Microbiology Ch 10

Metabolism

all chemicals and physicals workings of the cell. These chemical reactions fall into two categories:

Anabolism

Catabolism

Anabolism- uses energy

sometimes called “biosynthesis reactions where cell molecules and structures are produced.

*Require energy input

Catabolism- yields energy

(opposite of anabolism) Bonds of larger molecules are broken and energy is released.

Enzymes

Act as Catalysts-chemicals that speed up rate of a chemical reaction without becoming part of the products or being consumed in the reaction

** Reactions within a cell would occur too slowly for life to exist without enzymes

Catalysts

A substance that alters the rate of a reaction without being consumed or permanetly changed by it.

Accomplishment of Metabolism

1. Assembles smaller molecules into larger macromolecules for the cell, utilizing ATP

2. Metabolism degrades macromolecules into smaller molecules, process that yields energy

3. Metabolism collects and spends energy in the form of ATP or heat

Activation Energy in Chemical reactions

For a chemical reaction to proceed, chemical bonds in the reactants must be broken to form new chemical bonds in the products —→requires input of energy called activation energy

Enzymes Characteristics -majority name ends in -ase

• Proteins

• Act as organic catalysts to speed up the rate of the cellular reactions

• Lower activation energy required for chemical reaction to proceed

• Unique characteristics such as; shape, specificity and function

• They enable metabolic reactions to proceed at a speed compatible with life.

• They have an active site for target molecules (subtrates)

• They are much larger in size than their substrates

• They associate closely with subtrates but do not become integrated into the reaction products

• They can be recylced

• Greatly affected by temperature and pH

Enzymes work to overcome the required activation energy of a reaction by:

**position reactants in a favorable position for reaction to take place

AND stabilizing a reaction intermediary state that helps favor reaction completion

Conjugated enzymes

Contain one or more proteins portion of the enzyme combined with one other NONprotein molecule, called holoenzyme.

-An apoenzyme is the protein portion of the enzyme

• A cofactor is the nonprotein portion of the enzyme; this can be organic molecule called coenzyme