Microbiology Ch. 5 & 7 Flashcards

Metabolic Pathways and Enzymes

• Precursor metabolites are 12 essential molecules generated by catabolic pathways, vital for organic macromolecule synthesis.
• Active sites of enzymes are specifically shaped to fit substrates, enabling catalytic activity.
• Denaturation alters a protein's three-dimensional structure, which disrupts its function.
• Competitive inhibitors block enzyme activity by occupying the active site, preventing substrate access.
• Noncompetitive inhibitors bind to allosteric sites, inhibiting enzyme function without competing for the active site.

Fatty Acid and Lipid Metabolism

• Beta-oxidation is a catabolic process where fatty acids are broken down, forming acetyl-CoA.
• Lipases are water-soluble enzymes responsible for hydrolyzing lipids into glycerol and free fatty acids.
• Proteases are enzymes that degrade proteins into amino acids, functioning outside the cell wall in microbes and involved in inflammatory responses.

Biochemical Integration

• Amphibolism describes pathways integrating both catabolism (breaking down molecules) and anabolism (building up molecules), exemplified by fatty acid beta-oxidation.
• Gluconeogenesis generates glucose from non-carbohydrate sources such as pyruvate and amino acids.

Genetics Fundamentals

• Genetics encompasses the study of inheritance and traits expressed in an organism's genetic material.
• Genes are specific nucleotide sequences that code for proteins or RNA.
• The genome is the complete genetic material in a cell or virus, while the nucleoid comprises nucleic acid monomers.
• Histones are globular proteins found in the chromosomes of eukaryotes and archaea.

DNA and RNA Structure

• The leading strand is continuously synthesized toward the replication fork, whereas the lagging strand consists of short segments (Okazaki fragments).
• Genotype refers to the actual set of genes, differing from the genome which includes non-coding regions.
• Phenotype encompasses the observable traits and characteristics of an organism realized through genetic expression.

RNA and Protein Synthesis

• Messenger RNA (mRNA) conveys genetic information from DNA to ribosomes.
• Transfer RNA (tRNA) brings amino acids to ribosomes based on mRNA sequences.
• Transcription involves converting DNA to RNA, while translation synthesizes polypeptides from mRNA.

Genetic Mutations

• Mutations are permanent changes in the nucleotide sequence of a genome.
• Point mutations affect a few base pairs, whereas frameshift mutations displace subsequent nucleotide triplets.
• Mutagens are agents that induce mutations, and wild type refers to organisms found naturally without mutations.

Energy in Metabolism

• Redox reactions involve electron transfer, with oxidation (loss of electrons) and reduction (gain of electrons).
• Exergonic reactions release energy, typical of catabolic processes, while endergonic reactions require energy, characteristic of anabolic processes.
• Amphibolic reactions can function as either anabolism or catabolism.

ATP and Cellular Respiration

• Anaerobic respiration differs from fermentation, where organic molecules serve as final electron acceptors in fermentation.
• Substrate-level phosphorylation forms ATP through direct transfer of phosphate, while oxidative phosphorylation generates ATP from electron transport processes.
• Glycolysis initiates carbohydrate catabolism, yielding a net gain of 2 ATP molecules.
• The Krebs cycle, consisting of eight reactions, metabolizes acetyl-CoA, producing NADH and FADH2.
• O2 is the final electron acceptor in aerobic respiration, crucial for cellular energy production.

Enzymatic Activity and Regulation

• Saturation occurs when all active sites on enzymes are occupied by substrate molecules, inhibiting further reaction.
• During glycolysis, an initial investment of 2 ATP molecules leads to the net production of 2 ATPs from the process.
• NAD+ and FAD are key coenzymes that transport electrons in catabolic pathways.