21.

The amino acid, trytophan is the precussor for the synthesis of

• thyroxine and tri-iodothryonine

• estrogen and progesterone

• cortisol and cortisone

• cortisol and cortisone

One of the major components of cell wall of most fungi is

• peptidoglycan

• cellulose

• hemicellulose

• hemicellulose

A complex of ribosomes attached to a single strand of RNA is known as 

• Polymer

• Polypeptide

• Okazaki's fragment

• Okazaki's fragment

Which of the following features is not present in the phylum-Arthropoda?

• Metameric segmentation

• Parapodia

• Jointed appendages

• Jointed appendages

The Avena curvature is used for bioassay of

• GA₃

• IAA

• Ethylene

• Ethylene

A typical fat molecule is made up of

• One glycerol and three fatty acid molecules

• One glycerol and one fatty acid moleule

• Thre glycerol and three fatty acid molecules

• Thre glycerol and three fatty acid molecules

Which of the following features is not present in Periplaneta americana?

• Indeterminate and radical cleavage during embryonic development

• Exoskeleton composed of N-acetylglucosamine

• Metamerically segmented body

• Metamerically segmented body

Water-soluble pigments found in plant cell vacuoles are

• chlorophylls

• carotenoids

• anthocyanins

• anthocyanins

A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. there is no formation of cell plate and thus the cell is containing more number of chromosomes as compares to other dividing cells. This would result in

• polyploidy

• somaclonal variation

• polyteny

• polyteny

A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rate of photosynthesis at high temperatures and has improved efficiency of nitrogen utilisation. In which of the following physiological groups would you assign this plant?

• C₄

• CAM

• Nitogen-fixer

• Nitogen-fixer