Highest rates of substitutions in regions of the gene that have the least effect on function, such as the third position of a codon, flanking regions, and introns.

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#Id: 1884

#Unit 4. Cell Communication and Cell Signaling

T cells initiate the adaptive immune response by interacting MHC on antigen-presenting cells that have been exposed to pathogens.

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#Id: 6980

#Unit 8. Inheritance Biology

Polyploidy 

Some organisms possess more than two sets of chromosomes—they are polyploid.  Allopolyploidy Condition in which the sets of chromosomes of a polyploid individual are derived from two or more species.  Autopolyploidy Condition in which all the sets of chromosomes of a polyploid individual are derived from a single species.

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#Id: 5753

#Unit 10. Ecological Principles

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#Id: 7075

#Unit 3. Fundamental Processes

isoleucyl-tRNA synthetase has a nearby editing pocket (a deep cleft in the enzyme) that allows it to proofread the product of the adenylylation reaction. AMP-valine (as well as adenylylates of other small amino acids, such as alanine) can fit into this editing pocket, where it is hydrolyzed and released as free valine and AMP. In contrast, AMP-isoleucine is too large to enter the editing pocket and is therefore not subject to hydrolysis. As a consequence, isoleucyl-tRNA synthetase discriminates against valine twice: in the initial binding and adenylylation of the amino acid (discriminating by a factor of 100), and then in the editing of the adenylylated amino acid (again discriminating by a factor of 100), for an

overall selectivity of 10,000-fold (i.e., an error rate of 0.01%).

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#Id: 1541

#Unit 2. Cellular Organization

Kinesin-13 (End-Binding Proteins)

• Bind and curve the end of the tubulin protofilaments into the GDP-β-tubulin conformation

• Facilitate the removal of terminal tubulin dimers 

• Greatly enhancing the frequency of catastrophes