Question
What is innate immunity? How is it accomplished in a human body?
✓
Answer
- Innate immunity refers to all the defence elements with which an individual is born and is always available to protect the body.
- It is accomplished by the following types of barriers:
- Physical barriers:
- Skin is the main barrier to prevent the entry of microbes. The mucus coating of the epithelial lining of gastro-intestinal, urinogenital and respiratory tracts helps in trapping the microbes entering such sites.
- Physiological barriers
- Acids in the stomach.
- Lysozyme in saliva, tear and sweat prevents microbial growth.
- Cellular barriers
- Leucocytes like PMNL (neutrophils) and monocytes.
- Lymphocytes like natural killer cells.
- Macrophages in the tissues; all these types of cells phagocytose and destroy the microbes.
- Cytokine barriers
- Interferons are the glycoprotiens secreted by virus-infected cells.
- They protect the non-infected cells from viral infection.
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
A woman with blood group “A” marries a man with blood group “O”. Discuss the possibilities of the inheritance of the blood groups in the following starting with “yes” or “no” for each:
- They produce children with blood group “A” only.
- They produce children some with “O” blood group and some with “A” blood group.
Pistil of a flower does not accept pollen from any plant other than from its own kind. How does it happen? Explain.
(a) Describe the observations made on collection of white winged moths and dark winged moths in England between the years 1850 and 1920. What did these observations lead to?
(b) How is the use of herbicides, pesticides and antibiotics by humans for various, comparable with the observations made on moths in the above question? What is this type of phenomenon called?
(b) How is the use of herbicides, pesticides and antibiotics by humans for various, comparable with the observations made on moths in the above question? What is this type of phenomenon called?
Match the items in Column I with those in Column II.
| S.No | Column I | S.No | Column II |
| A. | ABO blood group in humans | 1. | Polygenic inheritance |
| B. | Flower colour in snapdragon | 2. | Mendelian genetic disorder |
| C. | Human skin colour | 3. | Sex-linked Mendelian disorder |
| D. | Phenylketonuria | 4. | Incomplete dominance |
| 5. | Multiple allelism |
Comment on the growth curve given below.
Why do you think the zygote is dormant for sometime in a fertilised ovule ?
Study the illustration given and answer the questions that follow:
Vivipary automatically limits the number of offsprings in a litter. How?
- With labelled diagrams, depict the stages in embryo development in a dicotyledonous plant.
- Endosperm development precedes embryo development. Why?
Answer the following questions:
Describe the stages of oogenesis in human females.
Describe the stages of oogenesis in human females.