1.2

1. What are the four macromolecules?

The four main macromolecules in biology are:

1. Carbohydrates
   
   

2. Proteins
   
   

3. Nucleic acids (DNA and RNA)
   
   

4. Lipids
   
   

2. What are the elements found in a carbohydrate?

• Carbohydrates are made up of carbon (C), hydrogen (H), and oxygen (O). The ratio of hydrogen to oxygen is usually 2:1.
  
  

3. What are three functions of carbohydrates in living organisms?

1. Energy storage: Carbohydrates like glucose provide a quick source of energy.
   
   

2. Structural support: In plants, cellulose (a carbohydrate) provides structural integrity to the cell wall.
   
   

3. Cell signaling: Carbohydrates on cell surfaces play a role in cell recognition and signaling.
   
   

4. What are the elements found in a protein?

• Proteins are composed of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). Some proteins may also contain sulfur (S).
  
  a. What are the functional groups found in all amino acids?
  
  

  • The two functional groups found in all amino acids are:
    
    

    1. Amino group (-NH₂): Acts as a base.
       
       

    2. Carboxyl group (-COOH): Acts as an acid.
       
       

5. What are three functions of proteins in living organisms?

1. Enzyme catalysis: Proteins speed up biochemical reactions (e.g., enzymes).
   
   

2. Structural support: Proteins provide structure to cells and tissues (e.g., collagen).
   
   

3. Transport: Proteins help transport molecules across cell membranes (e.g., hemoglobin transports oxygen in blood).
   
   

6. What are the elements found in nucleic acids?

• Nucleic acids are made up of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and phosphorus (P).
  
  a. What are parts found in all nucleotides?
  
  

  • A nucleotide consists of three parts:
    
    

    1. A phosphate group
       
       

    2. A sugar molecule (deoxyribose in DNA or ribose in RNA)
       
       

    3. A nitrogenous base (adenine, thymine, cytosine, guanine, or uracil)
       
       

7. What are three functions of nucleic acids in living organisms?

1. Genetic information storage: DNA stores the genetic code that dictates cell functions and inheritance.
   
   

2. Protein synthesis: RNA helps in protein synthesis by carrying genetic information from DNA to the ribosomes.
   
   

3. Energy transfer: Some nucleotides (e.g., ATP) are used in energy transfer processes.
   
   

8. What are the elements found in a lipid?

• Lipids are composed of carbon (C), hydrogen (H), and oxygen (O), but they have a much lower ratio of oxygen compared to carbohydrates.
  
  a. How are the three different types of lipids different?
  
  

  1. Fats (Triglycerides): Composed of glycerol and three fatty acids; used for energy storage and insulation.
     
     

  2. Phospholipids: Composed of glycerol, two fatty acids, and a phosphate group; they form the structural components of cell membranes.
     
     

  3. Steroids: Composed of four fused carbon rings; they include hormones like cholesterol and testosterone.
     
     

9. What are three functions of lipids in living organisms?

1. Energy storage: Lipids store energy efficiently in adipose tissue.
   
   

2. Cell membrane structure: Phospholipids form the basic structure of cell membranes.
   
   

3. Insulation and protection: Lipids protect organs and insulate the body (e.g., fat beneath the skin).
   
   

10. Which macromolecule(s) contain nitrogen?

• Proteins and nucleic acids contain nitrogen. Proteins contain nitrogen in their amino groups, while nucleic acids contain nitrogen in their nitrogenous bases.
  
  

11. Which macromolecule(s) contain phosphorus?

• Nucleic acids (DNA and RNA) contain phosphorus in their phosphate groups. Phospholipids also contain phosphorus.
  
  

12. Which macromolecule(s) contain sulfur?

• Proteins can contain sulfur, especially in the side chains of amino acids like cysteine and methionine.
  
  

13. How does the R group affect the folding of the protein? (Include polar and nonpolar R groups)

• The R group (side chain) of an amino acid affects how the protein folds by determining how it interacts with other parts of the protein and its environment.
  
  

  • Polar R groups: Tend to be hydrophilic (water-loving) and often face outward in the protein structure, interacting with the aqueous environment.
    
    

  • Nonpolar R groups: Tend to be hydrophobic (water-hating) and usually fold inward to avoid water, helping stabilize the protein's structure.
    
    

14. What is dehydration?

• Dehydration (also called condensation) is a chemical reaction where two molecules are joined together by the removal of a water molecule.
  
  a. Provide an example of dehydration.
  
  

  • The formation of a disaccharide (e.g., sucrose) from two monosaccharides (glucose and fructose) is an example. During the reaction, a water molecule is removed as the two sugars are linked.
    
    

15. What is hydrolysis?

• Hydrolysis is the process of breaking down a molecule by adding water, essentially the reverse of dehydration.
  
  a. Provide an example of hydrolysis.
  
  

  • The breakdown of a disaccharide (e.g., sucrose) into two monosaccharides (glucose and fructose) using water is an example of hydrolysis.