Download (null): Organic Model Kit Cutout

Organic Compounds: Carbohydrates
Problem: What is the structure of organic compounds?
Information:
All organic compounds contain the elements carbon and hydrogen.
Chemically carbon is unique because of its ability to form four covalent bonds with
other atoms, and its tendency to link with other carbon atoms into rings or long
chains.
Living things depend on organic compounds such as carbohydrates, proteins,
lipids and nucleic acids.
Part A: Structure and Formation of Carbohydrates
Examine the structural formula for glucose provided below.
Note that glucose contains the elements Carbon (C), Hydrogen (H), and Oxygen (O).
Each letter represents one atom of the element. The lines between the atoms
represent chemical bonds linking one atom to another. Answer questions 1-3 below
based on the information from the STRUCTURAL FORMULA.
1. What three elements are present in the sugar glucose?
2. If each letter represents an atom of the element, how many atoms of Carbon
are in each molecule of glucose? ________ How many Hydrogen? _______
Oxygen _______
3. The molecular formula for water is H20. There are 2 atoms of H and 1 atom
of O in a molecule of water. Write the molecular formula of glucose by
adding the correct subscripts:
C_____ H_____ O_____
4. The glucose structure provided is stable. Why? _______________________________________
________________________________________________________________. You and your partner will
now each build a stable glucose model. Try joining/bonding your models. They
cannot bond as they are stable. Now, one of you remove a single H from one end of
your model and have the other partner remove an OH from one end of their model.
What molecule is formed from the atoms you removed? ___________________. Build this
stable molecule.
5. By removing these atoms, each of you have made your glucose models unstable.
Make them stable once again by forming a covalent bond to join your two models
(from the C on one to the O of the other).
6. Two glucose molecules bonded together form maltose, a double sugar
(disaccharide). Write the molecular formula for maltose:
C_____ H_____ O_____ (remember what molecule is lost to form this new covalent bond)
Sugars belong to the group of macromolecules called carbohydrates. Many sugar
molecules bonded together in a chain form another kind of carbohydrate called
starch.
7. Now bond your maltose molecule with another group’s maltose molecule. Since
each maltose is stable, what must be removed to make each unstable? _____________.
8. What is the molecular formula for this carbohydrate of 4 glucose molecules
covalently bonded together: C_____ H_____ O_____ (again, remember what molecule you
have removed to make each maltose unstable)
9. What is the ratio of H to O in glucose:
____ H: ____ O
What is the ration of H to O in maltose:
____H: ____O
What is the ration of H to O in your 4 glucose chain: ____ H: ____ O
10. Dehydration means loss of water and Synthesis means to create. Why might
the process of bonding together glucose molecules be called dehydration
synthesis?
Part B: Fats/Lipids
To better understand the chemistry of lipids, it is helpful to first study the small
molecules (monomers) that bond to make up the lipids. The monomers of the
lipids are glycerol and fatty acids.
Glycerol: examine the structural formula for glycerol
1. What elements are present in glycerol? ________________________________________
2. Are there any elements in glycerol not in carbohydrates?
3. What is the molecular formula for glycerol? C_____ H_____ O_____
4. As in carbohydrates, are there exactly twice as many H atoms as O atoms in
glycerol?
The second monomer in a lipid is a fatty acid. Many different fatty acids exist, but
all are similar in several ways. Examine the structural formulas for the three fatty
acids below:
5. What elements are present in fatty acids? ________________________________________
6. a. What is the molecular formula for butyric acid? C_____ H_____ O_____
b. What is the molecular formula for caproic acid? C_____ H_____ O_____
c. What is the molecular formula for lauric acid? C_____ H_____ O_____
7. Are there exactly twice as many H atoms as O atoms in a fatty acid? __________
8. What pattern does appear in the fatty acid molecules regarding the number of
O atoms? __________________________
9. Notice the end of the butyric acid containing the O atoms. This special
arrangement of C, H, and O is called a carboxyl group.
10. Is the carboxyl group present in each of the fatty acids shown above? _______
11. List a similarity between glycerol and fatty acids:
12. Do fatty acids and glycerol both contain a carboxyl group? ___________________
Combining glycerol and fatty acids to form lipids. A fat/lipid molecule consists of
one glycerol and 3 fatty acids bonded together. One group member construct a
glycerol molecule. The other group member construct a butyric acid molecule.
13. Can the butyric acid bond to the glycerol? ___________
14. Remove an OH from the glycerol and H from the carboxyl of butyric acid.
Bond these to make a molecule of H2O and then bond the butyric acid to the
glycerol.
15. How many glycerol molecules are needed to form a fat molecule? ___________
16. If every C of glycerol were now bonded to a fatty acid, how many fatty acid
molecules would be/are needed to form a fat molecule? ____________
17. What type of chemical reaction bonds a fatty acid to a glycerol? (remember
what molecule you formed in 14 above)? ___________________ __________________
18. How many water molecules would be produced if 3 fatty acids are bonded to
a glycerol? _______Many fats exist in living organisms. The wide variety of fats
are formed by different combinations of fatty acids bonding to glycerol.
Many different fats/lipids exist in living organisms. The wide variety of fats are
formed by different combinations of fatty acids bonding to glycerol.
19. What molecule remains the same in ALL fats? _________________________
Proteins are macromolecules made up of monomers called amino acids.
Examine the structural formulas for four of the twenty different amino acids found
in living organisms:
1. The element N (Nitrogen) is found in every amino acid. Is N found in
carbohydrates? ______________
2. What is the molecular formula for
Glycine:
C____ H_____ O_____ N_____
Threonine: C____ H_____ O_____ N_____
Valine:
C____ H_____ O_____ N_____
Leucine: C____ H_____ O_____ N_____
3. Are the molecular formulas for ALL the amino acids the same? _________
4. What end arrangement of atoms is present in amino acids that is also present in
fatty acids? ___________________ _________________
5. Another end arrangement in all amino acids consists of a N atom and two H
atoms. This group is called an amino group:
6. Do structural formulas for all amino acids have amino groups? _____________
Combining Amino Acids to form Proteins: proteins are made of many amino acids
bonded together by dehydration synthesis.
You construct a model of the amino acid glycine and your partner construct a model
of the amino acid alanine.
7. Can these two stable amino acids covalently bond together? _________
8. Remove the OH from the carboxyl of one of the amino acids and a H from the
amino group of the other amino acid.
9. Bond these; what stable molecule do they produce? _______________
10. Now bond the glycine to the alanine. If you bonded 50 amino acids together,
how many H2O molecules would be produced? ________________
11. What is this process called that bonds amino acids together? (remember what
molecule is produced when you bond amino acids together) ______________________
_________________________.
12. There are thousands of different proteins in every living organism. The smallest
protein in humans consists of approximately 40 amino acids and the largest protein
consists of hundreds of amino acids bonded together. How might one protein differ
from another protein? _______________________________________________
______________________________________________________________________________________________.
Thought Question: what are the primary sources of protein in a typical human diet?