Question
What is a vaccine? How does a vaccine work?
✓
Answer
A vaccine is a special kind of preparation which provides immunity against a particular disease. Vaccine consists dead and weakened microbes which are harmless and do not cause any disease.
Vaccine works as follows:
$-$When the vaccine containing dead or weakened microbes is introduced into the body of a healthy person, the body fights and kills the microbes by producing some substance called antibodies.
$-$Some of the antibodies remain in the body for a long time and protect it from any future attack of disease germs. Thus, a vaccine develops the immunity from a disease.
Vaccine works as follows:
$-$When the vaccine containing dead or weakened microbes is introduced into the body of a healthy person, the body fights and kills the microbes by producing some substance called antibodies.
$-$Some of the antibodies remain in the body for a long time and protect it from any future attack of disease germs. Thus, a vaccine develops the immunity from a disease.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Mother gives birth to a baby but the baby has characters of both parents. How is this possible?
Observe the Fig and answer the following questions:
$a.$ Name the microorganism and the group to which it belongs.
$b.$ Name the food item on which the organism grows.
$c.$ Does it grow well in dry or in moist conditions?
$d.$ Is it safe to eat infected bread?
→$a.$ Name the microorganism and the group to which it belongs.
$b.$ Name the food item on which the organism grows.
$c.$ Does it grow well in dry or in moist conditions?
$d.$ Is it safe to eat infected bread?
A strip of impure copper metal is given to you. Describe briefly how you will purify it by using the chemical effect of electric current. Draw a labelled diagram of the experimental set up used for this purpose.
State the harmful effects of water pollution.
Who is responsible for the sex of the unborn child: father or mother? Why?
Name the constellation which appears to have the shape of:
$a.$ A big bear.
$b.$ A distorted $W$ or $M$.
$c.$ A hunter.
$d.$ A big lion.
→$a.$ A big bear.
$b.$ A distorted $W$ or $M$.
$c.$ A hunter.
$d.$ A big lion.
The substance $W$ is a fossil fuel. It occurs deep below the ground in certain areas of the earth. Another fossil fuel $X$ is found trapped above the deposits of $W$. When $W$ is subjected to a process called $Y$, then a number of different products are collected at different temperature ranges which are put to different uses. A special grade of product $Z$ obtained in this way is used as aviation fuel in jet aeroplanes.
$a.$ What are $(i) W$, and $(ii) X ?$
$b.$ What is the physical state of $(i) W$, and $(ii) X ?$
$c.$ Name the process $Y.$
$d.$ Name the product $Z.$
→$a.$ What are $(i) W$, and $(ii) X ?$
$b.$ What is the physical state of $(i) W$, and $(ii) X ?$
$c.$ Name the process $Y.$
$d.$ Name the product $Z.$
Fill in the blanks in the following: A person $1\ m$ in front of a plane mirror seems to be ____ __ $m$ away from his image.
→Complete the crossword Fig. with the help of the clues:
Across
$1.$ Non$-$metal which catches fire if exposed to air. $(10)$
$3.$ The lowest temperature at which a substance catches fire is called its $………$ temperature. $(8)$
$5.$ The most common fire extinguisher. $(5)$
Down
$2.$ A chemical process in which a substance reacts with oxygen to give off heat. $(10)$
$4.$ Petrol is used as a $……..$ in automobiles. $(4)$
$6.$ It is as hard as stone and black in colour. $(4)$
→Across
$1.$ Non$-$metal which catches fire if exposed to air. $(10)$
$3.$ The lowest temperature at which a substance catches fire is called its $………$ temperature. $(8)$
$5.$ The most common fire extinguisher. $(5)$
Down
$2.$ A chemical process in which a substance reacts with oxygen to give off heat. $(10)$
$4.$ Petrol is used as a $……..$ in automobiles. $(4)$
$6.$ It is as hard as stone and black in colour. $(4)$
What is meant by ‘Species’? Give any five examples of species.