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.
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.
Describe how do ‘flocs’ and ‘activated sludge’ help in sewage treatment.
Roles of ‘flocs’ and ‘activated sludge’ in sewage treatment are as follows: Flocs These are masses of bacteria held together by slime and fungal filaments to form mesh-like structures. Flocs are used during the secondary sewage treatment in the aeration tank to increase the rate of decomposition. The microbes digest a lot of organic matter, converting it into microbial biomass and releasing a lot of minerals. As a result, BOD of the sewage reduces. As the BOD of waste is reduced to 10-15% of raw sewage, it is passed into settling tanks. In these tanks, flocs are allowed to undergo sedimentation. Activated Sludge The sediment of settling tank is called activated sludge. A part of it is used as inoculum in aeration tanks. The remaining part is passed into a large tank called anaerobic sludge digester. In these tanks, anaerobic microbes are present that digest the organic mass as well as aerobic microbes of activated sludge. The remaining sludge is used as manure or compost.
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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