ (1)

(Total: 10 marks)

3. The following graph shows the effect of temperature on the activity of an enzyme.

a) Define the term optimum temperature of an enzyme.

____________________________________________________________________________________________________ (1)

b) From the graph above, find the optimum temperature of this specific enzyme.

____________________________________________________________________________________________________ (1)


c) Two samples of the enzyme were taken. Both Sample A and Sample B were stored at

5OC for several days. Sample A was however boiled before being stored. Both

samples were then warmed to their optimum temperature. Substrate was added to

both samples and the activity of the enzyme in each sample was measured.

(i) Predict what results you would expect from each sample.

____________________________________________________________________________________________________

________________________________________________________________________________________________ (2)

(ii) Give a reason for your answer.

____________________________________________________________________________________________________

________________________________________________________________________________________________ (2)

d) List TWO factors that need to be kept constant in order to make accurate

comparisons about the effect of temperature on the samples.

________________________________________________________________________________________________________

____________________________________________________________________________________________________ (2)

(Total: 8 marks)

4. The table below shows the vitamin and mineral content of three different food

substances.

Food substance Mg per 100g of food

Iron Calcium Vitamin C Vitamin D

Lentils 7.6 39 0 0

Milk 0.1 120 0.5 0.002

Lettuce 2.0 1 3 0

a) From the table above, name:

(i) ONE food suitable for a person suffering from anemia.

________________________________________________________________________________________________ (1)


(ii) ONE food which can prevent rickets.

________________________________________________________________________________________________ (1)

(iii) ONE food which can prevent scurvy.

________________________________________________________________________________________________ (1)

b) Lentils are rich in protein. Name the elements that make up proteins.

____________________________________________________________________________________________________ (1)

(Total: 4 marks)

5. A group of biology students set up the apparatus shown below to study the production of carbon dioxide by animals.

a) Describe the role of the suction pump in this experiment.

____________________________________________________________________________________________________ (1)

b) Describe the importance of bubbling the incoming air through potassium hydroxide

solution (in conical flask A) before it is supplied to the mouse.

____________________________________________________________________________________________________ (1)


c) Describe the importance of bubbling the incoming air through lime water (in conical

flask B) before it is supplied to the mouse.

____________________________________________________________________________________________________ (1)

d) The outgoing air is then bubbled though the lime water in conical flask C.

(i) Describe the colour change in flask C.

________________________________________________________________________________________________ (1)

(ii) Explain the colour change in flask C.

________________________________________________________________________________________________ (1)

e) Describe a suitable control for this experiment.

____________________________________________________________________________________________________ (1)

f) Name the process by which carbon dioxide is being produced by the mouse.

____________________________________________________________________________________________________ (1)

g) The students were discussing the amount of oxygen in the incoming air and the

outgoing air.

(i) Predict the difference between the percentage of oxygen in the incoming air

and the percentage of oxygen in the outgoing air.

________________________________________________________________________________________________ (1)

(ii) Explain this prediction.

________________________________________________________________________________________________ (1)

(Total: 9 marks)


6. A group of biology students set up the apparatus shown below to study the heat

production in germinating seeds.

a) State the aim of this experiment.

____________________________________________________________________________________________________ (1)

b) After a few days, the students read the temperature from the thermometer.

(i) Name the thermos flask which shows a higher temperature at the end of the

experiment. _______________________________________________________________________ (1)

(ii) Explain this difference in temperature.

____________________________________________________________________________________________________

________________________________________________________________________________________________ (2)

c) Describe the purpose of washing the seeds with disinfectant before starting the

experiment.

____________________________________________________________________________________________________ (1)


d) Explain why cotton wool (and not a rubber bung) was used to seal the thermos flask.

____________________________________________________________________________________________________ (1)

e) It is NOT advisable to fill the flasks completely with seeds. Explain this statement.

____________________________________________________________________________________________________ (1)

f) Describe the role of flask B.

____________________________________________________________________________________________________ (1)

(Total: 8 marks)

7. The table below shows the energy used by a typical 25-year old woman during various

activities. She has a mass of 60Kg.

Activity Energy used in KJ per minute

Sitting 5

Standing 9

Walking slowly 11

Dancing 19

Running 27

Running up and down the stairs 28

a) On the squared paper below, plot a bar chart of Activity on the x-axis versus Energy

used in KJ per minute on the y-axis. In your bar chart include: labelling of the axes,

title of the bar chart, and labelling of each column on the x-axis. Use an appropriate

scale. (5)


b) Name the activity which used the most energy per minute.

____________________________________________________________________________________________________ (1)

c) Calculate the percentage increase in energy used per minute when the woman has

been sitting down, then goes for a run. Show your working.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

____________________________________________________________________________________________________ (2)


d) Explain why running up and down the stairs uses more energy than walking slowly.

________________________________________________________________________________________________________

____________________________________________________________________________________________________ (2)

e) The data above applies to a 25-year old woman with a mass of 60Kg.

(i) Suggest what difference there would be in the energy used in KJ per minute if

the woman weighed 85Kg.

________________________________________________________________________________________________ (1)

(ii) Give a reason for your answer.

________________________________________________________________________________________________ (1)

(Total: 12 marks)


Section B

Answer question 1 and any TWO other questions. Each question carries 15 marks. This

section carries a maximum of 45 marks. Write the answers for section B on a foolscap

provided.

1. Read the following passage and answer the questions that follow.

Obstructive lung diseases are respiratory diseases characterized by airway obstruction.

Bronchitis is an obstructive lung disease which is caused by an inflammation of the bronchi of

the lungs, making the airways tighter and narrower. Symptoms include coughing up mucus,

wheezing, shortness of breath, and chest discomfort. Restrictive lung diseases are respiratory

diseases that restrict lung expansion, resulting in decreased lung volume.

a) Describe the position of the lungs in the human body. (1)

b) Describe TWO consequences of narrower airways caused by Bronchitis. (2)

c) Asthma is another example of an obstructive lung disease. Low quality air due to traffic

pollution and industry has been associated with asthma.

(i) Compare the risk of suffering from asthma for children living in Marsa with

those living in Mellieħa. (1)

(ii) Describe ONE way how car manufacturers can reduce pollution caused by

traffic. (1)

d) Explain the role of mucus in the human respiratory system. (1)

e) The Lung volume changes when a person is breathing in and breathing out.

(i) Compare the lung volume during breathing in and breathing out. (1)

(ii) Describe how this difference in lung volume is brought about. Name all the

muscles involved in breathing. Include diagrams if necessary. (4)

f) Describe ONE symptom of a reduced lung volume in individuals suffering from

restrictive lung disease. (1)

g) A smoker is 20 times more likely to develop bronchitis than a non-smoker. Explain. (3)


2. The kidneys are two bean-shaped organs that extract waste from blood, balance body fluids, form urine, and aids in other important functions of the body. They reside against the back muscles in the upper abdominal cavity.

a) The kidney is considered a homeostatic organ. Explain. (2)

b) List TWO ways how patients with kidney failure can be helped to lead a normal life.

List ONE disadvantage of each. (4)

c) The diagram below shows a kidney nephron.

(i) Name structure X and explain the process taking place at X. (3)

(ii) Structure Y is longer in animals living in dry regions. Name structure Y and

explain the importance of this. (2)

d) Name ONE substance that is NOT present in the urine of a healthy individual. (1)

e) The kidneys produce about 180 litres of glomerular filtrate each day, however the daily

production of urine is only about 1-2 litres. Explain. (2)

f) Different factors affect the amount of urine produced in a human being. Name and

explain ONE of these factors. (1)


3. A biology student wants to investigate the effect of the enzyme amylase on starch.

Explain how you would design an experiment of the sort. In your description include:

a) Aim of the investigation (1)

b) Apparatus and materials needed (2)

c) A well labelled diagram of the set up (3)

d) A detailed method, including a suitable control (5)

e) Results expected in the form of a table (2)

f) Interpretations of the expected results (2)

4. Explain the biological significance of the following statements:

a) Smaller mammals often have a higher respiration rate than larger animals. (3)

b) Aerobic and anaerobic respiration in mammals varies considerably. (4)

c) Alcoholic fermentation of yeast is of an economic importance. (4)

d) Bacteria can be used to produce yoghurt. (2)

e) Biogas is produced in the absence of oxygen. (2)

5. Describe why each of the following statements is incorrect.

a) As the pH increases, the rate of an enzyme catalyzed reaction increases. (2)

b) Once an enzyme is used to catalyze a reaction, it cannot be used again. (1)

c) All animals required specialized gas exchange organs. (2)

d) Anaerobic respiration produces as much energy as aerobic respiration. (2)

e) Extra protein in the body is immediately stored as fat. (3)

f) A balanced diet doesn’t include any fat. (2)

g) Water is only lost by the human body through urine. (3)

END OF EXAM

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