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TLS Online TPP Program

#Question id: 567

Penicillin and related drugs inhibit the enzyme; this enzyme is produced by 

#I Life Science/ Life Sciences Group – I-V

  1. B-lacamase; bacteria

  2. transpeptidase; human cells

  3. transpeptidase; bacteria

  4. lysozyme; human cells

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TLS Online TPP Program

#Question id: 4955

#SCPH28 | Zoology

If relatively small carbonaceous chondrites from space were a significant source of Earthʹs original amino acids, then which two of these would have been most important in permitting their organic materials to survive impact with Earth?

I. Carbonaceous chondrites must contain no D-amino acids.

II. Earthʹs early atmosphere must have had little free oxygen.

III. The chondrites must have arrived on Earth before 4.2 billion years ago.

IV. Earthʹs early atmosphere must have been dense enough to dramatically slow the chondrites before they impacted.

V. The chondrites must have impacted land, rather than a large body of water.
TLS Online TPP Program

#Question id: 361

#SCPH05 I Biotechnology

Calculate the percentage of histidine that has its imidazole side chain protonated at pH 7.3. The pKa values for histidine are pK1 = 1.8, pK2 (imidazole) = 6.0, and pK3 = 9.2.
TLS Online TPP Program

#Question id: 2283

#SCPH01 Biochemistry

Most cells are very small. A typical eukaryotic cell, both plant and animal, will occur in which of the following size ranges?
TLS Online TPP Program

#Question id: 18717

#SCPH01 Biochemistry

A common method to monitor synthesis of new DNA is 
TLS Online TPP Program

#Question id: 15617

#SCPH06 I Botany

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition you have a wild type (Lac+) strain carrying a Tn5 insertion known to be near several Lac genes on the E. coli chromosome. You grow P1 phage on this strain and use the resulting phage lysate to infect the lac1– strain, selecting for kanamycin resistance (Kanr). Among 100 Kanr transductants, you find that 82 are Lac– and 18 are Lac+. Express the distance between Tn5 and the lac1– mutation as a cotransduction frequency;