Cells and their organelles

• Cells contain specialised "organs" called organelles, each with a specific role in the functioning of the cell
• Nucleus:

  • Contains cellular DNA and controls cellular functions
  • Surrounded by nuclear envelope (controls what enters and exits nucleus) which contains nuclear pores
• Nucleolus:

  • A dense region within the nucleus containing cellular RNA required for transcription (protein synthesis step 1)
• Ribosome:

  • Site for translation (protein synthesis step 2)
  • Can be found on rough endoplasmic reticulum or freely in the cytoplasm
• Rough Endoplasmic Reticulum:

  • Location for protein synthesis and transport
  • Chemical reactions also occur on the membranes
  • Consists of ribosomes connected to flattened sacks
  • Connected to nuclear membrane
• Smooth Endoplasmic Reticulum:

  • Transport system for the cell and site of chemical reactions
  • Can synthesize lipids and detoxify drugs and alcohol
  • Consists of flattened sacks WITHOUT ribosomes
• Mitochondria:

  • Produce energy (ATP) through aerobic cellular respiration
  • Glucose + Oxygen => Carbon Dioxide + Water + Heat + ATP
• Golgi Body:

  • Packages molecules into vesicles for transport around the cell or body
  • Also packages unnecessary/hazardous molecules into lysosomes
• Lysosome:

  • Double membraned organelle that digests worn-out organelles, hazardous chemicals, etc. using the enzyme lysozyme
  • Produced by Golgi bodies
• Centriole:

  • Creates spindle for chromosomes to attach to during cellular reproduction (mitosis and meiosis)
• Cell Membrane:

  • A selectively permeable biphospholipid membrane that controls the movement of substances into and out of the cell
  • Allows for intercellular communication and provides receptor sites for cell-specific chemicals such as hormones
• Cytoplasm:

  • Jelly-like substance that takes up remaining space in the cell
  • Location for chemical reactions including anaerobic cellular respiration
  • Contains proteins, salts, ribosomes, and organelles