Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions

Briefly comment on the significance of heterospory.

Differentiate between the following:

Homosporous and heterosporous pteridophytes

Illustrate a glycosidic, peptide and a phospho-diester bond.

Explain ETS.

What is oxidative phosphorylation?

List five main groups of natural plant growth regulators. Write a note on discovery, physiological functions and agricultural/horticultural applications of any one of them.

Why is abscisic acid also known as a stress hormone?

Which one of the plant growth regulators would you use if you are asked to:

Induce immediate stomatal closure in leaves.

Would a defoliated plant respond to photoperiodic cycle? Why?

Give the diagrammatic representation of ETS

Which bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production?

Polluted water bodies have usually very high abundance of plants like Nostoc and Oscillitoria. Give reasons.

Apart from chlorophyll, algae have several other pigments in their chloroplast. What pigments are found in blue-green, red and brown algae that are responsible for their characteristic colours?

A Prothallus is ______.

Heterospory i.e., formation of two types of spores – microspores and megaspores is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophytes. Do you think heterospory has some evolutionary significance in plant kingdom?

How far does Selaginella one of the few living members of lycopodiales (pteridophytes) fall short of seed habit.

The heterosporous pteridophytes show certain characteristics, which are precursor to the seed habit in gymnosperms. Explain.

How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?

Gametophyte is a dominant phase in the life cycle of a bryophyte. Explain.

A piece of wood having no vessels (trachea) must belong to ______.