sci revision

• Circulatory system


  System that circulates blood through the body
• Artery


  Blood vessel that carries blood away from the heart
• Vein


  Blood vessel that carries blood towards the heart
• Structures in the circulatory system that ensure one-way flow of blood
• Part that separates the left side of the heart from the right side
• Artery wall


  Average thickness 0.5 mm
• Capillary wall


  Average thickness 0.0005 mm
• Vein wall


  Average thickness 1 mm
• Capillaries


  Function to facilitate exchange of materials between blood and body tissues
• Main components of blood


  • Red blood cells
  • White blood cells
• Carbon forms diamond and graphite
• Chlorine is a halogen
• Copper is electroplated onto another metal
• Aluminium is extracted from bauxite
• Sulfur is used in the manufacture of sulfuric acid
• Chlorine is used to sterilise drinking water
• Phosphorus oxide (P4O10)


  Contains 4 atoms of phosphorus and 10 atoms of oxygen
• Phosphorus oxide makes an acidic solution when it dissolves in water
• Elements commonly found in fertilisers


  • Nitrogen
  • Phosphorus
• Ultrasound


  High frequency sound waves
• It is not safe to scan unborn babies with X-rays
• 1. rays are used in hospitals to take images of the body
• γ-radiation is placed on the electromagnetic spectrum between X-rays and ultraviolet
• Albinism


  Condition where no pigment is made by the skin
• Allele for no albinism


  Dominant, represented by A
• Allele for albinism


  Recessive, represented by a
• Genotypes, phenotypes and descriptions for 3 people


  • Person 1: aa, albinism, homozygous recessive
  • Person 2: Aa, normal pigmentation
  • Person 3: AA, normal pigmentation, homozygous dominant
• Punnett square for offspring of Person 2 and Person 3


  1. AA

  2. Aa
• Chromosome


  Thread-like structure of DNA, carrying genetic information
• Chromosomes are found in the nucleus of human cells
• Sex chromosomes in male gametes are X or Y
• Male gametes in humans are sperm
• Organ where male gametes are produced in humans is the testes
• Argon


  Electronic structure is full outer shell, making it very unreactive