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TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Biology > Carbohydrates, Lipids and Proteins

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Draw the basic structure of a generalised amino acid

COOH

|

C H

|

NH₂

Draw the ring structure of an alpha-D glucose

13

Draw the basic structure of glycerol and a generalised fatty acid

 

CH₂0H

    |

CH₂OH

    |

CH²OH

 

Fatty Acid

C_xH_(2x+1)-COOH (saturated)

C_somethingH_bigsomethingCOOH (saturated)

Outline the role of condensation and hydrolysis in the relationships between monosaccharides and disaccharides; fatty acids, glycerol and trigylcerides, amino acids dipeptides and polypeptides

• Monosaccharide ---> Condensation Reaction ---> Disaccharide (Condensation, loss of a single water molecule)
• Disaccharide ---> Hydrolysis ---> Monosaccharide (Hydrolysis gain of single water molecule)

• Fatty Acids + Glycerol ---> Condensation Reaction ---> Fats

• Amino Acid (carboxyl group) + Amino Acid(amino group) ---> Condensation Reaction ---> Dipeptide

• Dipeptides + Amino Acids ---> Condensation Reaction ---> Polysaccharide

Draw the structure of a generalised dipeptide, showing the peptide linkage

                                         H   H

                                          \  /

                                              N

                                           |

                                          R₁-C-H

                                           |

                                       OC

                                            |

                                        H-N

                                            |

                                       R₂-C-H

                                             |

                                            C

                                          // \

                                         O     O-H

                              

                                     

Explain the relative solubility of carbohydrates, lipids, and proteins in water

• Most lipids are insoluble because they have a long hydrocarbon chain (hydrophobic)
• Carbohydrates are soluble because of the presence of OH groups
• Proteins are also soluble because of OH groups and other groups and charges
• Solubility decreases with size

Compare the energy content of carbohydrates, lipids, and proteins

Lipids have about twice the energy of carbohydrates and proteins in x mass.

List two examples of monosaccharides, disaccharides, and polysaccharides

• Monosaccharides
  • Glucose
  • Ribose
  • Fructose
• Disaccharides
  • Sucrose
  • Lactose
  • Maltose
• Polysaccharides
  • Glycogen
  • Cellulose
  • Chitin

State one function for a monosaccharide and for a polysaccharide

• Monosaccharide Glucose/Ribose/Fructose Respiratory Substrates
• Polysaccharide Glycogen Storage carbohydrate in plants and animals

State three functions of lipids

1. Energy Source
2. Energy Storage
3. Insulation
4. Protection
5. Waterproofing
6. Cell Membranes (Phospholipids are a major component of)

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