1. Metabolism Metabolism is “the chemical reactions of life; all the various processes by which you obtain energy, grow, heal, think, feel, and dispose of wastes”. Metabolic reactions are controlled by enzymes. Metabolism

3. ExergonicEndergonic

4. Immunological Transport Contractile Regulatory tRNA Amino acid Transcription mRNADNA Protein Translation Structural Enzyme Enzymes are Proteins Perfect opportunity for review… Enzymes are just one of the many types of proteins Folded into it’s primary, secondary and tertiary structure.

5. Metabolic Pathways A series of ‘steps’ from a starter molecule or precursor toward a final end product. Each step is catalyzed by a different enzyme. Enzyme B Enzyme A Intermediate chemical Precursor chemical End product When an enzyme is written on a reaction arrow, it means the enzyme catalyzes the reaction shown To catalyze means to “speed up” a reaction

6. Syllabus Statement 2.1.U4 Metabolism is the web of all the enzyme-catalyzed reactions in a cell or organism. Define metabolism and catalysis. State the role of enzymes in metabolism.

7. CYCLICAL PATHWAY Some metabolic pathways operate in a cyclic way. The scientists who elucidated two of the cycles have had their names attached to the pathways by the scientific community. Remember: each arrowed line in the pathway indicates an enzyme is used to make that step happen. Only the names of the reactants and products are shown. In this case, the names of the enzymes doing the reaction are NOT written.

8. Metabolism of Phenylalanine The metabolism of phenylalanine is an example of a CHAIN metabolic pathway. Failure of the enzymes controlling the metabolic pathway leads to a range of metabolic disorders. Protein in diet Carbon dioxide and water MelaninThyroxine Tyrosine Maleylacetoacetic acid Homogentisic acid Hydroxyphenylpyruvic acid Phenylalanine essential amino acid

9. Write the name of the enzyme required for each step of the pathway on the appropriate line. The example is just provided as an illustration of how complex and interrelated metabolic pathways can be. You are not expected to know the memorize the details of this pathway. T his is a perfect opportunity for review… keep in mind that each of the ENZYMES you list in this METABOLLIC PATHWAY is a PROTEIN created through TRANSCRIPTION and TRANSLATION of a GENE. The genes usually have two ALLELES, the “normal” version and the “diseased” version of the gene. The diseased allele is caused by a MUTATION in the DNA of the gene. The mutation results in a faulty enzyme because the AMINO ACID sequence (PRIMARY STRUCTURE) of the protein will not be correct. If the primary structure isn’t correct, the SECONDAY, TERIARY and QUARTENARY structures will also be incorrect. So, if the protein folds incorrectly, the functioning of the enzyme will be decreased or lost. See how much you know???!!! My smarty pants biology students make me proud.

10. Protein in Diet Phenylalanine hydroxylase Phenylalanine essential amino acid Phenylpyruvic acid Phenylketonuria “PKU” This in turn causes Faulty enzyme results in buildup of Tyrosine SYMPTOMS Mental retardation, 'mousy’ body odor, light skin color, eczema, excessive muscular tension and activity. All newborns in the USA are tested for PKU at birth. If present, then the diet is modified so no phenylalanine is ingested. If none is eaten, then there will be no symptoms of the disease.

11. a series of enzymes Thyroxine Tyrosine Protein in Diet Phenylalanine essential amino acid Faulty enzymes cause Cretinism Symptoms Dwarfism, mental retardation, low levels of thyroid hormones, retarded sexual development, yellowish skin color.

12. Tyrosinase Melanin Tyrosine Protein in Diet Phenylalanine essential amino acid Faulty enzyme causes Albinism Symptoms Complete lack of the pigment melanin in body tissues, including the skin and hair

13. Tyrosine Protein in Diet Phenylalanine essential amino acid Trans- aminase Hydroxyphenylpyruvic acid

14. Homogentisic acid Hydroxyphenylpyruvic acid oxidase Hydroxyphenylpyruvic acid Tyrosinosis Faulty enzyme causes Symptoms Death from liver failure or, if surviving, chronic liver and kidney disease. A diseased liver

15. Maleylacetoacetic acid Homogentisic acid oxidase Homogentisic acid Carbon dioxide and water Hydroxyphenylpyruvic acid Alkaptonuria Faulty enzyme causes Symptoms Dark urine, pigmentation of cartilage and other connective tissues, and, in later years, arthritis. Note the blue tint of the cartilage in the ear.

16. Maleylacetoacetic acid Homogentisic acid Carbon dioxide and water Hydroxyphenylpyruvic acid If every enzyme works the way it should, the final products in the digestion of phenylalanine are just CO2 and water!

17. Syllabus Statement 8.1.U4 Metabolic pathways consist of chains and cycles of enzyme- catalyzed reactions. Contrast metabolic chain reaction pathways with cyclical reaction pathways.