Answer: it’s distant objects shift in frequency toward red on the electromagnetic spectrum, which tells us objects are moving away from us!
Explanation: This is correct because I got this one right on my quiz and I took notes on it!
Answer:
Cells from the cheek are a type of epithelial cell, similar to skin. ... They can be seen faintly even at 40x (scanning power), but the most dramatic images are at 400x where the nucleus is clearly visible as a dark spot in the center of the cell.
Explanation:
Answer:
Western blot should be performed
Explanation:
Generally ELISA test is sensitive to elevated antibodies levels in the blood. Because HIV infection is characterise with increases in antibodies levels(HIV-antibodies levels)of the body, it is usually the first screening test for HIV,however it is also sensitive to elevated antibody from any other infection apart from HIV. Therefore for confirmation, the procedure is to run a second ELISA test, to determine if the antibody rise was due to HIV or not. If the second test turns positive, then Western blot can be applied.
The Western blot through secondary and primary antibodies binding , separates the investigating antibodies, and identity the specif HIV antibodies present to give a positive HIV-antibody, confirming ELISA positive test.
Thus for confirmation of HIV specific antibodies of the blood; ELISA test followed by Western blot is ideal
Organelle,
Cells,
Tissues,
Organs,
Organ System,
Organisms,
Populations,
Communities,
Ecosystems,
And Biosphere
Answer: A
Explanation:The Trp operon is responsible for synthesis of the amino acid trytophan when it is not available in the cellular environment.
When the tryptophan is plentiful, a repressor protein binds to two molecules of tryptophan.
Thiss repressor-tryptophan complex binds to the trp operator. This binding prevents the binding of RNA polymerase, so the operon is not transcribed, and no new trptophan is produce.
On the other hand, when tryptophan levels are reduced, the inactive repressor will not bind the tryptophan operator so the operon is transcribed.
Regulation of the trp operon is determined by the concentration of tryptophan; when adequate tryptophan is present in the growth medium, there is no need for tryptophan biosynthesis.
Transcription is turned off when a high concentration of tryptophan is present, and is turned on when tryptophan is absent. The regulatory signal is the concentration of tryptophan itself.
Therefore in the absence of tryptophan, the inactive repressor cannot bind trpO, so operon gene transcription occurs.
