Answer to Question 1
Protein turnover and nitrogen balance go hand in hand. In healthy adults, protein synthesis balances with degradation, and protein intake from food balances with nitrogen excretion in the urine, feces, and sweat. When nitrogen intake equals nitrogen output, the person is in nitrogen equilibrium, or zero nitrogen balance. Researchers use nitrogen balance studies to estimate protein requirements.
If the body synthesizes more than it degrades, then protein is added and nitrogen status becomes positive. Nitrogen status is positive in growing infants, children, adolescents, pregnant women, and people recovering from protein deficiency or illness; their nitrogen intake exceeds their nitrogen excretion. They are retaining protein in new tissues as they add blood, bone, skin, and muscle cells to their bodies.
If the body degrades more than it synthesizes, then protein is being lost and nitrogen status becomes negative. Nitrogen status is negative in people who are starving or suffering other severe stresses such as burns, injuries, infections, and fever; their nitrogen excretion exceeds their nitrogen intake. During these times, the body loses nitrogen as it breaks down muscle and other body proteins for energy.
Answer to Question 2
Transcription is the process of messenger RNA being made from a template of DNA.
Translation is the process of messenger RNA directing the sequence of amino acids and synthesis of proteins.
Trans and cis isomers of a peptide bond involving the imino nitrogen of proline
Smiling and talking to infants
Sample Exercise Program for Limited Older Adults (cont.)
Notice the reddish-brown haze caused by nitrogen oxides that is often over many major cities.
Fluid–solute balance in freshwater and marine bony fishes