Biology
Briefly explain the following terms:
(i) Genes.
(ii) Cytokinesis in plant cells.
(iii) Guttation.
(iv) Diabetes insipidus.
(v) Disinfectants.
Genetics
ICSE 2013
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Answer
(i) Genes are specific sequences of nucleotides on a chromosome that encode particular proteins which express in the form of some particular feature of the body. They are the units of heredity which are transferred from parents to offsprings and are responsible for some specific characteristics of the offspring.
(ii) Cytokinesis is the division of cytoplasm. In plant cells, a cell plate appearing at the centre of the middle grows up to the periphery, splitting the cytoplasm into two and thus producing two new cells.
(iii) Guttation is the process by which drops of water appear along leaf margins due to excessive root pressure. It occurs early mornings or late nights.
(iv) Deficiency of Vasopressin (Anti-diuretic hormone or ADH) causes Diabetes Insipidus in which urination is frequent and copious, resulting in loss of water from the body and the person becomes thirsty.
(v) These are the chemicals that kill microbes once they come in contact with them, they are too strong to be used on the body. Example — Phenol and Cresol.
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