Science

• Three main states of matter: solid, liquid, and gas
• All matter is made up of tiny particles; how they are arranged determines the state of matter and its properties
• Solid state:

  • Regular structure
  • No space between particles
  • Fixed volume and shape
  • Particles vibrate around a fixed point only
• Gas state:

  • Irregular structure
  • Large space between particles
  • Volume increases to fill capacity
  • Shape changes to fill capacity
  • Particles move randomly and rapidly
• Liquid state:

  • Irregular structure
  • Very little space between particles
  • Fixed volume but shape changes to fill container
  • Particles can move and flow but slowly
• Melting point: when a solid substance is heated, particles gain energy and begin to move around, leading to a change from solid to liquid
• Boiling point: when a liquid substance is heated, particles gain energy and move around more, leading to a change from liquid to gas
• Sublimation: when a solid changes directly to a gas without passing through the liquid phase
• Gas pressure is affected by the amount of gas, volume of container, and temperature
• Living organisms carry out respiration to release energy that takes place inside cells
• Respiration is not the same as breathing; it is a chemical reaction
• The energy released by respiration is used for life processes such as movement, growth and repair of cells, and control of body temperature in mammals
• Aerobic respiration involves the use of oxygen and occurs in mitochondria in animal and plant cells
• The word equation for aerobic respiration is: glucose + oxygen → carbon dioxide + water (+ energy)
• Anaerobic respiration occurs in the absence of oxygen and usually happens during strenuous exercise
• The word equation for anaerobic respiration in animals is: glucose → lactic acid (+ energy)
• Anaerobic respiration releases less energy than aerobic respiration
• Lactic acid can build up in the muscles during exercise, leading to cramp
• Fermentation is a type of anaerobic respiration carried out in plant cells and some microorganisms like yeast
• The word equation for fermentation is: glucose → ethanol + carbon dioxide (+ energy)
• Examples of products produced by fermentation are bread and alcoholic drinks, such as beer
• There are different types of cells, including muscle cells, nerve cells, skin cells, blood cells, bone cells, and red blood cells.

  
• Cells are the basic building blocks of life.

  
• The human body is made up of cells.