Class 5 General Science (G.Sc.) Notes: Unit-2: Micro-organisms - Solved Exercise ( MCQs, Questions and Answers)

General Science (G.Sc.) Class 5 Notes

Based on the Single National Curriculum, PK

(New Book/New Syllabus for 2023-2024 Exams and onward)

National Book Foundation
as
Federal Textbook Boards, Islamabad

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"1. Tick ( ✓ ) the Correct Answers"

i. Which group of microorganisms does mushrooms belongs:

(a) virus
(b) fungi
(c) bacteria
(d) protozoa

... Answer is (b)  fungi
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ii. What is the cause of polio disease?

(a) protozoa
(b) virus
(c) fungi
(d) bacteria

... Answer is (b)  virus
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iii. Penicillium is an example of which group?

(a) protozoa
(b) fungi
(c) bacteria
(d) virus

... Answer is (b) fungi
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iv. Which of the following is not an organism:

(a) Moisture
(b) microorganisms
(c) air
(d) heat

... Answer is (b) microorganisms
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v. Which one of the following is not a microorganism

(a) bacteria
(b) virus
(c) protozoa
(d) ant

... Answer is (d) ant
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👉Unit-2 YouTube Video Presentation -- Please subscribe also!👈

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"2. Write Short Answers"

Q(i). What is a pathogen? How does it enter the bodies of organisms? 

Ans: 

Pathogen: The microorganisms that cause diseases in their hosts are called pathogens. The diseases that occur due to them are called infections or infectious diseases. Pathogens usually enter our bodies through the mouth, eyes, nose, or through wounds. They can be spread through skin contact, airborne particles, Water, food, and animals.

Q(ii). Why are some bacteria and fungi called decomposers? 

Ans: Some bacteria and fungi break down the complex matters of dead bodies into Simple Components. That's why they are called decomposers.

Q(iii). Write two benefits and two harmful effects of bacteria? 

Ans. 

Benefits of bacteria:

i. Some bacteria help in the digestion of food and absorption of food components in our small intestine.

ii. Bacteria are used in food production.

Harmful effects of bacteria: 

i. Some types of bacteria can cause diseases in humans, plants, and animals e.g cholera typhoid, etc.

ii. Bacteria Spoil food e.g. rotting of fruits and vegetables, Souring of milk, etc.

Q(iv). How does the microorganism yeast work to Soften and raise the dough of flour? 

Ans: Yeast in the dough metabolizes the starches and sugars in the flour and then turns into carbon dioxide gas. This gas inflates the network of air bubbles which causes the bread to rise. 

Q(v). How does a mosquito transmit disease? 

Ans: When a mosquito bites and sucks the blood of a patient with malaria or dengue, it takes pathogens from the patient. When it bites a healthy person, it transmits those pathogens into him. 

"3. Constructed Response Question"

Q1. The soil of forests in a hot climate is always hot and moist, whereas the soil of forests in a cold climate is cold and dry. Out of these two areas where the decomposition of fallen leaves will take place faster? Explain.

Ans: The rate of decomposition increases with the increase in temperature, humidity, and oxygen. The soil of forests in a hot climate is always hot and moist, due to which the decomposing process is faster in both areas. That's why the decomposition of fallen leaves will take place more quickly and speedily in hot climates. 

"4. Investigate"

Q1: "All microorganisms are harmful and cause diseases" Prove this idea as incorrect. 

Ans: All microorganisms are not harmful. Some microorganisms are beneficial to us. 

1. Help in digestion: Bacteria live in the intestines of humans and animals help in the digestion of food. 

2. Help in plant growth: Microorganisms help the plant to absorb nutrients from the soil 

3. Help in decomposition: Microorganisms keep the atmosphere clean by decomposing dead animals and plants.

4. Making medicines: Many organisms are used for making medicines. Fungi and bacteria are used to make antibiotics.

Q: Many people use antibacterial soap to kill the bacteria present on their hands. However due to excessive use of soap, the Chance of getting infection increases instead of decreasing. Why does it happen?

Ans. Many people use antibacterial soap to kill the bacteria present in their hands. However excessive use of soap will reduce the healthy bacteria on your hands and remove the natural oil from your skin. Our hand's skin will be drier and cause infections like allergies.

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Shortcut Links For:

1.  5th Class: English Notes

2.  5th Class: Social Study (S.St.) Notes

3.  5th Class: General Science (G.Sc.) Notes

4.  5th Class: Urdu (اُردو) Notes

5.  5th Class: Islamiyat (اسلامیات) Notes

6.  5th Class: Mathematics Notes

7.  Easy English Grammar Notes

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