If a regular dose of drug or alcohol is not provided to an addicted person, he shows some withdrawal symptoms. List any four such withdrawal symptoms.
The withdrawal symptoms are
(i) anxiety
(ii) shakiness
(iii) nausea
(iv) sweating
Why is it that during changing weather, one is advised to avoid closed, crowded and air conditioned places like cinema halls etc?
During changing weather one is advised to avoid crowded places, because changing seasons are the time when infectious agents are more prevalent as moist condition favoures pathogen to grow fast and people are more vulnerable as their body system is busy in adapting the changing environmental conditions of temperature humidity, etc and they get infected to there pathogen easily.
The harmful allele of sickle-cell anaemia has not been eliminated from human population. Such afflicted people derive some other benefit. Discuss.
Sickle-cell anaemia still persists in the population despite being harmful because this mutation can also be beneficial in certain conditions.
The mutant $\mathrm{Hb}^5$ type haemoglobin is found at high frequencies (up to $20 \%$ and above) in the tropical Africa.
It is known that heterozygotes $\left(\mathrm{Hb}^{\mathrm{s}} / \mathrm{Hb}^{\mathrm{A}}\right)$, having both types of haemoglobin show resistance to malarial infection because the body targets the Plasmodium falciparum infected cell for destruction. In contrast, individuals homozygous for normal haemoglobin $\left(H b^A / H b^A\right)$ suffer high mortality rates in early childhood due to malarial infection.
Thus, the allele for sickle cells has been maintained because heterozygotes have a higher reproductive success than either of the two possible homozygotes.
Lymph nodes are secondary lymphoid organs. Explain the role of lymph nodes in our immune response.
Lymphoid Organs immune system of human beings consists of lymphoid organs. The organs whereas callid the maturation and proliferation of lymphocytes occurs are called lymphoid organs. Lymphoid organs are of two types. These are
Lymph nodes are small solid structures present at different points along the lymphatic system. They trap the microorganisms or other antigens that enter the lymph and tissue fluid. Antigens trapped in the lymph nodes activate the lymphocytes and produce an immune response.
Why is an antibody molecule represented as $\mathrm{H}_2 \mathrm{~L}_2$ ?
Each antibody molecule has four peptide chains, two small called light chains (represented by L ) and two longer called heavy chains (represented by H ). Hence, an antibody is represented as $\mathrm{H}_2 \mathrm{~L}_2$.