cell transport mechanisms and permeability

Question 1

facilitated diffusion

Answer 1

the movement of a substance from high to low with the aid of a carrier molecule

Question 2

carrier proteins

Answer 2

• transport hydrophilic or large molecules
• can move more than one substance (cotransport)
• can move more than one substance in opposite directions (countertransport)

Question 3

primary active transport

Answer 3

• requires ATP
• moves from low to high concentration

Question 4

secondary active transport

Answer 4

movement for one of two substances to follow the concentration gradient (cell uses ATP)

Question 5

vesicular transport & types

Answer 5

• materials move in sacs called vesicles, uses ATP
• endocytosis & exocytosis

Question 6

endocytosis

Answer 6

import extracellular substances into vesicles called endosomes

Question 7

exocytosis

Answer 7

movement of waste or secretory products from intracellular vesicle to outside the cell

Question 8

step 1 in receptor-mediated endocytosis

Answer 8

materials bind to receptors on the membrane surface

Question 9

step 2 in receptor-mediated endocytosis

Answer 9

saturated areas of receptors from pockets that pinch off to form an endosome

Question 10

step 3 in receptor-mediated endocytosis

Answer 10

clathrin-coated vesicles form

Question 11

step 4 in receptor-mediated endocytosis

Answer 11

the endosome fuses with a lysosome filled with digestive enzymes

Question 12

step 5 in receptor-mediated endocytosis

Answer 12

ligands are released from their receptors, and enter the cytoplasm

Question 13

step 6 in receptor-mediated endocytosis

Answer 13

the endosomal membrane detaches from the secondary lysosome

Question 14

step 7 in receptor-mediated endocytosis

Answer 14

the endosomal membrane returns to the cell surface, where its receptors become available to bind more ligands

Question 15

pinocytosis

Answer 15

brings fluid and small molecules into cell “cell drinking”

Question 16

phagocytosis

Answer 16

cytoplasmic extensions surround the object and bring it into the cell “cell eating”

Question 17

exocytosis

Answer 17

vesicle contents are releases into extracellular environment