Video Transcript
Glucose can be stored as the
polysaccharide starch in plant cells. What polysaccharide acts as the
primary unit of glucose storage in animal cells? (A) Cellulose, (B) chitin, (C)
glycogen, (D) 𝛼-glucose, or (E) glucagon.
This question is asking us to
recall what molecule functions as glucose storage in animal cells. Recall that glucose is the molecule
that cells primarily use to release cellular energy. That energy is transferred to a
molecule called ATP in a process called cellular respiration. ATP is then used to power almost
all life processes. Since glucose is so important to
the function of cells, it is important for organisms to have a way to store
glucose. This way, they can release energy
whenever it is needed. In plant cells, glucose is stored
as starch. The term polysaccharide means many
sugars. Many molecules of glucose, a type
of sugar, join together to make starch. Our answer choice will also be a
polysaccharide.
Let’s look at our answer choices
and see if we can use what we know to eliminate the incorrect items. Cellulose is a polysaccharide, but
it is not a form of energy storage. Cellulose makes up the cell walls
of plant cells. Chitin is also a polysaccharide,
but it is not a form of energy storage. Chitin makes up the cell walls of
fungus cells. It also provides structure to the
exoskeletons of many arthropods. 𝛼-glucose is not a
polysaccharide. It is an isomer of glucose, meaning
that it is one version of a glucose molecule. Glucagon is not a
polysaccharide. It is a hormone that helps to
regulate glucose concentration in the blood of humans. That leaves us with glycogen. Glycogen is the polysaccharide that
acts as the primary unit of glucose storage in animal cells.
