Molecules to metabolism

Topic 2.1

Essential idea: Living organisms control their composition by a complex web of chemical reactions.

Understandings

2.1.U1 Molecular biology explains processes in terms of the chemical substances involved

Chemistry of Life

Living organisms are composed of many chemical elements but the most frequently occurring elements are carbon, hydrogen, oxygen and nitrogen. As shown in Figure 1 below these four elements make up a majority of the human body, as well as most other living organisms. These are the four main elements of biological molecules such as carbohydrates, proteins, fats, and nucleic acids.

Figure 1: Most frequently occuring chemical elements in living organisms

otherelements

2.1.U2 Carbon atoms can form covalent bonds allowing a diversity of stable compounds to exist

Carbon bonding

2.1.U3 Life is based on carbon compounds including carbohydrates, lipids, proteins and nucleic acids

Glucose Condensation
Dipeptide Condensation
Lipid Condensation
Glucose Condensation
Dipeptide Condensation

2.1.U4 Metabolism is the web of all enzyme-catalyzed reactions in the cell organism

Diagram metabolic pathways

2.1.U5 Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules                      from monomers by condensation reactions

Condensation Reactions

Condensation reactions involve joining together simpler molecules (monomers) to form larger, more complex macromolecules. This chemical process involves the removal of water molecules. A monomer is a chemical subunit that serves as a building block of a polymer. Condensation reactions are important processes in anabolism. Outlined below are the hydrolysis reactions of: (i) disaccharides which breaks the glycosidic bond producing two monosaccharides, (ii) dipeptides which breaks the peptide linkage producing two amino acids, (iii) triglycerides which breaks the ester bond into fatty acids and glycerol, (iv) polypeptides into monosaccharides and (v) polypeptides into amino acids.

Place your mouse over the particular number to see the products of the reaction.

(i)Glucose Condensation
(ii)Dipeptide Condensation
(iii)Lipid Condensation
(iv)Glucose Condensation
(v)Dipeptide Condensation

2.1.U6 Catabolism is the breakdown of complex molecules into simpler molecules including hydrolysis of macromolecules                      into monomers

Hydrolysis Reactions

Hydrolysis reactions involve complex molecules which are broken down by the chemical addition of water molecules to the bonds to form simpler molecules (monomers). This chemical process is an important part of catabolism. Outlined below are the hydrolysis reactions of: (i) disaccharides which breaks the glycosidic bond producing two monosaccharides, (ii) dipeptides which breaks the peptide linkage producing two amino acids, (iii) triglycerides which breaks the ester bond into fatty acids and glycerol, (iv) polypeptides into monosaccharides and (v) polypeptides into amino acids.

Place your mouse over the particular number to see the products of the reaction.

(i)Glucose Condensation
(ii)Dipeptide Condensation
(iii)Lipid Condensation
(iv)Glucose Condensation
(v)Dipeptide Condensation

Applications

2.1.A1 Urea is an example of a compound that is produced by living organisms but can also be artificially synthesized

Urea production in organisms and industry

Skills

2.1.S1 Drawing molecular diagrams of glucose, ribose, a saturated fatty acids and a generalized amino acid

Glucose molecule
Ribose molecule
Fatty acid molecule
Amino acid molecule

2.1.S2 Identification of biomolecules such as sugars, lipids and amino acids from molecular diagrams

Shown below are the different structures (organic) of key carbohydrate and lipid structures. Can you guess the identity of each structure?

Place your mouse over the chemical structure for identification.

Glucose structure
Ribose structure
 Glycerol structure
Fatty acid structure
Amino acid structure
Polysaccharide structure
Dipeptide Condensation
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