Animal cell ultra structure

• Nucleus

  • contains DNA which controls protein synthesis which happens in cytoplasm
  • controls metabolic activities of cell
  • biggest organelle
  • double membrane called nuclear envelope which contains nuclear pores enabling exit of mRNA
  • contains chromatin which is DNA wrapped around proteins called justine’s
  • Chromatin coils and fold to become chromosomes
• Nucleolus

  • within nucleus made up of proteins and RNA
  • RNA is used to make ribosomal RNA which is combined with proteins to make ribosomes
  • produces ribosomes needed for protein synthesis
• Rough endoplasmic reticulum

  • network of membranes forms flattened sacs called cisternae
  • cisternae connected to outer membrane of nucleus
  • ribosomes bound to surface of cisternae
  • cells that release hormones or enzymes have more RER
  • responsible for synthesis and transport of proteins
• Smooth endoplasmic reticulum

  • membranes of flattened sacs called cisternae which are connected to outer membrane of nucleus
  • no ribosomes attached
  • responsible for lipid , carbohydrate synthesis and storage
• Golgi apparatus

  • similar to smooth endoplasmic reticulum
  • compact structure of cisternae with no ribosomes
  • modifies proteins
  • packages proteins into vesicles
• Mitochondria

  • larger than lysosomes
  • surrounded by double membrane
  • inner membrane folded into finger like projections which project into interior solution Matrix
  • carry out later stages of aerobic respiration and make ATP
  • help to make lipids
• Lysosomes

  • membranous sacs made up of a single membrane with fluid inside
  • specialised vesicles containing hydrolytic enzymes
  • used for storage transport
  • breakdowns waste material in cells
  • breakdowns old organelles
  • breakdowns pathogens in immune system
  • play a role in programmed cell death
• Plasma membrane

  • thin
  • made from phospholipid bilayer containing proteins and cholesterol
  • partially permeable controlling exchange between cell and environment
• Cytoskeleton

  • found within cytoplasm of all eukaryotic cells
  • network of fibers needed for shape and stability of cell
  • controlls movement of organelles within cell and controls movement of cells
• Centrioles

  • hollow cylinder
  • 2 centrioles per cell form the centrosome
  • made from ring of microtubules
  • form part of cytoskeleton
  • grow spindle fibres needed for nuclear division (mitosis )
• Flagella

  • made from microtubules arranged in ring of 9 which can slide over each other enabling movement
  • stick out from cells
  • longer than cilia
  • some can detect chemical changes in environment
• Cilia

  • short but a lot of them
  • covered by an extension of plasma membrane
  • microtubules that grow from structure called a basal body in cytoplasm
  • can be stationary or mobile
  • in nose
  • moves fluids or objects