TLS Online TPP Program

#Id: 9297

#Unit 6. System Physiology – Plant

Nitrite reductase

Nitrite (NO2-) is a highly reactive, potentially toxic ion.

Plant cells immediately transport the nitrite into chloroplasts or plastids.

The enzyme nitrite reductase reduces nitrite to ammonium.

Leaf chloroplasts and root plastids contain different forms of nitrite reductase.

Each polypeptide contains two prosthetic groups, an iron-sulfur group and a specialized heme.

NO3-, high sucrose conc, and light induce the transcription of nitrite reductase mRNA.

Asparagine and glutamine repress the induction.

TLS Online TPP Program

#Id: 2621

#Unit 13. Methods in Biology

Examples of restriction endonuclease nomenclature.

TLS Online TPP Program

#Id: 7351

#Unit 11. Evolution and Behavior

Negative assortative mating

People only select mates who are phenotypically different from themselves for selective traits. 

Increases the frequency of heterozygous genotypes (Aa).

TLS Online TPP Program

#Id: 10330

#Unit 4. Cell Communication and Cell Signaling

The idea behind CARs was to engineer the T-cell receptor to trigger activation of ZAP70 in response to the presence of a tumor-specific antigen rather than the MHC peptide complex. 

TLS Online TPP Program

#Id: 9440

#Unit 11. Evolution and Behavior

Polyandrous

In polyandrous mating systems, one female mates with many males.

Honeybees are polyandrous because the queen often mates with multiple males.