Inheritance + Waves

    Cards (37)

    • Light travels at different speeds depending on its colour, with violet being the fastest and red being the slowest.
    • Wave speed = Frequency x Wavelength
    • The speed of light is approximately 300 million metres per second (m/s).
    • Inheritance is the transmission of genetic information from generation to generation.
    • Chromosomes are thread-like structures made of DNA, carrying genetic information in the form of genes.
    • Chromosomes are located in the nucleus of the cell.
    • A gene is a length of DNA found on a chromosome with a sequence of bases that code for a specific protein, eg enzymes, collagen.
    • Genes control our characteristics and are the code for protein.
    • Alleles are forms of genes that differ in the nucleotide sequence of the DNA.
    • Humans have 23 different chromosomes in each cell, 2 pairs of each meaning we have 46 chromosomes.
    • In average body cell, we have 44 chromosomes, these are diploid cells.
    • Gametes have half the number of normal chromosomes and are haploid (they have 23 chromosomes)
    • Mitosis is used to repair broken tissue, replace cells, growth, and asexually reproduce.
    • Meiosis is used to produce gametes with half the number of chromosomes
    • During meiosis, homologous chromosome pair up and exchange genetic material through crossing over.
    • Waves are periodic disturbances that transfer energy but not matter
    • Transverse waves oscillate perpendicular to direction of wave travel
    • Longitudinal waves oscillate parallel to direction of wave travel
    • Longitudinal waves have compressions and rarefactions. Eg, sound and P-earthquake waves.
    • Transverse waves have crests and troughs. Eg, Electromagnetic radiation, S-earthquake waves, vibration along a string.
    • Only electromagnetic radiation does not rely on a medium.
    • Wave equation: v=fλ
    • v= velocity in ms^-1
      f= frequency in Hertz (s^-1)
      λ= wave length in m.
    • If a wave speeds up when moving into another medium, it will bend away from the normal.
    • refractive index , n = speed of light in a vacuum (2.998*10^8) / speed of light in material (perspex: 2.0*10^8)
    • Snells law is that when light enters a denser medium it slows down and bends towards the normal.
    • snells law is n = sin i / sin r
    • Convex lenses make light rays converge to a real focal point (F)
    • Concave lenses make light rays diverge out and make a virtual focus.
    • Images created by lenses can be classified as
      * inverted or upright
      * diminished, magnified, same size
      * real, virtual
    • Radio waves can travel long distance before being absorbed and reflect off the atmosphere. Therefore they are used for communication.
    • Microwaves are absorbed easily by water, therefore are used to heat up food.
    • All things easily absorb infrared waves, therefore they increase heat. They are used in ovens, toasters, and infrared cameras.
    • Visible light waves have short wavelengths and high energy and are absorbed by human eyes. They are used in communication and sight.
    • Ultraviolet waves have shorter wavelengths and higher energy and, therefore are used in energy-efficient lightbulbs and sun tanning.
    • X ray waves are absorbed by bones but not tissue, so are used to print medical images and treat cancer.
    • Gamma rays are the most penetrative rays, therefore are used to make medical images and treat cancer.
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