Biology Study Guide- Diffusion, Concentration Gradients, Osmosis, Active Transport, Endocytosis, and Exocytosis

What is the fuel that drives active transport?

ATP

What is active transport?

Active transport is the energy-demanding transfer of a substance across a cell membrane against its concentration gradient, i.e., from lower concentration to higher concentration.

What is diffusion?

Diffusion is the net passive movement of particles (atoms, ions, or molecules) down the concentration gradient.

What is endocytosis?

Endocytosis is the process by which materials move into the cell.

What molecules can be transported via osmosis?

ONLY water.

Diffusion is a form of [ACTIVE/PASSIVE] transport.

Passive.

What are the two types of diffusion?

Simple diffusion and facilitated diffusion.

What is the concentration gradient?

The concentration gradient is the gradual difference in the concentration of solutes in a solution between two regions.

What is exocytosis?

Exocytosis is a process by which materials are exported out of the cell via secretory vesicles. In this process, the Golgi complex packages macromolecules into transport vesicles that travel to and fuse with the plasma membrane. This fusion causes the vesicle to spill its contents out of the cell.

What role does exocytosis play in life?

Exocytosis is important in expulsion of waste materials out of the cell and in the secretion of cellular products such as digestive enzymes or hormones.

What is facilitated diffusion?

Facilitated diffusion is the movement of more specific molecules down a concentration gradient, passing through the membrane via a specific carrier protein. Each carrier has its own shape and only allows one molecule (or one group of closely related molecules) to pass through. Think of it like puzzle pieces.

What does it mean to "go down the concentration gradient"?

Going down the concentration gradient means going from an area with a higher concentration of particles to an area with lower concentration of particles.

What does it mean to "go up the concentration gradient"?

Going up the concentration gradient means going from an area with a lower concentration of particles to an area with higher concentration of particles.

What is phagocytosis?

In phagocytosis or "cellular eating," the cell's plasma membrane surrounds a macromolecule or even an entire cell from the extracellular environment and buds off to form a food vacuole

What is pinocytosis?

In pinocytosis or "cellular drinking," the cell engulfs drops of fluid by pinching in and forming vesicles.

What are the two types of passive transport?

Osmosis and diffusion.

What is osmosis?

Osmosis is the movement of water molecules through a selectively permeable membrane from higher water concentration to a lower water concentration, down a concentration gradient.

What is the difference between active transport and passive transport?

Passive transport does not require the cell to use energy. Active transport requires the cell to use energy to take in or expel substances.

Osmosis is a form of [ACTIVE/PASSIVE] transport.

Passive.

What are the three types of endocytosis?

Phagocytosis, pinocytosis, and receptor-mediated endocytosis.

What is Receptor-mediated endocytosis?

Receptor-mediated endocytosis is an extremely selective process of importing materials into the cell. The cell will only take in an extracellular molecule if it binds to its specific receptor protein on the cell's surface. Once bound, the coated pit on which the bound receptor protein is located then pinches in to form a coated vesicle.

What is simple diffusion?

Simple diffusion is a process where a substance passes through a membrane without the aid of an intermediary (for example,an integral membrane protein.) The force that drives the substance from one side of the membrane to the other is the force of diffusion. This only occurs with small, hydrophobic molecules. What this basically means is that the particles passively pass through the membrane, going down the concentration gradient.