Membranes & transport - active & bulk transport

Question 1

What are the three processes responsible for the transport of individual molecules or ions across cell membranes?

Answer 1

Diffusion, osmosis, and active transport

Question 2

What is the term for bulk transport into cells?

Answer 2

Endocytosis

Question 3

What is the term for bulk transport out of cells?

Answer 3

Exocytosis

Question 4

Do bulk transport processes require energy?

Answer 4

Yes - they are forms of active transport

Question 5

What are vesicles?

Answer 5

Small spherical sacs of plasma membrane containing substances for transport

Question 6

What is required for the formation of vesicles?

Answer 6

Fluidity of membranes

Question 7

What is the process by which the plasma membrane engulfs material to transport it into cells?

Answer 7

Endocytosis

Question 8

What is phagocytosis?

Answer 8

The bulk intake of solid material by a cell

Question 9

What are cells that specialize in phagocytosis called?

Answer 9

Phagocytes

Question 10

What are phagocytic vacuoles?

Answer 10

Vacuoles formed during phagocytosis

Question 11

What is pinocytosis?

Answer 11

The bulk intake of liquids

Question 12

What is exocytosis?

Answer 12

The process by which materials are removed from, or transported out of, cells

Question 13

What do secretory vesicles do during exocytosis?

Answer 13

They package substances to be released outside the cell

Question 14

What are gated ion channels?

Answer 14

Specialized ion channels that operate in response to chemical or electrical stimuli

Question 15

What type of gated ion channel is a nicotinic acetylcholine receptor?

Answer 15

Neurotransmitter-gated ion channel

Question 16

What ions can pass through nicotinic acetylcholine receptors when activated?

Answer 16

Calcium (Ca2+) or sodium (Na+)

Question 17

What is the function of sodium-potassium pumps?

Answer 17

To generate an electrochemical gradient between the inside and outside of a nerve cell

Question 18

How many sodium ions are moved out of the cell by sodium-potassium pumps?

Answer 18

Three sodium ions

Question 19

How many potassium ions are moved into the cell by sodium-potassium pumps?

Answer 19

Two potassium ions

Question 20

What is the process of pumping sodium and potassium ions called?

Answer 20

Active transport

Question 21

What happens when nerve cells are stimulated?

Answer 21

Sodium ion channels open and sodium ions rush in

Question 22

What is co-transport?

Answer 22

The coupled movement of substances across a cell membrane via a carrier protein

Question 23

What does indirect active transport use to move one molecule against its concentration gradient?

Answer 23

The energy released by the movement of another molecule down its concentration gradient

Question 24

What is a sodium-dependent glucose co-transporter?

Answer 24

A co-transporter protein involved in the absorption of glucose into the blood

Question 25

What is the role of sodium-potassium pumps in glucose absorption and how does glucose move into the cell via the sodium-dependent glucose co-transporter?

Answer 25

1. They actively transport sodium ions into the blood, reducing sodium concentration in the cell 2. Sodium ions move down their concentration gradient into the cell via a cotransporter protein 3. Glucose is drawn into the cell along with sodium ions via the same cotransporter protein (against its concentration gradient) 4. Glucose then moves down its concentration gradient into the blood

Question 26

What is required for glucose to enter the epithelial cell?

Answer 26

Sodium ions must be present

Question 27

Where else does the reabsorption of glucose into the blood take place?

Answer 27

In the kidney