Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
127 Cards in this Set
- Front
- Back
|
Phosphofructokinase |
Considered the pacemaker of respiration (allosteric enzyme with receptor sites for specific inhibitors and activators) |
|
|
Catabolic pathways and ATP |
Organic compounds possess potential energy due to electron arrangement, act as fuel Through enzymes, cells degrade these organic compounds to products with less energy Some is used for work, rest is heat Fermentation and cellular respiration (aerobic and anaerobic) |
|
|
Degradation of glucose |
Exergonic, store less energy than the reactants, can happen spontaneously Free energy change of -686 kcal |
|
|
Cellular respiration |
Both aerobic and anaerobic process Used mostly to describe aerobic A combustion reaction Carbs, fats, and proteins can be used for fuel |
|
|
Aerobic respiration |
Most efficient catabolic way Oxygen is consumed as a reactant with another organic fuel (organic molecules)-produces ATP Most eukaryotic and prokaryotic cells can do this |
|
|
Anaerobic respiration |
Mostly with prokaryotic cells Use substances other than oxygen as reactants to get chemical energy (fermentation) |
|
|
How do catabolic pathways that decompose glucose and other organic fuels yield energy? |
Based on transfer of electrons during chemical reactions which releases energy used to in ATP |
|
|
Redox reactions |
Oxidation and reduction occurs The transfer of electrons during chemical reactions stored in organic molecules Shifts to a more electronegative atom (closer to oxygen) releases energy |
|
|
Oxidation |
Loss of electrons from a substance |
|
|
Reduction |
Addition of electrons to another substance (Reduces positive charge) |
|
|
Reducing agent |
The electron donor The one that is oxidized or loses an electron It does the reducing |
|
|
Oxidizing agent |
The electron acceptor The substance being reduced it does the oxidizing |
|
|
The more electronegative the atom... |
The more energy needed to take the electron away (to oxidize it) |
|
|
Oxidation of organic fuel molecules in cellular respiration |
Glucose is oxidized and oxygen is reduced The electrons lose energy along the way and energy is released Molecules that have an abundance of hydrogen are excellent fuels |
|
|
Hydrogen is transferred from what to what? |
Glucose to oxygen The energy state of the electron changes as hydrogen (with its electron) is transferred to oxygen |
|
|
Fuels with multiple C-H bonds oxidized into products with |
Multiple C-O bonds |
|
|
Nicotinamide adenine dinucleotide (NAD) |
A coenzyme Derived from vitamin niacin Organic molecules are first transferred to NAD Carries hydrogen atoms to oxygen Cycles easily from its oxidized form NAD to its reduced form NADH Each NADH represents stored energy |
|
|
How does NAD trap electrons? |
Dehydrogenases (enzyme) remove a pair of hydrogen atoms (2 electrons and 2 protons) from the substrate, thereby oxidizing it Delivers 2 electrons and 1 proton to NAD reducing it to NADH |
|
|
Most versatile electron acceptor |
NAD It is involved in several of the redox steps during the breakdown of glucose Functions as a oxidizing agent |
|
|
Electron transport chain |
A number of molecules mostly proteins built into the inner membrane of the mitochondria in eukaryotic cells and the plasma membrane in prokaryotic cells Electrons moved to top higher energy end of the chain and at the bottom lower energy end O captures those electrons along with H forming water |
|
|
Each downhill carrier is more |
Electronegative than its uphill neighbor This capable of oxidizing |
|
|
3 metabolic (pathway) stages of cellular respiration |
Coupled with ATP to harvest energy of glucose 1. Glycolysis (breaks down glucose into two molecules) 2. Pyruvate oxidation and the citric acid cycle (completes breakdown of glucose) 3. Oxidative phosphorylation (accounts for most of ATP synthesis) |
|
|
Glycolysis |
Breaks down molecules into 2 molecules of a compound called pyruvate Occurs in cytosol Harvest chemical energy by substrate-level phosphorylation |
|
|
Pyruvate |
Two molecules of a compound formed from the degradation of glucose Enters the mitochondria and is oxidized to a compound called acetyl CoA |
|
|
Citric acid |
Breakdown of glucose to CO2 (Krebs cycle) In prokaryotes takes place in cytosol Some of the steps involve redox reactions Pyruvate enters mitochondrion matrix and is oxidized to Acetyl CoA By substrate level phosphorylation |
|
|
Oxidative phosphorylation |
Synthesis of ATP (powered by redox reaction) 3rd stage where the electron transport chain accepts electrons from NADH or FADH (generates during the first two stages) At end of chain, Electrons form water Energy released at each step is stored in a form that mitochondrion can use to make ATP |
|
|
Chemiosmosis |
Process making up oxidative phosphorylation Site where electron transport occurs on the inner membrane of mitochondrian powering ATP |
|
|
Substrate-level phosphorylation |
S mall amount of ATP is formed in a few reactions of glycolysis and citric acid Occurs when enzymes transfer a phosphate group from a substrate molecule to ADP rather than adding an inorganic phosphate |
|
|
Energy flows into the ecosystem as...and leaves as... |
Sunlight and heat |
|
|
ATP powers cellular work by coupling... |
Exergonic and endergonic reactions Use exergonic process to drive an endergonic one 3 types of cell work: chemical, transport, mechanical |
|
|
Regeneration of ATP |
Endergonic process requiring energy Renewable resource (generates by adding a phosphate grp to ADP) Energy from adding a phosphate group comes from catabolic reactions(cellular respiration) in cell ie: a working muscle cell recycles all it’s ATP once each minute (more than 10 million ATP molecules per second per cell) |
|
|
Photosynthesis |
Generates oxygen and organic molecules which are used in cellular respiration Light energy from sun powers a chemical process that makes organic molecules These molecules set stage for stored energy and ATP through h the catabolic reactions (cellular respiration) |
|
|
Catabolic pathways get energy by... |
Oxidizing organic molecules (these molecules possess potential energy as a result of the arrangement of electrons) Breakdown of these molecules=Exergonic reaction |
|
|
Redox in photosynthesis |
Hydrogen atoms are transferred from water to CO2 and glucose is formed (more energy is needed to pull an electronegative atom away) Chloroplasts concert solar energy to ATP to use to reduce CO2 to glucose |
|
|
Redox summary |
Back (Definition) |
|
|
Summary of NAD and FAD |
Back (Definition) |
|
|
Electron transfer |
From glucose To oxygen Start out with more energy but lose more after each transfer Stairs-after each step they release energy and it is captured in ATP This prevents an explosion of energy |
|
|
The quantity of ATP is appropriate for.. |
Energy level of work needed in cell Cell makes up to 32 molecules of ATP Each molecule is 7.3 kcal of free energy |
|
|
Glycolysis |
Breaks down glucose into 2 pyruvate Energy investment phase and energy payoff phase Occurs whether or not O2 is present Initial step-enzyme mediated-occurs in cytoplasm-ATP synthesized by substrate phosphorylation |
|
|
Energy investment phase |
Cell spends ATP Kinase transfers of phosphate grips Mutate movement of functional group within molecule Isomerase converts molecule from isomer to another Aldolase reversible conversion of fructose |
|
|
Energy payoff phase |
This investment is repaid with interest ATP is producer by substrate-level phosphorylation and NAD is reduced to NADH by electrons |
|
|
Oxidation of pyruvate to Acetyl CoA |
Link glycolysis to the citric acid cycle Pyruvate is converted into Acetyl coenzyme A Carries out by pyruvate dehydrogenase complex |
|
|
Pyruvate dehydrogenase complex |
1. Carboxyl group is removed as CO2 (CO2 has little energy due to being oxidized) 2. Remaining 2-Carbon fragment is oxidized to form acetate. An enzyme transfers the pair of electrons to NAD to form NADH 3. Acetate combined with coenzyme A to form molecule Acetyl CoA |
|
|
Electrons are passed through a number of proteins including... |
Cytochromes Each with an iron atom that accepts and donates electrons to O2 |
|
|
To prepare pyruvic acid to enter citric acid cycle |
Back (Definition) |
|
|
The citric acid cycle was created by... |
Krebs cycle (Hans kreb 1930) Completes breakdown of pyruvate to CO2 |
|
|
The cycle oxidizes organic fuel derived from... |
Pyruvate Releases: 1 ATP- 3 NADH- and 1FADH per turn |
|
|
Citric acid cycle has...steps |
8 and each step is catalyzed by a specific enzyme The Acetyl CoA joins the cycle by combining with oxaloacetate forming citrate The next 7 steps decompose the citrate back to oxaloacetate |
|
|
Only place where H+ molecules can diffuse back to the matrix |
ATP synthase |
|
|
Has a tendency to diffuse down its gradient |
H+ |
|
|
Oxidative phosphorylation |
Most of the ATP produced by respiration Occurs when the NADH and The FADH produces by the citric acid cycle relay the electrons to the electron transport chain Phosphorylation of ADP to ATP |
|
|
Pathway of the electron transport |
Back (Definition) |
|
|
Proton-motive force |
H+ gradient The force drives H+ back across the membrane through ATP synthases |
|
|
Electron transport is located in the.. |
Cristae (the folded inner membrane of the mitochondrion) It’s a collection of molecules, most of the chains components are proteins which exist in multiprotein complexes |
|
|
2 of 3 reasons |
ATP yields vary slightly friending on the type of shuttle used to transport electrons in cytosol |
|
|
Chemiosmosis |
The energy-coupling mechanism Energy released as electrons are passed down the electron transport chain is used to pump H+ from the mitochondrial matrix to the inter membrane space This creates a higher concentration of H+ and it diffuses back to the cristae through diffusion (ATP synthase) |
|
|
ATP synthase |
Uses exergonic flow of H+ to drive phosphorylation of ATP H+ binds to sites on rotor causing it to spin in a way that catalyzes phosphorylation of ADP to ATP (Example of chemiosmosis: use of energy in an H+ gradient to drive cellular work) |
|
|
Efficiency of cellular respiration |
I |
|
|
Fermentation uses and electron transport chain with a final electron acceptor other than |
Oxygen Sulfate with H2S produced rather than H2O |
|
|
Fermentation uses this instead of electron transport |
Substrate-level phosphorylation |
|
|
Two types of fermentation |
Alcohol fermentation Lactic acid fermentation |
|
|
Alcohol fermentation |
Only occurs in bacteria and yeast Yeast used in brewing wine making baking Pyruvate is converted into ethanol in 2 steps |
|
|
Pyruvate dehydrogenase complex |
1. Carboxyl group is removed as CO2 (CO2 has little energy due to being oxidized) 2. Remaining 2-Carbon fragment is oxidized to form acetate. An enzyme transfers the pair of electrons to NAD to form NADH 3. Acetate combined with coenzyme A to form molecule Acetyl CoA |
|
|
2 steps of alcohol fermentation |
1. Releases CO2 2. Produces ethanol |
|
|
Number of ATP produced in cellular respiration |
30-32 |
|
|
Efficiency of cellular respiration |
Back (Definition) |
|
|
A sulfer-containing compound derived from a B vitamin |
Acetyl CoA Has a high potential energy Exergonic |
|
|
To prepare pyruvic acid to enter citric acid cycle |
I |
|
|
The citric acid cycle was created by... |
Krebs cycle (Hans kreb 1930) Completes breakdown of pyruvate to CO2 |
|
|
Alcohol fermentation |
Only occurs in bacteria and yeast Yeast used in brewing wine making baking Pyruvate is converted into ethanol in 2 steps |
|
|
Citric acid cycle has...steps |
8 and each step is catalyzed by a specific enzyme The Acetyl CoA joins the cycle by combining with oxaloacetate forming citrate The next 7 steps decompose the citrate back to oxaloacetate |
|
|
Lactic acid fermentation |
Pyruvate is reduced by NADH to form NAD and lactate as products ( no release if CO2) With some bacteria/fungi used to make cheese and yogurt Muscle cells use it to generate ATP during strenuous exercise when oxygen is scarce |
|
|
How many ATP are produced through substrate-level phosphorylation? |
4 of the 32 2 net ATP from glycolysis and 2 ATP from citric acid cycle NADH and FADH2 account for most of the energy extracted from glucose |
|
|
Comparing fermentation with anaerobic and aerobic respiration |
Different mechanisms for oxidizing NADH Fermentation: an organic molecule (pyruvate or acetaldehyde) acts as final electron acceptor Cell respiration: electrons are transferred to electron transport chain Produces 2 ATP versus 32 ATP per glucose molecule |
|
|
7 small biomolecules |
NADH, FADH, CO2, O2, ATP, H2O, NH4 |
|
|
Obligate anaerobics |
Carry out fermentation or anaerobic respiration Cannot survive the presence of O2 But use SO4 (cause tetanus and gangrene |
|
|
Facultative anaerobes |
Yeast and many bacteria Can survive using either fermentation or cell respiration Pyruvate is a fork in the metabolic road that leads to 2 catabolic routes Cellular muscle |
|
|
Evolution and glycolysis |
Ancient process Early prokaryotes likely used glycolysis to produce ATP before O2 accumulated in the atmosphere Occurs in cytosol so does not need organelles of eukaryotic cells |
|
|
Proteins must be digested to amino acids |
Amino groups removed via deamination Nitrogenous waste is excreted as NH3, urea, or another waste product |
|
|
Fats are digested to |
Glycerol and fatty acids (used in Acetyl CoA) Fatty acids are broken down into 2 carbon fragments via beta oxidation and yield actual CoA, NADH, and FADH An oxidized gram of fat produces more than twice as much ATP as an oxidized gram of carbohydrate |
|
|
Metabolic pathways |
4 classes of macromolecules 6 primary metabolites 7 small biomolecules |
|
|
Metabolic pathways |
4 classes of macromolecules 6 primary metabolites 7 small biomolecules |
|
|
4 classes of macromolecules |
Protein Nucleic acids Carbohydrates Lipids |
|
|
6 primary metabolites |
Amino acids, nucleotides, glucose, fatty acids, pyruvate, Acetyl CoA |
|
|
Glycolysis and citric acid cycle function as |
Metabolic interchanges Allowing cells to convert one molecule to another as needed Excess carbs and proteins can be converted into fats |
|
|
Metabolism is... |
Versatile and adaptable |
|
|
Feedback inhibiton |
Metabolic control If ATP concentration drops, respiration speeds up If ATP is plentiful, respiration slows down |
|
|
Phosphofructokinase |
Considered the pacemaker of respiration (allosteric enzyme with receptor sites for specific inhibitors and activators) |
|
|
The energy that keeps us alive is what, not what? |
Released, not produced |
|
|
3 categories of Poisons (interference of cell respiration) |
1. Rotenone 2. Cyanide 3. Carbon monoxide |
|
|
Glycolysis and citric acid cycle function as |
Metabolic interchanges Allowing cells to convert one molecule to another as needed Excess carbs and proteins can be converted into fats |
|
|
Metabolism is... |
Versatile and adaptable |
|
|
Feedback inhibiton |
Metabolic control If ATP concentration drops, respiration speeds up If ATP is plentiful, respiration slows down |
|
|
Phosphofructokinase |
Considered the pacemaker of respiration (allosteric enzyme with receptor sites for specific inhibitors and activators) |
|
|
The energy that keeps us alive is what, not what? |
Released, not produced |
|
|
3 categories of Poisons (interference of cell respiration) |
1. Electron transport chain blockers: prevent ATP synthesis (Rotenone, Cyanide, Carbon monoxide) 2. ATP synthase inhibitors 3. Uncouplers |
|
|
Rotenone (pesticide) |
Interferes with ETC by inhibiting the transfer of electrons from iron-sulfur centers Interferes with NADH during the creation of usable cellular energy ATP |
|
|
Cyanide |
Inhibits enzyme in the mitochondria called cytochrome c oxidase (last enzyme in ETC) |
|
|
Carbon monoxide |
Combines with hemoglobin to form caroxyhemoglobin in the blood Prevents hemoglobin from releasing oxygen in tissues, reducing the oxygen-carrying capacity of blood |
|
|
ATP synthase inhibitors |
Blocks passage of H ions Cell cannot use potential energy gradient to make ATP ie: obligomycin: reduces flow of electron through ETC but some continues through diffusion of a uncoupling protein (thermogenesis) |
|
|
Uncouplers (3of 3 categories) |
Makes membrane of mitochondria leaky to H No H ions concentration gradient, no ATP ie: dinitrophenol: inhibitor of ATP production, uncouples oxidative phosphorylation by carrying protons across the mito. Membrane, rapidly consumes energy without generating ATP |
|
|
Diseases of cellular metabolism |
Glycolytic mutations Cancer Alzheimer’s Leigh’s syndrome |
|
|
Glycolytic mutations |
Rare Result in an inability for cell to respire Death of cell at early age |
|
|
Cancer |
Warburg effect (1930)-malignant rapidly growing tumor cells (glycolic rates 200 times higher than normal) Caused by dysfunctionality in mito. Metabolism rather than bc of uncontrolled growth of cells Increased glycolysis is a normal protective process of the body and that malignant change could be primarily caused by energy metabolism |
|
|
Leigh’s syndrome |
Rare neurological in children CNS degenerates, motor skills and muscle movement weaken Related to problems with cell respiration Breakdowns in both ETC and the conversion of pyruvate to Acetyl CoA Slower metabolism and take up less oxygen and glucose Treatment: vitamins (necessary in cell respiration) like thiamin, coenzyme Q10, C, K, and E |
|
|
Fructose-1 6-phosphate |
Molecule that possesses most chemical energy during glycolysis Receives 2 phosphate groups from ATP, conserving some of the energy derived from hydrolysis of ATP in this molecule |
|
|
When protein molecules are used for cell respiration, what is produced as waste? |
Amino groups |
|
|
Most of NADH is produced during which cycle |
Citric acid cycle |
|
|
Why is the citric acid cycle called a cycle |
The 4 carbon acid that accepts Acetyl CoA in the first step is regenerated by the last step of the cycle |
|
|
How many molecules of ATP are gained by substrate-level phosphorylation from a single molecule of glucose? |
4 A net gain of 2 from glycolysis 1 from each molecule of Acetyl CoA oxidized in citric acid cycle |
|
|
What is the energy produced by citric acid cycle |
Each turn release: CO2 1 ATP by oxidative phosphorylation Passes 3 NAD and 1 FAD |
|
|
Electrons from oxidation of glucose are used to |
Reduce NAD and produce a proton gradient for ATP synthesis |
|
|
How efficient is the process of cell respiration |
About 38% Rest is lost in heat |
|
|
Source of energy that produces the chemiosmotic gradient in mito. |
Movement of electrons down the ETC |
|
|
What purpose does recruitment of blood vessels to growing tumors serve? |
Supplies oxygen for cell respiration rather than fermentation And supplies glucose to rapidly dividing cells Anti-cancer drugs attempt to block this process of recruitment |
|
|
Extra step in fermentation during glycolysis |
Enables cell to recycle NADH to NAD Usually these would be used in ETC |
|
|
Fructose-1 6-phosphate |
Molecule that possesses most chemical energy during glycolysis Receives 2 phosphate groups from ATP, conserving some of the energy derived from hydrolysis of ATP in this molecule |
|
|
When protein molecules are used for cell respiration, what is produced as waste? |
Amino groups |
|
|
Most of NADH is produced during which cycle |
Citric acid cycle |
|
|
Why is the citric acid cycle called a cycle |
The 4 carbon acid that accepts Acetyl CoA in the first step is regenerated by the last step of the cycle |
|
|
How many molecules of ATP are gained by substrate-level phosphorylation from a single molecule of glucose? |
4 A net gain of 2 from glycolysis 1 from each molecule of Acetyl CoA oxidized in citric acid cycle |
|
|
What is the energy produced by citric acid cycle |
Each turn release: CO2 1 ATP by oxidative phosphorylation Passes 3 NAD and 1 FAD |
|
|
Electrons from oxidation of glucose are used to |
Reduce NAD and produce a proton gradient for ATP synthesis |
|
|
How efficient is the process of cell respiration |
About 38% Rest is lost in heat |
|
|
Source of energy that produces the chemiosmotic gradient in mito. |
Movement of electrons down the ETC |
|
|
What purpose does recruitment of blood vessels to growing tumors serve? |
Supplies oxygen for cell respiration rather than fermentation And supplies glucose to rapidly dividing cells Anti-cancer drugs attempt to block this process of recruitment |
|
|
Extra step in fermentation during glycolysis |
Enables cell to recycle NADH to NAD Usually these would be used in ETC |
