Question

A higher plant cell covered with cutin and suberin is placed in water. After 15 minutes, the cell:
(a) Will be killed
(b) Size will increase
(c) The size will remain unchanged
(d) Size will decrease

Answer 1

Hint: Cutin and suberin are substances that form the covering of many plants as well as animal cells and tissues. They are responsible for a hard, impermeable coating. Cutin is a waxy substance and thus repels water. Hence, these substances should repel or block water from entry if kept in contact.

Complete step by step answer:
- Suberin and cutin are polymers present in higher plants as a macromolecule component of the periderm and epidermis of the cell wall. Their main function is to protect the cell from external unwanted substances and water.
- If a cell covered in cutin and suberin is placed in water, the cell will not show any change as the polysaccharides protect the cell by preventing the water from flowing inside by osmosis.
- Suberin is a complex polyester that is lipophilic and hydrophobic in nature. It is a constituent of cork.
- Cutin is a waxy polymer that forms the cuticle and covers all the aerial surfaces of the plant.
So, the correct answer is ‘size will remain unchanged’.

Additional Information:
- Cell walls of higher plants are composed of cellulose, hemicellulose, and pectin.
- Algal cell walls are composed of polysaccharides and glycoproteins such as carrageenan and agar. Bacterial cell walls are composed of peptidoglycan. Cell walls of archaea are varied in composition, consisting of pseudopeptidoglycan, glycoprotein S-layers, or polysaccharides. Fungal cell walls are composed of chitin, an N-acetylglucosamine polymer.
- Cell walls provide rigidity to the cell in the sense that despite the cell being flexible, it has a considerable amount of tensile strength.

Note:
- Suberin is a component of the Casparian strip - a band of cell wall material deposited on the radial and transverse walls of the endodermis (the innermost cortex layer). It is composed of lignin and suberin.
- The cell wall can be composed of up to three layers - the primary cell wall, the middle lamella, and the secondary cell wall.
- The polysaccharides form the components of the primary cell wall. The secondary cell wall is composed mainly of cellulose, xylan, and lignin.