Bulk transport across the plasma membrane

• Bulk transport is how we move lot's of something small or big across the membrane.
• There are two types of bulk transport:

  1. Exocytosis
  2. Endocytosis
• Exocytosis is when material moves out of the cell, it can be vesicles (secretory) or fluid (cytotoxic).
• Exocytosis has 2 types:

  1. Constitutive Cytosine: releasing extracellular matrix proteins and contributes to things that make up things around the cell.
  2. Regulatory cytosine: releasing hormones and neurotransmitters and are not released at random.
• Endocytosis is when materials enter the cell through endocytose vesicles.
• Phagocytosis is where cells engulf large particles like bacteria and dead cells.
• A lysosome digests and breaks down the food particle into something the cell can use.
• Pinocytosis is where the cell takes in a whole bunch of fluid. It is the uptake of extracellular fluid and the inside will be solutes.
• The process of pinocytosis is forming a vesicle and shape inside the vesicle and then the fluid will float into the vesicle to close it and move away from the plasma membrane.
• Receptor-mediated endocytosis is where there is a receptor on the surface of the cell, which binds with a ligand (a molecule). By using pinocytosis alone requires these receptors to capture required solutes.
• Lysosomes helping big digestions require enzymes. enzymes require specific environments. The organelle will have a distinctive environment. Inside the organelle are the hydrolytic enzymes to cut what we put inside, which needs to be acidic.
• Waste that can still be used for different functions, so we fuse them with the lysosome and the enzymes can recycle and renew them. This is called a Autotagy.
• If waste cannot be recycled or repurposed, they get rid of it by exocytosis. Exocytosis is when the cell releases its contents outside of itself.
• The vacuole is a large fluid filled sac that stores cell sap and helps maintain the cell's shape. It is derived from rER and Golgi Apparatus.
• Vacuoles are important in plants because they perform lysosome-like functions and absorbs water allowing plant cells to grow without a large increase in cytoplasm.