Which molecule is believed to have preceded the other three during the evolution of life?

A. DNA
B. ATP
C. Proteins
D. RNA


Answer: D

Biology & Microbiology

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In bryophytes:

A. the diploid gametophyte produces haploid spores by meiosis. B. the haploid gametophyte produces diploid spores by fertilization. C. the male gametes require water to reach the female gametes. D. the male gametes are dispersed by wind. E. the sporophyte produces spores by mitosis.

Biology & Microbiology

Mutations in ____________________ cells will be passed on by cell division, but cannot be transmitted to future generations

Fill in the blank(s) with correct word

Biology & Microbiology

Your colleagues are attempting to study the citric acid cycle in the lab. To do so, they have dissolved oxaloacetate in water, then stirred in sufficient quantities of every required enzyme, coenzyme, and oxidizing agent, before adding ADP and acetyl CoA. After waiting a sufficient period of time, they test the solution for ATP and are disappointed to find significantly less ATP than expected. What is the flaw in their experiment?

a. Pyruvate dehydrogenase is not water soluble and is unable to convert pyruvate into acetyl CoA outside mitochondria. b. Stirring the solution will introduce oxygen molecules, which will bond to ADP, preventing further phosphorylation. c. Without subsequent pathways to oxidize NADH and FADH2, no NAD+ and FAD are available to continue the cycle. d. ADP molecules spontaneously dephosphorylate in the presence of acetyl CoA outside of mitochondria.

Biology & Microbiology

Which statement best describes autotrophic organisms?

a. Autotrophs are exemplified by fungi. b. Autotrophs are exemplified by animals. c. Autotrophs cannot carry out cellular respiration. d. Autotrophs depend on heterotrophs for food. e. Autotrophs synthesize complex molecules from CO2, water, and energy.

Biology & Microbiology