can someone help me with this genetics question 5. See figure 1 below. E. coli h
ID: 187062 • Letter: C
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can someone help me with this genetics question
5. See figure 1 below. E. coli have been genetically engineered to express the genes encoding the enzymes seen in the figure. Notice each enzyme catalyzes a different reaction, the products of which are colored: lycopene (yc is red), carotene (car is orange) and lutein (lut) is yellow. Production of these compounds causes the bacterial colonies to take on the respective color. According to the central dogma, what are the steps necessary to generate functional protein from a gene? (2pts) What color would the bacterial colony be if (assume all other enzymes except the one provided are functioning normally; explain your answers, 2pts each): a. b. i. Enzyme 2 lacked a Shine Delgano sequence? ii. The gene encoding enzyme 4 did not have a promoter ii. The gene encoding enzyme 1 did not contain an ATG iv. The gene encoding enzyme 2 did not have a stop codon Phy Enzyme 1 LVC Enzyme 2 Car Enzyme 4 Lut Figure 1. Carotenoid biosynthetic pathway (highly simplified)Explanation / Answer
a) According to central dogma of molecular biology the two processes involved in protein synthesis is Transcription and Translation. Transcription is the synthesis of mRNA while Translation is the synthesis of protein from this mRNA by joining amino acids.
b)1) Bacterial colony will be red in colour, because shine dalgarno sequence is the ribosome binding site in bacteria. So, when this ribosomal binding site is absent, ribosome cannot bind and translation doesnot occur. So, enzyme 2 is not produced and therefore the remaining pathway is also stopped and therefore Lyc cannot be converted to Car and hence colony will be red in colour.
11) Promoters are regions of DNA that initiates transcription. It is necessary for the binding of RNA polymerase to synthesize mRNA. Absence of this promoter leads to absence of transcription and therefore no translation and hence no enzyme 4. Therefore car cannot be converted to Lut. Hence colony will be orange in colour.
iii) ATG is translation initiation codon. Absence of ATG results in absence of translation and hence no enzyme 1 and therefore Phy cannot be concverted into Lyc.
IV) Since there is not a stop codon the gene expresses continously therefore enzyme 2 is produced continously. Therefore the entire pathway functions and final gene product is produced and therefore colours yellow.
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