Organelle/Cell Structure (Function/Description)

• Cell membrane

  A semipermeable barrier that controls the movement of substances into and out of the cell’s internal environment
• Semipermeable - allows certain molecules into or out of the cell
• Cell wall

  • A rigid, protective external layer of the cell
  • Provides structural support and rigidity
  • Reduces dehydration
• Chloroplasts


  Contains chlorophyll (pigment), which enables it to convert energy from sunlight into simple sugars (food) through a chemical process called photosynthesis
• Cytoplasm


  A watery fluid within the cell that contains many dissolved substances and facilitates chemical reactions occurring
• Cytosol

  • The watery medium containing dissolved solutes (not organelles)
  • Prokaryotes only has a cytosol (not cytoplasm)
• Solutes - the substance that is being dissolved
• DNA


  The main form of genetic material found in a cell, containing instructions for cellular activity
• Endoplasmic Reticulum (ER)

  • Produces lipids and proteins and are responsible for detoxification
  • Provides a connection of pathways (transport) between the nucleus and the cell’s environment
  • Processes cell products: rough ER & smooth ER
  • Rough ER - appears rough as it is covered in ribosomes that produce proteins. This organelle assists in transporting the proteins after production. It can also synthesise lipids.
  • Smooth ER - produces lipids, steroids and hormones such as cholesterol and testosterone; essential for membrane repair and manufacture
• Flagella

  • A tail-like structure that uses motor proteins to whip around
  • This provides the cell with motility (movement)
  • Flagellum (singular)
• Genes

  Consist of DNA and contain the ‘recipe’ or ‘code’ for making proteins
• Golgi apparatus / Golgi body

  Modifies and exports proteins
• Lysosome

  • Contains destructive enzymes to digest waste (within the cytoplasm of animal cells)
  • Lysosome ruptures → releases destructive enzymes → digests the contents of the cell (waste), killing it in the process
• Mitochondria

  • The ‘powerhouse’ of a cell
  • Produces the cell’s energy through a special chemical reaction called respiration
  • During this process, the mitochondria combine oxygen with sugars to release energy in the form of ATP
• Peroxisome

  Contains enzymes for oxidation of lipids
• Plastids

  A small organelle in the cytoplasm of plant cells; it contains either pigment or dissolved nutrients
• Ribosome

  • A structure within the cell that uses information from genes to produce proteins (protein synthesis)
  • Found free in the cytoplasm or scattered over the surface of ER
  • The only organelles in a prokaryotic cell
• Nucleus

  Stores genetic material (found as DNA and proteins) and controls all cell activities
• Plasmid

  Small, circular, double-stranded DNA molecules
• Proteins

  Substances produced by the ribosomes within the cells, using the code provided by genes
• Vacuoles

  • Store nutrients and wastes
  • Collects water to provide rigidity in plants
  • Larger in plant cells than animal cells
• • Organelles only work at their best when their environment is regulated
  • Environment is maintained by the cell membrane