In step 7 of the citric acid cycle, fumarase catalyzes the addition of a water molecule to a carbon–carbon double bond (see Panel 13¬–2). Can this be considered an oxidation reaction? Explain your answer
What will be an ideal response?
Yes. In the citric acid cycle, the overall process oxidizes carbon molecules to produce carbon dioxide. Although, fumarase does not directly remove electrons from its substrate (as do the enzymes that catalyze steps 3, 4, 6, and 8), the addition of water across the double bond in fumarate leaves one of its carbon atoms in a more oxidized state. This is because one of the carbons becomes bonded to an oxygen atom. In this arrangement, the carbon atom shares its electrons unequally across the new bond (see Figure 3–11).
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Answer the following statements true (T) or false (F)
1. RNA polymerase can bind to the promoter region of the DNA even when the lac repressor is bound to the operator site. 2. Both eukaryotes and prokaryotes require a promoter region for gene transcription. 3. A cis-effect is a form of gene regulation that can occur between two DNA segments that are not physically adjacent. 4. Eukaryotic genes are almost always organized in groups, similar to operons in prokaryotes.
A cell placed in a(n) ____________________ solution will swell
Fill in the blank(s) with the appropriate word(s).
You are classifying an organism and trying to determine to which domain it belongs. The organism is unicellular and was isolated from a very unusual environment. This organism probably belongs in which domain?
A) Eukarya B) Archaea C) Bacteria D) None of the domains above is correct.
The largest threat to global biodiversity, as identified by the International Union for Conservation of Nature (IUCN), is
A) habitat destruction. B) global warming. C) lack of farmland. D) introduced species. E) phosphate pollution.