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39 Cards in this Set
- Front
- Back
Describe what metabolism is.
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× Collection of ALL biochemical reactions that take place within cells of an organism
× The ultimate function of metabolism is to reproduce the organism |
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What are the two classes of chemical reactions in metabolism.
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× ANABOLISM:
-Building of complex molecules from simpler ones - Process by which all cell is built up - Energy requiring process (endergonic processes) × CATABOLISM - Process by which complex molecules are broken down into simpler ones- energy broken down into simpler ones- energy released (exergonic processes) |
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What are the processes of metabolism?
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× Nutrient uptake
× Conversion of nutrients into cell components × Conversion of nutrients into energy × Excretion of waste products × *compounts are taken in, converted, and some are made into waste and excreted |
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What are Enzymes.
HINT: chemical reactions within the cell are directed by enzymes |
× Protiens that catalyze (accelerate) chemical reactions
× They are specific; they catalyze a single type of chemical reaction × During the reaction they do not permanently change (*so they can start a new reaction) and can be reused × The enzyme molecule is bigger then a substrate molecule and serves as physical site for reaction |
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How do enzymes work?
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× They catalyze the reaction by lowering activation energy
× Activation energy is the energy needed to disrupt the stable chemical bonds |
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Name the parts of the enzyme structure.
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× Apoenzyme (protien)
× Cofactor- non protein (metal ion × Coenzyme- organic molecule( Type of cofactor) (vitamins) × Cofactor or coenzyme placed together with apoenzyme make holoenzyme( Conjugated enzyme) |
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What is an active site of an Enzyme?
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× Tertiary and quaternary structure provide the active site- the site where the substrate binds (groove)
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Describe enzyme-substrate interaction.
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× Substrate and enzyme make a temporary union
× Substrate is inserted into the active site × The process is reversible |
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What are the roles of coenzymes.
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× Removes of donates atoms from or to a substrate
× Electron carriers (remove electrons from the substrate; transfer them to other molecules) × Many enzymes are vitamins × Most important enzymes: - Nicotinamid adenin dinucleotide (NAD+)—catabolic reaction - Nicotinamid adenin dinucleotide phosphate (NADP+)—anabolic reactions - Derrives of B vitamin |
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What do vitamin deficiencies prevent?
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it prevents the honoenzyme from being formed.
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Describe the mechanism of enzymatic action.
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× Enzyme attaches to the substrate at the active site
× Enzyme-substrate complex is formed × Substrate molecule is transformed—products of the reaction are released × The unchanged enzyme can start a new reaction × *example shown… fructose is the substrate being placed within the enzyme biphosphate aldolase |
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What are the 6 types of enzymes based on mode of action.
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× Hydrolases- breaking of bonds with addition of water
× Isomerases- rearrangement of atoms × Ligases- joining of two molecules with the removal of water × Lyases- removal or adding of groups of atoms without hydrolysis × Oxidoreductases- transfer of electron from one substrate to another × Transferases- transfer of functional group |
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Explain synthesis reaction in metabolism.
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× Synthesis
Anabolic reactions in which two molecules are united into a new bigger molecule - This dehydration reaction (ATP used and H20 molecule is released) |
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Explain hydrolysis (digestion) reaction in metabolism.
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× Hydrolysis
- Digestion of macroMolecules - Breaking the bonds require an imput of H20 (*one water molecule is added) |
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Describe oxidation-reduction reactions
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× Oxidation- removal of electrons (+energy)
Note: Compound that looses electron is oxidized. × Reduction- gain of electrons Note: Compound that receives electron is reduced. × These reactions are always coupled × *once electrons are removed they must be attached to another… so oxidation always happens around the same time as reduction |
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Describe enzymes sensitivity to their environment.
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× Environmental factors affect the activity of the enzymes
× The enzymes are unstable in extreme conditions (high temperatures, extreme pH, osmotic pressure) × These conditions cause- Denaturation- the shape of the enzyme molecule is changed |
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Why is denaturation bad for enzymes?
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It changes the shape of the enzyme molecule, so it prevents substrate from attaching.
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Describe Ribozymes in metabolism.
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× Some RNA molecules called ribozymes can act as a catalyst
× Active on RNA strands only × Removes sections of RNA joining together the remaining pieces |
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What are the two types of enzyme control?
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- Constitutive- present in constant amounts
- Regulated- their concentration is regulated by two different things |
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In enzyme regulated control, what are the two ways of regulated control.
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× Direct control:
o Competitive inhibition o Noncompetitive inhibition × Control of enzyme synthesis o Enzyme repression o Enzyme induction |
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Describe competitive inhibition.
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× Substances with similar structure as the real substrate bind to the enzyme's active site, preventing substrate to bind.
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Describe noncompetitive inhibition.
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× Interact with another part of the enzyme- allosteric site
× Causes changing the shape of the active site Enzyme with 2 sites, active site and regulatory site. Enzymes are regulated by binding of molecules other than the substrate in their regulatory site. |
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What are the two controls of enzyme synthesis.
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x Repression
- The excess of the end product suppresses the synthesis of enzyme × Induction - Presence of a particular substrate induces the synthesis of the relevant enzyme |
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What are the two types of energy transactions?
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- Exergonic- release of energy
× X + Y ---enzyme---> Z+ Energy (release) - Endergonic- consumption of energy × Energy + A + B --- Enzyme---> C |
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What is catabolism?
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getting materials and energy
× Glucose is the most frequent nutrient used for obatining energy × There are three metabolic pathways which glucose is transformed - Glycolysis - Aerobic respiration (Krebs cycle) ( Electron transport chain) - Anaerobic respiration (fermentation) |
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What are the 3 stages of respiration of glucose?
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× Glycolysis
× The krebs cycle × Electron transport chain system |
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Where does gyclolysis occur?
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×Occurs in cytoplasm of most cells
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Describe the proces of glyclolysis.
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× Involves splitting of a six-carbon glucose
× Direct transfer of phosphate between two substrates- substrate level phosphorylation × Net gain of - Two ATP molecules - Two molecules of NADH - Pyruvic acid × Three-carbon molecules are oxidized to - Two molecules of pyruvic acid - 2 NAD 1 NADH+ - 4 ATP formed - Energy balance of glycolysis = 2 ATP |
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What is substrate level of Phosphorilation?
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× High energy P directly transferred from a substrate to ADP
× C-C-C~P + ADP -------> C-C-C+ATP |
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Describe the krebs cycle (tricaboxylic acid cycle).
HINT: pg.228 |
× A series of biochemical reaction in which chemical energy is released stop by step
× Starting compound is pyruvic acid (from glycolysis) which Is transformed into Acetyl CoA × Acetyl CoA is decaboxilated (loss of CO2 molecule) and entered into tricarboxylic acid cycle × The reduced coenzymes are formed NAHH+ and FADH2 (energy stored)- enter the Respiratory Chain × In this cycle ATP, NADH, and FADH are formed × NADH and FADH enter the electron transport chain |
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Describe the electron chain transport.
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× Sequence of carrier molecules that can be oxidized and reduced
× Located in plasma membrane of prokaryotic cells of in mitochondria in eukaryotic cells × Energy is released by transfer of electron from hgih energy to lower energy compounds × Protons (H+) are actively pumped out |
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What is the net yield of ATP of glycloloysis, krebs cycle and electron chain transport.
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Glyclolysis= 2 ATP
Krebs= 2 ATP Electron chain= 34 ATP TOTAL= 38 |
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What is chemoiosmosis?
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As the electron transport carriers shuttle electrons, they actively pump hydrogen ions (protons) into the outer compartment of the mitochondrion.
× Acumulated protons (H+) from outer compartment diffuse through the ATP synthase to inner compartment × Rotation of the ATP synthase causes bonding of ADP and Pi --> ATP × Cytochrome aa3 catalizes the reaction between H+ and O2 --> H2O |
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What is anaerobic respiration?
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Fermentation
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Describe fermentation.
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× Further oxidation of Pyruvic acid (obtained in glycolysis) without the presence of 02
× Partial oxidation without the presence of O2 × Final product is organic molecule (not H20) × Only small amounts of ATP is revovered × Different bactreia perform different types of fermentation × Final product: lactic acid, ethanol, propionic acid, CO2, H2, acetic acid, etc. |
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What is photosynthesis?
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× light energy --> ATP, NADPH = Synthesis of organic molecules
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Describe photosynthesis.
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× Conversion of light energy into chemical energy
× Present in plants and photosynthetic bacteria and algae- Photoautotrophs × Chemical energy used for conversion of CO2 into reduced carbon compounds (sugars) |
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WHat are the two stages of photosynthesis.
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× 1. Light dependent stage (reactions)
- (light energy converted into ATP- photophosphorilation *when you convert light into ATP* - Light --> Chlorophyll--> e- --> electron transport chain ---chemiosmosis-->ATP - Electrons from chlorophyll are replaced by electrons from water × 2. Light independent stage (reactions) - (ATP produced in the previous stage is used to reduce CO2 into sugars) *light independent reactions gets the energy made in the first stage and breaks it down into glucose* |
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What is osygenic and anoxygenic?
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× Osygenic- plants, algae, cyaenobacteria
6CO2+ 12H20+ Light Energy = C6H12O6 + H20 + 6O2 602= end product × Anoxygenic- *is* purple sulgur, and green sulfur bacteria 6CO2+ 12 H2S + Light energy = C6H12O6 +H20+ 12S 12S= End product |