Microbial Metabolism

Factors Influencing Enzymatic Activity

Active vs Denature

How do enzymes perform their functions?

By activation energy. 1) Are proteins, produced by living cells; they catalyze chemical reactions by lowering the activation energy Ex: heat energy might be the activation energy introduced to a chemical reaction to encourage the reaction to occur. Enzymes reduce the amount of activation energy necessary to bring the components of a chemical reaction together or to force them to separate.

Summary

Feedback inhibition occurs when the end product of a metabolic pathway inhibits an enzyme's activity near the start of the pathway.

Metabolic pathways

A) Are a series of chemical reactions in which the product of one reaction is the substrate for the next reaction. B) The chemical reactions are catalyzed by enzymes, so the metabolic pathways present in an organism depend on the enzymes present in the organism. C)The enzymes present in an organism depend on the genes present in the organism.

Are enzymes susceptible to chemical and physical environmental changes?

A) At high temperatures, enzymes undergo denaturation and lose their catalytic properties; at low temperatures, the reaction rate decreases B) Enzymes are proteins, b/c proteins are susceptible to chemical and physical changes in the environment, enzymes are equally susceptible. C) For example, excessive heat causes enzyme proteins to lose their 3-dimensional structure, a process called denaturation. D) Enzyme denaturation is one reason why high heat kills cells. E) Similarly, chemical substances such as acids, bases, phenol, and many disinfectants destroy microorganisms because they destroy their enzymes.

Is energy required for the reactions of metabolism to take place?

A) Catabolism Creates High energy molecules. B) Nutrients have high energy e- associate w/ chemical bonds. C) Catabolism remove e- (oxidize) & estore energy in high energy bonds Ex: ATP: Has high energy or unstable bonds, which allow the energy to be quickly released.

Concept of Definitions: Into which broad areas can metabolism be subdivided?

A) Catabolism: is the overall chemical process in which cells break down large molecules into smaller ones. 1) Catabolism is a process that generally results in the liberation of energy (release). B) Anabolism: is the overall process by which cells synthesize molecules and structures. It is also referred to as biosynthesis. 1) Is a building process that generally requires an input of energy.

Do enzymes have any special names? (ase)

A) Contemporary enzyme names end in the suffix "-ase." 1) What precedes the suffix may be the name of the substrate, or it may have to do with the reaction the enzyme causes, or it may refer to the group to which the enzyme belongs. For example, the enzyme lact(ase) breaks down the substrate lactose, the enzyme hexokin(ase) breaks down the six-carbon sugar glucose, and the enzyme lig(ase) catalyzes the union of two chemical molecules to form a single chemical molecule. B) It should be noted that some enzymes have traditional names that do not end in "-ase." For example, pepsin is the gastric enzyme that breaks down protein.

Naming Enzymes

A) Enzyme names usually end in -ase. B)) The six classes of enzymes are defined on the basis of the types of reactions they catalyze. 1) Oxidoreductase - catalyzes redox reactions. 2)Transferase - catalyzes transfer of functional groups. 3) Hydrolase - splits chemical bonds by addition of water. 4) Lyase - splits chemical bonds without using water (not a hydrolysis reaction). 5) Isomerase - rearranges atoms within a molecule. 6) Ligase - forms a chemical bond between two atoms.

What are enzymes composed of?

A) Enzymes are composed of proteins, and, in some cases, they contain nonprotein parts. B) Simple enzymes contain proteins alone. C) Conjugated enzymes contain a nonprotein portion. 1) The conjugated enzyme is sometimes referred to as a holoenzyme; the protein portion is called an apoenzyme, while the nonprotein portion is called a cofactor (cause of disease.

Enzymes

A) Enzymes are generally globular proteins with characteristic three- dimensional shapes. B) The active site is the binding site for the enzyme's substrate. C) Enzymes are specific for substrate molecules. This is all shape driven, so anything that alters the shape of the active site will affect enzyme activity. D) Enzymes are efficient, can operate at relatively low temperatures, and are subject to various cellular controls.

What terms are given to the reactants in a metabolic reaction?

A) In any metabolic reaction catalyzed by enzymes, the chemical reactants taking part are known as [substrates]. B) Once the enzyme has acted on the substrate or substrates, the products of the reaction are known as [end products].

Catabolism

A) Is the overall chemical process in which cells [break down] large molecules into smaller ones. 1)Catabolism is a process that generally results in the liberation of energy(release). 2) Energy is stored in ATP 3) Reduced NAD & FAD

Anabolism

A) Is the overall process by which cells synthesize molecules and structures. It is also referred to as biosynthesis. B) Anabolism is a [building block] process that generally requires an input of energy.

Why is metabolism necessary for a cell?

A) Metabolism contributes to the stability of a living cell while providing a dynamic pool of building blocks for synthesis reactions. B) In addition, metabolism permits cells to extract energy for their life processes and to continue to grow and multiply. C) Metabolism takes place in an organism 1) Prokaryote (Cytoplasm) 2) Involves the cell or plasma membrane of the microorganism.

Cofactors

A) Metal ion (iron, copper, magnesium, manganese, zinc, calcium, or cobalt) B) Complex organic molecule known as a coenzyme (NAD+, NADP+, FMN, FAD, or coenzyme A).

How are the reactions of metabolism brought about?

A) The chemical reactions of metabolism are typically catalyzed through the activity of a special category of proteins called [enzymes]. B) Enzymes are biological catalysts that influence chemical reactions while themselves remaining unchanged. C) The reactions would occur, but they would take an enormously long period of time. Enzymes reduce the time for a reaction to occur to milliseconds. D) Enzymes are proteins, produced by living cells; they catalyze chemical reactions by lowering the activation energy.

Are there different kinds of cofactors in enzyme molecules?

A) The cofactors of an enzyme molecule I) Organic molecules ***NAD*** (nicotinamide adenine dinucleotide) *** FAD*** (flavin adenine dinucleotide). ***coenzyme*** II) Inorganic molecules a)Metals: such as iron, magnesium, copper, manganese, zinc, and cobalt. b) In many cases, the cofactor is the active portion of the enzyme molecule.

Enzymatic activity

A) The pH at which enzymatic activity is maximal is known as the optimum pH. B) Within limits, enzymatic activity increases as substrate concentration increases. C) Competitive inhibitors compete with the normal substrate for the active site of the enzyme. D) Noncompetitive inhibitors act on other parts of the apoenzyme or on the cofactor and decrease the enzyme's ability to combine with the normal substrate.

What is Microbial metabolism?

A) Use for chemical reactions occurring in all living things. 1) Metabolism Change or to change B) Except for viruses, metabolism is a characteristic of all microorganisms, plants, and animals. C) Chemical processes in a living cell or organism necessary for life. D) Organized to yield energy or synthesized. E) Organisms (anabolism) F) Organic molecules are broken down (anabolism)

How do enzyme molecules work to bring about a chemical reaction?

A) When an enzyme and substrate combine, the substrate is transformed into the product, and the enzyme is recovered. B) Enzymes are characterized by specificity, which is function of their active sites. C) An enzyme molecule and its substrate or substrates combine at the active site of the enzyme molecule. D) Generally, the substrate and active site fit closely together. Once the union has occurred, the complex is called the [enzyme-substrate complex]. The enzyme then undergoes a slight alteration in its shape, and the chemical reaction occurs.

How large are enzyme molecules and what form do they take?

A) few thousand to over a million daltons. B) As protein molecules, they have primary, secondary, and tertiary structures, and they are often folded into three-dimensional molecules. C) In this huge molecule, there is generally one or more areas called the [active site], where the enzyme interacts with the substrate.

Do enzymes act in different chemical reactions?

A)Enzymes are highly specific. 1) Based on the shape of the enzyme. 2) Each enzyme participates in (1) reaction 3) After the reaction has occurred, the enzyme is set free to activate another chemical reaction.