sodium ions

Question 1

Na+ is required for the transport of ……………… across /……

Answer 1

Na+ is required for the transport of glucose and amino acids across cell-surface membranes (e.g. in the small intestine)

Question 2

Glucose and amino acid molecules can only enter cells (through carrier proteins) alongside

This process is known as ?

Answer 2

Na+

co-transport

Question 3

First, Na+ is actively transported out of the …………………..that line the villi

Answer 3

epithelial cells

Question 4

The Na+ concentration inside the epithelial cells is now ……. than the Na+ concentration in the …………………. of the small intestine

Answer 4

lower

lumen

Question 5

Na+ now re-enters the cells (moving ……………the concentration gradient) through co-transport proteins on the surface membrane of the epithelial cells, allowing glucose and amino acids to enter ………………

Answer 5

down

at the same time

Question 6

Na+ is also required for the transmission of

Answer 6

transmission of nerve impulses