TLS Online TPP Program

#Question id: 1324


What are the two major proteins that comprise tight junctions?

#Unit 4. Cell Communication and Cell Signaling
  1. Claudins and adherins.

  2. Occludins and connexins.

  3. Claudins and occludins.

  4. Claudins and protocadherins.

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TLS Online TPP Program

#Question id: 11385

#Unit 10. Ecological Principles

Which of the following biomes is correctly paired with the description of its climate?

A) savanna-low temperature, precipitation uniform during the year

B) tundra-long summers, mild winters

C) Taiga-relatively short growing season, Low precipitation

D) temperate grasslands-relatively warm winters, most rainfall in summer

E) tropical forests-nearly constant day length and temperature

TLS Online TPP Program

#Question id: 11392

#Unit 9. Diversity of Life Forms

Modes of obtaining nutrients, used by at least some bacteria, include all of the following except

TLS Online TPP Program

#Question id: 11393

#Unit 9. Diversity of Life Forms

Given that the enzymes that catalyze nitrogen fixation are inhibited by oxygen, what are two ʺstrategiesʺ that nitrogen-fixing prokaryotes might use to protect these enzymes from oxygen?

1.  couple them with photosystem II (the photosystem that splits water molecules)

2.  package them in membranes that are impermeable to all gases

3.  be obligate anaerobes

4.  be strict aerobes

5.  package these enzymes in specialized cells or compartments that inhibit oxygen entry

TLS Online TPP Program

#Question id: 11394

#Unit 9. Diversity of Life Forms

Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods would not generally inhibit bacterial growth?

TLS Online TPP Program

#Question id: 11395

#Unit 9. Diversity of Life Forms

Mitochondria are thought to be the descendants of certain alpha -proteobacteria. They are, however, no longer able to lead independent lives because most

genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

TLS Online TPP Program

#Question id: 11396

#Unit 9. Diversity of Life Forms

Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?