active transport

Question 1

active transport definition

Answer 1

movement of ions or molecules across a membrane from a region of its lower concentration to a region of its higher concentration against its concentration gradient, with the use of energy in the form of ATP (adenosine triphosphate)

Question 2

ATP and energy rs

Answer 2

energy is released when ATP is hydrolysed

Question 3

active transport examples:

Answer 3

• roots uptake of ions
• reabsorption in kidney nephron
• absorption int he intestines

Question 4

roots uptake of ions

Answer 4

• when the concentration of ions is many times greater in the root parenchyma cells than in the surrounding soil solution, the uptake of ions from soil solution into rood parenchyma cells is by active transport

Question 5

reabsorption in Kidney Nephron

Answer 5

• the uptake of sodium ions and glucose from the lumen of the proximal convoluted tubule of kidney nephron to the tubule cell is by active transport

Question 6

absorption in the intestines

Answer 6

• glucose and amino acids are absorbed by active transport when there is lower concentration of these digested food substances in the lumen

Question 7

many of the substances that a cell requires occur in low concentratioins in the surroundings outside the plasma membrane
- plants absorb mineral salts and nitrate ions from very dilute solution present in the soil to build their proteins

Question 8

muscle fibers

Answer 8

• absorb calcium ions from surrounding tissue fluid to enable them to contract
• cell bathe in tissue fluid also make use of active transport to remove unwanted substances even when their concentrations are greater outside the cell.