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. Next you isolate a mutation, designated MelB–, which gives uninducible melibiase activity. Mapping experiments show that MelB– is linked to Mel1. Using an F' factor that carries the chromosomal region surrounding Mel1, you perform the following genetic tests:

 

Describe the proposal for the type of regulatory functions affected by the MelB– mutation.

#Question id: 9201

#SCPH06 I Botany

Erwin and Scott used an insecticidal fog to knock down insects from the top section of a L. seemannii tree. The researchers identified over 900 species of beetles among the individuals that fell. Erwin also projected that this entire tree from top to bottom is host to about 600 arthropod species that are unique to this tree species and not found on any other tree species. There are approximately 50,000 species of tropical trees. Although it could not be entirely accurate, what would be the best way to estimate the total number of arthropod species?

#Question id: 9201

#SCPH28 | Zoology

Erwin and Scott used an insecticidal fog to knock down insects from the top section of a L. seemannii tree. The researchers identified over 900 species of beetles among the individuals that fell. Erwin also projected that this entire tree from top to bottom is host to about 600 arthropod species that are unique to this tree species and not found on any other tree species. There are approximately 50,000 species of tropical trees. Although it could not be entirely accurate, what would be the best way to estimate the total number of arthropod species?

#Question id: 9202

#SCPH06 I Botany

Which of the following statements regarding extinction is accurate?

#Question id: 9202

#SCPH28 | Zoology

Which of the following statements regarding extinction is accurate?

#Question id: 9203

#SCPH06 I Botany

The human impact that scientists determined has caused the most extinctions on record is ________, and beyond further losses from this impact, the other impact with the largest potential to cause future extinctions is ________.

#Question id: 9203

#SCPH28 | Zoology

The human impact that scientists determined has caused the most extinctions on record is ________, and beyond further losses from this impact, the other impact with the largest potential to cause future extinctions is ________.