Microbiology Ch. 5 & 7 Flashcards

Questions and Answers

What are precursor metabolites?

Enzymes that catalyze reactions

Molecules generated by an anabolic pathway

Proteins that provide structural support

Any of 12 molecules generated by a catabolic pathway (correct)

What is an active site?

Functional site of an enzyme, whose shape is complementary to the shape of the substrate.

What is denaturation?

Process by which a protein's three-dimensional structure is altered, eliminating function.

What are competitive inhibitors?

Inhibitory substances that block enzyme activity by blocking active sites. Signup and view all the answers

What are noncompetitive inhibitors?

Inhibitory substances that block enzyme activity by binding to an allosteric site. Signup and view all the answers

What is beta-oxidation?

A catabolic process in which enzymes split pairs of hydrogenated carbon atoms from a fatty acid to form acetyl-CoA. Signup and view all the answers

What does a lipase do?

A water-soluble enzyme that catalyzes hydrolysis of lipids. Signup and view all the answers

What is the function of proteases?

Enzymes that degrade protein molecules. Signup and view all the answers

Define amphibolism.

A biochemical pathway that involves both catabolism and anabolism. Signup and view all the answers

What is gluconeogenesis?

A metabolic pathway that generates glucose from non-carbohydrate carbon substrates. Signup and view all the answers

What is genetics?

The study of inheritance and inheritable traits Signup and view all the answers

What are genes?

Specific sequences of nucleotides that code for polypeptides or RNA molecules. Signup and view all the answers

Define genome.

The sum of all the genetic material in a cell or virus. Signup and view all the answers

What is a nucleoid?

A region made up of phosphate attached to a nucleoside. Signup and view all the answers

What are histones?

Globular proteins found in eukaryotic and archaeal chromosomes. Signup and view all the answers

What is the leading strand?

A strand that is synthesized continuously toward the replication fork. Signup and view all the answers

What is the lagging strand?

A daughter strand synthesized in short segments that are later joined. Signup and view all the answers

What is a genotype?

The actual set of genes in an organism's genome. Signup and view all the answers

What is a phenotype?

Physical features and functional traits of an organism. Signup and view all the answers

What is messenger RNA?

Molecules that carry genetic information from DNA to ribosomes. Signup and view all the answers

What is transfer RNA?

Molecules that deliver the correct amino acids to ribosomes. Signup and view all the answers

What is transcription?

The process that converts DNA to RNA. Signup and view all the answers

What is translation?

The process where RNA molecules synthesize polypeptides. Signup and view all the answers

What is a codon?

A triplet of mRNA nucleotides that codes for specific amino acids. Signup and view all the answers

What is an anticodon?

Portion of tRNA that is complementary to a codon on mRNA. Signup and view all the answers

What is a mutation?

A permanent change in the nucleotide base sequence of a genome. Signup and view all the answers

What is a point mutation?

A genetic mutation affecting only one or a few base pairs. Signup and view all the answers

Define frameshift mutation.

Type of mutation where nucleotide triplets are displaced due to insertion or deletion. Signup and view all the answers

What are mutagens?

Physical or chemical agents that introduce a mutation. Signup and view all the answers

What is wild type?

A cell normally found in nature; a nonmutant. Signup and view all the answers

What is the Ames test?

Method for screening mutagens to identify potential carcinogens. Signup and view all the answers

Of anabolism, catabolism, or both; which breaks down larger molecules into smaller ones?

Catabolism only. Signup and view all the answers

Of anabolism, catabolism, or both; which is exergonic?

Catabolism only. Signup and view all the answers

Of anabolism, catabolism, or both; which is endergonic?

Anabolism only. Signup and view all the answers

Of anabolism, catabolism, or both; which involves the production of cell membrane constituents?

Anabolism only. Signup and view all the answers

What does exergonic mean?

When catabolic pathways break down large molecules and release energy. Signup and view all the answers

What does endergonic mean?

When reactions require more energy than they release. Signup and view all the answers

What is an amphibolic reaction?

A reversible metabolic reaction; it can be anabolic or catabolic. Signup and view all the answers

Of anabolism, catabolism, or both; which includes metabolism?

Both anabolism and catabolism. Signup and view all the answers

What are redox reactions?

Reactions involved in the transfer of energy through electrons. Signup and view all the answers

What is a redox reaction?

(Oxidation-reduction reaction) any metabolic reaction involving the transfer of electrons. Signup and view all the answers

What does it mean when a reduced molecule has gained electrons?

It signifies a reduction process. Signup and view all the answers

What is activation energy?

Energy that is lowered by the action of organic catalysts. Signup and view all the answers

What are coenzymes?

Organic cofactors. Signup and view all the answers

Under ideal conditions, how many ATP molecules are gained from the fermentation of one glucose molecule by a bacterium?

Two. Signup and view all the answers

Under ideal conditions, how many ATP molecules are gained from the complete aerobic oxidation of one glucose molecule by a bacterium?

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The glycolysis pathway is basically what type of process?

Catabolic. Signup and view all the answers

What happens when all active sites on substrate molecules are filled?

Saturation. Signup and view all the answers

How many ATP molecules are produced in glycolysis after the initial input of two ATP molecules?

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What is the Krebs cycle?

A cyclic series of eight reactions involved in the catabolism of acetyl-CoA. Signup and view all the answers

The final electron acceptor in aerobic respiration is what?

O2. Signup and view all the answers

What are the main coenzymes that carry electrons in catabolic pathways?

NAD+ and FAD. Signup and view all the answers

Study Notes

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.

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Test your knowledge with these flashcards covering key concepts from Chapters 5 and 7 of Microbiology. Explore terms like precursor metabolites, active sites, and denaturation to reinforce your understanding of essential biochemical processes.