Biology 9700 · AS & A Level · Transport mechanisms
Transport mechanisms — practice question
The enzyme glutamyl-tRNA reductase (GluTR) is found in many bacteria and is needed to produce a compound that is vital for their survival. GluTR acts on the substrate glutamyl-tRNA, which consists of the amino acid glutamic acid attached to a tRNA. Fig. 3.1 displays the structure of glutamyl-tRNA and another compound, glutamycin.
(a)[4]
Explain the way in which glutamycin can inhibit the enzyme GluTR.
(b)[3]
The bacteria absorb glutamic acid by active transport. Describe the process of active transport.
(c(i))[1]
In leguminous plants, glutamic acid is also needed for the development of root nodules that contain the bacterium Rhizobium. Name the stage in the nitrogen cycle that is carried out by Rhizobium.
(c(ii))[2]
Suggest the advantages of Rhizobium living in the root nodules of leguminous plants.
(c(iii))[2]
Explain the role of Rhizobium in helping leguminous plants grow.
Worked solution & mark scheme
This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Glutamycin has a shape similar to the substrate / glutamyl-tRNA” …