Energy spent climbing a flight of stairs I would like to know whether there is any difference in the energy consumed in climbing a flight of stairs, if the steps are taken one at a time vs taking them 2 at a time
 A: It shouldn't make any difference. The only force you're acting against is gravity if you don't take friction into consideration, and gravity is a conservative force, which means that the work it does (and hence the work that you do in this situation) doesn't depend on the path you take. So, the amount of energy you consume wouldn't depend on taking the steps one or two at a time. 
Approximately, the energy you consume would be $mgh$, where $m$ is your mass, $g$ is the gravitational field near the Earth's surface, and $h$ is the total height you climb. 
This is all ideal, of course; it assumes you are a point particle, for example. There is no accounting for the discomfort your leg would feel upon having to stretch and contract an additional amount, so in a real-life situation, there would probably be a deviation from what I stated above, and maybe it would require extra energy for you to climb two steps at a time. From a simplistic point of view, this is because since your leg has to reach up farther and contract more when it pulls you up (when you're climbing two steps at a time), there will be more energy lost due to friction between your joints and the difference in how your muscles contract. 
From a different point of view, climbing two steps at a time can probably get you upstairs faster, and you will therefore spend less time climbing the stairs. If you spend less time climbing, you will spend less energy on things like maintaining body temperature, and breathing (since you are climbing for less time). So while climbing the stairs, you may spend less energy on those processes as a result of going up two steps at a time.
The human body is a pretty complicated system, and as you can see from the above speculations, it's not easy to see how exactly its processes would change when you change the way you climb stairs. However, you can approximately say that you spend the same amount of energy with both paths (let's pretend we're particles, it makes everything more simple :D). 
A: $E=m(g-a)h$ is the energy spent in a Climb, where $a$ is your own acceleration. Consider yourself a forklift/lift trying to lift yourself at every step. You will notice it's harder to climb a steeper staircase than one that is bent closer to the ground (creates a smaller angle with horizontal axis). With a smaller angle the height is greatly lessened at $L\sin\theta$,  ($L$ being length of ladder), as you only calculate the vertical distance in $h$. 
Another way to conserve energy will be faster movement or increasing a, unfortunately as an Engine, our body will feel feeble/tiresome after this maneuver.    
