Question 1

Q1: What are the various public health measures, which you would suggest as safeguard against infectious diseases?

Accepted Answer

Various public health measures that serve as safeguards against infectious diseases include: 1.  Proper disposal of waste and excreta: This prevents the contamination of soil, water, and food, which are common sources of pathogens for diseases like typhoid, amoebiasis, and ascariasis. 2.  Periodic c...

Question 2

Q10: What are the various routes by which transmission of human immunodeficiency virus takes place?

Accepted Answer

The transmission of Human Immunodeficiency Virus (HIV) occurs through contact with infected body fluids. The various routes are: 1.  Sexual Contact: Unprotected sexual contact with an infected person is the most common mode of transmission. 2.  Transfusion of Contaminated Blood and Blood Products: R...

Question 3

Q11: What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?

Accepted Answer

The AIDS virus, HIV, causes a deficiency of the immune system by systematically destroying a crucial component of it. The mechanism is as follows: 1.  Entry into Host Cells: After entering the body, HIV first infects macrophages. The viral RNA genome replicates to form viral DNA using an enzyme call...

Question 4

Q12: How is a cancerous cell different from a normal cell?

Accepted Answer

Question 5

Q13: Explain what is meant by metastasis.

Accepted Answer

Metastasis is the process by which cancer spreads from the primary site where it originated to other, distant parts of the body. It is the most feared property of malignant tumors. The process involves several steps: 1.  Cancer cells from the primary tumor break away (slough off). 2.  These cells in...

Question 6

Q14: List the harmful effects caused by alcohol/drug abuse.

Accepted Answer

The harmful effects of alcohol/drug abuse are wide-ranging and affect the individual, their family, and society. Immediate Effects:    Reckless behaviour, vandalism, and violence.    Excessive doses can lead to coma and death due to respiratory failure, heart failure, or cerebral hemorrhage. Long-te...

Question 7

Q15: Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?

Accepted Answer

Yes, friends and peer pressure can significantly influence an adolescent to take alcohol or drugs. During adolescence, there is a strong desire to fit in and be accepted by one's peer group. If the peer group considers smoking, drinking, or using drugs as 'cool' or progressive, an individual may fee...

Question 8

Q16: Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.

Accepted Answer

Once a person starts taking alcohol or drugs, it becomes difficult to get rid of the habit due to two main phenomena: addiction and dependence. 1.  Addiction: This is a psychological attachment to the effects of drugs and alcohol, such as euphoria and a temporary feeling of well-being. This creates...

Question 9

Q17: In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?

Accepted Answer

Motivations for youngsters to take to alcohol or drugs: 1.  Curiosity and Experimentation: A child's natural curiosity and a desire for adventure and excitement can motivate them to experiment with drugs and alcohol. 2.  Peer Pressure: The desire to be accepted by friends and the perception that it...

Question 10

Q2: In which way has the study of biology helped us to control infectious diseases?

Accepted Answer

The study of biology has been instrumental in helping us control infectious diseases in several ways: 1.  Understanding Pathogens: Biology has enabled us to identify and study various disease-causing organisms (pathogens) like bacteria, viruses, fungi, protozoans, and helminths. Understanding their...

Question 11

Q3: How does the transmission of each of the following diseases take place? (a) Amoebiasis (b) Malaria (c) Ascariasis (d) Pneumonia

Accepted Answer

(a) Amoebiasis (Amoebic dysentery): This disease is caused by the protozoan parasite Entamoeba histolytica. Transmission occurs through the faecal-oral route. Houseflies act as mechanical carriers, transferring the parasite from the faeces of an infected person to food and food products. The main so...

Question 12

Q4: What measure would you take to prevent water-borne diseases?

Accepted Answer

To prevent water-borne diseases like typhoid, amoebiasis, and ascariasis, the following measures should be taken: 1.  Consumption of Clean Drinking Water: Always ensure that drinking water is safe. This can be done by boiling, filtering, or using water purifiers. 2.  Proper Disposal of Waste: Sewage...

Question 13

Q5: Discuss with your teacher what does 'a suitable gene' means, in the context of DNA vaccines.

Accepted Answer

In the context of DNA vaccines, a 'suitable gene' refers to a specific segment of DNA isolated from a pathogen that codes for an antigenic protein or polypeptide. This gene must have the following characteristics: 1.  It must be antigenic: The protein produced from this gene must be recognized as fo...

Question 14

Q6: Name the primary and secondary lymphoid organs.

Accepted Answer

The primary and secondary lymphoid organs are:    Primary lymphoid organs: These are the organs where immature lymphocytes differentiate into antigen-sensitive lymphocytes. They are:     1.  Bone marrow     2.  Thymus    Secondary lymphoid organs: These organs provide the sites for the interaction o...

Question 15

Q7: The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form: (a) MALT (b) CMI (c) AIDS (d)...

Accepted Answer

(a) MALT: Mucosa-Associated Lymphoid Tissue (b) CMI: Cell-Mediated Immunity (c) AIDS: Acquired Immuno Deficiency Syndrome (d) NACO: National AIDS Control Organisation (e) HIV: Human Immuno deficiency Virus

Question 16

Q8: Differentiate the following and give examples of each: (a) Innate and acquired immunity (b) Active and passive immunity

Accepted Answer

Question 17

Q9: Draw a well-labelled diagram of an antibody molecule.

Accepted Answer

A diagram of an antibody molecule cannot be drawn in text format. However, the structure can be described based on Figure 7.4 in the textbook. An antibody molecule is a Y-shaped structure composed of four peptide chains. These are: 1.  Two identical Heavy Chains: These are longer polypeptide chains....

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