1
QUESTIONS ON ‘CHEMISTRY OF LIFE’
GRADE 10 CTLi TRAINING SESSION
29 MARCH 2012
1. Study the following completed crossword puzzle and answer the questions that
follow:
1.1
Identify TWO nutrients from the crossword puzzle and give ONE function of each.
(4)
1.2
Write down TWO deficiency diseases from the crossword puzzle and next to each
the nutrient needed to prevent it.
(4)
2
2. The following table shows an analysis of the nutrients found in a 100 g portion of
breakfast. The breakfast was made up of eggs, bread and butter.
Use the information in the table to answer the following questions:
2.1 Name (a)
(b)
ONE nutrient that is essential for the manufacture of enzymes
(1)
A vitamin deficiency disease that could result from a diet that consists
mainly of eggs.
(1)
2.2
Identify the food type that would be best for a person who suffers from nightblindness. Give a reason for your answer.
(3)
2.3
Calculate the amount of iron found in a 500 g serving of the above breakfast. Show
ALL calculations.
(4)
2.4
Which food type will show no colour change when it is tested with Millon’s Reagent /
Biuret solution?
(1)
2.5
Briefly explain why an athlete should include bread in his/her breakfast. (2)
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3
3. The pie chart below indicate the composition of two types of foods. Answer the
questions based on it. (2004p9)
3.1 Which food is best suited to prevent constipation? Give a reason for the answer.
(2)
3.2 What percentage of food Y consists of calcium?
(2)
3.3 List THREE functions of water in nutrition.
(3)
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4. Describe a test you would perform to determine the presence of fats in a food
sample.
[5]
___________________________________________________________________
(5)
4
5.During a field trip learners collected dung (Faeces) from two different species of
mammals, A and B. They broke up the dung and observed these under the microscope.
In addition, they also tested solutions of the dung for different food substances.
The results are indicated in the table below.
COMPOSITION OF DUNG
Epidermal cells of grass
Epidermal cells of shrubs
Seeds
Starch
Sugars
Soluble protein
Mammal fur
Fat
MAMMAL A
Present
Present
Present
Present
Present
Present
Absent
Absent
MAMMAL B
Absent
Absent
Absent
Absent
Present
Present
Present
Present
5.1
State one major difference in the type of diet of the two mammals.
(2)
5.2
Identify TWO sources of fibre eaten by mammal A.
(2)
5.3
List Three functions of fibre in the diet.
(3)
[7]
___________________________________________________________________
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6.
Use the information in the graph below to answer the questions.
6.1
At which temperature does the enzyme work best?
(2)
6.2
What mass of food is broken down at 25°C?
(2)
6.3
Give an explanation fot the shape of the graph between 5°C to 35°C.
(4)
6.4
What does the information in the graph suggest about the amount of food that
would be broken down at 65°C? Explain the answer.
(3)
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___________________________________________________________________
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7.
Read the extract below very carefully and then answer the questions that
follow.
EXTREMELY MALNOURISHED CHILDREN ADMITTED TO HOSPITAL
Two boys from town in Gauteng, who are eight and twelve years old respectively,
were admitted to hospital for treatment of the worst form of malnutrition – they
were just skin and bone.
Normally an eight-year-old should weigh 25 kg and a twelve-year-old should
weigh 30 kg. However, both these boys weighed only 10 kg each.
Both boys were only given porridge without milk to eat. Their brain activity was
lower than that of other children of their age.
Serious malnutrition has an overall effect on children’s development. The body
tissues and skeleton do not develop. The heart muscles are weak, the liver is
virtually absent and no fat layer is visible under the skin.
[Adapted and translated from: Rapport, 12 March 2000]
7.1
Briefly describe what you understand by the following:
(a)
malnutrition
(2)
(b)
‘ …… they were just skin and bone’ (line 3)
(2)
7.2
How many kilograms was the twelve-year-old boy underweight compared with the
normal weight? Show your calculation.
(2)
7.3
Using the symptoms mentioned in the extract (lines 6 – 7), name the following:
(a)
TWO food groups that are needed to balance the diet
(2)
(b)
TWO elements that were possibly missing in the diet and are necessary for
developing and building healthy bones
(2)
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___________________________________________________________________
7
8.
List:
(a)
THREE functions of roughage (fibre) in the digestive system.
(3)
(b)
TWO functions of water in the movement of food along the digestive
system.
(2)
[5]
___________________________________________________________________________
8
9.
The diagram below shows the apparatus and materials that were used to investigate
the influence of the enzyme in saliva on cooked starch.
Study the diagram and answer the questions that follow:
9.1
After 10 minutes which test tube, A or B, would most likely test positive for the
presence of starch?
(1)
9.2
Name the product that was formed in the test tube which tested negative for starch.
(1)
9.3
Briefly describe why test tube C would also test positive for starch.
(3)
9.4
Why is test tube D necessary?
(1)
9.5
Describe how you will test fot the presence of glucose.
(3)
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___________________________________________________________________
9
10.
The diagram below shows the nutritional composition of various types of food. Study
the diagram and answer the questions that follow.
10.1
Name ONE food type that is most suitable for a young sportswoman.
(1)
10.2
Explain your answer to 10.1.
(4)
10.3
Name an organic compound of ALL the various foods (A to D).
(1)
10.4
Which food type (A, B, C or D):
(a)
Is best suited to prevent constipation? Give a reason for your answer.
(3)
(b)
Should be given to person wanting to be slim and lose weight? Give a reason
your answer.
(3)
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