The phrase one gene-one enzyme is associated with the work of
A. Lederberg.
B. Watson and Crick.
C. Beadle and Tatum.
D. Mendel.
A student argued that aerobic and anaerobic respiration should produce the same amount of energy.
He argued that both processes are essentially the same-only the terminal electron acceptor is different. What's wrong with his argument?
A. Nothing-they SHOULD both produce the same amount of energy. Clearly he knows more than his professors or the writers of his textbook.
B.
Not all electrons are brought into the electron transport chain with the same amounts of potential energy. NADH, for example, enters the electron transport chain further up than FADH2-so it will lead to less proton motive force being generated, and thus less eventual ATP.
C.
Not all electron acceptors are the same-some are closer in terms of electronegativity to their high-energy electron carrier molecules (e.g., NADH) than others. The amount of energy that can eventually be obtained is directly proportional to the degree of difference in electronegativity between the high-energy electron carrier and the eventual terminal electron acceptor. The greater the difference, the greater the energy obtained. Oxygen typically has the highest electron affinity of the terminal electron acceptors utilized.
D. He should believe what his instructors tell him, without question-and they say aerobic respiration is better, so it MUST be so.
Chemolithotrophs near hydrothermal vents support a variety of life forms. Why is this analogous to photosynthetic microbes supporting life forms closer to the surface of the planet?
A.
Because all life forms need some energy source, electron source, and carbon source. Chemolithotrophs fix inorganic carbon and, if consumed by other microbes, could serve as sources for all three requirements for life. This is very similar to the role that photosynthetic microbes play in the top levels of the oceans/lakes.
B. Because chemolithotrophs will also utilize energy from sunlight to form their sugars/get their chemical energy...much like photosynthetic microbes.
C. Because chemolithotrophs also pull in carbon dioxide as their carbon source, just like photosynthetic microbes.
D. Because photosynthetic microbes utilize heat energy from the sun as an energy source. Chemolithotrophs utilize heat energy from hydrothermal vents, but it's still heat energy. This makes both microbes similar.
How would cellulose-degrading bacteria in the rumen (stomachs) of a cow benefit the animal?
A.
The bacteria would produce, secrete, and incorporate organic molecules as they obtain energy from the cellulose in grass and replicate. The cow could then digest both the secreted organic molecules AND the bacteria that synthesized them.
B. The bacteria would produce sugars as they digested the cellulose. These sugars would be given off to the cow as a symbiotic relationship in exchange for the protected location of the stomachs of the cow for the bacteria to grow and replicate in.
C. They wouldn't benefit the animal-they would replicate and cause disease in the animal, leading to its death.
D. They wouldn't benefit the animal-only the bacteria within the animal. This is why cows must have food sources other than grass in order to survive.
A worker in a cheese-making facility argued that whey, a nutrient-rich by-product of the process, should be dumped into a nearby pond to serve as fish food.Is this a good idea or a bad one, and why?
A. It's a great idea Let's feed the fish and help them multiply
B. Bad idea-the fish won't be able to eat the whey, so it will sit there rotting and pollute the waters, making them uninhabitable for the fish.
C. Bad idea-bacteria would thrive on this rich nutrient source and multiply readily. As they multiply, they'll use the oxygen in the water to harvest the energy from the whey, depleting it. As the oxygen depletes below a certain point, the fish (and perhaps other organisms) will not be able to survive.
D. Great idea This will not only feed the fish, but also microbes and other small organisms. It'll enhance the entire food chain and help all of them
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