Worksheet: Topic 3: The chemistry of life (water, proteins, carbohydrates, lipids)

1. Which is not a primary function of protein molecules?A. HormonesB. Energy storage C. TransportD. Structure

2. Which structure represents an amino acid?

Answer: - D

3. What are the three most commonly occurring elements? Carbon, Hydrogen, Oxygen

4. State one function of each of these elements: a. Iron: - present in blood (Hemoglobin) b. Sulfur: - Present in hair (Sulfur Bonds) c. Calcium Strengthens bones and teeth d. Phosphorous: - Present in DNA e. Sodium: - Helps in neurotransmission.

5. Define organic molecule? Any molecule containing Carbon-Hydrogen (hydrocarbon) bonds or Carbon-Carbon bonds.

6. What are three carbon-containing groups or molecules that are not organic? Amino Groups, Carboxyl Groups and Hydroxyl Groups.

7. Draw three water molecules attracted to one another by hydrogen bonding. Include labels to show the polarity of the molecules?

8. Draw the structure of a general amino acid. Include (and label) the amino, carboxyl and ‘R’ groups.

9. Draw the generalized structures of fatty acids and glycerol.

10. Using labeled diagrams, describe how a monosaccharide (glucose) is converted to a disaccharide (maltose). What is the name of this process?

11. What is the name of the process through which polypeptides, polysaccharides or triglycerides are catabolised (broken down)? Hydrolysis

12. Outline condensation and hydrolysis in proteins, saccharides and triglycerides. Label the reactions and bonds formed/ broken clearly.

13. State functions of lipids, carbohydrates and proteins? Lipids: - Long-term energy storage.Carbohydrate: - Instant Energy for the body. Proteins: - Building blocks of the body.

14. Compare lipids and carbohydrates in terms of energy storage:

carbohydrates lipidsStored as…?

GlycogenAdipose Tissue

Long/short term storage?Short

Long

Ease of digestion/ release of energy?Easy

Complex

Energy per gram?4 Calories

9 Calories

Solubility in water?(and consequence)

Soluble Non Soluble

Use of oxygen in metabolism?(and consequence) C6H12O6+ 6O2---> 6CO2+ 6H2O

O2 + C58H112O6

CO2 + H2O + energy

15. Describe the significance of water to living organisms.

1. 'Coolant: Allows us to perform homeostasis. (We sweat to cool ourselves down). Additionally, water's high heat of vaporization allows water molecules to absorb large amounts of energy from the body before evaporating - thus, the sweating individual loses heat.

2. Transport medium: Digestion, also important to help transport blood. Phloem in plants transport nutrients dissolved in water using the cohesive and adhesive properties.

3. Habitat: Organisms need water; the ready availability of it is essential in the choosing of a habitat. Water's high heat capacity (the amount of energy needed to increase the temperature of 1gm of water by 1 Degrees Celcius) and high heat of vapourization (amount of energy absorbed by 1gm of liquid to be converted to the gaseous form) prevents from plants and animals from overheating and dying.

16.

Identify the structures?

I. Lipid ChainII. Fructose moleculeIII. Glucose MoleculeIV. Amino Acid

17. State one food rich in lipids suitable for a vegan diet. Nuts

18. Discuss the possible health problems associated with diets rich in lipids.

When people think of excess lipids, they are usually thinking of blood measurements for lipids that measure cholesterol and triglycerides. High levels of certain lipids in the blood can increase the risks of a number of health conditions. Some being Heart Disease, Diabetes, High Blood Pressure, High Cholesterol, and Obesity.

HL:

19. The complex structure of proteins can be explained in terms of four levels of structure, primary,Secondary, tertiary and quaternary.

(a) Primary structure involves the sequence of amino acids that are bonded together to form aPolypeptide. State the name of the linkage that bonds the amino acids together. Peptide Bond

(b) Beta pleated sheets are an example of secondary structure. State one other example.

(c) Tertiary structure in globular proteins involves the folding of polypeptides. State onetype of bond that stabilizes the tertiary structure.

(d) Outline the quaternary structure of proteins.

20. State one named example of a fibrous protein and one named example of a globularproteinFibrous: ........................................... Globular: ...........................................

21. Explain the significance of secondary structure to the structure of a protein.

22. Explain the significance of polar and non-polar amino acids within the cell.