Question 7

Molecules move from high concentration to low concentration without using energy.

Molecules typically move from areas of high concentration to areas of low concentration through a process known as diffusion, which does not require energy.

A) They can travel through all cell membranes

This statement is incorrect because not all molecules can pass through cell membranes. The permeability of a membrane depends on the size, charge, and polarity of the molecules, as well as the specific properties of the membrane itself.

B) They move from low concentration to high concentration without using energy

This option is incorrect because molecules do not naturally move from low to high concentration without the input of energy. Such movement requires active transport mechanisms, which utilize energy to move molecules against their concentration gradient.

C) They move from high concentration to low concentration without using energy

This statement is correct and reflects the fundamental principle of diffusion. Molecules will spontaneously move down their concentration gradient until equilibrium is reached, and this process does not require energy input.

D) They cannot move

This statement is false as it contradicts the basic principles of molecular motion. Molecules are always in motion due to thermal energy, and they can naturally diffuse within their environment unless otherwise restricted.

Conclusion

The correct answer is C, as it accurately describes the natural tendency of molecules to move from areas of high concentration to low concentration without the need for energy. Options A, B, and D are incorrect because they misrepresent the behavior of molecules in relation to cell membranes and the principles of concentration gradients.