Cellular Transport Biology 2017 Cellular Transport Every living

Cellular Transport Biology 2017

Cellular Transport • Every living cell exists in a liquid environment that it needs to survive. • The plasma membrane is selectively permeable. • This means only certain molecules are allowed in and out of cells.

Diffusion Notes • Diffusion- particles tend to move from an area where they are more concentrated to an area less concentrated. • Facilitated diffusion- molecules that cannot diffuse on their own that move through protein channels in the cell membrane.

Osmosis ctd… • Osmosis effects cells depending on the type of solution that they are in: isotonic, hypertonic, or hypotonic. Egg Experiment on You. Tube • Isotonic- solution which the concentration is the same inside AND outside the cell. • Hypertonic- solution that has more water inside the cell than outside, so water moves out causing the cell to shrink. • Hypotonic- solution that has more water outside the cell than inside, so water moves in causing the cell to swell.

Types of Transport • Passive Transport- in cells, substances can diffuse across membranes WITHOUT requiring the use of energy. • Active Transport- transport protein (aka carrier protein) REQUIRES energy to help move particles across the membrane against a force. • This is known as a concentration gradient.

Endocytosis vs Exocytosis Endocytosis Exocytosis • Large particles are engulfed, then enclosed by a cell membrane as it moves into the cell. • Large particles are released from a cell by secreting them or expelling them.

Osmosis and Homeostasis • Osmosis- the diffusion of water across a selectively permeable membrane. • Homeostasis- enables the cell membrane to regulate the cell’s internal environment.

Follow Up Does a cell use passive transport or active transport to move molecules? Both Depending on the molecule and if it needs to move against the concentration gradient.