Class 12 Biology - Chapter Human Health and Disease NCERT Solutions | How is a cancerous cell different from a
How is a cancerous cell different from a normal cell?
|
|
Normal cell |
|
Cancerous cell |
|
1. |
Normal cells show the property of contact inhibition. Therefore, when these cells come into contact with other cells, they stop dividing. |
1 |
Cancerous cells lack the property of contact inhibition. Therefore, they continue to divide, thereby forming a mass of cells or tumor. |
|
2. |
They undergo differentiation after attaining a specific growth. |
2. |
They do not undergo differentiation. |
|
3. |
These cells remain confined at a particular location. |
3 |
These cells do not remain confined at a particular location. They move into neighboring tissues and disturb its function. |
y B� �y0� ��� and T-lymphocytes.
4
It does not have a specific memory.
4
It is characterized by an immunological memory.
(b) Active and passive immunity
|
|
Active immunity |
|
Passive immunity |
|
1. |
It is a type of acquired immunity in which the body produces its own antibodies against disease-causing antigens. |
1. |
It is a type of acquired immunity in which readymade antibodies are transferred from one individual to another. |
|
2. |
It has a long lasting effect. |
2. |
It does not have long lasting effect. |
|
3. |
It is slow. It takes time in producing antibodies and giving responses. |
3. |
It is fast. It provides immediate relief. |
|
4. |
Injecting microbes through vaccination inside the body is an example of active immunity. |
4. |
Transfer of antibodies present in the mother’s milk to the infant is an example of passive immunity. |
More Questions From Class 12 Biology - Chapter Human Health and Diseas
- Q:- How does the transmission of each of the following diseases take place?
(a) Amoebiasis
(b) Malaria
(c) Ascariasis
(d) Pneumonia - Q:- Draw a well-labelled diagram of an antibody molecule.
- Q:- What are the various public health measures, which you would suggest as safeguard against infectious diseases?
- Q:- In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?
- Q:- List the harmful effects caused by alcohol/drug abuse.
- Q:- What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?
- Q:- Name the primary and secondary lymphoid organs.
- Q:- Differentiate the following and give examples of each:
(a) Innate and acquired immunity
(b) Active and passive immunity - Q:- In which way has the study of biology helped us to control infectious diseases?
- Q:- Discuss with your teacher what does a suitable gene means, in the context of DNA vaccines.
Popular Questions of Class 12 Biology
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
- Q:-
Fill in the blanks:
(a) Humans reproduce __________. (asexually/sexually)
(b) Humans are__________. (oviparous/viviparous/ovoviviparous)
(c) Fertilization is __________ in humans. (external/internal)
(d) Male and female gametes are __________. (diploid/haploid)
(e) Zygote is __________. (diploid/haploid)
(f) The process of release of the ovum from a mature follicle is called__________.
(g) Ovulation is induced by a hormone called the __________.
(h) The fusion of male and female gametes is called _____________.
(i) Fertilisation takes place in _____________.
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus and uterus is called ____________. - Q:- What do you think is the significance of reproductive health in a society?
- Q:- Mention the advantages of selecting pea plant for experiment by Mendel.
- Q:- Group the following as nitrogenous bases and nucleosides:
Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine. - Q:- Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.
- Q:- Explain in brief the role of animal husbandry in human welfare.
- Q:- Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?
- Q:- Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).
Recently Viewed Questions of Class 12 Biology
- Q:- Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.
- Q:-
Fill in the blanks:
(a) Humans reproduce __________. (asexually/sexually)
(b) Humans are__________. (oviparous/viviparous/ovoviviparous)
(c) Fertilization is __________ in humans. (external/internal)
(d) Male and female gametes are __________. (diploid/haploid)
(e) Zygote is __________. (diploid/haploid)
(f) The process of release of the ovum from a mature follicle is called__________.
(g) Ovulation is induced by a hormone called the __________.
(h) The fusion of male and female gametes is called _____________.
(i) Fertilisation takes place in _____________.
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus and uterus is called ____________. - Q:- Draw a labeled diagram of sperm.
- Q:- In our society the women are often blamed for giving birth to daughters.
Can you explain why this is not correct? - Q:- Who had proposed the chromosomal theory of inheritance?
- Q:- If the sequence of one strand of DNA is written as follows:
5-ATGCATGCATGCATGCATGCATGCATGC-3
Write down the sequence of complementary strand in 5→3 direction - Q:- Higher organisms have resorted to sexual reproduction in spite of its complexity. Why?
- Q:- Can we call human evolution as adaptive radiation?
- Q:- Give three hypotheses for explaining why tropics show greatest levels of species richness.
- Q:- Give an example for:
(a) An endothermic animal
(b) An ectothermic animal
(c) An organism of benthic zone
- All Chapters Of Class 12 Biology
- All Subjects Of Class 12