Question

Define the 3 different types of passive transport and be sure to tell me what direction molecules move in each (down or against the concentration gradient?)

Answer 1

PASSIVE TRANSPORT

Passive transport is the movement of ions across cell membrane without use of energy that is ATP.

The three different types of passive transport are as follows

1. DIFFUSION

It is defined as the movement of ions, atoms or molecules of solutes, liquids or gases from a region of their higher concentration two region of their lower concentration when in direct contact.

Diffusion takes place until equilibrium is attained, that is, both the regions have balanced.

Diffusion is a slow process and therefore small solutes can only pass through it.

2. FACILITATED DIFFUSION

Molecules such as glucose are hydrophilic in nature ( water soluble) and the plasma membrane is hydrophobic. Therefore they require some special type of proteins(porins) known as carrier or transport proteins to allow these molecules to pass through the membrane. There is no energy required therefore it is also a form of passive transport.

These molecules also moves from the region of higher concentration to a region of lower concentration with the help of porins.

3. OSMOSIS

Osmosis is defined as the diffusion of water or solvent from a region of higher water concentration to a region of lower water concentration through a semipermeable membrane (plasma membrane).

Semipermeable means allowing only solvent particles to pass through it and not the solute particles.

When water enters the cell through osmosis , it makes the cell turgid due to and endosmosis.

When water leaves the cell through osmosis, it makes the cell flaccid due to exosmosis.

Note: in passive transport, all the three types will be down the concentration gradient and not against the concentration gradient because it does not require any form of energy.

In active transport , the molecules move from a region of lower concentration to a region of higher concentration. This will always be against the concentration gradient and therefore requires energy in the form of ATP (ADENOSINE TRIPHOSPHATE).

Answer 2

Passive transport is a cellular process that allows the movement of molecules across the cell membrane without the expenditure of energy by the cell. There are three different types of passive transport:

1. Simple Diffusion: In simple diffusion, molecules move freely across the cell membrane from an area of higher concentration to an area of lower concentration. This movement occurs down the concentration gradient, which means that molecules move from an area where there is a higher concentration of the molecule to an area where there is a lower concentration. This process continues until equilibrium is reached, and the concentration of molecules is uniform throughout the cell.

2. Facilitated Diffusion: Facilitated diffusion is similar to simple diffusion, but it involves the assistance of specialized transport proteins embedded in the cell membrane. These transport proteins act as channels or carriers that facilitate the movement of specific molecules across the membrane. Like simple diffusion, facilitated diffusion also occurs down the concentration gradient, from an area of higher concentration to an area of lower concentration.

3. Osmosis: Osmosis is a specific type of passive transport that involves the movement of water molecules across a semipermeable membrane. Water moves from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration). This movement occurs down the concentration gradient, and the process continues until the concentration of water is equal on both sides of the membrane.

In summary, all three types of passive transport (simple diffusion, facilitated diffusion, and osmosis) involve the movement of molecules or water down their respective concentration gradients, from an area of higher concentration to an area of lower concentration. These processes are essential for maintaining cellular homeostasis and ensuring the proper functioning of cells.

Answer 3

Passive transport is a type of cellular transport that does not require the input of energy from the cell. Molecules move across the cell membrane along their concentration gradient, which means they move from regions of higher concentration to regions of lower concentration.

There are three main types of passive transport:

1. Simple Diffusion:In simple diffusion, small non-polar molecules, such as oxygen and carbon dioxide, move freely through the cell membrane down their concentration gradient. They pass directly through the lipid bilayer of the membrane without the assistance of any transport proteins. This process occurs until equilibrium is reached when the concentration of the molecule is the same on both sides of the membrane.

Direction of movement: Down the concentration gradient (from higher concentration to lower concentration).

2. Facilitated Diffusion:Facilitated diffusion involves the movement of larger or charged molecules, such as glucose and ions, across the cell membrane. These molecules cannot easily pass through the lipid bilayer, so they require the help of specific transmembrane proteins called transporters or channels. These transport proteins create a pathway for the molecules to move down their concentration gradient.

Direction of movement: Down the concentration gradient (from higher concentration to lower concentration).

3. Osmosis:Osmosis is a special case of passive transport that specifically refers to the movement of water molecules across a selectively permeable membrane. Water moves from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration). This movement of water helps to equalize the concentration of solute particles on both sides of the membrane.

Direction of movement: Down the concentration gradient (from an area of lower solute concentration to an area of higher solute concentration, or equivalently, from an area of higher water concentration to an area of lower water concentration).

It's important to note that in all three types of passive transport, molecules move along their concentration gradient without the expenditure of energy by the cell. This is in contrast to active transport, where the movement of molecules is against the concentration gradient and requires the input of cellular energy.

Answer 4

Passive transport is a type of cellular transport that does not require the input of energy from the cell. Molecules move across the cell membrane along their concentration gradient, which means they move from regions of higher concentration to regions of lower concentration.

There are three main types of passive transport:

1. Simple Diffusion:In simple diffusion, small non-polar molecules, such as oxygen and carbon dioxide, move freely through the cell membrane down their concentration gradient. They pass directly through the lipid bilayer of the membrane without the assistance of any transport proteins. This process occurs until equilibrium is reached when the concentration of the molecule is the same on both sides of the membrane.

Direction of movement: Down the concentration gradient (from higher concentration to lower concentration).

2. Facilitated Diffusion:Facilitated diffusion involves the movement of larger or charged molecules, such as glucose and ions, across the cell membrane. These molecules cannot easily pass through the lipid bilayer, so they require the help of specific transmembrane proteins called transporters or channels. These transport proteins create a pathway for the molecules to move down their concentration gradient.

Direction of movement: Down the concentration gradient (from higher concentration to lower concentration).

3. Osmosis:Osmosis is a special case of passive transport that specifically refers to the movement of water molecules across a selectively permeable membrane. Water moves from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration). This movement of water helps to equalize the concentration of solute particles on both sides of the membrane.

Direction of movement: Down the concentration gradient (from an area of lower solute concentration to an area of higher solute concentration, or equivalently, from an area of higher water concentration to an area of lower water concentration).

It's important to note that in all three types of passive transport, molecules move along their concentration gradient without the expenditure of energy by the cell. This is in contrast to active transport, where the movement of molecules is against the concentration gradient and requires the input of cellular energy.