Cell Ultrastructure

• What are Eukaryotic cells?

  A cell that has a nucleus and membrane-bound organelle.
• What is a Prokaryotic cell?

  A single-celled organism that lacks a nucleus and other membrane-bound organelles.
• What are Organelles?

  Structures within cells that perform specific functions.
• What is the function of a nucleus?

  The nucleus houses and stores genetic material (chromatin). Ribosomes are also produced in the center of the nucleus and transported through pores in the membrane to the endoplasmic reticulum (ER).
• What are the functions of the endoplasmic reticulum?

  Rough endoplasmic reticulum > Covered in ribosomes where proteins are synthesised (intercellular transport network)

  
  

  Smooth endoplasmic reticulum > Creates and synthesizes lipids
• The function of the cell membrane is to regulate the movement of substances in and out of the cell and to provide protection and support for the cell.

  
• Endoplasmic reticulum

  
• The Golgi apparatus in a cell functions to modify, sort, and package proteins and lipids for transport to their final destinations within the cell or for secretion outside of the cell.

  
• What is the function of Mitochondria?

  The site of aerobic respiration produces ATP.

  
• What is the function of Chroloplast?

  It is the site of photosynthesis.

  
• What is the function of Lysosomes?

  They contain hydrolytic enzymes involved in breaking down waste materials.

  
• What is the function of Centrioles?

  Cilia and Flagella have similar structures made up of 9+2 arrangements of microtubes

  
• What is the Cytoskeleton?

  A network of protein filaments that provide structural support and facilitate cell movement.

  
• How does the production and secretion of proteins work?

  Production and secretion of proteins:

  1. A section of DNA (a gene) is copied into mRNA
  2. mRNA leaves the nucleus via the nucleic pore and travels to a ribosome on the Rough Endoplasmic Recticule AKA Translation (protein synthesis occurs)
  3. Protein is placed into a transport vesicle and sent to the Golgi for modification and packaging.
  4. Modified protein is placed into a secretory vesicle and sent to the surface membrane
  5. The secretory vesicle fuses with the cell surface membrane and protein is released. (Exocytosis)