Getting Into and Out of Cells

Cell Transport

Types of Cell TransportPassive Transport - no cellular energy required to occur - goes with the concentration gradient

- diffusion- facilitated diffusion

- osmosisActive Transport - requires cellular energy to occur - goes against the concentration gradient

- Endocytosis/Exocytosis

Concentration GradientThe concentration gradient is the

distribution of particles across space from high to low concentration

DiffusionPrimary means of cell transport - molecules move from high to low

concentration - movement continues with the gradient

until the molecules are evenly distributed - equilibrium is achieved

Passive Transport Energy for passive transport comes from

the molecules themselvesIn passive transport, molecules move with

the concentration gradient - move from high concentration to low

concentration

Facilitated DiffusionParticles move with the concentration

gradient across a transport protein in the membrane

- ions, sugar and amino acids all move into and

out of cells by facilitated diffusion

OsmosisIs the diffusion of water through a

membrane .If the concentration of water is higher outside

a cell than inside, water moves into the cell. If the concentration of water is higher inside

of a cell than outside, the water moves out of the cell.

Uses cellular energy/ ATPGoes against the concentration gradient - Low concentration to High concentration

Active Transport

o Endocytosis – taking things into cells◦ Phagocytosis- cell eating – takes in food◦ Pinocytosis- cell drinking – takes in liquid - membrane encircles food or liquid, forming

a vacuole

Endocytosis

White blood cell engulfing bacteria (bacillus)

Exocytosis-moving materials out of cells

- wastes/ undigestible material

- cellular products like: antibodies, hormones, enzymes and neurotransmitters

-vacuole/vesicle containing the substance travels to the cell membrane where it fuses and releases it contents out of the cell

Exocytosis

Research 16.31) Describe diffusion using real world examples,

and why it is important to life functions2) Describe how passive transport works and how

does the cell benefit from this?3) Why do plant leaves shrink, and how can this be

remedied?4) Describe active transport, and why it is

important. 5) What are the differences between endocytosis

and exocytosis, and why they are necessary?6) How does cell size and shape affect cell

transport?

Answers1) When you walk into a bakery you can smell the bread baking. This is the process of diffusion where molecules spread out and fill the space. This helps cells maintain conditions necessary for life ex oxygen enters cells and carbon dioxide leaves cells.

2)The materials move without using the cell’s energy. Cells benefit from passive transport because some materials can move in or out without any input of energy

3) Plants wilt due to osmosis where water moves through a membrane. As the soil dries the water leave the plant cells by osmosis and they shrink. This can be remedied by watering the plant and water will fill the cells giving them shape

Answers4) Active transport is the process of using energy to move materials through a membrane. This is important to cells for being able to remove excess salt from the body.

5) Endocytosis is where the cell moves materials that are too large into the cell. Where as Exocytosis is the process of moving materials that are too large out of the cell. This helps your body defend against bacteria and viruses, and expel proteins or hormones made by the cells.

Answers6) The amount of cell membrane limits the ability of cells to either get materials through the cell membrane this is related to surface area. The larger a cell time comes when its surface area is not large enough to allow resources to travel to all parts so it stops growing. The cells shape affects the amount of surface area.