Basic Education - THUNDEREDUC

Basic Education

KwaZulu-Natal Department of Basic Education REPUBLIC OF SOUTH AFRICA

PINETOWN AND ILEMBE DISTRICTS

LIFE SCIENCES

Grade 11

TOPIC TEST: Micro-organisms

MARKS: 50

TIME: 60 minutes

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SECTION A

Question 1

1.1

Various options are provided as possible answers to the following questions.

Choose the correct answer and write only the letter (A to D) next to the

question number (1.1.1 to 1.1.3) in your ANSWER BOOK, for example

1.1.4 D.

1.1.1

Viruses are mainly composed of ...

A protein and nucleic acid. B DNA and RNA. C cytoplasm and nuclei. D cellulose and protein.

1.1.2

All viruses are ...

A prokaryotes. B unicellular. C cellular in structure. D acellular and non-living.

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Life Sciences

2 NSC ? Grade 11

Test: Micro-organisms

1.1.3

A young woman stepped on a dirty, rusty nail. The following diagrams show bacteria isolated from the wound and a range of antibodies that were already present in her body. The antibodies have a specific shape that binds with the antigen found on the surface of the bacteria.

Which type of bacterium will most likely cause a severe infection?

A M B N C O D P

(3 x 2) (6)

1.2

Give the correct biological term for each of the following descriptions.

Write only the term next to the question number (1.2.1 to 1.2.4) in the

ANSWER BOOK.

1.2.1 Organisms that cause disease

1.2.2

Life forms that are so small that they cannot be seen with the naked eye

1.2.3 The mass of hyphae that makes up the vegetative part of a fungus

1.2.4 The kingdom to which the malarial parasite belongs

(4 x 1) (4)

TOTAL SECTION A: 10

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Life Sciences

SECTION B

3 NSC ? Grade 11

Test: Micro-organisms

Question 2

2.1

Study the extract below about malaria.

Malaria is a parasitic disease which occurs mainly in the tropical and subtropical regions of the world. It is transmitted in humans through the bite by a female mosquito of the Anopheles species, which is the vector for the parasite.

The most effective way of managing malaria is to destroy its vector. An insecticide which has been successful to date is DDT. The inner walls of the house are sprayed with DDT so that the mosquitos die if they sit on or near them. However, the use of DDT has been banned since 1972.

In South Africa, the incidence of malaria has been less than 10 000 cases per year. South Africa only stopped its use of DDT in 1996. The number of infections recorded since increased to 64 000 in 2000. When the use of DDT was re-introduced only for disease-vector control, the reported cases decreased to 7 000 in 2005 in South Africa.

2.1.1 2.1.2 2.1.3 2.1.4

2.1.5

2.1.6

2.1.7

State any TWO ways to avoid contracting malaria.

(2)

What is a vector?

(1)

Which genus is the vector for the malarial parasite?

(1)

Describe how the malaria parasite is passed from one person to

another.

(2)

Explain how an increase in the number of malaria infections would

affect the South African economy.

(2)

Suggest ONE way in which the data about the number of infections

may have been collected.

(1)

Give ONE reason why the number of infections might have been

more than the estimated 7 000 in the year 2005.

(1)

(10)

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Life Sciences

4 NSC ? Grade 11

Test: Micro-organisms

2.2

The table below shows the number of cases of TB and the number of deaths

from TB around the world in 2009. Use the information in the table to answer

the questions that follow.

REGION

Africa The Americas Eastern Mediterranean Europe South-East Asia Western Pacific

NUMBER OF CASES OF TB

(in 1000s)

3 900 350

1 000 560

4 900 2 900

NUMBER OF DEATHS FROM TB

(in 1000s)

430 20 99 62

480 240

2.2.1 State the total number of deaths from TB in Africa.

(1)

2.2.2

Calculate the percentage of deaths from TB compared to the

number of cases of TB in Africa. Show your working.

(3)

2.2.3

Draw a bar graph to show the number of deaths from TB for the

following 4 regions: Africa, Eastern Mediterranean, South-East

Asia and Western Pacific.

(6)

(10)

[20]

Question 3

3.1

Tabulate TWO general structural differences between bacteria and fungi.

(5)

3.2

Describe the symbiotic relationship between bacteria and leguminous plants

(5)

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Life Sciences

5 NSC ? Grade 11

Test: Micro-organisms

3.3

An investigation was carried out to test the effectiveness of four antifungal

treatments (Fungiclear, Mycocide, Mycoban, and Fungisan) on preventing the

growth of yeast in humans.

The petri dish with the treatments and yeast culture used in the investigation was placed in an incubator at 37 oC.

The results are shown in the diagram below.

Fungiclear Mycocide

Mycoban Fungisan

KEY Yeast growth No yeast growth

Antifungal treatment

3.3.1 For this investigation, state the:

(a) Dependent variable

(1)

(b) Independent variable

(1)

3.3.2 3.3.3 3.3.4 3.3.5

Explain why the investigator put the petri dish in an incubator at

37 oC.

(2)

State any TWO factors that the investigator had to control in order

for the investigation to be valid.

(2)

State TWO ways in which the investigator could have increased

the reliability of the investigation.

(2)

Arrange the anti-fungal treatments in the order from MOST

effective in preventing the growth of yeast to the LEAST effective in

preventing the growth of yeast.

(2)

(10)

[20]

TOTAL SECTION B: [40]

GRAND TOTAL: [50]

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