TLS Online TPP Program

#Question id: 12187


How cells know whether sister kinetochores are properly attached to the mitotic spindle?

#Unit 2. Cellular Organization
  1. When sister chromatids are correctly attached to microtubules, their kinetochores are under tension. Mitotic spindle attached to the kinetochores pull at them, and the cohesin molecules that hold the sister chromatids together withstand these forces, creating tension at kinetochores.
  2. When sister chromatids are correctly attached to microtubules, their kinetochores are not under tension. One kinetochore attaches to microtubules emanating from two opposite spindle poles.
  3. When sister chromatids are correctly attached to microtubules, their kinetochores are not under tension. Both sister kinetochores attach to microtubules emanating from the same spindle pole.
  4. When sister chromatids are correctly attached to microtubules, their kinetochores are not under tension. Only one of the two sister kinetochores attaches to microtubules.
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TLS Online TPP Program

#Question id: 5003

#Unit 11. Evolution and Behavior

Fruit fly eyes are of the compound type, structurally very different from the camera-type eyes of mammals. Even the camera-type eyes of mollusks, such as octopi, are structurally quite different from those of mammals. Yet, fruit flies, octopi, and mammals possess very similar versions of Pax-6. The fact that the same gene helps produce very different types of eyes is most likely due to

TLS Online TPP Program

#Question id: 5004

#Unit 11. Evolution and Behavior

Pax-6 usually causes the production of a type of light-receptor pigments. In vertebrate eyes, though, a different gene (the rh gene family) is responsible for the light-receptor pigments of the retina. The rh gene, like Pax-6, is ancient. In the marine ragworm, for example, the rh gene causes production of c-opsin, which helps regulate the wormʹs biological clock. Which of these most likely accounts for vertebrate vision?

TLS Online TPP Program

#Question id: 5005

#Unit 11. Evolution and Behavior

Fossilized stromatolites

TLS Online TPP Program

#Question id: 5006

#Unit 11. Evolution and Behavior

The oxygen revolution changed Earthʹs environment dramatically. Which of the following adaptations took advantage of the presence of free oxygen in the oceans and atmosphere?

TLS Online TPP Program

#Question id: 5007

#Unit 11. Evolution and Behavior

Select the factor most likely to have caused the animals and plants of India to differ greatly from species in nearby Southeast Asia.

TLS Online TPP Program

#Question id: 5008

#Unit 11. Evolution and Behavior

Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception.