bio

• Eukaryotic cells


  Cells that contain their genetic material enclosed in a nucleus
• Eukaryotic cells

  • Contain a nucleus
  • Contain a cell membrane
  • Contain cytoplasm
• Prokaryotic cells

  Cells where the genetic material is not enclosed in a nucleus
• Prokaryotic cells

  • Do not have a nucleus
  • Have a cell membrane
  • Have a cell wall
  • Contain cytoplasm
  • May have plasmids
• Prokaryotic cells

  Are much smaller than eukaryotic cells
• Eukaryotic cells include animal and plant cells
• Prokaryotic cells include bacterial cells
• one order of magnitude means 10x the size
• every order of magnitude is 10x greater than the one before
• 10x=one order of magnitude

  100x=two orders of magnitude

  1000=three orders of magnitude

  (use the amount of 0 to remember)
• animal cells

  the function of a nucleus is to enclose the genetic material
• the cytoplasm is a watery solution where chemical reactions take place
• the cell membrane controls the molecules that can enter and leave the cell
• mitochondria is where aerobic reparation takes place
• ribosomes are the sites of protein synthesis
• plant cells have a regular shape
• animal cells can easily change their shape
• plant cells

  chloroplasts contain chlorophyll and are the sites of photosynthesis
• the cell wall is made from cellulose. this strengthens the cell
• animal cells contain:

  ribosomes

  nucleus

  mitochondria

  cell membrane

  cytoplasm
• plant cells contain:

  cytoplasm

  ribosomes

  nucleus

  mitochondria

  cell membrane

  permanent vacuole

  chloroplasts

  cell wall
• the vacuole is filled with a fluid called cell sap. the vacuole helps give the plant cell its shape
• animal cell specialisation:

  most animal cells have adaptations which help them to carry out their particular function

  when cells become specialised, scientists call that differentiation
• the job of a sperm cell is to join with an ovum (egg cell). we call that process fertilisation
• during fertilisation, the genetic information of the ovum and the sperm combine
• sperm cells contain their genetic information in the nucleus. however, sperm cells only contain half the genetic information of a normal adult cell
• sperm cells have a long tail which allows them to swim to the ovum. they are also streamlined to make this easier
• sperm cells are packed full of mitochondria. these provide the energy needed for swimming
• sperm cells contain enzymes which allow them to digest their way through the outer layer of the ovum
• the job os a nerve cell is to send electrical impulses around the body
• the axon carries the electrical impulses from one part of the body to another
• myelin insulates the axon and speeds up the transmission of nerve impulses
• the end of the axon has synapses. synapses are junctions which allow the impulse to pass from one nerve cell to another
• dendrites increase the surface area so that other nerve cells can connect more easily
• muscle cells can contract (get smaller)
• muscle cells contain protein fibres which can change their length
• when a muscle cell contracts, these protein fibres shorten, decreasing the length of the cell
• these muscle cells are also packed full of mitochondria to provide energy for muscle contraction
• muscle cells work together to form muscle tissue
• root hair cells

  hairs increase surface area of the root, so it can absorb water and dissolved minerals more effectively