Download 7.3 Translation assessment statements

Potential command term assessment statements
Topic 7: Nucleic acids
7.3 Translation
Essential Idea: Information transferred from DNA to mRNA is translated into an amino acid sequence.
Nature of science: Developments in scientific research follow improvements in computing—the use of
computers has enabled scientists to make advances in bioinformatics applications such as locating
genes within genomes and identifying conserved sequences.
State that free ribosomes synthesize proteins for use primarily within the cell.
State that bound ribosomes synthesize proteins primarily for secretion or for use in lysosomes.
State that translation can occur immediately after transcription in prokaryotes due to the absence of a nuclear
membrane.
Explain that each tRNA molecule is recognized by a tRNA activating enzyme that binds a specific amino acid to
the tRNA using ATP for energy. tRNA-activating enzymes illustrate enzyme–substrate specificity and the role of
phosphorylation in energy transfer.
Explain the process of translation:
 Takes place in the 5’ to 3’ direction, the same as replication and translation.
 Initiation of translation involves assembly of the components that carry out the process.
o mRNA is received by the mRNA binding site on the small ribosomal subunit
o tRNA with start codon and corresponding amino acid (AUG start codon with MET=methionine)
o large ribosome subunit joins with three tRNA binding sites
 Synthesis of the polypeptide involves a repeated cycle of events. The names of the tRNA binding sites
are expected as well as their roles.
o A site = Aminoacyl site where the tRNA first joins
o P site = Peptidyl site where the tRNA is shifted to so that a peptide bond forms between amino
acids connected to adjacent tRNA found in both A and P sites at the same time.
o E site = Exit site where the tRNA is shifted to as it is released from its amino acid and mRNA.
 Disassembly of the components follows termination of translation.
Analyse the structure of eukaryotic ribosomes and tRNA molecules with of molecular visualization software.
Identify polysomes in electron micrographs of prokaryotes and eukaryotes.
Explain the four levels of protein structure indicating the significance and main bonding that occurs in the
formation of each level.
 The sequence and number of amino acids in the polypeptide joined together by condensation to form
peptide bonds is the primary structure.
 The secondary structure is the formation of alpha helices and beta pleated sheets stabilized by
hydrogen bonding.
 The tertiary structure is the further folding of the polypeptide stabilized by interactions between R
groups including disulfide bonds, hydrophobic interactions between non-polar amino acids, hydrogen
bonds and ionic bonds between polar amino acids.
 The quaternary structure exists in proteins with more than one polypeptide chain and the possibility of
a prosthetic group as found in hemoglobin with 4 polypeptides and a prosthetic iron (heme) group to
form a conjugated protein.