Which characteristic is NOT true for bacteria and viruses?

The characteristic that is not true for bacteria and viruses is that they are too large to cross an intact dialysis membrane. This is correct because most viruses and certain bacteria are actually small enough to pass through these membranes, which are designed to filter out larger particles such as cells and cellular debris.

In the context of dialysis, the membranes used (like hemodialysis membranes) have pore sizes that can allow small microorganisms such as viruses and bacteria to pass through, creating a potential risk for infection if not properly managed.

The other characteristics, like the ability of bacteria and viruses to grow rapidly and produce endotoxins, are generally true. Bacteria, in particular, can multiply quickly under favorable conditions, and some species produce endotoxins that can cause adverse reactions in hosts. Hence, identifying that they are capable of crossing intact dialysis membranes highlights a critical aspect of infection control and risk management in dialysis treatment.