2. Active Transport Sometimes cells must move against the concentration gradient- low concentration to areas of high –From areas of low concentration to areas of high –This requires the cell’s energy “ATP” –Done by transport proteins called “pumps” –Larger molecules can also be transported across the membrane by endocytosis and exocytosis endocytosis and exocytosis

5. Active Transport Lab Background Information: Congo red is a biological dye, that diffuses easily into the cell, like water This diffusion does not require energy You are using yeast cells, that I woke up by adding water and sugar- they are currently alive …

6. Lab Results 1.Macroscopically… which sample is darker? 2.Microscopically…. Which cells have absorbed the dye? 3.Are the (not boiled) yeast cells alive? 4.Are the boiled yeast cells alive? 5.Which cells moved the dye via active transport? 6.Of the cells that moved the dye…Did they move the dye in or out? 7.If active transport was used to move the dye, out via what mechanism did the dye get in?

7. Active Transport Endocytosis Phago-Pino- Exocytosis Protein Pumps

8. Endocytosis Endocytosis taking material into the cell by means of infoldings, of the cell membrane. –The pocket is called an ENDOSOME – Large molecules, clumps of food, and even whole cells can be taken up in this way. – Two examples phagocytosis and pinocytosis.

10. Phagocytosis Phagocytosis means “cell eating.” In phagocytosis, extensions of cytoplasm surround a particle and package it within a food vacuole. The cell then engulfs it. Amoebas use this method of taking in food.

12. PINOCYTOSIS “Cell drinking” cells take up liquid from the surrounding environment. Tiny pockets form along the cell membrane, fill with liquid, and pinch off to form vacuoles within the cell. Occurs continuously and in almost all cells

14. EXOCYTOSIS Many cells also release large amounts of material from the cell. Vesicles in the cell travel to the cell membrane, fuse with it, and expel the contents to the ECF.

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