Chapter Eight (quiz four) – Flashcards
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| Metabolism |
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| all chemical reactions and physical work of the cell |
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| Functions of Metabolism |
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| 1. Assembles smaller molecules into larger macro-molecules needed for the cell 2. Degrades macro-molecules into smaller molecules and yields energy 3. Energy is conserved into the form of ATP or HEAT |
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| Anabolism (biosynthesis) |
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| Any process that results in the synthesis of cell molecules and structures (usually requires energy input) -making new molecule from existing parts |
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| Catabolism |
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| the breakdown of bonds of larger molecules into smaller molecules (often releases energy) |
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| Enzymes? |
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| are proteins that work as catalysts |
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| Catalysts |
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| chemicals that increas the rate of a chemical reaction without becoming part of the products of being consumed in the reaction |
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| What do catalysts do to activation engery |
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| lower it |
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| What is unique about each catalyst? |
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| unique characteristics such as shape, specificity and function |
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| Substrates? |
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| target molecule; each enzyme has a active site for these |
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| What are enzymes greatly effected by |
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| temperature and pH |
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| 1st enzyme in glycolysis? |
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| Hexokinase |
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| Energy of Activation |
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| the amount of energy which must be overcome for a reaction to proceed |
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| How do enzymes promote a reaction? |
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| by serving as a PHYSICAL SITE upon which the reactant molecules (substrates) can be positioned for various interactions |
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| Enzyme-substrate interaction |
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| -for a reaction to take place, a temporary enzyme-substrate union must occur at the active site -"lock and key" fit -these bond are weak and easily reversible |
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| What is an ES complex? |
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| the enzyme and substrate bound together |
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| What are cofactors? |
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| supporting the work of enzymes |
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| Metallic cofactors? |
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| activate enzymess, help bring the active site and substrate close together, and participate directly in chemical reaction with the enzyme-substrate complex |
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| Coenzymes are? |
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| Organic compounds that work in conjunction with a apoenzyme to preform a necessary alteration of a substrate |
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| Coenzymes do? |
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| remove a chemical group from one substrate molecule and adds it to another substrate |
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| What is one of the most important components of coenzymes? |
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| VITAMINS |
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| Holoenzyme? |
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| apoenzyme (protein enzyme) + co-factor = holoenzyme = catalyzes actual function/reaction |
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| Classification of enzymes? (3 ways) |
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| 1. Site of action 2. type of action 3. substrate in which they work with |
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| hydrolase (enzyme) |
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| breaks down lactose down into glucose and galatose AND hydrolyzes beta-lactam ring |
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| transferase (enzyme) |
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| synthesizes a strand of DNA using the complementary strand as a model |
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| oxidoreuctase (enzyme) |
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| catalyzes the conversion of pyuvric acid to lactic acid AND catalyzes the reduction 02 |
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| Constitutive Enzymes? |
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| always present and in relatively constant amounts (ex. enzymes of glycolysis) |
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| Regulated enzymes? |
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| Production is either induced or repressed in response to a change in the concentration of the substrate (ex. lactose (lac) operon in E. coli) |
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| Lac operon in E. coli? |
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| the E. coli n the presence of lactose turns on its enzymes to break down lactose... regulated enzyme you fool! |
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| Dehydration recation |
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| water is one of the products |
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| Hydrolysis |
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| breaking down peptide bonds between amino acids. requires a water molecule that adds H and OH to the amino acids |
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| Virulence factors or toxins |
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| -unique exoenzymes that pathogens secrete -these help them avoid host defenses or promote multiplication in tissues |
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| Labile enzymes? |
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| when enzymes are subjected to changes in normal conditions they become unstable or labile |
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| Denaturation? |
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| the weak bond that maintain the native shape of the apoenzyme are broken |
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| Enzymes that play a role in necessary molecular conversions by directing the transfer of function groups |
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| -aminotransferases -phosphotransferases -methyltransferases -decarboxylases |
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| How do metabolic reactions usually occur? |
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| in a multi-series step or pathway -each step is catalyzed by an enzyme -each pathway has one or more enzyme pacemakers that set the rate of a pathway's progression |
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| What are intermedates in a metabolic pathway? |
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| Not the start or finished product... DUH |
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| Competitive inhibition? |
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| It is a direct control on the action of enzymes -the cell supplies a molecule that resembles the enzyme's normal substrate, which then occupies and blocks the enzyme's active site |
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| Non-Competitive inhibition? |
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| direction controls on the action of enzymes -the enzymes has TWO binding sites- the active site and the regulatory site; a regulator molecule binds to the regulatory site providing a negative feed back mechanism |
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| Enzyme Repression? |
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| Decrease enzyme expression (product goes back to DNA and says "ENOUGH!") |
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| Enzyme Induction? |
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| Increase enzyme expression (product goes back to DNA and says "MORE MORE") |
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| Exergonic Reactions? |
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| a reaction that releases energy as it goes forward: -delta G usually catobolic RXNS |
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| Engergonic Reactions? |
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| a reaction that is driven forward with the addition of energy: +delta G usually anabolic RXNS |
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| Redox reaction |
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| how biological systems extract energy, always occur in pairs (an electron donor paired with an electron acceptor |
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| Electron Carriers |
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| Repeatedly accept and release electrons and hydrogen -some are coenzymes that transfer electrons and hyrogens -ex. NAD, FAD, NADP |
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| ATP |
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| adenosine triphosphate -Metabolic Money |
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| ATP molecular structure |
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| -nitrogen base -5 carbon sugar -chain of three phosphate group |
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| How does ATP yield energy |
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| breaking of bonds between two phosphates of ATP yeilds ADP plus the inorganic phosphate -the most energy comes from breaking the 3rd group |
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| how much energy comes from ATP |
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| -7.3 kcal/mol |
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| Substrate Level Phosphorylation |
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| phosphate off substrate to ATP OR the transfer of phosphate group - phosphoenolpyruvate+ADP -> pyruvate+ATP |
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| What is a pathway? |
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| a series of biochemical reactions |
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| what is often the nutrient going through catabolism? |
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| glucose! |
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| What are the three major catabolism pathways? |
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| 1. Aerobic respiration 2. Fermentation 3. Anaerobic Respiration |
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| Aerobic Respiration? |
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| series of reactions that convert glucose to CO2 and allows the cell to recover significant amounts of energy; requires OXYGEN (makes water) |
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| Fermentation? |
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| use only glycolysis to incompletely oxidize glucose |
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| Anaerobic respiration? |
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| does not use molecular oxygen as the final acceptor |
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| Anaerobic random ifo |
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| -its a series of enzyme-catalyzed reactions -electrons are transfered from fuel molecules to oxygen as a final electron acceptor -provides ATP and metabolic intermediates for many other pathways -glucose is the starting compound |
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| What does glycolysis convert glucose to? |
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| it goes through several steps into pyruvic acid OR pyruvavte |
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| 3 phases of glycolsis |
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| 1st phase: 2 ATP taken in 2nd phase: 2 three carbon molecules made 3rd phase: making 4 ATP and 2 NADH |
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| Products of Glycolysis |
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| -2 pyruvate molecules (can under go more catabolic RNX to extract more energy) -2 ATP -2 NADH |
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| What does Glycolysis convert glucose into? |
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| Pyruvate |
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| 3 phases of pyruvate |
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| 1st: 2 atp taken in 2nd: 2 three carbon molecules made 3rd: making 4 atp and 2 nadh |
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| Products of Glycolysis |
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| 2 pyruvate molecules 2 ATP 2 NADH |
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| What does pyruvic acid serve as? |
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| an important position in several pathways |
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| Krebs Cycle take place where? |
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| in the cytoplasm of bacteria and mitochondrial matrix in eukaryotes |
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| Products of krebs cycle? |
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| 1 glucose molecule makes 2 pyruvate each pyruvate makes: 3 CO2, 4 NADH, 1 FADH2, 1 ATP so total 8 NADH 2 FADH2 2 ATP |
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| After Krebs cycle what is up with glucose? |
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| It has now be completely oxidized to carbon dioxide |
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| What is the final processing mill |
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| electron transport chain |
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| What do electrons pass through in the electron transport chain? |
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| membrane carries called CYTOCHROMES |
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| How is atp formed in electron transport chain |
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| the protons pass through ATP synthase to form ATP this is an endergonic reaction-- energy comes from protons moving down the gradient |
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| 1 FADH2 = _____ ATP |
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| 2 |
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| 1 NADH = ____ ATP |
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| 3 |
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| Aerobic respiration yields....? |
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| 36-38 ATP per gulcose |
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| Anaerobic respiration |
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| functions like aerobic system except it utilizes oxygen-containing ions rather than free oxygen as the final electron acceptor |
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| Anaerobic Respiration yield? |
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| 2-36 ATP |
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| Fermentation is..? |
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| the incomplete oxidation of glucose or other carbohydrates in the absence of oxygen |
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| What does fermentation use as the terminal electron acceptor |
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| organic compounds |
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| How are bacteria able to grow as fast using fermentation as they would in the presence of O2 |
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| they increase the rate of glycolysis.. the 2 ATP build up |
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| Products of fermentation? |
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| alcoholic beverages, organic acids, dairy products, vitamins, antobiotics |
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| Two general categories of fermentation? |
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| 1. Alcoholic fermentation 2. Acidic Fermentation |
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| Commonality between Alcoholic and Acidic Fermentation |
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| NADH getting reformed into NAD... this allows glycolysis to continue |
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| Alcoholic fermentation products |
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| ethanol, CO2 and NAD |
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| Acidic Fermentation products |
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| varied... but always lactic acid |
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| lactic acid bacteria fermentation product |
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| they ferment pyruvate and reduce it to lactic acid (occurs in our muscles) |
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| Heterolactic fermentation |
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| when glucose is fermented to a mixture of lactic acid, acetic acid, carbon dioxide and NAD |
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| Mixed acid fermentation |
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| Produced a combination of acetic, lactic, succinic and formic acids and lowers the pH of a medium to about 4 |
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| homolactic bacteria? |
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| S. coccus or latobacilus form lacti acid... souring of milk |
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| Amphibolism |
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| The property of a system to integrate catabolic and anabolic pathways to improve cell efficiency |
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| where do monosaccharides, amino acids, fatty acids, nitrogen bases and vitamins come from (in regards to anabolism) |
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| 1. enter the cell from outside as nutrients 2. Can be synthesized through various cellular pathways |
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| Amino acids, protein synthesis and nucleic acid synthesis? |
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| some organisms can synthesize all 20 amino acids other organisms (especially animals) must acquire the essential ones from their diets |
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| Assembly of the cell |
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| when anabolism produces enough macro-molecules to serve two cells, then the cell undergoes binary fisson |
