Question

due:nov 12 activity: what is \energy\ in living systems? investigating chemical energy
background
energy within the cell exists in the form of chemical energy. a source of this chemical energy is a compound called adenosine triphosphate (atp). atp, when changed to a compound called adenosine diphosphate (adp), releases energy for biological work in a cell. adp can be changed back to atp, but this chemical reaction requires energy. where does all this energy come from?? remember that energy is \stored\ in the bonds of biomolecules like carbohydrates and lipids. food such as glucose contains much energy! to learn more about chemical energy you will:
(a) use paper models to construct molecules of atp and adp,
(b) determine similarities and differences between atp and adp,
(c) illustrate energy release when atp is changed to adp, and
(d) study the atp - adp cycle.
procedure
part a. the chemical structure of adenosine triphosphate (atp)
atp is made up of smaller molecules of subunits - ribose, adenine, and phosphoric acid (or phosphate groups).

1. ribose molecule

examine the structural formula of ribose. ribose is a carbohydrate, or a sugar. it is different from glucose in one very important way. glucose has six atoms of carbon in each molecule, and has the chemical formula ( c_6h_{12}o_6 ). keep this in mind when answering the following questions.
based on its name, how do we know that ribose is a carbohydrate, or sugar?
the molecular formula of glucose is ( c_6h_{12}o_6 ). notice that the number of atoms of each element present is written as a subscript. now you try it! looking at the ribose molecule above, what is the molecular formula of ribose? (hint: count the # of atoms of each!).
ribose: c_h_o_
how does the number of hydrogen atoms compare to the number of oxygen atoms in ribose?
in observing the molecular formulas of both glucose & ribose, what difference do you observe about the two molecules?

Explanation:

Step1: Count carbon atoms

Looking at the ribose molecule structure, count the number of carbon atoms. There are 5 carbon atoms.

Step2: Count hydrogen atoms

Count the hydrogen atoms in the ribose molecule. There are 10 hydrogen atoms.

Step3: Count oxygen atoms

Count the oxygen atoms in the ribose molecule. There are 5 oxygen atoms.

Carbohydrates often have names ending in -ose. Ribose ends with -ose, which is a common naming convention for sugars (carbohydrates).

In ribose (\( C_5H_{10}O_5 \)), divide the number of hydrogen atoms by the number of oxygen atoms. \(10\div5 = 2\).

Compare the sub - scripts of each element in the molecular formulas. Glucose has 6 carbon, 12 hydrogen, and 6 oxygen atoms while ribose has 5 carbon, 10 hydrogen, and 5 oxygen atoms.

Answer:

Ribose: \( C_5H_{10}O_5 \)

For the question "Based on its name, how do we know that ribose is a carbohydrate, or sugar?":