Active Transport ATP ATP Using Energy ATP Active

Active Transport ATP ATP Using Energy ATP

Active Transport • Transport methods that involve work (energy) energy by the cell are forms of active transport

• Carrier molecules are proteins in the cell membrane that transport large molecules or molecules that cannot dissolve in the lipids that make up the cell membrane. • They pick up molecules on one side of the membrane and move them to the other side.

2 Kinds of Carrier Transport 1. facilitated diffusion substances move with the concentration gradient • Carrier proteins speed things up • passive transport because energy is not used • ex: glucose

2. active transport - involves the movement of materials against the concentration gradient • requires the use of cellular energy • ex: Liver cells store glucose and have higher concentration than the blood. The cells use active transport to move glucose from the blood into the liver. • Ex: Na+ – K+ pump

Bulk Transport Movement in Vesicles

Endocytosis • endo = to enter • cyte = cell

• Large molecules, such as protein, enter the cell when they are surrounded by the cell. • This forms a vesicle for the transport of these molecules. • This process is called endocytosis

Phagocytosis “ cell eating ” • Solid particles enter through a vesicle ex: white blood cells eating bacteria

Phagocytosis = cells eating

Pinocytosis “ cell drinking ” • Particles enter as a droplet (liquid) Ex: human egg cell absorbs nutrients Ex: absorption of nutrients by cells in the intestines

Pinocytosis = cells drinking

Exocytosis • exo = to exit • cyte = cell

• When large particles leave the cell, they use a vesicle that fuses with the cell membrane. • The releasing of these molecules is called exocytosis

ex: secretion of proteins by a cell

The End