B1/B2 - Cells and Organisms
Cells and organisms This guide covers syllabus sections 1 and 2: characteristics and classification of living organisms, organisation of the organism, specialised cells, and magnification. Characteristics of living organisms Use MRS GREN: Movement: an action by an organism or part of an organism. Plants show movements such as phototropism. Respiration: chemical reactions in cells that release energy from nutrients. Sensitivity: detecting and responding to changes in the internal or external environment. Growth: a permanent increase in size and dry mass by an increase in cell number or size. Reproduction: production of offspring, sexually or asexually. Excretion: removal of toxic materials, waste products of metabolism, and substances in excess of requirements. Nutrition: taking in materials needed for energy, growth, and development. A species is a group of organisms that can reproduce with one another to produce fertile offspring. The binomial system gives each species two names: the genus followed by the species name, for example Homo sapiens. ...