STD 12 - 7. human health and disease — NEET STD 11 Science — Question

Statement I: Some of the spermatogonia called primary spermatocytes periodically undergo meiosis.
Statement II: A primary spermatocyte completes the second meiotic division and form secondary spermatocytes, which have only 23 chromosomes.

Which one of the following statements are correct ?
(i) Neutrophils and monocytes leucocytes are phagocytic cell; basophils are involved in inflammatory reactions; and eosinophils are associated with allergic reaction.
(ii) Lymphocytes are of two major types - B and T forms. They are responsible for immune response of the body.
(iii) Platelets are also called thrombocytes and are cell fragments produced from microkaryocytes. Blood normally contains 1,500,00-3,500,00 platelets mm^-3.
(iv) Person with O blood groups are called as universal donor' and person with AB blood groups are 'universal recipients".
(v) A condition in which Rh-ve mother has successive pregnancy with Rh-ve foetus is called Erythroblastosis foetalis, which can be fatal to foetus due to production of Rh antibodies by mother. This can be avoided by administering antiRh antibodies to the mother immediately after the delivery of first child.
(vi) Fibrins are formed by the conversion of inactive fibrinogens in plasma by the enzyme thrombokinase.
(vii) Prothrombin are converted into thrombins byenzyme complex thrombokinase.
(viii) Calcium ions plays important role in clotting of blood.
(ix) The fluid present in the lymphatic system is called lymph. It help in absorption of proteins by lacteals present in the intestinal villi.
(x) Fishes has 2 chambered heart; amphibians have 3 and mammals have 4 chambered heart.
(xi) Heart is endodermal in origin.
Choose the correct option given below :-

Assertion: The movement of air into and out of the lungs is carried out by creating a pressure gradient between the lungs and the atmosphere.
Reason: The diaphragm and a specialised set of muscles-external and internal intercostals between the ribs, help in generation of such gradients.

Which one of the following cannot be explained on the basis of Mendel’s law of dominance?

Statement I: Impulse transmission across an electrical synapse is always faster than that across a chemical synapse.
Statement II: Electrical synapses are more common in our system.

Inspiration is initiated by

When a neuron is stimulated to generate nerve impulse, the electrical potential on the inside of the nerve membrane changes

Trygon has

What is the function of Bowman's capsule and Glomerulus