The 3D structure of the complete Escherichia coli ribosome with bound mRNA and tRNAs revealed that the very amino terminus of one protein (L27) does reach into the active site. This finding suggested a role for this protein in catalysis. To test this possibility, the nine amino acids at the L27 amino terminus that were in close proximity to the active site were eliminated by mutation. The following possible outcomes were found to be correct as

A. The resulting cells produced ribosomes with reduced but detectable peptidyl transferase activity

B. Region of the L27 protein contributes to peptidyl transferase activity

C. The mutant ribosomes, didn’t synthesised wildtype levels of cells

D. Vast majority of this increase in peptide bond formation is retained, even without the presence of L27 in the active site

E. The most likely role for L27 is to correctly position one or more of the RNA components of the active site

TLS Online TPP Program

#Question id: 19117

#Unit 8. Inheritance Biology

You are conducting genetic linkage studies of an autosomal recessive disease whose chromosomal location has not been firmly established. You are focused on two SSR markers that may be linked to each other and to the disease. Here are two families in which some individuals are affected:

 

Calculate LOD scores for linkage at θ= 0.02 between the disease and SSR43 in Family 2.

TLS Online TPP Program

#Question id: 19118

#Unit 8. Inheritance Biology

You are conducting genetic linkage studies of an autosomal recessive disease whose chromosomal location has not been firmly established. You are focused on two SSR markers that may be linked to each other and to the disease. Here are two families in which some individuals are affected:

                               

Calculate LOD scores for linkage at θ= 0.02 between SSR42 and SSR43 in Family 1.

TLS Online TPP Program

#Question id: 19119

#Unit 8. Inheritance Biology

You are conducting genetic linkage studies of an autosomal recessive disease whose chromosomal location has not been firmly established. You are focused on two SSR markers that may be linked to each other and to the disease. Here are two families in which some individuals are affected:

                     

Calculate LOD scores for linkage at θ= 0.02 between SSR42 and SSR43 in Family 2.

TLS Online TPP Program

#Question id: 19120

#Unit 8. Inheritance Biology

Trisomy 18 is one of the most common trisomies observed in human populations. You prepare DNA samples from two unrelated infants, both with trisomy 18, and from their parents. You then type the infants and their parents for four SSRs distributed along chromosome 18:

 

                                      

In which parent did nondisjunction occur in Family 1?

TLS Online TPP Program

#Question id: 19121

#Unit 8. Inheritance Biology

Trisomy 18 is one of the most common trisomies observed in human populations. You prepare DNA samples from two unrelated infants, both with trisomy 18, and from their parents. You then type the infants and their parents for four SSRs distributed along chromosome 18:

 

                                              

In which parent did nondisjunction occur in Family 2?

TLS Online TPP Program

#Question id: 19122

#Unit 8. Inheritance Biology

Trisomy 18 is one of the most common trisomies observed in human populations. You prepare DNA samples from two unrelated infants, both with trisomy 18, and from their parents. You then type the infants and their parents for four SSRs distributed along chromosome 18:

     

             

                                         

In which division of meiosis did nondisjunction occur in Family 2?