Microbiology - Chapter 5

Metabolism

What is the sum of all chemical reactions within a living organism?

Catabolism

What reactions break down complex molecules and provide energy and building blocks for anabolism? These can be considered hydrolytic or exergonic reactions.

Anabolism

What reactions use energy and building blocks to build complex molecules? These can also be considered biosynthetic reactions, dehydration synthesis, or endergonic reactions?

Metabolic pathways

What are sequences of enzymatically catalyzed chemical reactions in a cell?

Enzymes

What determines metabolic pathways?

Genes

What encodes enzymes?

Collision theory

What states that chemical reactions occur when atoms, ions, and molecule collide?

Activation energy

What is the collision energy required for a chemical reaction to occur?

Reaction rate

What is the frequency of collisions containing enough energy to bring about a reaction called?

Enzymes, increased temperature, increased pressure, or increased concentration

What four things can increase the reaction rate?

Catalysts

What speeds up chemical reactions without being altered?

Enzymes

What is a biological catalyst?

Substrate

What is a substance which an enzyme attaches to in order to lower the activation energy?

10^8 to 10^10 times faster

How fast can enzymes speed up a reaction?

Turnover number

What is the number of substrate molecules an enzyme converts to a product per second? (Generally 1 to 10,000, but can be as high as 500,000)

Oxidoreductase

What enzymes catalyzes oxidation-reduction reactions?

Transferase

What enzyme catalyzes the transfer of functional groups?

Hydrolase

What enzyme catalyzes hydrolysis?

Lyase

What enzyme catalyzes the removal of atoms without hydrolysis?

Isomerase

What enzyme catalyzes the rearrangement of atoms?

Ligase

What enzyme catalyzes the joining of molecule using ATP?

Apoenzyme

Enzyme components: Protein portion (inactive when alone)

Cofactor

Enzyme component: nonprotein component

Coenzyme

Enzyme component: Organic cofactor

Holoenzyme

Enzyme Component: Apoenzyme plus cofactor (whole, active enzyme form)

Temperature, pH, substrate concentrations, and inhibitors

What are four factors that influence enzyme activity?

Competitive inhibitors

What fills the active site of an enzyme and competes with the substrate?

Noncompetitive inhibitors

What interacts with another part of the enzyme (allosteric site) rather than the active site?

Feedback inhibition

What acts on the first enzyme in a metabolic pathway to allosterically inhibit the enzymes?

Ribozymes

What is RNA that functions as a catalyst by binding to substrates and acting upon them? These are used in cells to cut and splice RNA and they are involved in protein synthesis.

Oxidation

What is the removal of electrons?

Reduction

What is the gain of electrons?

Redox reaction

What is an oxidation reaction paired with reduction reaction?

Dehydrogenations

What are biological oxidations called?

Phosphorylation

What is the addition of a phosphate to a chemical compound?

Substrate-Level Phosphorylation

What is it called when ATP is generated when high-energy PO4- is directly transferred from a phosphorylated compound (substrate) to ADP?

Not very effective

What is the effectiveness of substrate-level phosphorylation?

Oxidative phosphorylation

What is it called when electrons are transferred from one electron carrier to another along an electron transport chain on a membrane that releases energy to generate ATP?

Photophosphorylation

What is it called when light energy is converted to chemical energy in the form of ATP during the transfer of electrons (oxidation) from chlorophyll as they pass through a system of carrier molecules?

Glucose

What is the most common carbohydrate energy source?

Cellular respiration and fermentation

What are the two general processes of carbohydrate utilization?

Glycolysis, Krebs cycle, and Electron Transport Chain (ETC)

What three steps does cellular respiration include?

Cytoplasm for both

Where does glycolysis occur in eukaryotes and prokaryotes?

Glucose is turned into two pyruvic acid molecules. Creates net 2 ATP and 2 NADH.

Briefly describe Glycolysis.

Pentose phosphate pathway

What is it called when glycolysis breaks down five-carbon sugars and produces NADPH? This can also provide intermediates for synthesis reactions.

Entner-Doudoroff pathway

What is it called when NADPH, NADH, and ATP are produces. This occurs in pseudomonas, rhizobium, and agrobacterium.

Oxygen

What is the final electron acceptor in aerobic respiration (glycolysis, Krebs cycle, electron transport chain)?

Another molecule besides oxygen

What is the final electron acceptor in anaerobic respiration?

Pyruvic acid is converted into Acetyl CoA and NADH

What happens in the transition step between glycolysis and the Krebs cycle?

Oxidation of acetyl CoA makes NADH, FADH2, and ATP. CO2 is a waste product.

What happens in the Krebs cycle?

A series of carrier molecules are oxidized and reduced as electrons are passed down the chain. Energy released is used to produce ATP by chemiosmosis.

What happens in the Electron Transport Chain (ETC)?

Plasma membrane (p) and inner mitochondrial membrane (e)

Where does the ETC take place in prokaryotes and eukaryotes?

Chemiosmosis

What is it called when electrons (from NADH) pass down the ETC while protons are pumped across the membrane? The protons in higher concentration on one side of the membrane diffuse through ATP synthase which releases the energy needed to synthesize ATP.

3 and 2

How many ATP molecules can be produces by NADH and FADH2?

Aerobic

Does anaerobic respiration or aerobic respiration produce more energy?

38 ATP

What is the total amount of ATP produced in aerobic respiration?

It doesn’t use the Krebs cycle or ETC and only produces small amounts of ATP.

Briefly describe fermentation?

Lactic acid fermentation

What produces lactic acid?

Homolactic fermentation

What is another name for lactic acid fermentation that only produces lactic acid?

Heterolactic fermentation

What is another name for lactic acid fermentation that produces lactic acid and other compounds?

Alcohol fermentation

What produces ethanol and CO2?

Streptococcus, Lactobacillus, Bacillus

Fermentation: What produces lactic acid?

Saccharomyces (yeast)

Fermentation: What produces ethanol and CO2?

Propionibacterium

Fermentation: What produces propionic acid, acetic acids, CO2, and H2?

Clostridium

Fermentation: What produces butyric acid, butanol, acetone, isopropyl alcohol, and CO2?

Escherichia, Salmonella

Fermentation: What produces ethanol, lactic acid, succinic acid, acetic acid, CO2, and H2?

Enterobacter

Fermentation: What produces ethanol, lactic acid, formic acid, butanediol, acetoin, CO2, and H2?

If they are deaminated, decarboxylated, and desulfurized, they can.

Can proteins and lipids enter the Krebs cycle?

By detecting enzymes.

In a biochemical test, how is bacteria identified?

Decarboxylation, deamination, fermentation, oxidation, and H2S production

What are five examples of biochemical tests?

Fermentation test

What is a test in which bacteria that catabolize carbohydrates or proteins produce acid, causing the pH indicator to change color?

Oxidase test

What test identifies bacteria that have cytochrome c oxidase (ex. Psedomonas)?

Light-dependent (light) reactions

Photosynthesis: What is the reaction in which light energy in converted into chemical energy (ATP and NADPH)?

Light-independent (dark) reactions

Photosynthesis: What is the reaction in which ATP and NASPH are used to reduce CO2 to sugar (carbon fixation) via the Calvin-Benson cycle?

Chemoheterotrophs

What are organisms that use chemicals as an energy source and organic compounds as a carbon source?

Chemoautotrophs

What are organisms that use chemicals as an energy source and CO2 as a carbon source?

Photoheterotrophs

What are organisms that use light for energy and organic compounds for a carbon source?

Photoautotrophs

What are organisms that use light as energy and CO2 for a carbon source?

Amphibolic pathways

What are metabolic pathways that function in both anabolism and catabolism?