The waxy substance that waterproofs the leaf surface is:
A. Lignin
B. Cellulose
C. Cutin
D. Suberin
Answer: Option C
Solution (By JKSSB Mock Tests)
Cutin, along with waxes, forms the cuticle on the epidermis of leaves and stems, reducing water loss and providing protection. Lignin strengthens cell walls, cellulose is the wall polysaccharide, suberin is in cork cells and root endodermis.
Explanation:
A plasmid used as a cloning vector in genetic engineering must have certain essential features: an Origin of Replication (ori) to ensure its replication within the host cell, a Selectable Marker (like an antibiotic resistance gene) to identify and eliminate non-transformants, and at least one unique Restriction Site (cloning site) for the insertion of the foreign DNA.
Explanation:
Ion exchange chromatography separates proteins based on their net surface charge; positively charged proteins bind to cation exchangers, negatively to anion exchangers. Gel filtration separates by size, affinity by specific binding, SDS-PAGE by molecular weight.
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