| Term | Definition |
|---|---|
What is metabolism? | The sum of all chemical rxns that happen within the cell |
What are examples of catabolic processes/reactions? | -fueling rxns
-energy-conserving rxns |
What are examples of anabolic processes/reactions? | -synthesis of complex organic molecules from simpler ones |
What is the purpose of catabolic processes for metabolism? | -providing ready source/reducing power with electrons
-Generating precursors for biosynthesis |
What is the purpose of anabolic processes for metabolism? | Requires energy from fueling reactions |
What is the purpose of enzymes? | To regulate, catalyze, and control chemical reactions. |
Catabolism ______ energy. | Releases |
Anabolism ______ energy. | Consumes |
What does glucose break down into? | CO2 and H2O |
What does ATP break down into? | ADP and inorganic phosphate (Pi) |
What is the electron transfer for reduction? | Gaining an electron. |
What is the electron transfer for oxidation? | Losing an electron. |
What common "vessel" does biological-chemical reactions transfer electrons through? | Hydrogens |
What is the change of free energy with exergonic reactions? | Negative change. |
What is the change of free energy with endergonic reactions? | Positive change |
What free energy change does spontaneous vs non-spontaneous reactions have? | Spontaneous reactions = negative change = exergonic
Non-spontaneous reactions = positive change = endergonic |
More negative standard reduction potential means what? | It's a better electron donor. |
More positive standard reduction potential means what? | It's a better electron acceptor. |
How do exergonic breakdown of ATP become more favorable? | It will couple with an endergonic reaction. |
What is substrate level phosphorylation? | The synthesis of ATP from ADP by phosphorylation coupled with the exergonic breakdown of a high-energy organic substrate molecule. |
What is the source of the phosphoryl group during substrate-level phosphorylation? | PEP (phosphoenolpyruvate) |
What are all the processes possible of creating ATP? | -Aerobic respiration
-Anaerobic respiration
-Fermentation
-Phototrophy
-Chemolithotrophy |
What are all the processes capable of breaking down ATP? | -Chemical work
-Transport work
-Mechanical work |
What is the role of NAD+? | It usually transfers electrons from an electron source to an ETC. |
What is an Electron Transport Chain (ETC)? | A series of electron carriers that operate together to transfer electrons from donors to acceptors. |
What is the best electron acceptor for ETC to use? | Oxygen. |
What is the order of electron carriers in an ETC going in? | Most to least negative standard reduction potential (E knot). |
What is a common role of NADP+? | An electron carrier in biosynthetic metabolism. |
What is oxidative phosphorylation? | Electrons transferred from one electron carrier to another in ETC using oxygen electron acceptor. |
What is chemiosmosis? | The process of ATP being generated from ADP using energy from ETC. |
What cells can operate photophosphorylation? | Photosynthetic cells. |
What are prime examples of electron carriers? | -NAD
-FAD
-NADP
-Coenzyme Q (CoQ)
- Cytochromes |
Where is the potential energy stored in ETCs? | The first redox couple. |
What makes up a holoenzyme? | Apoenzyme + cofactor
(A protein and non-protein component) |
What is an apoenzyme? | The protein component of a holoenzyme. |
What is an cofactor? | The non-protein component of a holoenzyme. |
What is a prosthetic group? | A covalently attached cofactor. |
What are examples of a prosthetic group? | -NAD
-FAD |
What is a coenzyme? | A loosely attached component that can dissociate. |
What are the three major mechanisms of regulating metabolism? | 1. Metabolic channeling
2. Regulation of gene expression
3. Post-translational regulation |
Why is it important to regulate metabolism? | To conserve energy and materials |
What is metabolic channeling? | The influence of pathway activity by localizing metabolites and enzymes in different parts of a cell. |
What is compartmentation? | A common metabolic channeling mechanism involving distributing enzymes and metabolites into separate structures/organelles. |
What is regulation of gene expression? | Limiting the synthesis of certain enzymes by changing the rate of transcription or translation based on the present of specific enzymes/molecules. |
What is posttranslational regulation? | Changing the activity o a protein after synthesis through structural modifications like phosphorylation or conformational change. |
What are allosteric enzymes? | Enzymes whose activity alters by noncovalent binding of an allosteric effector at the regulatory site. They ultimately lead to an enzyme activation or inhibition. |
What are allosteric effectors? | The small molecule that changes an allosteric enzyme through its regulatory site. |
What types of allosteric effectors are there? | -Positive (encourages/increases activity)
-Negative (inhibits activity) |
What is covalent modification? | The addition or removal of a particular chemical group. |
What chemical groups can be involved in covalent modification? | -Phosphoryl
-Methyl
-Adenylyl |
What regulation processes are reversible? | -Allosteric regulation
-Covalent modification |
What is Feedback Inhibition/end product inhibition? | A negative feedback mechanism in which an end product inhibits the activity of an enzyme in the pathway leading to its formation. |
What commonly catalyzes feedback inhibition? | Peacemaker enzyme. |
What does "photo" vs "chemo" refer to? | Both are prefixes referring to the energy sources with
photo= light
chemo= inorganic chemicals |
What does "litho" vs "organo" refer to? | Both are prefixes referring to the carbon source so
Litho= CO2
Organo= Organic Carbon |
What does auto vs hetero refer to? | Both refer to the electron source with
auto= inorganic electron donor
hetero= organic electron donor |
What are the 3 main products fueling reactions generate? | -ATP
-Reducing power
-Precursor metabolites |
What are the two chemoorganotrophic fueling processes? | 1. Respiration
2. Fermentation |
What is respiration? | An energy yielding process in which energy substrate is oxidized using exogenous or externally derived electron acceptor. |
What is electron acceptor for aerobic respiration? | Oxygen |
What is the electron acceptor for anaerobic respiration? | Other substrates (SO4-, NO3-, Fe+3, etc.) |
What separates fermentation from respiration? | -Doesn't use a ETC (it is its own proton pump)
-Uses endogenous or local electron acceptors unlike oxygen. |
What is the order of most ATP produced from each fueling reaction? | 1. Aerobic respiration (38)
2. Anaerobic respiration (34)
3. Fermentation (2) |
What is the electron acceptor for fermentation specifically? | Pyruvate or a derivative |
What synthesizes ATP during respiration processes? | Proton motive force (PMF) |
What synthesizes ATP during fermentation? | Substrate-level phosphorylation. |
What is an amphibolic pathway? | A metabolic process that operates with both catabolic and anabolic pathways. |
What are the different examples of an amphibolic pathway? | -EMP
-Pentose phosphate pathway
-TCA cycle |
What are the three different forms of glycolysis? | -EMP
-EDP
-Pentose phosphate pathway |
What is the purpose of glycolysis? | To break down glucose (C6) into 2 pyruvates (C3) |
What is Embden- Meyerhof pathway (EMP)? | The classic glycolysis process where glucose degrades into pyruvates. |
What are the end products of the 1st/6-carbon phase of EMP? | -fructose
-1,6 biphosphate |
What are the end products of the 2nd/3-carbon phase of EMP? | -4 ATP (2 ATP in net yield)
-2 NADH
-2 pyruvate
-2 H+ |
What is Entner-Doudoroff pathway (EDP)? | A glycolysis pathway involving glucose converting into pyruvate and glyceraldehyde 3 -phosphate by producing 6- phosphogluconate and then dehydrating it. |
What specific bacteria use EDP glycolysis? | -Gram-negative bacteria (very rarely gram positive have as well).
-Aerobic bacteria > anaerobic. |
What are the net end products of EDP? | -1 glyceraldehyde
-1 pyruvate
-1 3-phosphate
-1 ADP
-1 NADPH
-1 H+ |
What is pentose phosphate pathway/hexose monophosphate pathway? | A glycolytic pathway that oxidizes glucose 6-phosphate to ribulose 5-phosphate and then converts it to a variety of 3-7 carbon sugars. |
What processes can be used at the same time as pentose phosphate pathway? | Both EMP and EDP. |
What is pentose phosphate pathway significant for? | -Biosynthesis precursor
-Catabolism
-Providing reducing power |
What precursor for nucleotide biosynthesis is produced during pentose phosphate pathway? | Ribose-5-phosphate. |
What is the TCA/Krebs/Citric acid cycle? | The cycle that oxidizes acetyl-CoA into Co2 and generates NADH and FADH2 for oxidation in the ETC. |
Why must the TCA cycle run twice to oxidize one glucose molecule? | It takes 2 acetyl-CoA molecules to oxidate the glucose to create a large enough negative change in free energy. |
What is the total amount of end products produced for each acetyl-CoA molecule that's oxidized through TCA cycle? | -2 CO2
-3 NADH
-1 FADH2
-1 GTP=ATP |
What is chemiosmotic hypothesis? | Proton and electrochemical gradients are generated by electron transport and then used to drive ATP synthesis by oxidative phosphorylation. |
What is oxidative phosphorylation? | Synthesis of ATP from ADP using energy made available during electron transport initiated by the oxidation of a chemical energy source. |
What results in the formulation of concentration gradient of protons and a charge gradient according to chemiosmotic hypothesis? | Proton expulsion. |
What makes up the PMF according to chemiosmotic hypothesis? | Combination of chemical and electrical potential differences |
What drives the formation of ATP? | PMF/diffusion of protons. |
What is the enzyme that catalyzes ATP synthesis? | ATP synthase |
What is an equivalent to ATP? | GTP |
In a theoretical max production of ATP, how much ATP does glycolysis produce? | 8 ATP |
In a theoretical max production of ATP, how much ATP does the preparatory step produce? | 6 ATP |
In a theoretical max production of ATP, how much ATP does the TCA cycle produce? | 24 |
What is dissimilatory nitrate reduction? | Using nitrate as a terminal electron acceptor |
What is denitrification? | Reduction of nitrate to nitrogen gas (NO3 to N2) |
What makes it unavailable for a cell to assimilate or uptake with nitrogen? | The anaerobic reduction of nitrate |
What is photosynthesis? | The trapping of light energy and converting it into chemical energy that's reduces CO2 to use in organic molecules. |
What are the different processes during photosynthesis? | Dark and light reactions |
What are the light reactions of photosynthesis? | -Photophosphorylation
-trapping light energy and converting it into ATP (chemical energy) and NADPH (reducing power) |
What is photophosphorylation? | The synthesize of ATP from ADP using energy from absorbing light. |
What are the dark reactions of photosynthesis? | Using ATP and reducing power to fix CO2 and synthesize cell constituents. |
Which organisms use oxygenic photosynthesis? | Eucaryotes and cyanobacteria |
Which organisms use anoxygenic photosynthesis? | Purple/green sulfur photosynthetic bacteria. |
What is oxygenic photosynthesis? | Photosynthesis that oxidizes water to form oxygen. |
What is anoxygenic photosynthesis? | Photosynthesis that does not oxidize water to produce oxygen. |
What is bacteriohodopsin? | A membrane protein that functions as a light driven proton pump. |
What organisms use bacteriorhodopsin as a form of phototrophy? | Some archae. |
What inhibits anabolic pathways? | Antibiotics |
What is turnover? | The process of nongrowing cells continuously degrade and resynthesize cellular molecules. |
What balances out the rate of turnover? | The rate of biosynthesis. |