Protein synthesis can be studied in cell-free systems using free amino acids, mRNA and an extract of… Show more Protein synthesis can be studied in cell-free systems using free amino acids, mRNA and an extract of wheat germ, which contains ribosomes and all of the cofactors necessary for translation. (Note that “microsomes” are vesicles of endoplasmic reticulum.) You are using such a system in your lab to study translocation of nascent proteins. For each of the experimental conditions below, indicate whether the protein is completely synthesized, whether the mature protein still has the signal sequence, and whether it is translocated across a membrane. Explain each of your answers. 13 Experimental Conditions Protein completely synthesized? (Yes/No) Signal Sequence cleaved? (Yes/No) Translocated across a membrane? (Yes/No) mRNA codes for cytosolic protein; no SRP present; no SRP receptor present; no microsomes present mRNA codes for secretory protein; no SRP present; no SRP receptor present; no microsomes present mRNA codes for secretory protein; exogenous SRP added; no SRP receptor present; no microsomes present mRNA codes for secretory protein; exogenous SRP added; free (not membrane bound) SRP receptor added; no microsomes present mRNA codes for secretory protein; exogenous SRP added; exogenous SRP receptor added; microsomes added • Show less