CIE IGCSE Biology

Revision Notes

1.1 Characteristics

Characteristics of Living Organisms: Basics

  • Movement: an action by an organism causing a change of position or place
  • Respiration: the chemical reactions that break down nutrient molecules in living cells to release energy
  • Sensitivity: the ability to detect and respond to changes in the environment
  • Growth: a permanent increase in size
  • Reproduction: the processes that make more of the same kind of organism
  • Excretion: the removal from organisms of toxic materials and substances in excess of requirements
  • Nutrition: the taking in of materials for energy, growth and development

Exam Tip

Use this mnemonic to help you remember these processes:

MRS. H. GREN

Movement
Respiration
Sensitivity
Homeostasis
Growth and development
Reproduction
Excretion
Nutrition

Extended Only

Characteristics of Living Organisms

  • Movement: an action by an organism or part of an organism causing a change of position or place
  • Respiration: the chemical reactions that break down nutrient molecules in living cells to release energy for metabolism
  • Sensitivity: the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
  • Growth: a permanent increase in size and dry mass by an increase in cell number or cell size or both
  • Reproduction: the processes that make more of the same kind of organism
  • Excretion: the removal from organisms of toxic materials, the waste products of metabolism (chemical reactions in cells including respiration) and substances in excess of requirements
  • Nutrition: the taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds, ions and usually need water

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Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.
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