Science Definitions

• Organism


  Living thing
• Vertebrate


  • Animal that has a backbone e.g. horse
• Invertebrate


  • Animal that does not have a backbone e.g. snake
• Diversity


  Huge range e.g. diversity of living things on earth
• Biodiversity


  Range of living things
• Cell


  Basic building blocks of all living things
• Zygote


  A single cell
• Nutrition


  Way which living things get their food
• Excretion


  Way which living things get rid of wastes they produce
• Response


  Way which living things react to changes in their surroundings
• Reproduction


  Way which living things produce new living things
• Cell membrane

  • Very thin layer, surrounds cell, controls what passes in and out of cell
• Nucleus


  • Round usually, control centre of cell
• Cytoplasm


  • Watery liquid, supports tiny cell structures e.g. chloroplasts
• Vacuole

  • Liquid, gives strength to cell
• Microscope


  To view objects that are too small to be seen by eyesight alone
• Mitochondrion


  • Powerhouse, supply energy of the cell
• Chloroplasts


  • Tiny green structures which allow a plant to make its own food
• Gamete


  Sex cell
• Fertilisation


  Joining or fusing of sex cells (male and female gametes) to form a zygote
• Characteristics


  Traits or features of an organism that can be passed on from parents to their offspring
• Variation


  Differences- genetic e.g. eye colour or non- inherited e.g. reading
• DNA


  Deoxyribonucleic acid, is a chemical which makes chromosomes
• Dominant


  The version of a gene that prevents the other (recessive) from working
• Recessive


  The version of a gene that is prevented from working by another (dominant) version
• Genes


  Short sections of DNA located on chromosomes, control inherited characteristics
• Chromosomes


  Thread-like structures found in the nucleus of each plant and animal cell
• Fossils


  Remains of very ancient living things
• Species


  Group of living things that can reproduce together to produce offspring which themselves can reproduce
• Evolution


  Process by which different kinds of living things develop from earlier forms during the history on earth
• Natural selection


  The process whereby organisms that are better adapted to their environment tend to survive and produce more offspring
• Mutation


  Changes in genes
• Adaptation


  A characteristic that helps an organism to survive and reproduce
• Digestion


  Breakdown of food
• Enzyme


  Biological catalysts
• Catalyst


  A substance that speeds up a reaction
• Amylase


  An enzyme that converts starch to maltose
• Maltose


  A simple sugar
• Oesophagus


  A muscular tube that forces food down from the mouth to the stomach
• Peristalsis


  A wave of muscular action that moves food from mouth to stomach