1. Difference between diffusion and osmosis

Diffusion and osmosis are both passive transport processes that involve the movement of molecules across a membrane. However, they differ in terms of the types of substances being transported and the direction of movement.

Diffusion:
- Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.
- It occurs in both liquids and gases and can happen in an open system or across a selectively permeable membrane.
- The driving force behind diffusion is the random movement of molecules due to their kinetic energy.
- It does not require any energy input, as it is a passive process.
- Diffusion can occur for all types of molecules, including gases (such as oxygen and carbon dioxide) and small non-polar molecules (such as water and lipids).
- The rate of diffusion is influenced by factors such as concentration gradient, temperature, and the size of the molecules.

Osmosis:
- Osmosis is a specific type of diffusion that involves the movement of water molecules across a selectively permeable membrane.
- It occurs when there is a difference in the concentration of solute molecules on either side of the membrane.
- The water molecules move from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration).
- This process is driven by the tendency of water molecules to equalize the concentration of solutes on both sides of the membrane.
- Osmosis is essential for various biological processes, such as the absorption of water by plant roots and the regulation of water balance in animal cells.
- The rate of osmosis is influenced by factors such as the concentration gradient, temperature, and the pressure exerted on the solution (osmotic pressure).

2. Types of passive transport and their explanations

Passive transport refers to the movement of molecules across a cell membrane without the need for energy expenditure by the cell. There are three main types of passive transport:

Simple Diffusion:
- Simple diffusion is the movement of molecules directly through the lipid bilayer of the cell membrane.
- It occurs for small, non-polar molecules, such as oxygen, carbon dioxide, and water.
- The molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.
- This process is driven by the random motion of molecules due to their kinetic energy.
- The rate of simple diffusion is influenced by factors such as the concentration gradient, temperature, and the size of the molecules.

Facilitated Diffusion:
- Facilitated diffusion is the movement of molecules across the cell membrane with the help of specific transport proteins.
- It occurs for larger molecules, polar molecules, and ions that cannot readily pass through the lipid bilayer.
- The transport proteins, known as carrier proteins or channel proteins, provide a pathway for these molecules to move across the membrane.
- The molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.
- This process does not require any energy input and relies on the concentration gradient of the molecules.

Osmosis:
- Osmosis is a specific type of passive transport that involves the movement of water molecules across a selectively permeable membrane.
- It occurs when there is a difference in the concentration of solute molecules on