This bacterium derives nutrition by digesting human intestinal contents (in other words, food). humans lacking this bacterium have no measurable reproductive advantage or disadvantage relative to humans who harbor this bacterium. consequently, the bacterium can be properly described as which of the following? 1. symbiont 2. endotoxin 3. mutualist 4. commensal
1 and 2
4 only
2 and 3
2 and 4
1 and 4

Protein and polypeptide sequences can be determined by first partially hydrolyzing the protein or polypeptide followed by amino acid sequencing of the fragment pieces using the chemical degradation process known as edman degradation. determine the sequence of the initial (18-amino acid) polypeptide that produces the following five partial sequences after hydrolysis and edman degradation.

According to the rna world hypothesis, rna acted as the genetic material and catalyzed reactions in ancient cells. what conclusion can you draw from this?               a.  this implies that dna and proteins aren't essential in cells today.    b.  this implies that rna can catalyze any chemical reaction that enzymes catalyze.    c.  this implies that if a cell has a problem with its dna, its rna can compensate for the damaged dna.    d.  this implies that dna and proteins evolved after rna.

Enzymes are both ph and temperature specific. seen here are the reaction rates of three common digestive enzymes. based on the data, which enzyme's optimum activity occurs in a basic environment while another's is very acidic?