Biology paper 1

• Fossils


  • Remains of organisms from many thousands of years ago
  • Found in rocks
  • Provide evidence that organisms lived
  • Can tell us about how much or how little organisms have changed over time
  • Things like teeth, shells and bones don't easily decay
• Endocrine disorders can result from abnormalities in the production, secretion, or action of hormones.
• Hormones are chemical messengers produced by various organs or tissues, including the pituitary gland, thyroid gland, adrenal glands, pancreas, ovaries (in females), testes (in males), and placenta during pregnancy.
• Summarize important concepts using bullet points, keywords, or phrases.

  
• Oxygenated blood 


  Flows into the left atrium and then into the right ventricle.
• What is a tissue

  A group of specialized cells with a similar structure and function.
• What is human digestive system

  An organ system as it is made up of organs working together to perform a certain function
• What is the process of distillation

  Evaporation of a liquid is followed by condensation.
• What can distillation be used for

  To separate liquids from a mixture if they have different boiling points.
• The atom 


  Smallest uncuttable unit of matter
• covalent bonding- when non-metal atoms bond together they share pairs of electrons to make covalent bonds.
• Compounds- atoms join together to make comounds.
• Metallic Bonding - Metals contain many positive ions held together by strong electrostatic forces between them.
• Ionic Bonding - When metals react with non-metals, metal atoms lose their outermost electron(s) to become positively charged ions (cations). Non-metal atoms gain these electrons to become negatively charged ions (anions)
• Molecules- molecules are formed when two or more atoms join together to form a compound.
• Sound waves are longitudinal
• Waves moves parallel to the direction of energy transfer e.g sound.
• Rarefaction is when the waves spread out.
• Light travels at different speeds through different materials
• The speed of transverse waves depends on the medium it travels through.
• Light travels faster through vacuum than it does through matter because there's no resistance from particles in a vacuum so it can travel freely without any collisions.
• The speed of light is constant at 299792458 m/s
• Electromagnetic radiation travels through space as transverse waves without any medium
• Transverse waves move perpendicular to the direction of energy transfer e.g light
• Compression is where the wave gets closer together
• The speed of light in air is approximately 300 million metres per second.
• Transverse waves move perpendicular to the direction of energy transfer e.g light, radio waves, microwaves.
• When light passes from one material into another, some of its energy is transferred to the new medium as heat energy.
• Electromagnetic radiation is made up of electric and magnetic fields that oscillate at right angles to one another.
• In solids, light travels fastest because the atoms are packed tightly together with little space between them which means that the photons don’t have much distance to travel between atoms.
• Radio waves have the longest wavelength and lowest frequency.
• Sound travels slower through solids, liquids and gases as they have more resistance to vibrations.
• In liquids, light travels slower as the molecules are more spaced apart compared to solids but still close enough together for light to pass easily through them.
• Infrared radiation has longer wavelengths than visible light but shorter wavelengths than radio waves.
• Radio waves are used to transmit radio signals, TV broadcasting, satellite communication, radar systems, microwave ovens, and wireless internet connections.
• In gases, light travels slowest because the molecules are far apart meaning that the photon has further to travel between molecules.
• Longitudinal waves move parallel to the direction of energy transfer e.g sound
• Microwaves are used in cooking food with microwave ovens, satellite communications, and radar systems.
• Radio waves are used by radios to transmit signals over long distances.
• Rarefaction is when the wave spreads out