Unit 4 ExamChapters 7,8,11,1260 questions90 points50 minutes

The rise of an oxygen-rich atmosphere had profound impacts on life. Which of the following is a major benefit of an oxygen atmosphere for complex life forms?

A scientist is studying biochemical pathways in a bacterium, those that break down complex molecules to release energy, and those that use that energy to build new, complex molecules. What two major categories of metabolic processes are they studying?

When ethanol (alcohol) is consumed, the body detoxifies it by first breaking it down to acetaldehyde, a toxic carcinogen, and then converting the acetaldehyde into acetate, which is further broken down and eliminated. Acetaldehyde binds to the active site of the enzyme acetaldehyde dehydrogenase (ALDH2 in humans). The medication disulfiram binds to a different site on the enzyme ALDH2, changing its shape and preventing acetaldehyde from binding. This causes a buildup of acetaldehyde at even low levels of alcohol consumption, leading rapidly to symptoms of a hangover including flushing, headache, nausea, sweating, and vomiting, among others. By producing such an acute sensitivity to drinking alcohol, disulfiram has been used as a medication to treat chronic alcoholism. Given that it binds to a different site than acetaldehyde on ALDH2, disulfiram is an example of what kind of inhibitor?

The central metabolic pathways of aerobic respiration are split between the cytoplasm and the mitochondria in eukaryotic cells. Glycolysis takes place in the cytoplasm, while the citric acid cycle and the electron transport chain occur in the mitochondria. How does the endosymbiotic theory explain this spatial separation?

Carotenoids are accessory pigments found in plant leaves that can absorb light energy in the blue-green range. What is the importance of these pigments?

In the process of blood clotting, thrombin, a serine protease, converts the soluble protein fibrinogen into insoluble fibrin strands, which form the clot. Which of the following correctly identifies the enzyme, its substrate, and the product of this reaction?

A plant leaf appears green because the chlorophyll pigments within its chloroplasts reflect green light. What does this indicate about the role of chlorophyll in photosynthesis?

The consumption of milk caused a direct mutation in the lactase gene, which was then passed on to offspring.

Human blood has a pH range of 7.35 to 7.45. This pH is maintained very strictly because a significant deviation can be fatal. How is the pH of blood best classified?