Microorganisms: Friend and Foe Science - Microorganisms: Friend and Foe

Pathogenic microorganisms present in host cells are killed by medicines called

A disease in human beings caused by virus is

Which of the following reproduces only inside a host cell ?

Payal dug two pits. A and B in her garden. In pit A, she put a polythene bag packet with some agricultural waste. In pit B, she dumped the same kind of waste, but without packing it in a polythene bag. She then covered both the pits with soil. What did she observe after a month ?

Alcohol is produced with the help of

____________ is the vector of dengue virus.

____________ is a process of heating the milk at high temperature then cooling it suddenly and storing it.

The process in which sugar is converted into alcohol is called ____________ .

____________ could be due to the consumption of food spoilt by some microorganisms.

Pathogens are ____________ causing organisms.

Arya and Unnati discuss about vaccination. Unnati came up with her fear that vaccines can be dangerous as it contains microbes itself. Arya explained and removed her fear.
(i) What is a vaccine ?
(ii) Suggest what could be Arya's explanation ?

Prakhar came back from school and ate the cooked rice that was kept outside on the dining table. After few hours, he complained of diarrhoea and abdominal pain. His mother took him to the doctor who explained why this happened and asked them to preserve their food properly.
(i) What must have happened to Prakhar ?
(ii) Give the probable cause for his condition.

During biology class, teacher was telling about microbes and how they are useful to humans. Hearing this, Jasmine got confused as she knew the TB caused to her uncle is due to a microbe. She asked her teacher about it. The teacher appreciated her for the question and explained the whole class.
(i) What are microbes ?
(ii) How are microbes helpful to humans ?

Why does the milk that comes in packets not spoil? What is pasteurisation ?

Why are children/ infants given vaccination ?

Viruses can be seen by simple microscopes.

The atmospheric nitrogen cannot be utilised by the living organisms.

Jams, jellies and squashes are preserved by adding salt.

Microorganisms are also used in cleaning up of the environment.

All microbes are disease causing.

How can we prevent the following diseases ?
(i) Cholera
(ii) Typhoid
(iii) Hepatitis-A

Observe the figure and answer the following questions.

(i) Name the food item on which the organism grows.
(ii) Does it grow well in dry or in moist conditions ?
(iii) Is it safe to eat infected bread ?

What are antibiotics? What precautions must be taken while taking antibiotics ?

Write the role of immunisation in eradicating diseases from a country.

Give reasons for the following.
(i) Fresh milk is boiled before consumption while processed milk is stored in packets and can be consumed without boiling.
(ii) Raw vegetables and fruits are kept in refrigerators, whereas jams and pickles can be kept outside.
(iii) Farmers prefer to grow beans and peas in nitrogen deficient soils.
(iv) Mosquitoes can be controlled by preventing stagnation of water though they do not live in water. Why ?

Explain food preservatives with examples.

Explain the main steps of nitrogen cycle with the help of a diagram.

Write 10 lines on the usefulness of microorganisms In our lives.

What are the major groups of microorganisms ?

Paheli wonders how food can become a 'poison' ?

Why the teacher keeps telling the students not to let water collect anywhere in the neighbourhood ?

How do you prevent the spread of communicable diseases ?

Paheli saw that her mother added a little curd to warm milk to set curd for the next day. She wonders why ?

(i) Name two diseases that are caused by virus.
(ii) Write one important characteristic of virus.