UNIT NO.2
Microorganism
(Solved Exercise)
1. Choose the correct answer.
i. Which of the following are ways to keep food free from germs?
a. freezing
b. cooking
c. sterilising
d. all of these
ii. Which of the following is not a microorganism?
a. a fly
b. bacteria
c. mould
d. a virus
iii. Bacteria are used to prepare
a. yoghurt
b. bread
c. cake
d. milk
iv. Which type of germ causes pneumonia?
a. viruses
b. bacteria
c. fungi
d. protozoa
v. Milk is pasteurised at a temperature of
a. 30°C
b. 40°C
c. 60°C
d. 80°C
2. Fill in the blanks.
i. Foods packed in a factory contain preservatives.
ii. Milk can be preserved by a process called pasteurisation.
iii. Living things which are made of one cell are called unicellular organisms.
iv. A useful type of bacteria is used in making yoghurt.
v. A mushroom is an example of an edible Fungi.
3. Mark these sentences with ✔ or ✘.
i. Infections cannot be caused by small worms. ✘
ii. Germs are killed by pasteurisation. ✔
iii. Influenza is caused by a virus. ✔
iv. All kinds of bacteria are harmful. ✘
v. The body gets vitamin D from sunlight. ✔
7. Answer these questions.
i. How are germs kept out of tinned foods?
Answer:
1. Sterilization: Food is heated at specific temprature to kill germs.
2. Sealed Can: Air tight cans prevent new germs from enterning
3. Heat Treatment: Can are heated again after sealing to kill any remaining germs.
ii. What is pasteurisation?
Answer:
It is process where liquids like milk or juice are heated to a high temprature (to 60°C)and then cooled quickly. Most of the germs are killed off in this process.
iii. What are the main kinds of microorganisms?
Answer:
These are four main kinds of microorganisms:
1. Viruses
2. Bacteria
3. Fungi
4. Protozoa
iv. In what ways are diseases spread from person to person?
Answer:
Diseases can spread from person to person though:
1. Direct contact (Touching)
2. Caughing or sneezing
3. By the bite of insects such as mosquitoes, fleas, bugs and sand flies.
v. How can we stop diseases from spreading?
1. Washing handsfrequently with soap and water.
2. Using masks.
3. Getting vaccinated
4. Practicing soil distancing
5. Using clean water
6. Avoiding close contact with sick people
7. Covering mouth and nose wheng coughing
vi. Define the following terms:
a. microorganism b. microscopic
Answer:
Microorganism
A microorganism is a tiny living things that cannot be seen with the naked eye.
Microscopic
Microscopic mean something is too small to be seen with naked eye and requires a microscope to be visible.
vii. Name any three places where you can find bacteria.
Answer:
1. Human gut
2. Soil
3. Water
viii. How are fungi useful for human beings? Give two examples.
Answer:
Some fungi are edible like mashroom, and yeast is a fungus used to making bread and some antibiotics.
ix. List six ways in which microorganisms can enter your body.
Answer:
Microorganisms enter in your body through:
1. Air (Coughing , sneezing)
2. Cuts in the skin
3. Insects ( flies, mosquitoes)
4. Infected water
5. Vomit of patient in hospitals
6. Infected food