Long Answer TypeGive reasons why:
a. Most zygotes in angiosperms divide only after certain amount of endosperm is formed.
b. Groundnut seeds are exalbuminous and castor seeds are albuminous.
c. Micropyle remains as a small pore in the seed coat of a seed.
d. Integuments of an ovule harden and the water content is highly reduced, as the seed matures.
e. Apple and cashew are not called true fruits.
a. Development of embryo depends upon the amount of endosperm present in the nucleus, as the embryo obtain its nutrition from the endosperm only. The cells of the endosperm tissue are filled with reserve food materials and provide nourishment to the developing embryo.
b. Utilization of the endosperm vary among plants, in some plants endosperm, gets exhausted or used up and produce exalbuminous seeds e.g groundnut.
In plants like castor some part of the endosperm persist in the seeds and are used during seed germination, these seeds are termed as albuminous
c. Seeds are covered by a hard covering called as integument, except at the top part of seed called as micropyle. Mycropyle helps in the entry of O2 and H2O during seed germination. Pollen tube enters the ovary through the micropyle.
d. Maturation of seed is preceded by reduction in water content and increase hardening of integuments. Reduced content of water makes the seed metabolically slow and dry. Then embryo enters into dormancy stage. When seeds are subjected to adequate moisture, oxygen and suitable temperature they start to grow.
e. Maturation of ovules into seed and development of ovary into fruit occur simultaneously. When fruit develops from thalamus rather than from ovary are termed as false fruit.
Short Answer TypePlenty of algal bloom is observed in a pond in your locality.
(a) Write what has caused this bloom and how does it affect the quality of water.
(b) Suggest a preventive measure.
(a) List the three states the annuals and biennial angiosperms have to pass through during their life cycle.
(b) List and describe any two vegetative propagules in flowering plants.
Explain the role(s) of the following in biotechnology.
(a) Restriction endonuclease
(b) Gel-electrophoresis
(c) Selectable markers in pBR322
Long Answer TypePublic all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident’s Welfare Association of your locality organised an awareness programme entitled ‘Bury not burn’. They invited you, being a biology student to participate.
(a) How would you justify your arguments that promote burying and discourage burning?
(Give two reasons)
(b) With the help of flow charts, one for each practice, depict the chain of events that follow.
Short Answer TypeSecondary treatment of the sewage is also called Biological treatment. Justify this statement and explain the process
How did a citizen group called Friends of Arcata Marsh, Arcata, California, USA, help to improve water quality of the marshland using Integrated Waste Water Treatment ? Explain in four steps.
Looking at the deteriorating air quality because of air pollution in many cities of the country, the citizens are very much worried and concerned about their health. The doctors have declared a health emergency in the cities where the air quality is very severely poor.
(a) Mention any two major causes of air pollution.
(b) Write the two harmful effects of air pollution on plants and humans.
(c) As a captain of your school Eco-club, suggest any two programmes you would plan to organise in the school so as to bring awareness among the students on how to check air pollution in and around the school
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