Week 2

• Active transport = low to high across a membrane

  • Uses special transport proteins in the membrane

    • Proteins in membrane:

      • Carrier proteins (protein pumps) --> active transport

      • Channel proteins --> facilitated transport

  • ATP!!! + energy

Sodium potassium pump (HL only) --> do more research:

• Require two ions --> sodium IN and potassium OUT

• For every three NA+ there is to K+ that gets ejected

Active transport:

1. Protein pumps (found in membrane) e.g. Na+/k+ pump

2. Endocytosis (IN)/Exocytosis (OUT) --> Used for larger molecules, then more of cell membrane is used

   • BOTH rely on ATP and the fluid nature of the plasma membrane

   • Endocytosis (research PROCESS, refer to ppt):

     • Pinocytosis --> Pino = to drink; takes in macromolecules (liquid molecules that a cell may have to take in) --> takes in when substance is a PARTICLES

     • Phagocytosis --> Phag = to eat (e.g. macrophages; BIG EATERS!!) --> takes in when substance is in a SOLUTION

   • Exocytosis (research PROCESS, refer to ppt):

Video Notes (research the process of pinocytosis vs phagocytosis/compare and contrast):

• Pinocytosis takes in macromolecules

  • Has a bunch of cell receptors on one area

  • Catherin is attached on the INSIDE of the cell

  • When molecules go in, the Catherin pulls down, and squeezes the membrane around the molecule before returning back to where it was before

• Phagocytosis only includes some cells

  • Tissue macrophage

  • Some WBC

  • Breaks the particle down with lysosome and turns into small molecules like amino acids, glucose and phosphate into cytoplasm

Practice questions:

1. A root hair cell takes in minerals from the soil, even when the soil has lower mineral concentration

   1. Identify the type of transport used

Active transport

1. Justify your answer

Because it is going from a low concentration to a high concentration

1. Compare active transport and facilitated diffusion

Active transport is when molecules move  AGAINST the concentration gradient (from low to high) which require ATP whereas facilitated diffusion is when the molecules move WITH the concentration gradient (high to low concentration) and does not require ATP.

1. A red blood cell is placed in a very salty solution

   1. Predict what will happen to the cell

The cells will shrivel because it is in a HYPERTONIC solution

1. Explain the movement of water involved

Water is LEAVING the cell (inside --> outside) to balance out the highly concentrated solution to reach equilibrium

1. Describe how the structure of the sodium-potassium pump enables active transport

• Selective capability --> only allows three Na+ to bind and only two K= to leave

• Since it has binding sites, for the molecules to bind, ATP would be required so the cells can move from inside to outside of the cell

• This will move molecules from low to high concentration.

• Transmembrane

• Protein pump