organelles function

• • RER - system of membranes covered with ribosomes
  • folds and processes proteins made at the ribosomes
• SER- Has no ribosomes but is a system of membranes

  synthesises and processes lipids
• • vesicle- small fluid filled sac in the cytoplasm surrounded by a membrane
  • transports substances in and out cell and between organelles
  • some formed by Golgi apparatus of the ER some formed at cell surface
• Plasma membrane- found in surface of animal cells and inside plant cell wall. Made of lipids and protein

  regulates movement of substances in and out cell

  has receptor molecules which allows it to respond to chemicals like hormones
• Golgi apparatus : group of fluid filled membrane-bound, flattened sacs. vesicles often seen at the edges of the sacs.

  • processes and packages new lipids and proteins and makes lysosomes
• mitochondrion: oval shaped and have a double membrane - inner one is folded to form cristae. inside the matrix, contains enzymes involved in respiration.

  site of aerobic respiration, ATP is produced. found in large numbers in active cells that require a lot of energy
• centrioles : small , hollow cylinders, made of microtubules found in animal cells. but only some plant cells

  involved with the seperation of chromosomes during cell division.
• cell wall- rigid structure that surrounds plant cells and made mostly of cellulose and supports plant cells
• nucleus - a large organelle surrounded by the nuclear envelope, the nucleus contains chromatin (made from DNA and proteins) and controls the cells activities. DNA contains instructions to make proteins and the pores allow substances to move between nucleus and cytoplasm
• lysosome - round organelle surrounded by a membrane and contains digestive enzymes and can be used to digest invading cells or break down worn out cell components
• ribosome - very small organelle that floats free in cytoplasm or attached to RER.

  • made up of proteins and RNA.
  • no membrane
  • site of protein synthesis
• chloroplast - small flattened sac structure in plant cells

  • surrounded by double membrane
  • has thylakoid membranes which are stacked up in some parts of the chloroplast to form grana which are linked together by lamellae
  • site of protein synthesis some happen in grana and some in stroma
• centriole - small, hollow cylinders made of microtubules involved with separation of chromosomes during cell divison
• cilia - small, hair like structures found on surface membrane of animal cells.

  • in cross-section outer membrane ring of 9 pairs of protein microtubules and 2 in the middle
  • microtubules allow cilia to move which is used by the cell to move substances along the cell surface
• flagellum - stick out from cell surface and are surrounded by the plasma membrane and microtubules contract to make flagellum move and flagella are used to propel cells forward