Video Transcript
Which of the following is not a use
of ATP in cells? (A) Providing the energy required
for substances to be actively transported across cell membranes. (B) Providing cells with the energy
to transport water molecules within the cytoplasm by osmosis. (C) Providing cells with the energy
to build macromolecules from their monomers. (D) Increasing the reactivity of
metabolites by phosphorylation. (E) Providing the energy for
muscles to contract.
We get energy from the food we eat,
and much of this comes from the sugar molecule glucose. This glucose has energy stored in
its chemical bonds. And this energy can be extracted by
a process called cellular respiration to convert glucose into carbon dioxide and
water. During this process, ATP is
produced.
ATP, or adenosine triphosphate,
stores this energy in the form of high-energy phosphate bonds. The three phosphate groups are
linked to one another by high-energy bonds that can be broken to release energy. When energy is needed, the covalent
bond between the second and third phosphate groups of ATP is broken and released for
numerous biological processes in the cell.
Now let’s go through our answer
choices to see which of these processes is not a use of ATP in the cell.
In answer choice (A), you’ll notice
the key phrase “actively transported.” This refers to ATP being used to
power a process, so this is an example of the use of ATP in the cell and is
incorrect.
In answer choice (B), energy is not
required to transport water molecules by osmosis. So this seems like a good example
of something that doesn’t use ATP and is a correct option. But let’s look at the remaining
options before making our final decision.
Answer choice (C) describes forming
bonds between monomers to build macromolecules. This process requires the use of
ATP and is therefore incorrect.
Answer choice (D) involves
phosphorylation, which is the attachment of a phosphate group to a molecule. ATP can be used to transfer one of
its phosphate groups during phosphorylation, so this is a use of ATP and is
incorrect.
In answer choice (E), muscle
contraction does involve the use of ATP, so this is incorrect.
Therefore, the option that
describes a process that doesn’t involve ATP is given by answer choice (B):
providing cells with the energy to transport water molecules within the cytoplasm by
osmosis.
