Microorganisms: Friends and Foe

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Questions and Answers

The gas released during the preparation of bread is:

Sulphur dioxide
Carbon dioxide (correct)
Nitrogen
Oxygen

Which of the following helps in making curd from milk?

Salmonella
Lactobacillus (correct)
Plasmodium
Yeast

A disease in human beings caused by virus is

Influenza (correct)
Typhoid
Dysentry
Cholera

Bacteria are harmful for curd.

False (B) Signup and view all the answers

The replenishment of soil with nutrients is done by some microorganisms.

True (A) Signup and view all the answers

Malaria, Dengue can be prevented by using mosquito net and mosquito repellent.

True (A) Signup and view all the answers

Match the diseases with their respective pathogens:

Fungus = Ringworm Protozoan = Cholera Bacteria = AIDS Virus = Malaria Signup and view all the answers

The female Aedes mosquito is a carrier of the ______ disease.

Malaria Signup and view all the answers

______ are chemicals that inhibit microbial growth.

Antibiotics Signup and view all the answers

______ is a unicellular fungus

Yeast Signup and view all the answers

______ made the first vaccine.

Edward Jenner Signup and view all the answers

Name two diseases which are spread by mosquitoes.

Malaria and Dengue Signup and view all the answers

Mention two ways to control the growth of mosquitoes and their larvae.

Using mosquito nets and repellants, and removing stagnant water Signup and view all the answers

What is food poisoning and how we can prevent it?

Food poisoning is an illness caused by consuming contaminated food, and can be prevented by proper hygiene and food handling practices. Signup and view all the answers

Discuss two important ways in which bacteria are useful to us and two ways in which they are harmful.

Bacteria are beneficial in processes like nitrogen fixation and curd formation; however, they can cause diseases like typhoid and tuberculosis. Signup and view all the answers

Why do you think: (a) Curd sets faster in summer than in winter? (b) Curd turns sour faster in summer than in winter? (c) The sealed packets in which food items such as chips are sold are usually filled with nitrogen.

(a) Warmer temperatures create a more favorable environment for bacteria to thrive, leading to faster curd formation. (b) The bacteria responsible for souring curd are more active at higher temperatures. (c) Nitrogen acts as an inert gas, preventing oxidation and spoilage of food items. Signup and view all the answers

We should not use the towel, utensils of a person suffering from tuberculosis. (a) What does this statement mean? (b) What are the various indirect methods of transmission of communicable disease? (c) Give the names of some carriers that transmit communicable disease.

(a) This statement suggests that tuberculosis can be spread through contaminated objects and surfaces, potentially affecting others. (b) Indirect transmission can occur through contaminated objects, air, or surfaces. (c) Some carriers of communicable diseases include mosquitoes, flies, and rodents. Signup and view all the answers

Identify the given organisms.

The given organisms are a bacterium, a fungus, an algae, and a virus. Signup and view all the answers

Microorganisms decompose the organic matter and help to clean the environment. (a) How does a microbe help in cleaning the environment? (b) What would happen if microorganisms do not perform this function?

(a) Microorganisms act as decomposers, breaking down organic matter and recycling nutrients back into ecosystems. (b) Without decomposers, organic waste would accumulate, leading to environmental imbalances. Signup and view all the answers

Give one example of the following: (c) A protozoan showing photosynthesis (d) A filamentous alga (e) A single celled fungus

(c) Euglena is a protozoan that can perform photosynthesis. (d) Spirogyra is an example of a filamentous alga. (e) Saccharomyces cerevisiae is an example of a single-celled fungus. Signup and view all the answers

Describe the principal on which the following method of food preservation are based: (f) Boiling (g) Canning (h) Freezing (i) Dehydration

(f) Boiling involves heating food to high temperatures, killing microorganisms and enzymes. (g) Canning uses heat to sterilize food and seal it in jars; the vacuum prevents spoilage. (h) Freezing lowers the temperature, slowing down microbial activity and inhibiting growth. (i) Dehydration removes water, making it difficult for microorganisms to survive. Signup and view all the answers

Identify a, b, c, d.

a = Plants uptake nitrogen from the atmosphere b = Bacteria convert nitrogen into usable form c = Nitrogen compounds in the soil d = Nitrogen compounds in plants are used to make proteins e = Animals eat plants and get nitrogen from them f = Animals excrete nitrogen containing wastes which decompose to replenish nitrogen in the soil g = Plants release nitrogen back into the atmosphere by decomposition Signup and view all the answers

Examine the data and answer the questions that follow: The temperature and of the organism's body may have an effect on the growth patterns of many species of viruses. A study of viral reproduction was under taken by a local university. It measured the temperature of the organism and the change viral number over a 2 day period. The results of the study are found in the data table below.

Temperature of the organism in °C Number of virus A per cell Number of virus B per cel

30 60 77

35 115 88

36 128 260

37 143 200

38 243 150

40 47 34

45 21 2

46 2 2

(a) At what temperature did virus A develop the best? (b) Based on the above data, what temperature(s) seem to be the best for viral development? (c) What term is used if the temperature in a human goes above 98.6 degrees F? (d) Virus cannot replicate alone. Viruses must infect cells and use components of the host cell to make copies of themselves. Often, they kill the host cell in the process, and cause damage to the host organism. At what temperature(s) would the most cell destruction take place for Virus A? Why? (e) Can viruses be killed by antibiotics?

Temperature of the organism in °C	Number of virus A per cell	Number of virus B per cel
30	60	77
35	115	88
36	128	260
37	143	200
38	243	150
40	47	34
45	21	2
46	2	2

(a) Virus 'A' appears to reach the highest number at the temperature of 38 degrees Celcius. (b) Based on the data provided, the temperatures ranging from 36-38 degrees Celsius appear to be ideal for the development of both viruses. (c) The term used if the temperature in a human goes above 98.6 degrees F is Fever. (d) The most cell destruction for virus 'A' would likely occur at 38 degrees Celsius, as this is where it proliferates the fastest. (e) No, antibiotics cannot kill viruses, as they specifically target bacterial cells. Signup and view all the answers

Assertion (A): Bacteria are harmful for curd. Reason (R): Milk is converted into curd by Lactobacillus.

False (B) Signup and view all the answers

Assertion: The replenishment of soil with nutrients is done by some microorganisms. Reason: Fungi and bacteria are common decomposer.

True (A) Signup and view all the answers

Assertion: Malaria, Dengue can be prevented by using mosquito net and mosquito repellent. Reason: The causative organism spread through contaminated food and water.

False (B) Signup and view all the answers

Match the diseases with their respective pathogens: List-1 (Pathogen) (A) Fungus (B) Protozoan (C) Bacteria (D) Virus List-2 (Disease) (i) Cholera (ii) Ringworm (iii) AIDS (iv) Malaria

Fungus = Ringworm Protozoan = Cholera Bacteria = AIDS Virus = Malaria Signup and view all the answers

Municipal Corporation has deputed to check for mosquito breeding in your school. (b) Mention two ways to control the growth of mosquitoes and their larvae.

Using mosquito nets and insecticides. Signup and view all the answers

Flashcards

Gas released during bread preparation

The gas that causes dough to rise is carbon dioxide, produced by yeast during fermentation.

Curd formation from milk

Lactobacillus is the bacteria that converts milk into curd by fermentation.

Disease caused by a virus

Influenza is a disease in humans caused by a virus that affects the respiratory system.

Role of Lactobacillus

Lactobacillus is beneficial, contrary to the assertion that all bacteria are harmful in curd preparation.