Question

Which substance, needed for protein synthesis, is carried into a leaf from the stem?
A.carbon dioxide
B.nitrate
C.oxygen
D>starch

Answer 1

Answer:

carbon dioxide

this is the correct answer

Answer 2

The substance, needed for protein synthesis, which is carried into a leaf from the stem is B.nitrate.

• Proteins are large molecular mass molecules which are made up of amino acids, there are 20 essential amino acids.
• Amino acids of protein are made up of amino group (NH2) and COOH group and exist in zwitterionic form.
• The nitrogen of NH2 comes from nitrate (NO2-) ion which is transported from stem to leaf.
• The plant can utilise nitrogen in nitrate and nitrate form so, nitrogen undergoes nitrogen fixation to form ammonia and then it is later converted to nitrites and nitrate.