Long Answer TypeExplain how does:
(a) a primary succession start on a bare rock and reach a climax community?
(b) the algal bloom eventually choke the water body in an industrial area?The following is the illustration of the sequence of ovarian events (a to i) in a human female.
i) Identify the figure that illustrates ovulation and mention the stage of oogenesis it represents.
(ii) Name the ovarian hormone and the pituitary hormone that have caused the above mentioned event.
(iii) Explain the changes that occur in the uterus simultaneously in anticipation.
(iv) Write the difference between c and h.
(v) Draw a labeled sketch of the structure of a human ovum prior to fertilization.
How does the megaspore mother cell develop into 7-celled, 8 nucleate embryo sac in an angiosperm? Draw a labeled diagram of a mature embryo sac.
The nucleus of the functional megaspore mother cell divides mitotically to form two nuclei which move to the opposite poles, forming the 2-nucleate embryo sac. Subsequent mitotic nuclear divisions result in the formation of the 4-nucleate and later the 8-nucleate stages.
of the embryo sac. These mitotic divisions are strictly free nuclear in nature, that is, nuclear divisions are not followed immediately by cell wall formation. Among the eight nuclei, six are enclosed by cell walls and organised into cells, while the remaining two nuclei (called polar nuclei) are situated above the egg apparatus in a large central cell. Out of the six cells, three are grouped at the micropylar end, and constitute the egg apparatus out of which two are synergids and one egg cell. The other three cells are located at the chalazal end, and are called antipodals. All this leads to the organisation of the typical female gametophyte or embryo sac which is 8-nucleated and 7-celled.
What is the inheritance pattern observed in the size of starch grains and seed shape of Pisum sativum? Workout the monohybrid cross showing the above traits. How does this pattern of inheritance deviate from that of Mendelian law of dominance?
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