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TLS Online TPP Program

#Question id: 2228

Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this fact most probably mean?

#Unit 2. Cellular Organization

  1. Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.

  2. The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism.

  3. Cells of each domain evolved proton pumps independently when oceans became more acidic.

  4. Proton pumps are necessary to all cell membranes.

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TLS Online TPP Program

#Question id: 10739

#Unit 10. Ecological Principles

 A rat that is "maze-dull"
TLS Online TPP Program

#Question id: 947

#Unit 1. Molecules and their Interaction Relevant to Biology

 Which is not part of the synthesis reactions for histidine?
TLS Online TPP Program

#Question id: 14831

#Unit 2. Cellular Organization

A spirochete is a member of the phylum Spirochaetota, which contains distinctive diderm gram-negative bacteria, most of which have long, helically coiled cells. Movement of spirochetes occurs by means of structures called 
TLS Online TPP Program

#Question id: 11090

#Unit 7. System Physiology – Animal

An aviator is flying at 30,000 ft where the barometric pressure is 226 mm Hg. He is breathing 100% oxygen, his alveolar PCO2 is 40 mm Hg, and his alveolar water vapor pressure is 47 mm Hg. What is the alveolar PO2 of the aviator (in mm Hg)? (Assume that the respiratory quotient is equal to 1.)
TLS Online TPP Program

#Question id: 3891

#Unit 3. Fundamental Processes

Protein amino acid side chains can hydrogen bond in the major groove of DNA, and discriminate between each of the four possible base pairs.  In which one of the following groups of amino acids can all three members potentially be used in such DNA-protein recognition?