One individual, however, expresses only a small number of these molecules—up to six different class I molecules and 12 or more different class II molecules.

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#Id: 5995

#Unit 3. Fundamental Processes

From the speed of replication, it is evident that a mammalian genome could be replicated in 1 hour if all replicons functioned simultaneously. S phase actually lasts for 6 hours in a typical somatic cell, though, which implies that no more than 15% of the replicons are likely to be active at any given moment.

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#Id: 6290

#Unit 3. Fundamental Processes

Consensus Sequences

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#Id: 7217

#Unit 5. Developmental Biology

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: 2554

#Unit 13. Methods in Biology

Fluorescent probes are commonly used to detect rapid biochemical changes in single living cells

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#Id: 9415

#Unit 11. Evolution and Behavior

Lack the form of sex based on meiosis that is familiar from animals and plants, they exchange genes using a variety of mechanisms that together are called “parasexuality”