Animal cells

• Features of an animal cell

  • cytoplasm
  • nucleus
  • ribosome
  • mitochondria
  • cell membrane
• • mitochondria are visible with the light microscope but can't be seen in detail
  • ribosomes are only visible with the electron microscope
• Cytoplasm

  • a jelly-like material
  • contains dissolved nutrients and salts and structures called organelles
  • where many of the chemical reactions happen
• Nucleus

  • contains genetic material including DNA
  • controls the cell's activities
• Cell membrane

  • its structure is permeable to some substances but not to others
  • controls the movement of substances in and out of the cell
• Mitochondria

  • organelles
  • contain the enzymes for respiration
  • where most energy is released in respiration
• Ribosomes

  • a tiny structure
  • where protein synthesis occurs
• Specialised animal cells

  • sperm cell
  • nerve cell
  • muscle
• Sperm cell

  • head of the sperm contains the genetic material for fertilisation
  • the acrosome in the head contains enzymes so that the sperm can penetrate an egg
  • the middle piece is packed with mitochondria to release energy needed to swim and fertilise the egg
  • the tail enables the sperm to swim
• Features of a sperm cell

  • tail
  • midpiece containing mitochondria
  • haploid nucleus
  • acrosome
• Nerve cell

  • the nerve cell is extended so that nerves can run to and from different parts of the body to the central nervous system
  • the cell has extensions and branches so that it can communicate with other nerve cells, muscles and glands
  • the nerve cell is covered with a fatty sheath which insulates the nerve cell and speeds up the nerve impulse
• Features of a nerve cell

  • dendrite
  • cytoplasm
  • nucleus
  • cell membrane
  • axon
  • nerve ending
• Muscle

  • muscle cells contain filaments of protein that slide over each other to cause muscle contraction
  • the arrangement of these filaments causes the banded appearance of heart muscle and skeletal muscle
  • they contain many well-developed mitochondria to provide the energy for muscle contraction
  • in skeletal muscle, the cells merge and the muscle fibres contract in unison
• Features of a muscle

  • heart muscles
  • smooth muscle cells
  • skeletal muscles
• animal cells can be observed in a laboratory, using a light microscope
• • animal cells may have vacuoles
  • these are small and temporary
  • commonly used to store or transport substances