Explain what happens from the time of an interrupt request, (i.e., IRQ line is asserted), through the start of executing an interrupt service routine, and then how control returns to the interrupted program. Assume that the interrupt request does not occur at the same time as any other interrupt request. (Note: There are many steps involved, so take your time and be specific.) in ARM Assembly. Solution Answer From the time of an interrupt request through the start of executing an interrupt service routine below steps occur:.

1. Far from being "primitive", bacteria have evolved until they are ideally suited for the
environment in which they live. For each of the following bacteria, describe and explain the
particular evolutionary adaptation(s) that allow(s) them to colonize the environment in which
they live.
A. Thermophiles - How have their membranes (lipids and proteins) evolved to survive in their
preferred environment?
B. Microaerophiles - How have they evolved to locate their preferred environment in soil?
C. Halophiles - How have they adapted (proteins and cytoplasmic contents) for their preferred
environment?
D. Motile bacteria - How have they evolved to be able to locate and uptake nutrients from
nutrient-poor environments?
Solution
A.Thermophiles- they are survive in preferred environment due to its unique structure of polar
lipid Sn-glycerol-1-Phosphate backbone,ether linkage and isoprenoid hydrocarbon chains which
make them stable in extremely hot condition. Enzymes having sulphur also provide stability and
can work in high temperature.
B. Microaerophiles- The respiratory chain enzyme of microaerophiles bacteria should play a
major role in their suviving behavior in soil having low oxygen. The gene encoding NADH
quinone reductase (NDH-1) , the ubiquinol, cytochome C oxidoreductase ( bc 1 Complex ) the
thermak oxidases causes these bacteria to preferred eenvironment in soil.
C. Halophiles- they adapt their preferred environment by having 2 characteristics-
1. It exclude salt from their cytoplasm to avoid protein aggregation.
2. Selective influx of potassium ions in to the cytoplasm.
D. Motile bacteria - They consume nutrients by chemotactic response towards food. The sense
stimulant gradient which causes clustering of signals and then they swim by flagella and get their
food in low nutrient condition.