Cell Transport and Homeostasis

Homeostasis and cellular transport

Passive Transport

passive transport does not require energy to move particles across the membrane.
examples include osmosis, diffusion, and facilitated diffusion
this type of transport happens when molecules move with the concentration gradient, from areas of high concentration to low concentration.

Active Transport

Active transport requires energy in the form of ATP and a transport protein - such as a sodium-potassium pump. This type of transport happens when the molecules being transported are going against the concentration gradient, from areas of low concentration to areas of high concentration.

Multiple Choice

Which of the following is a good comparison to make of going against the concentration gradient?

• trying to get back into a crowded concert

• letting the current in a lazy river take you downstream

• following traffic and going the same way as all the cars around you

• water rushing into a hole in a boat

types of cell transport

​diffusion

Diffusion occurs when dissolved molecules move from high to low concentration without assistance from a channel protein, they just slip through the membrane.
This type of transport does not require ATP.

types of cell transport

​Facilitated Diffusion

Diffusion occurs when dissolved molecules move from high to low concentration with assistance from a channel protein, they cannot just slip through the membrane.
This type of transport does not require ATP.

types of cell transport

osmosis

Diffusion of water molecules across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.
This type of transport does not require ATP.

types of cell transport

​Active transport

Active transport occurs when dissolved molecules move from an area of low solute concentration to high solute concentration.
This type of transport requires ATP and channel proteins.

types of cell transport

​Endocytosis

Endocytosis happens when the cell uses its membrane to surround molecules and bring them into the cell.
This type of transport requires ATP.

types of cell transport

​Exocytosis

Exocytosis happens when the cell uses vesicles to surround molecules and remove them from the cell.
This type of transport requires ATP.

Multiple Choice

Which of the following structures lets particles/molecules in and out of the cell?

• mitochondria

• cell membrane

• chloroplast

• vacuole

Multiple Choice

The cell membrane contains channels and pumps that help move materials from one side to the other. What are these channels and pumps made of?

• carbohydrates

• lipids

• bilipids

• proteins

Multiple Choice

the diffusion of water across a membrane is called

• osmosis

• pinocytosis

• active transport

• facilitated diffusion

Multiple Choice

which means of particle transport requires input of energy from the cell?

• diffusion

• osmosis

• facilitated diffusion

• active transport

Multiple Choice

molecules move from high to low concentration in -

• endocytosis

• exocytosis

• passive transport

• active transport

Multiple Choice

the picture is an example of -

• active transport

• passive transport

• diffusion

• osmosis

Multiple Choice

what is this an example of?

• active transport

• exocytosis

• passive transport

• easy transport