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TLS Online TPP Program

#Question id: 8717

Molecular clocks are more reliable when ________.

#SCPH05 I Biotechnology
  1. the surrounding pH is close to 7.0
  2. most mutations of highly conserved DNA sequences should have no functional effect
  3. the DNA codes for amino acid sequences whose side groups (or R groups) have a neutral pH
  4. a significant proportion of mutations are not acted upon by natural selection
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TLS Online TPP Program

#Question id: 18904

#SCPH01 Biochemistry

Advantages of using short half-life isotopes
TLS Online TPP Program

#Question id: 760

#SCPH28 | Zoology

Which force can stabilize a DNA double-helix?
TLS Online TPP Program

#Question id: 1623

#SCPH01 Biochemistry

Which of the following is a complement component that is strongly chemotactic for neutrophils?
TLS Online TPP Program

#Question id: 15653

#SCPH01 Biochemistry

You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium. You have isolated a mutation that causes constitutive melibiase activity, which you designate MelA–. P1 phage mapping experiments using a Tn5 insertion linked to Mel1 show that MelA– is not linked to Mel1. Moreover you find that when an amber suppressor is introduced into a MelA– mutant, normal melibiase regulation is restored. Classify the MelA– mutation on the basis of genetic properties,  make a proposal for the type of regulatory functions affected by the MelA– mutation?
TLS Online TPP Program

#Question id: 1662

#SCPH05 I Biotechnology

What is the approximate number of D segment genes in the immunoglobulin heavy chain gene locus?