If you took a sample of magnetotactic bacteria from the northern hemisphere to t
ID: 1416631 • Letter: I
Question
If you took a sample of magnetotactic bacteria from the northern hemisphere to the southern hemisphere, would you expect them to survive?
If you took a sample of magnetotactic bacteria from the northern hemisphere to the southern hemisphere, would you expect them to survive?
Both in the northern and in the southern hemispheres, the earth's field points down. So the bacteria are likely to survive. In the northern hemisphere, the vertical component of the earth's field points up, and in the southern hemisphere, it points down. So the bacteria are not likely to survive. In the northern hemisphere, the vertical component of the earth's field points down, and in the southern hemisphere, it points up. So the bacteria are not likely to survive. Both in the northern and in the southern hemispheres, the earth's field points up. So the bacteria are likely to survive.Explanation / Answer
Note that the geometric north pole of the earth is its magnetic south pole and the magnetic north pole of the earth is its geometric south pole.
So, By saying the northern hemisphere we mean the geometric north pole which is the magnetic south pole. And we know that the magnetic field lines go INTO the south pole of a bar magnet. So, magnetic field lines and hence the magnetic field points down in the Northern hemisphere.
And similarly, the Southern hemisphere of the earth is magnetic north pole and since we know that the magnetic field lines go OUT OF a bar magnet, we conclude that the magnetic field lines and hence the magnetic field points upwards in the Southern hemisphere.
Having said this, we know that Magnetotactic bacteria are a polyphyletic group of bacteria that orient along the magnetic field lines of Earth's magnetic field. To perform this task, these bacteria have organelles called magnetosomes that contain magnetic crystals. The alignment is believed to aid these organisms in reaching regions of optimal oxygen concentration. So, when you take the sample to the southern hemisphere, they follow the magnetic field lines and move upwards, which is not we want. So, they cannot survive in the Southern hemisphere.
So, option C is correct.