Video Transcript
For the following statements about
blood glucose, state the key scientific terms being described. What hormone is released in
response to a decrease in blood sugar? What is the name of the
polysaccharide storage molecule that sugar is converted to in the liver? What do we call the main sugar that
is obtained from carbohydrates to be broken down in cellular respiration?
This question is asking us to
recall certain key terms about blood glucose and its control in the body. The questions specifically ask us
about a hormone and a polysaccharide and the main sugar used in cellular
respiration. So in order to answer this
question, we’ll first review the steps of blood glucose control that these terms
will be describing.
Glucose control in the body seeks
to maintain a constant normal concentration of glucose in the bloodstream. When our blood glucose
concentration increases above normal, a hormone called insulin is released into the
bloodstream. Hormones are chemical messengers,
and insulin carries the message to the cells of the body, telling them to increase
their storage of glucose and increase their usage of glucose, which will remove
glucose from the blood, returning the blood glucose concentration to normal.
One of the main uses of glucose in
the body is the process of cellular respiration. Glucose can be converted into fat
for storage in our fat cells, or it can be stored as glycogen in the cells of our
liver and our muscles. And when our blood glucose
concentrations fall below normal, a hormone called glucagon is released. Glucagon carries the opposite
message to our cells, telling them to release glucose from storage and to decrease
their usage. Within the liver, glycogen is
converted back into glucose and released into the bloodstream, which increases the
concentration of glucose in the blood, returning our blood glucose concentration to
normal.
Now we’re ready to return to our
question. The hormone that’s released in
response to a decrease in blood sugar is glucagon. Some students find it helpful to
remember the phrase that when the glucose is gone, we release glucagon.
The sugar storage molecule that we
find in the liver is glycogen. Glycogen is a complex carbohydrate
that’s made up of many glucose molecules joined together. Another clue in this question is
the word polysaccharide. Since poly- means many and
saccharide is another word for sugar, we know that glycogen, which contains many
glucose sugars, is the correct response.
And finally, the main sugar that’s
broken down in cellular respiration is glucose. During cellular respiration,
glucose is broken down, releasing energy that’s transferred to be used in other life
processes, which is why glucose is exactly what we mean when we’re talking about
blood sugar.
