The following diagram shows the process of protein synthesis.
Identify stage X.
[1 mark]
State where in the cell stage X occurs.
[1 mark]
Label molecule A and B in the diagram.
[2 marks]
State one difference in structure between DNA and molecule A identified at part b).
[1 mark]
Molecule B is synthesised from monomers.
Identify the monomers of molecule B.
[1 mark]
The diagram below shows one of the stages in protein synthesis.
Identify the stage of protein synthesis represented by the diagram.
[1 mark]
State one reason for your answer in part i).
[1 mark]
Enzyme Y plays an important role during the stage of protein synthesis identified at part a) i).
Identify enzyme Y.
[1 mark]
State the role of this enzyme during protein synthesis.
[1 mark]
Explain the purpose of creating an mRNA copy of the genetic code on the DNA molecule.
[2 marks]
The following DNA base triplets form part of a gene coding for a polypeptide.
CCC ATA CTT GGA
State the mRNA codons that would be transcribed from this section of the gene.
[2 marks]
The gene mentioned in part a) formed an mRNA molecule that consisted of 180 nucleotides.
Calculate the number of amino acids that will be coded for by this gene. Show your working.
[2 marks]
The table below shows mRNA codons and their corresponding amino acids.
Use this table to state the amino acid sequence of the section of the gene given in part a).
[2 marks]
The diagram below shows the structure of a ribosome.
Identify parts A and B of the ribosome.
[2 marks]
State one substance that a ribosome is composed of.
[1 mark]
Describe the role of a ribosome in the process of protein synthesis.
[2 marks]
The mRNA molecule that is shown in the diagram at part a) carries the genetic code in the form of codons.
Define the term 'codon'.
[1 mark]
One mark is available for clarity of communication throughout this question.
Describe how the structure of a tRNA molecule contributes to the accuracy of the translation.
[3 marks]
Draw a labelled diagram of two nucleotides bonded together within the same DNA strand.
[5 marks]
Outline the three stages of polymerase chain reaction (PCR).
[7 marks]
