Download Topic 3 The chemistry of life - wfs

Topic 3.2 Review Book
Carbohydrates, Lipids & Proteins
Name ____________________
Topic 3 The chemistry of life
3.1 Carbohydrates, Lipids, and Proteins (Textbook Pages 44-52)
Key facts
1. Compounds containing carbon that are found in living organisms (except hydrogencarbonates,
carbonates, and oxides of carbon) are regarded as organic. Therefore, carbon dioxide is not
considered an organic compound.
2. Amino acids contain the following groups: amino group (NH2), carboxyl group (COOH), and an R
group (variable).
3. Glucose is a six carbon ring structure. One carbon is outside the ring.
4. Ribose is a five carbon ring structure. One carbon is outside the ring.
5. Fatty acids contain a carboxyl group and are not a ring structure.
6. Monosaccharides are the simplest carbohydrates and include glucose, galactose, and fructose.
7. Disaccharides include two monosaccharides bonded together. Examples are maltose, lactose, and
sucrose.
8. Polysaccharides are long chain carbohydrates, and include starch, glycogen and cellulose.
9. In animals glucose is carried by the blood to transport energy to cells all through the organism.
10. Lactose in animals provides energy to young mammals until they are weaned from their mothers.
11. Glycogen is used in animals to store energy in the liver and muscles.
12. In plants, fructose makes fruit sweet tasting. This attracts animals, allowing dispersal of the seeds in
the fruit.
13. Sucrose is the form of carbohydrates that is transported by the plant’s phloem (vascular tissue). It
represents an energy source.
14. Cellulose is used in plants to produce fibers that allow the construction of the cell wall.
15. In condensation two simple molecules are joined together to form a larger molecule. When this
occurs water is formed.
16. In hydrolysis larger molecules are broken down into smaller molecules. Water molecules are used
up in this reaction.
17. Four functions of lipids include: energy storage, heat insulation, buoyancy, and they are an essential
part of cellular membranes.
18. Both lipids and carbohydrates serve to store energy.
19. Lipids store twice the amount of energy as an equal mass of carbohydrates. However, carbohydrates
are more easily digested than lipids to release their energy. Also, carbohydrates are water soluble
and are easier to transport.
20. Because lipids are insoluble in water, they do not cause problems with osmosis in cells.
Name ______________________________
Section _____________
Draw assessment statements from this topic
1. Draw the general structural formula for an amino acid.
2. Draw the structural formula for glucose.
3. Draw the structural formula for ribose.
4. Draw the general formula for a fatty acid.
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Name ______________________________
Section _____________
Complete the following.
1. Tell whether the following compounds are organic or inorganic:
a. CO2 _________________
b. CH4 __________________________
c. H2O _________________
d. C6H12O6 ________________________
2. Large molecules of organic compounds are called macromolecules and are made up of specific subunits. What are the subunits of:
a. carbohydrates ______________________
b. proteins ____________________
c. lipids _______________________
3. Name three monosaccharides.
4. Name three disaccharides.
5. Name three polysaccharides.
6. What monosaccharide is carried by the blood to transport energy to cells throughout the body?
7. What is the value of fructose to plants?
8. What disaccharide provides energy to young mammals before they are weaned?
9. What disaccharide transports energy in the phloem of plants?_________________
10. Of what value is cellulose to plants?
11. Where in animals would one find energy stored as glycogen?__________________
12. Explain what, in general, happens in all condensation reactions.
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Name ______________________________
Section _____________
13. Explain what, in general, happens in all hydrolysis reactions.
14. Tell whether the following represents hydrolysis or condensation.
a. amino acid + amino acid --------- dipeptide + water ______________
b. glucose + fructose ----------- sucrose + water ________________
c. glycogen + water ----------- monosaccharides ________________
d. lipid + water ---------------- glycerol + fatty acids ________________
15. How do lipids provide buoyancy in animals?
16. What form of lipids provide energy storage in plants?______________ in animals?______________
17. What two major macromolecules provide energy to living organisms?
18. Of these two, which allows the most rapid release of energy?
19. Are lipids or are carbohydrates soluble in water?_____________________
20. Which of the compounds used to store energy is most often used for long-term
storage?_________________
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