active transport

• uses energy to move molecules an ions across plasma membranes against a concentration gradient
• 1. molecule attaches to carrier protein, protein changes shape, moves molecule across membrane releasing on other side
  2. energy is used from ATP to move solute against its concentration gradient
• endocytosis -

  1. some molecules are too large e.g. proteins, lipids, some carbs
  2. a cell surrounds a substance with a section of its plasma membrane
  3. membrane then pinches off to form a vesicle in the cell containing ingested substance
  4. uses ATP
• endocytosis process

  A) cytoplasm

  B) substance

  C) nucleus

  D) plasma membrane

  E) vesicle

  
• exocytosis -

  • some substances produced by cell ( digestive enzymes, hormones, lipids) need to be released
  • vesicles containing these substances pinch off from the sacs of the Golgi apparatus and move to the plasma membrane
  • vesicles fuse with plasma membrane and release contents outside the cell
  • some substances (membrane proteins) aren't released out the cell but inserted straight into the plasma membrane
  • uses ATP
• EXOCYTOSIS PROCESS

  A) vesicle buds off from Golgi apparatus

  B) vesicle moves to plasma membrane

  C) vesicle fuses with plasma membrane

  D) contents of vesicle released outside cell