EXERCISE
A.
Choose the correct option for each of the following:
1.Which of the following diseases is
not caused by virus
a)Polio
b)Chicken
pox
c)Tuberculosis
( ✔)
d)Influenza
2.Bubbles of gas that raise the dough are due to the release of carbon dioxide during
a)Fermentation
( ✔)
b )Pasteurization
c)Vaccination
d)Sun
drying
3.Which of the following diseases
can’t be prevented by vaccination ?
a)Malaria ( ✔)
b)small pox
c)Tuberculosis
d)Hepatitis
4.Which of the following is a nitrogen
fixing bacterium ?
a)Lactobacillus
b)Rhizobium( ✔)
c)Yeast
d)
Acetobacter
5.Which of the following is not a
method of food preservation?
a)Vaccination( ✔)
b)Salting
c)Pasturisation
d)Canning
B.
State whether the following statement are true (T) or False
(F) .
1.Viruses
reproduce only inside the host organism. (T)
2.The
fluffy texture of bread is due to the release of water.
(F)
3.Microorganism
are found in volcanoes. (T)
4.Vaccination
is also called immunization. (T)
5.Penicillium
is an antibiotic drug derived from the fungus penicillin.
(F)
C.
Fill in the blanks using the correct words.
1. The
bacterium which is involved in the conversion of milk to curd is – Lactobacillus (Rhizobium/Lactobacillus)
2.Disease-causing
microorganisms are called – pathogens (pathogens/antibodies)
3.The
process by which the microorganisms play an important role in keeping the
environment clean is called- degradation
(degradation/prevention)
4.The
carrier of the dengue fever disease is – Aedes
mosquito.(Anopheles/Aedes)
5.Formation
of vinegar takes places by the action- Acetobacter
(Acetobacter/Streptococcus)
D.
Define the following terms.
1)Pathogens-The microorganisms that cause diseases
are known as pathogens or germs. Example- Fungi,Virus,Bacteria.
2)Virions- The non-living state of a virus is called
Virions.
3)Antibiotics-Substances that destroy certain
disease-causing microorganisms is are called Antibiotics.
4)Biodegradation-
The process by which complex material breakdown into simple molecules by
the action of microorganisms is called Biodegradation.
5)SCPs- SCPs(single-celled protein) are the dietary supplement which are rich source of proteins made of
single cell algae (spirulina,chlorella)
6)Canning- The food preservation technique by which
foods after heating ,are stored in air tight containers to prevent
contamination due to microorganism is called canning.
7)AIDS &HIV - AIDS(Acquired immune deficiency Syndrome) is a
viral disease which is difficult to cure. It is cause by a virus called
HIV(Human immunodeficiency virus).
8) Vaccination – The process of administration of a vaccine to help the immune system
develop protection from a disease by orally or injection is called Vaccination.
E.
Answer the following questions briefly.
1.How does common cold spread?
ANS:-Common cold spread through air. The person suffering from common cold
when sneezes or coughs he or she
releases germs into the air and enter a healthy person body when this air
inhaled by them.
2.Explain the technique of
pasteurization.
ANS:-Pasteurization is a technique used to store milk .Milk is heated to about 70°C for a
minute to kill the microorganism present on it and cooled quickly so that heating can’t affect its flavour .
3.What are different shapes of
bacteria ?
ANS:-The different shapes of bacteria are –
a)Rod
shaped- e.g. bacilli
b)Spherical
–e.g. Cocci
c)Coma-shaped
–e.g. Vibrio
d)Spiral
–e.g. Spirilla
4.What is alcoholic fermentation?
ANS:-It is a fermentation process used to prepare wine where it turns grape
juice into an alcoholic beverage. During this ,yeast converts sugar in the
juice to create ethanol, commonly known as ethyl alcohol, releasing carbon
dioxide.
5.Name two diseases of humans and
plants caused by fungi?
ANS:-
Human
–a)Ringworm b)Skin infection
Plant-
a)Potato blight b)Leaf rust
6.Name one human and one plant disease caused by bacteria?
ANS:-
Human
–a)Cholera b)Typhoid
Plant-
a)Pseudomonas tomato b) Xanthomonas axonopodis
7.What organisms are use to prepare
ice creams and jellies?
ANS:-Fucus, Kelp and Gracilaria are different kinds of algae used in ice
creams and jellies as a thickening agent.
8.How is freezing used in preservation
of food?
ANS:-In refrigerators temperature is maintain at 5°C.This prevents
the growth of microorganism in the food. Deep-freezing is used to store food
for a longer duration of months at temperature below -18°C (minus
eighteen)
9.How do microorganisms play an
important role in keeping the environment clean?
ANS:-Organic matter or the dead remains of plants and animals undergo
decomposition to form simpler components .This chemical and physical breakdown
is brought about by bacteria and saprophytes. That’s how microorganisms play an
important role in keeping the environment clean. Without this degradation our
earth would filled with dead and waste remains.
10.What are carriers ?Give examples.
ANS:-Some insects (mosquitoes, houseflies) carry pathogens from an infected
person to a healthy person. Hence they are called carriers or vectors.
Example:
a)Female Anopheles mosquito carry malaria causing Plasmodium protozoan. b)Aedes
mosquito carry dengue fever causing virus.
F.
Answer the following questions in detail.
1.How do diseases spread? Explain with
suitable examples.
ANS:-The disease causing pathogens can spread through different medium .Some
of them are –
a)Air- When a sick person cough or sneezes ,he or
she releases germs into the air. This
germs enter a healthy person’s body when they inhaled this affected air. Example
of air born disease are -Common cold, TB, mumps, chickenpox.
b)Food and
water – Germs also can enter our body when we take contaminated food and water .Germs start
multiplying inside the body to cause disease. Example-Cholera, Diarrhoea , typhoid.
c)Contact- Contact
with sick person can cause diseases like ringworm ,Chickenpox, Flu.
d)Carriers-
Carriers like insects (mosquitoes, houseflies) carry pathogens from an infected
person to a healthy person. Example- Malaria caused by female Anopheles
mosquito .
2.What are vaccines and how do they prevent diseases?
ANS:-A vaccine is a biological preparation that provides immunity against a
particular disease.
Vaccine are
two types. They may contain dead or weakened microorganisms , which on
administration induce the body to produce substances called antibodies. Antibodies
destroy disease-causing microbes and
remain in the body to prevent further attack of same microbes. This type of
vaccine can give long term immunity. E.g- vaccine for polio,measles.
On the
other hand some vaccine contain readymade antibodies which give short time
immunity. E.g. vaccine for Typhoid.
3.How is fungal fermentation
beneficial to human beings?
ANS:-Fungal fermentation is very useful in food industry. Some examples are-
a)In Baking
bread- Yeast is a type of fungi ,release carbon dioxide which gets trapped
within the dough, forming small air spaces .This raises the dough and makes the
bread light and fluffy.
b)In
preparation of Wine- In this process yeast converts sugar in the juice to create
ethanol ,commonly known as ethyl alcohol ,releasing carbon dioxide.
4.How are bacteria and fungi useful to
us? Also, discuss their harmful effects.
ANS:-
Some usefulness of
A)Bacteria: –
a)The
bacterium Lactobacillus is used in the preparation of curd from milk. Acetobacter
aceti helps to convert alcohol into acetic acid or vinegar.
b)Bacteria
like Lactobacillus and streptococcus are used in the preparation of cheese and
paneer.
c)The
bacteria streptomyces griseus is used in the preparation of antibiotics
streptomycin.
d) In
agriculture a bacteria called Rhizobium
helps in the process of nitrogen fixation
B)Fungi:-
a)In food
industry a type of fungi yeast is used in baking bread and preparing wine.
b)The
wonder drug penicillin is an antibiotic which is derived from fungus called
Penicillium.
c)Mycorrhiza
fungi form a symbiotic relationship with the roots of many plant species.
Some
harmful effects of
a)Bacteria- It causes various diseases like Cholera, Typhoid, Tetanus
etc. Some bacteria are responsible for spoilage of food and food poisoning in
humans.
b)Fungi- It can causes various diseases like ringworm, skin
infection, athlete’s foot etc. Various fungi are also responsible for spoilage
of food.
5.Write a note on the agricultural
uses of microorganisms.
ANS:-In agriculture microorganism are very useful. Some examples are-
a)Mycorrihiza
fungi from a symbiotic relationship with the roots of many plant species .The
plant provide nutrient to the fungi and in return plant gain the higher
absorptive capacity for water and minerals.
b)Nitrogen-fixing
plants live in a symbiotic relationship with a bacteria called Rhizobium.This
bacteria capable of fixing the atmospheric nitrogen into the soil so that
plants can use it easily.
c)Bacillus
thuringiensis a bacteria is used in genetically modified crops to protect them
from pests. E.g.- Bt-toxins present in the groundnuts leaves.
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