The K-T boundary is a layer present in strata worldwide that marks the boundary between the ________ periods, when ________
a. Proterozoic-Cambrian / oxygen accumulated in the atmosphere
b. Cretaceous-Tertiary / an asteroid impact caused the extinction of the dinosaurs
c. Triassic-Jurassic / dinosaurs appeared
d. Devonian-Carboniferous / land tetrapods appeared
b
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In Siamese cats, enzymes that code for dark fur color are only active in cooler temperatures. Thus, the tips of a
Siamese cat’s ears, feet, and tail are dark but not the warmer regions of its body core. This is an example of ____.
a. Pleiotropy b. environmental effects c. epistasis d. incomplete dominance e. co-dominance
Why is RNA thought to have been the first genetic material?
A) RNA is structurally simpler than DNA. B) RNA has been found on meteorites. C) RNA is capable of self-replication D) Primitive organisms, such as some viruses, have RNA as their genetic material.
Transformation, conjugation, and transduction are forms of vertical gene transfer for prokaryotes
____________________ Indicate whether the statement is true or false.
You are studying the affects of transcription factors on the activation of gene expression. However, when first starting your study, you notice that some of the transcription factors bind further away from the DNA that it is aiming to transcribe. What description best explains this?
A. The transcription factor transcribes small RNAs that then bind to the promoter and activate the gene's expression. B. The assistance of RNA looping moves the transcription factor closer to the promoter. C. DNA looping transports the transcription factor closer to the promoter and initiates gene transcription. D. Signals originate via inducers from the transcription factor to the site of promotion that activate transcription of the gene.