Question

1. __________ are hollow cylinders of protein between cells that allow selected small molecules to pass between adjacent cells. where do you find these in the body? 3.3 passive membrane transport is diffusion of molecules down their concentration gradient a. there are three types of passive transport: ________, ________, and ________. b. ________ is the movement of molecules down a concentration gradient, from areas of high concentration to areas of low concentration. 1. what is the difference between simple diffusion and facilitated diffusion? 2. ________ is the diffusion of water through a selectively permeable membrane. a. compared to cells, solutions may be ________ (same solute concentration), resulting in no net movement of water between the solutions, ________ (higher solute concentration), resulting in movement of water out of the cell, or ________ (lower concentration), resulting in movement of water into the cell. 3.4 active membrane transport directly or indirectly uses ________. a. active transport 1. in ________ active transport, energy in the form of atp is used to directly power pumps to move substances against a concentration gradient. 2. ________ active transport uses energy indirectly from ionic gradients created by primary active transport to transport molecules. b. ________ uses membranous sacs to transport large particles, macromolecules, and fluids across the plasma membrane, or within the cell. ________ transports particles out of the cell and __________ transports particles into the cell.

Explanation:

1. Gap junctions are the hollow cylinders of protein between cells allowing selected small - molecules to pass and are found in many tissues like cardiac muscle and some neural tissues.
2. The three types of passive transport are simple diffusion, facilitated diffusion, and osmosis.
3. Diffusion is the movement of molecules down a concentration gradient. Simple diffusion occurs without the help of membrane proteins while facilitated diffusion uses membrane - bound transport proteins.
4. Osmosis is the diffusion of water through a selectively permeable membrane. Solutions can be isotonic (same solute concentration), hypertonic (higher solute concentration), or hypotonic (lower solute concentration) relative to cells.
5. Active membrane transport directly or indirectly uses energy. In primary active transport, ATP is used directly. In secondary active transport, energy is indirectly used from ionic gradients. Vesicular transport uses membranous sacs to transport large particles etc., with exocytosis transporting particles out of the cell and endocytosis transporting particles into the cell.

Answer:

1. Gap junctions; found in cardiac muscle, some neural tissues etc.
2. A. Simple diffusion, Facilitated diffusion, Osmosis
3. B. Diffusion

• 1. Simple diffusion occurs without membrane - protein help; facilitated diffusion uses membrane - bound transport proteins.
• 2. Osmosis
• a. Isotonic, Hypertonic, Hypotonic

1. Energy

• A. 1. Primary
• 2. Secondary
• B. Vesicular transport; Exocytosis; Endocytosis