Which of these systems give the best mode for turning trp operon off?

#Question id: 59

#Unit 1. Molecules and their Interaction Relevant to Biology

Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium?

#Question id: 60

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following is true for the reaction?

3H₂ + N₂   2NH₃

#Question id: 61

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following correctly describes chemical equilibrium?

#Question id: 62

#Unit 1. Molecules and their Interaction Relevant to Biology

We can represent atoms by listing the number of protons, neutrons, and electrons—for example, 2p+, 2n0, 2e- for helium. Which of the following represents the 18O isotope of oxygen?

#Question id: 63

#Unit 1. Molecules and their Interaction Relevant to Biology

The two molecules shown in the figures are best described as ________.

#Question id: 64

#Unit 1. Molecules and their Interaction Relevant to Biology

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? Testosterone and estradiol ________.