Microbes in Human Welfare Test

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Microbes in Human Welfare Test - 18

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Question 1
1 / -0

Read the following text and answer the any four questions on the basis of the same:
Large quantities of sewage is generated every day in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluted. Given below is the flow diagram of one of the stages of STP.
Observe the given flow diagram and answer the questions accordingly.
Q. Primary effluent is passed into large aeration tanks:

A
To allow bacterial flocs to settle down

B
To allow anaerobic sludge digestion

C
To allow fast growth of useful aerobic microbes into flocs

D
None of these

Solution

The primary effluent is transferred into large aeration tanks where it is constantly agitated mechanically and the air having oxygen is pumped into it which allows fast growth of useful aerobic microbes into flocs (masses of bacteria associated with fungal filaments to form mesh-like structures).
Question 2
1 / -0

Read the following text and answer the any four questions on the basis of the same:
Large quantities of sewage is generated every day in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluted. Given below is the flow diagram of one of the stages of STP.
Observe the given flow diagram and answer the questions accordingly.
Q. Identify the correct set of gases produced during digestion of sludge:

A
A. methane, hydrogen sulphide and carbon dioxide

B
B. methane, sulphur and carbon dioxide

C
C. carbon monoxide, methane, hydrogen sulphide

D
D. methane, hydrogen sulphide and nitrogen

Solution

During this digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide, and carbon dioxide. These gases form biogas and can be used as a source
of energy. The treated effluent from the secondary treatment plant is generally released into natural water bodies like rivers and streams.
Question 3
1 / -0

Read the following text and answer the any four questions on the basis of the same:
Large quantities of sewage is generated every day in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluted. Given below is the flow diagram of one of the stages of STP.
Observe the given flow diagram and answer the questions accordingly.
Q. Technical term used for sediment formed in sewage treatment is:

A
Flocs

B
Activated sludge

C
Effluents

D
Anaerobic sludge

Solution

The effluent after primary treatment is passed into the settling tank where the bacterial 'flocs' are allowed to settle down and this sediment is called Activated sludge. A small part of the activated sludge is pumped back into the aeration tank to serve as the inoculum(starter).
Question 4
1 / -0

Read the following text and answer the any four questions on the basis of the same:
Large quantities of sewage is generated every day in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluted. Given below is the flow diagram of one of the stages of STP.
Observe the given flow diagram and answer the questions accordingly.
Q. The technology of biogas production from cow dung was developed in India largely due to the efforts of :

A
A. Gas authority of India

B
B. Oil and Natural Gas Commission

C
C. Indian Agriculture Research Institute, Khadi and Village Industries Commission.

D
D. Indian Oil Corporation

Solution

The technology of biogas production from cow dung was developed in India largely due to the efforts of Indian Agricultural Research Institute (IARI) and Khadi & Village Industries Commission (KVIC) .
So, the correct option is 'Option C' .
Question 5
1 / -0

Read the following text and answer the any four questions on the basis of the same:
Large quantities of sewage is generated every day in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluted. Given below is the flow diagram of one of the stages of STP.
Observe the given flow diagram and answer the questions accordingly.
Q. The significance of the above sediment formed is that:

A
A. It acts as inoculum

B
B. It serves in formation of flocs

C
C. It helps in formation of natural water bodies

D
D. It helps in anaerobic sludge digestion

Solution

The activated sludge is pumped back into the aeration tank to serve as the inoculum(starter).
Question 6
1 / -0

Read the following text and answer any four questions on the basis of the same :
Ecological Indicators : The presence of dragonflies can reveal changes in the water ecosystems more quickly than studying other animals or plants. In fact, from the nymph to the adult stage, the dragonfly has a significant, positive ecological impact. Dragonfly eggs are laid and hatched in or near water, so their lives show an impact on both water and land ecosystems. Once hatched, dragonfly nymphs can breathe in the air or underwater which enables them to eat mosquito larvae, other aquatic insects and worms, and even small aquatic vertebrates like tadpoles and small fish. Adult dragonflies capture and eat adult mosquitoes.
Community wide mosquito control programs that spray insecticides to kill adult mosquitoes also kill dragonflies.
Q. The approach to biological control includes :

A
A. Import and release of an insect pest to a new area to provide hosts for natural enemies.

B
B. Import and release of natural enemies from the native home of an alien insect pest that has invaded a new area.

C
C. Preservation of natural enemies (predators & parasites) that are already established in an area.

D
D. Use of insecticides to reduce alien insect pests to establish a new equilibrium position.

Solution

The approach to biological control includes Preservation of natural enemies(predators & parasites) that are already established in an area.
Question 7
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Read the following text and answer any four questions on the basis of the same :
Ecological Indicators : The presence of dragonflies can reveal changes in the water ecosystems more quickly than studying other animals or plants. In fact, from the nymph to the adult stage, the dragonfly has a significant, positive ecological impact. Dragonfly eggs are laid and hatched in or near water, so their lives show an impact on both water and land ecosystems. Once hatched, dragonfly nymphs can breathe in the air or underwater which enables them to eat mosquito larvae, other aquatic insects and worms, and even small aquatic vertebrates like tadpoles and small fish. Adult dragonflies capture and eat adult mosquitoes.
Community wide mosquito control programs that spray insecticides to kill adult mosquitoes also kill dragonflies.
Q. The most effective stages in the life cycle of dragonfly are eradicating mosquitoes area.

A
A. Larvae and adult

B
B. Caterpillar and adult

C
C. Nymph and adult

D
D. Pupa and adult

Solution

Dragonflies are large and heavy bodied insects. The larvae (or Nymphs), which live in water, eat almost anything living that is smaller than themselves. The adult dragonfly larvae are even known to catch and eat small fish. Usually they eat bloodworms or other aquatic insect larvae. Dragonfly nymphs are such good hunters because they move really fast - by what looks like jet propulsion. One of the benefits of having dragonflies live nearby is that they eat many times their weight in mosquitoes every day. Dragonflies also eat many different kinds of flies. Using a basketlike arrangement of their legs, adult dragonflies can actually catch and eat other bugs while they are flying.
Question 8
1 / -0

Read the following text and answer any four questions on the basis of the same :
Ecological Indicators : The presence of dragonflies can reveal changes in the water ecosystems more quickly than studying other animals or plants. In fact, from the nymph to the adult stage, the dragonfly has a significant, positive ecological impact. Dragonfly eggs are laid and hatched in or near water, so their lives show an impact on both water and land ecosystems. Once hatched, dragonfly nymphs can breathe in the air or underwater which enables them to eat mosquito larvae, other aquatic insects and worms, and even small aquatic vertebrates like tadpoles and small fish. Adult dragonflies capture and eat adult mosquitoes.
Community wide mosquito control programs that spray insecticides to kill adult mosquitoes also kill dragonflies.
Q. Two diseases less likely to occur in a region with plenty of dragonflies are_____

A
A. Yellow fever and amoebic dysentery

B
B. Malaria and Yellow fever

C
C. Anthrax and typhoid

D
D. Cholera and typhoid
Question 9
1 / -0

Read the following text and answer any four questions on the basis of the same :
Ecological Indicators : The presence of dragonflies can reveal changes in the water ecosystems more quickly than studying other animals or plants. In fact, from the nymph to the adult stage, the dragonfly has a significant, positive ecological impact. Dragonfly eggs are laid and hatched in or near water, so their lives show an impact on both water and land ecosystems. Once hatched, dragonfly nymphs can breathe in the air or underwater which enables them to eat mosquito larvae, other aquatic insects and worms, and even small aquatic vertebrates like tadpoles and small fish. Adult dragonflies capture and eat adult mosquitoes.
Community wide mosquito control programs that spray insecticides to kill adult mosquitoes also kill dragonflies.
Directions : In the following questions a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
Assertion : Releasing dragonflies in areas where there is an outbreak of malarial diseases can be an environment friendly method of control.
Reason : Dragonflies are dominant species and will not allow mosquitoes to reproduce.

A
A. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

B
B. Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

C
C. Assertion (A) is true but reason (R) is false.

D
D. Assertion (A) is false but reason (R) is true.

Solution

Dragonflies have a role in controlling the mosquitoes population and ultimately malarial disease as they are predators on them but they have no role to allow mosquitoes to reproduce.
Question 10
1 / -0

Read the following text and answer any four questions on the basis of the same :
Ecological Indicators : The presence of dragonflies can reveal changes in the water ecosystems more quickly than studying other animals or plants. In fact, from the nymph to the adult stage, the dragonfly has a significant, positive ecological impact. Dragonfly eggs are laid and hatched in or near water, so their lives show an impact on both water and land ecosystems. Once hatched, dragonfly nymphs can breathe in the air or underwater which enables them to eat mosquito larvae, other aquatic insects and worms, and even small aquatic vertebrates like tadpoles and small fish. Adult dragonflies capture and eat adult mosquitoes.
Community wide mosquito control programs that spray insecticides to kill adult mosquitoes also kill dragonflies.
Q. Dragonflies indicate positive ecological impact as :

A
A. The presence of dragonflies indicates polluted water.

B
B. Dragonfly nymphs selectively eat mosquito larvae.

C
C. They help to decrease the probability of diseases spread by vectors.

D
D. Dragonflies do not cause any harm to beneficial species.

Solution

Adult dragonflies are beneficial because they eat pests, flying insects, particularly midges and mosquitoes and help to decrease the probability of diseases spread by vectors.
Question 11
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Read the following and answer the question given below:
Villagers in a place near Chembur started planning to make power supply for agricultural purposes from cow dung. They have started a biogas plant for the purpose.
Study the flow chart for biogas production given below and answer the following questions.
Q. Biogas is composed of majorly:

A
A. methane, CO₂ and O₂

B
B. CO₂, H₂S, and H

C
C. methane, CO₂

D
D. H₂S, H and O₂

Solution

Biogas is composed of Methane(50-70%), CO₂(30-40%) with traces of hydrogen sulphide and hydrogen.
Question 12
1 / -0

Read the following and answer the following question:
Microorganisms include bacteria, viruses, fungi and protozoa. In our mind, we presume, most of the time, that microbes are always harmful. Microbes are, of course, the causal agents of many infections diseases of plants and animals including humans but they also have lots of beneficial role. Lactic acid bacteria (LAB) are one of this kind of useful group. These are Gram positive, non-sporulating, either rod shaped or spherical bacteria. They produce lactic acid in milk products as major metabolic end product of carbohydrate fermentation. LAB are considered as natural fermentors. Lactobacillus is a common LAB which converts lactose sugar of milk into lactic acid, that causes coagulation and partial digestion of milk protein casein. Milk is then changed into curd, yoghurt and cheese. Lactobacillus is also used in probiotics which have potentially beneficial effect on gut ecosystem of humans. Some other probiotic strain used belong to the Genus Bifidobacterium.
Q. Which of the following is not a lactic acid producing bacteria?

A
Streptococcus

B
Saccharomyces

C
Lactococcus

D
Enterococcus

Solution

Microbes such as. Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it into curd. During growth, such bacteria produce adds (mainly lactic add) that coagulate and partially digest the milk proteins. A small amount of curd, known as starter, is added to the milk and kept at a suitable temperature, where lactic acid bacteria multiply in millions and converts milk into curd that also improves its nutritional quality by increasing vitamin BI2. It also checks the growth of disease-causing microbes in the stomach.
Question 13
1 / -0

Read the following and answer the question given below:
Villagers in a place near Chembur started planning to make power supply for agricultural purposes from cow dung. They have started a biogas plant for the purpose.
Study the flow chart for biogas production given below and answer the following questions.
Q. In the given flow chart, 'A' denotes :

A
A. aerobic bacteria

B
B. methanogenic bacteria

C
C. cellulose degrading bacteria

D
D. yeast and protozoa

Solution

The methanogenic bacteria are anaerobic organisms that convert CO₂ to methane via a sequence of reactions.
Question 14
1 / -0

Read the following and answer the question given below:
Villagers in a place near Chembur started planning to make power supply for agricultural purposes from cow dung. They have started a biogas plant for the purpose.
Study the flow chart for biogas production given below and answer the following questions.
Q. If 'A' is not added in the procedure

A
A. methane will not be formed

B
B. CO₂ will not be formed

C
C. organic compounds will not be converted to H₂S

D
D. O₂will not be formed

Solution

If methanogenic bacteria is not added in the procedure methane formation will not take place.
Question 15
1 / -0

Read the following and answer the question given below:
Villagers in a place near Chembur started planning to make power supply for agricultural purposes from cow dung. They have started a biogas plant for the purpose.
Study the flow chart for biogas production given below and answer the following questions.
Q. What is represented by 'B' in the flow chart?

A
A. Carbohydrates

B
B. Protein polymers

C
C. Organic acids

D
D. Fat globules

Solution

In the second stage of biogas production, the simple soluble compounds or monomers are acted upon by fermentation causing microbes and converted into organic acids especially acetic acid.