Nitrifying bacteria participate in the nitrogen cycle mainly by

TLS Online TPP Program

#Question id: 18073

#Unit 11. Evolution and Behavior

During which geological period was there an first definite evidence of land plants and algae dominant of many plants?

TLS Online TPP Program

#Question id: 11152

#Unit 9. Diversity of Life Forms

When sufficient heat is applied, double-stranded DNA denatures into two single-stranded molecules as the heat breaks all of the hydrogen bonds. In an experiment, molecules of single-stranded DNA from species X are separately hybridized with putatively homologous single-stranded DNA molecules from five species (A-E). The hybridized DNAs are then heated, and the temperature at which complete denaturation occurs is recorded. Based on the data below, which species is probably most closely related to species X?

TLS Online TPP Program

#Question id: 9575

#Unit 10. Ecological Principles

The warm counter current known as El niño moves southward along the coast of peru each year around christmastime. When this counter current flows strongly, it displaces the cold peru current offshore and results in:

TLS Online TPP Program

#Question id: 16126

#Unit 13. Methods in Biology

2 You are studying regulation of the yeast enzyme glutamine synthetase (GS), which is encoded by the GLN1 gene. You have isolated two mutants, designated gln2– and gln3–, that give decreased GS activity. Mating of either gln2– or gln3– haploids to wild type produces heterozygous diploids that show normal amounts of GS expression. When you cross either a gln2– or gln3– haploid to a gln1– strain the resulting diploids show normal expression of GS, that could explain the effect of the gln2– and gln3– mutations on the regulation of GLN1.

The GLN1 gene shows a rather complex regulation in response to different amino acids. When either glutamate (glu) or glutamine (gln) is added to the medium, the amount of GS expression diminished and when both glutamate and glutamine are added to the medium GS expression is shut off completely. The effects of different mutants on the response to glu and gln are shown below.

TLS Online TPP Program

#Question id: 29109

#Unit 8. Inheritance Biology

If the probability of being blood types are;

Blood type A = 1/4

Blood type B = 3/4

Blood type O = 1/2

what is the probability of being either blood-type A  or blood-type B ?