module 1: absorption in the small intestines videos

Question 1

when transporting nutrients across the cell membrane, the bigger the nutrients, the bigger the _______

Answer 1

transporter

Question 2

describe the potassium leak channel

Answer 2

due to the high concentration of potassium inside the cell, potassium will flow down its concentration gradient to exit the cell

Question 3

what kind of transport is the K+ leak channel?

Answer 3

passive transport (facilitated diffusion)

Question 4

what is passive transport?

Answer 4

transport that doesn’t require energy

Question 5

what are the types of passive transport and describe them

Answer 5

diffusion- movement of solutes in space
osmosis- movement of water
filtration- as occurs in the kidneys
facilitated diffusion- utilizes help of protein channel

Question 6

why is there a lot of potassium inside the cell and lot of sodium outside the cell?

Answer 6

because of the energy used to set up the ion gradient

Question 7

what is the Na+/K+ ATPase pump?

Answer 7

moves Na+ against its gradient to exit the cell and import K+ into the cell while utilizing ATP using active transport (primary)

Question 8

what is primary active transport? example?

Answer 8

directly uses ATP
Na+/K+ ATPase

Question 9

what are enterocytes

Answer 9

cells of the GI tract

Question 10

what are symports?

Answer 10

transport both molecules in the same direction

Question 11

what is secondary active transport? example

Answer 11

transport that uses energy indirectly, uses a gradient setup using energy
ex. Na+ transport with glucose via symport

Question 12

after Na+ and glucose are absorbed into the intestine (enterocytes), where must they go?

Answer 12

bloodstream

Question 13

how does glucose exit the cell to enter the capillary?

Answer 13

antiport- two molecules moving in the opposite direction
ex. glucose exiting cell and Na+ entering cell down its concentration gradient (secondary active transport)

Question 14

what is a vesicle?

Answer 14

small pocket of cell membrane that surrounding “cargo” (ex. amino acids, etc.)

Question 15

describe how proteins can enter the cell via endocytosis

Answer 15

vesicles when it gets close enough to the membrane, it fuses which creates an opening inside of the vesicle connecting it to the inside of the cell and the protein can enter inside

Question 16

true or false: endocytosis does not utilize energy

Answer 16

false

Question 17

describe how acetylcholine can exit the cell via exocytosis

Answer 17

once vesicle is made with ACH, from the golgi apparatus it floats towards cell membrane and fuses, allowing ACH to exit the cell

Question 18

true or false: exocytosis does not use energy

Answer 18

false

Question 19

why is it important to know how things are transported across the cell membrane?

Answer 19

helps us understand and combat infectious diseases

Question 20

how are amino acids shuttled into cells?

Answer 20

via primary active transport

Question 21

how do sugar monosaccharides enter the cell?

Answer 21

secondary active transport

Question 22

what mechanism do the nucleoside and base use?

Answer 22

primary active transport

Question 23

what is special about fat and its absorption in the small intestine?

Answer 23

• nonpolar tail allows for diffusion across the membrane
• once inside enterocyte, all fatty acids are reorganized into chylomicrons
• chylomicrons are too big to enter capillary

Question 24

where are chylomicrons abosrbed into?

Answer 24

lymphatic capillary where are they are broken down and end up in veins, sending the digested fat into the heart and eventually arteries

Question 25

true or false: the duodenum is where most of the digestion occurs in the GI tract

Answer 25

true

Question 26

where does the most absorption occur in the GI tract?

Answer 26

jejunum