Transport Across the Membrane (Unit 1)

Question 1

Active Transport

Answer 1

Used when substances must travel against the concentration gradient, using pumps to control movement. Requires energy in the form of ATP or an electrochemical gradient.

Question 2

ATP stands for

Answer 2

Adenosine Triphosphate

Question 3

What does ATP do?

Answer 3

ATP contains energy stored in the bonds connecting phosphate molecules together. Releasing a phosphate releases usable energy for cell processes.

Question 4

Transport Types

Answer 4

Primary Active Transport and Secondary Active Transport

Question 5

Primary Active Transport

Answer 5

Uses ATP to power pumps that transport molecules and ions across the membrane. Used for ions. Active transport pumps move positively charged ions.

Question 6

Electrochemical Gradient

Answer 6

The combined effects of a difference in electrical potential energy and difference in ion concentration gradients.

Question 7

Secondary Active Transport

Answer 7

Transport of molecules across the membrane without using ATP. Uses electrochemical gradient, created by pumping ions out of the cell through primary active transport. Stage 1: Sodium ions move using primary transport to outside the cell, creating an electrochemical gradient. Sodium ions want to move back to low concentration, so take a glucose inside with them

Question 8

Examples of Active Transport

Answer 8

Intestines to bring glucose or phosphate into cells

In thyroid gland cells to concentrate iodide. Symport or antiport

Question 9

Symport

Answer 9

Substances transported by primary active transport can pull other substances through cell membrane in same direction

Question 10

Antiport

Answer 10

Substances transported by primary active transport can pull other substances through cell membrane in the opposite direction

Question 11

Membrane Assisted Transport

Answer 11

Uses vesicles to move large, complex, molecules across the membrane
Large particles like proteins, food, fluid droplets, are packaged in vesicles and moved into or out of the cell

Question 12

Types of Membrane Assisted Transport

Answer 12

Exocytosis
Endocytosis (Phagocytosis, Pinocytosis, Receptor Mediated)

Question 13

Exocytosis

Answer 13

Vesicles from inside cell fuse with membrane to secrete its contents from the cell. Ex. gland cells secrete hormones, digestive tract cells secrete mucous and digestive enzymes, plant cells secrete carbohydrates to build cell wall

Question 14

Endocytosis

Answer 14

Moves large particles into the cell. Cell membrane extends out, surrounds the material and pinches off inside making a vesicle. Phagocytosis, pinocytosis or receptor mediated endocytosis

Question 15

Phagocytosis

Answer 15

Moves particles into the cell

Question 16

Pinocytosis

Answer 16

Moves fluid droplets into the cell

Question 17

Receptor Mediated Endocytosis

Answer 17

Molecules to be taken in are bound to the outer cell surface by receptor proteins (needs a signal to occur). Moves proteins into the cell