CH.3 ENERGY, CHEMICAL REACTIONS & CELLULAR RESPIRATION Flashcards
What is Energy?
-The capacity to do work
-Differs from matter because it has no mass and does not take up space.
What are the 2 classes of Energy?
Potential Energy
Kinetic Energy
What is Potential Energy?
-Energy of position/ stored energy
- Exhibited by the position of electrons in the E- shells position to the Atom’s Nucleus.
-Exhibited in cells when a concentration gradient exists across the plasma membrane.
*E- can move from higher energy shell to lower energy shell & when they move during a chem reaction, they do it w/ the same chem structure or from one chemical reaction to another (ETC)
What is Kinetic Energy?
-Energy of Motion.
-Ex: Releasing a arrow from a stretched Bow.
Explain the Na+ Concentration Gradient & it’s connection with Energy
-Na+ concentration is greater on the outside of the cell.
-Potential energy when waiting to go in (Water on top of a dam)
-Kinetic Energy: When it goes from high to low concentration (water falling out of the dam)
What are Two Forms of Energy
-Chemical Energy (One form of Potential)
-Kinetic Energy
What is Chemical Energy?
-Energy stored in a molecule’s chemical bonds (Most important form of energy in human body)
-Ex: Synthesis of Molecules & Establishment of Concentration gradient.
-Energy released when bonds are broken during chemical reactions.
What are the Three important molecules in the human body in Chem Energy?
- Tryglycerides: Long term storage in Adipose CT.
- Glucose: Stored in Live & Muscle tissue.
- ATP : Stored in all cells in limited amounts & contiunously produced. Used immediately.
What are the 5 forms of Kinetic Energy?
- Electrical Energy: Movement of charged particles.
Ex: Movement of E- - Mechanical: Exhibited by an object in motion due to an applied force.
Ex: Muscle Contraction - Sound: Compression of molecules that move in the three forms of Matter, is caused by a vibrating object.
Ex: Head of a drum. - Radiant: Energy of Electromagnetic waves traveling in the Universe.
- Heat: Ramon motion of Atoms, Ions, or molecules.
-Unusable form of energy/ waste product, since does not do work.
-Measured by temp of a substance.
What are the Details of Radiant Energy?
- Consists of the spectrum of Wave length and Frequency.
-Higher the frequency, the greater amount of radiant energy.
All forms of this energy with a higher freq than visible light, can mutate DNA by penetrating the body.
Ex: Melanin protects our skin from UV rays.
What isThermodynamics?
Study of Energy Transformations.
Ex: Eat food (Chem) -> ATP (Muscle Contract)-> Heat (Keep us warm).
What is the First Law of Thermodynamics?
-Energy cannot be created or destroyed, only converted or transformed.
Ex: Candle is burned. (Chem energy is the burning wax to convert both heat and light).
What is the Second Law of Thermodynamics?
-Every energy converted from one form to another, some of that energy must be converted into heat.
Ex: Chem to Mechanical of a car= 25%, then 75% of gas chem energy converts to sound and heat.
What is Metabolism?
Collective term for all biochemical reactions in living organisms
What is Chemical Reactions?
-Occurs when chem bonds in an existing molecular structure is broken & new ones form to produce a different structure. (Na+ + Cl- = NaCl-)
What are Chemical Equations?
A summary of the changes that happens in Chemical Reactions.
-Contain Reactants & Products.
What are Reactants?
-Substrates or substances that are present prior to the start of a chem reaction.
-Left side
What are Products
-Substances that formed from reactants by chem reaction.
-Right side.
Ex: Ca+2 + 2Cl- -> CaCl2 (Calcium Chloride)
What are the 3 ways Chemical Reactions are Classified?
- Changes in Chemical Structure
- Changes in Chem Energy
3:Reactions are either Irreversible or Reversible
What are the 4 ways to Classify changes in Chemical Structure?
- Decomposition Reaction
- Synthesis Reaction
- Exchange Reaction
- Oxidation-Reduction Reactions
What is Decomposition Reaction?
-Large molecules is digested or broken down into smaller structures.
-Ex: Hydrolysis Reaction of Sucrose into Glucose & Fructose.
-This is Catabolic: Breaking down large molecules into smaller ones.
What is a Synthesis Reaction?
-When two or more atoms, Ions, or molecules are combined to form to make larger chem structure, as existing bonds are broken and new ones forms.
Ex: Dehydration Synthesis of Formation of dipeptides.
- This is an Anabolic: Required energy to build up new molecules.
What is an Exchange reaction?
-Atoms, Molecules, Ions, or Electrons are exchanged between two chemical structures.
-(Most prevalent type, has both Decomposition and Synthesis Components.
-Ex: Production of ATP in Muscle, Creatine Phosphate + ADP= Creatine + ATP.
What is an Oxidation-Reduction Reactions
-It is a specific type of exchange reaction that involves the movement of electrons from one chemical structure to another.
Electron transferred from one chemical to another may be moved Alone or accompanied by H+
-Ex: NAD+ Modified Dinucleotide that is linked to P and N & Adenine, is important in ATP Synthesis.
What are the two Classifying changes in Chemical Energy?
-Exergonic: Reactants have more potential energy than Products. (Energy going out/released)
Ex: Decomposition
-Endergonic: Reactants have less energy than the products. (Energy going in, supplied).
Ex: Synthesis
What is ATP Cycling?
-Continuous Formation & Breakdown of ATP.
-Endergonic: ADP + P = ATP
-Exergonic: ATP = ADP +P
What are the two ways Chemical Reactions classify their reactions?
Irreversible Reaction &
Reversible Reactions
What is Irreversible Reactions?
Reactants converted to products at a rate that yields a net loss or Reactants & net gain in products.
Ex: A+B= AB or AB = A+B
What is Reversible Reactions:
-Reactants can become products, as products can become reactants at an equal rate (Once Equilibrium is reached).
- NO net change in concentration in both when in state of equilibrium.
Ex: A+B <=>AB
-Remains in the Equilibrium if left distrubed (Distrubed if changes in amount of Reactant & products)
What direction does the Reversible Equation go if it Increases in Reactants & Decreases in Products?
Drives equation to the right.
-Forms additional product until new equilibirum is reached.
What direction does the Reversible Equation go if Decreases in Reactants & Increases in Products?
-Drives it to the left
-Formed additional Product until the new equilibrium is reached.
What is a Reaction Rate?
-The rate a reaction reacts. -Determines the amount of product formed per unit of time.
*A Reaction Rate is influenced is the energy required to break the chem bonds so that new bonds can form a product.
What is Activation Energy? (Ea)
-Energy required to break existing chemical bonds for chemical reactions to Proceed.
-Needs to initiate reaction to occur.
Ex: Increase in temp, increases the Kinetic energy of molecules to break chemical bonds. (Not with cells bc it will denature)
What are Enzymes?
-They are biological Catalysts that facilitate chemical changes in the human body by decreasing Activation Energy.
-Increases production
- Change in shape is because of stress on chem bonds.
What are Catalysts?
- Substances that accelerate or promote chemical reactions
Example of Enyzme with Sucrose, Type of Chemical Energy classification, Catalyzed by who?
-Sucrose is Exergonic (More potential energy than of Glucose and Fructose).
-Ea Initates reaction.
-Reaction is Catalyzed by the enyzme : Carbonic Anhydrase
What type of Tertiary Protein Structure is an Enzyme?
- Most are Globular Proteins from small (60AA) to large (2500AA).
What is an Active Site?
-A site that is ready for a substrate to bind to the specific site of the enzyme.
What is an Enzyme Substrate Complex?
A temporary reaction where the substrate is binded to the Active Site of the Enzyme to make the Product.
Why is the Specificity in the Shape of an Active Site so important?
-It only permits a single or type of substrate to bind with the active site.
Where is the location of the Enzyme once Synthesized?
- Remains in the Cell: RNA polymerase. RNA to DNA.
- Embedded within Plasma Membrane: Lactase, which digest Lactose, found in cell membrane of small Intestine.
- Secreted from Cell: Pancreatic Amylase released from the pancreas into the small intestine to help digestion of starch.
What are Cofactors?
- Helper Ion or molecules to ensure a reaction occurs.
-Non-protein structure that may either be a Organic Or Inorganic substance associated with a particular enzyme or enzymatic reaction.
What are Inorganic Cofactors
-Attached to enzymes, and are required for normal function.
Ex: Zinc ion is bound to Carbonic Anyhydrase enzyme, w/o Zinc, the enzyme would not be able to function.
What are Organic Co-Factors?
-Not attached to enzymes and have specific functions in assisting enzymes.
- Also referred as Co-enzymes.
- Ex: NAD+ coenyzmes accept Hydrogen during Chem reactions to become NADH.
What are the 6 Major Classes of Enzymes?
- Oxidoreductase
- Transferase
- Hydrolase
- Isomerase
- Ligase
- Lyase
What are Oxidoreductase?
Transfers Electrons from one substance to another.
Ex: Dehydrogenase uses NAD+ or a molecule other than O2 as a E- acceptor.
Denhydrogenase move Hydrogen from one to another
What is Transferase?
-Transfers a Function Group/ Atoms or Molecules between Chemical Structures.
- Kinase transfer a phosphate functional group, from ATP to another molecule.
What is Hydrolase
-Splits a chemical bond using water.
-Ex: Phospatase removes Phospate
Lipase splits Lipids (Tryglycerides).
What is Isomerase?
Converts one Isomer to another.
Ex: Mutase transfers atoms within a molecule.
What is Ligase?
- Bonds two Molecules together
Ex: Synthetase bonds two Molecules using ATP.
What is Lyase?
-Splits a chemical bond in the absence of water.
-Ex: Decarboxylase cleaves a molecule to release CO2.
What are the 3 conditions that influence the reaction rates catalyzed by Enzymes?
- Enzyme & Substrate Complex: Affect the Concentration of these two.
- Temperature
- pH
How does Enzyme & Substrate Concentration affect Reaction Rates?
- The rate of chemical reactions may be accelerated by increasing the enzyme or substrate concentration.
-Increases Rate of Reaction till the point of Enzyme Saturation.
What is Saturation?
-Occurs when so much substrate is present that all Enzyme molecules are actively engaged in chemical reaction= No more increase in Concentration.
How does Temperature take Effect on Reaction Rates?
-Human Enzymes function at (37C/98.6F)
-Activity of Human Enzymes increase when body temp rises (40C/104F) Until Optimal temp is reached.
-However temp increase above, then it denatures (destroying the Intramolecular bonds).
How doe pH effect Reaction Rates?
-Optimal pH 6 to 8
- If pH is out of this range then it denatures.
-Disrupts the Electrostatic Interactions (Help shape of Enzyme).
*Not all have the same pH like stomach Enzyme).
How are Enzymes Controlled and What are the Two types of them?
-By using Inhibitors such as:
Competitve or Noncompetitve.
What is the Function of an Inhibitor?
-It turns off the enzyme and prevents from the substance catalyzing the reaction.
-Needed when uncontrolled enzymes that have depleted substrate and product concentration levels.
What is a Competitive Inhibitor?
-Interferes directly w/ Active site of enzyme so substrate cannot bind.
*Greater concentration of Substrate= Less likely this inhibitor will occupy Active Site.
What is a Non-competitive Inhibition?
-Allosteric Inhibitor, changes the enzymes Active Site shape so substrate cannot bind to enzyme.
-Not influenced by the Substrate concentration.
-Greater amount of Inhibitor= Greater degree of Action.
-Binds to Allosteric Site.
Most Enzymes are arranged in either what to be able convert initial substrate to final product?
-Metabolic Pathways or as a Multienzyme Complex
What is a Metabolic Pathway?
-Formed by Numerous enzymes.
-Each enzyme catalyzes one progressive change to the specific substrate molecule then releases the products.
- Product of one enzyme becomes the substrate to the next enzyme.
What is the Multi-enzyme Complex?
-Group of enzymes that are physically attached to each other through non-covalent bonds to form the complex (Assemebly line to perform a specific part of that pathway).
Ex: Pyruvate Dehydrogenase: Type of multi-enzyme complex involved in glucose breakdown.
What are the 2 Major Advantages of the Multi-enzyme Complex?
- The product from one chemical reaction is immediately bound to the next enzyme in the complex. (More likely of needed product is formed and the substance does not diffuse away & come in contact with a different enzyme.)
- The Enzymatic Pathway can be regulated by controlling the single complex rather than multiple individual enzymes.
How is Metabolic Pathways & Multi-enzyme Complex regulated to prevent overproduction of unneeded products & exhaustion of substrates that could be used elsewhere?
-Negative Feedback.
-The product from the Metabolic Pathway acts as an allosteric inhibitor to turn off Enzyme.
- As the product accumulates= less product formed.
-#of product & # of allosteric inhibitor bounded to enzyme decreases, as the activity of the pathway increases.
What is the 2 specific mechanisms that regulate enzymes?
-Phosphorylation
-Dephosphorylation.
What is Phosphorylation?
Addition of a phosphate group.
-May turn on some enzymes but turn off others.
What is Dephosphorylation?
Removal of a phosphate group.
-May cause opposite effects.
What is the enzyme that adds Phosphate?
Phosphorlyases or Kinases.
What is the enzyme that removes the Phosphates?
Phosphatases.
What is Cellular Respiration?
A multistep Metabolic Pathway, where Organic Molecules are broken down to create ATP.
What happens during Cellular Respiration
We begin on Glucose (or mother main fuel molecules) then we break it down (Exergonic) then use Energy released from break down to Synthesize ATP (Endergonic).
What are the 4 steps of Cellular Respiration?
Glycolysis, Intermediate Stage, Citric Acid Cycle, Electron Transport Chain.
What is Glucose’s Molecular Formula?
C6H12O6
What does Glucose look like after is it disassembled during Cellular Respiration?
6CO2 + 6H2O
What is Glucose Oxidation? And what type of Energy Reaction is it?
-Oxidation of Glucose, and it is an Exergonic Reaction.
Energy transferred from the broken chemical bond (ADP +P) to form ATP is through what?
Directly(Least Common)
Indirectly
How is Energy transferred from ADP to form ATP Direct?
-It synthesizes ATP
-Substrate-level Phosphorylation.
-Direct contact with substrate that goes straight to the enzyme to make ATP.
How is Energy transferred from ADP to form ATP Indirectly?
-Energy is released by co-enzymes (NAD+ FAD), which then carry the e- to make ATP.
& O2 is final Electron acceptor
-Oxidative Phosphorylation.
How many enzymes are involved in Glucose Cellular Respiration?
20 different enzymes in both Cytosol and Mitochondria.
What & Where is Glycolysis? Does it need Oxygen? & How many times does it happen?
-First steps of breaking down Glucose into energy
-Cytosol
-Does not need Oxygen
-Happens twice when glucose is split into two (Steps 6-10)
How many enzymes are included in Glycolysis?
10 enzymes
What happens in Step 1-5 of Glycolysis?
-Only occurs once per glucose
Glucose enters & is split into two G3P
- 2 ATP is invested from step 1&3 (Kinase enzyme transfers P to ATP)
- The phosphate group was transferred to break down glucose.
What happens in Steps 6 & 7 in Glycolysis?
-Occurs twice in Oxidation of Glucose
-6) Transferring free “P” to the substrate
6) NAD+ becomes NADH bc of extra H.
7) ATP is directly made by Kinase.
What happens in steps 8-10 of Glycolysis
-Occurs twice
-Converting molecule made in step 7 into an Isomer & loss of water molecule.
-ATP made through Direct transfer.
What is the Initial Substrate & product of Glycolysis that is used in the Intermediate Stage.
-Glucose
-2 Pyruvate
What is the Net energy molecules produced in Glycolysis?
2 ATP & 2 NADH
(Created 4 but used 2 ATP to make 2ATP)
What type of Pathway or Complex is Glycolysis using?
Metabolic Pathway
How is Glycolysis Regulated?
-By negative feedback.
-ATP acts as an allosteric inhibitor to turn off.
-ATP levels increase, and Glycolysis decreases.
Describe the Mitochondrion Structure.
-Inward folds= Cristae (ETC)
-Outer Compartment= (between two membranes, fluid-filled space) H+ gradient
-Matrix= Innermost space (CAC & intermediate stage)
Inner membrane= Close to the Cristae (Atp Synthase)
What is the Intermediate Stage & How many times must it occur?
-A phase that happens after Glycolysis & before CAC.
- Pyruvate Dehydrogenase happens (Brings pyruvate & CoA together =Acetyl CoA)
-Must occur twice for complete digestion of the 2 pyruvate.
What does Pyruvate Dehydrogenase Do?
It brings the pyruvate & the CoA together to make Acetyl CoA
What is Decarboxylation and why does it happen in the Intermediate Stage?
- Carboxyl group (1C & 2O2) releases from the pyruvate as CO2 .
-Energy release creates NADH.
Where is Intermediate Stage located & does is need O2?
Mitochondria, and yes, will inhibit if doesn’t
What is the Substrate of the Intermediate Stage?
2 pyruvate
What is the Products of the Intermediate Stage?
2 Acetyl CoA, 1CO2 per Pyruvate (So 2). 2NADH
Is the Intermediate Stage a Pathway or Complex?
It is a multienzyme Complex
What is the net energy molecules produced in the Intermediate stage
1 NADH per pyruvate.
What is the Citric Acid Cycle (Krebs Cycle)
-Metabolic Process in the Mitochondria
-Needs O2
- Uses Acetyl CoA to make 2Co2 & 1CoA
-Completely breaks down Glucose
How many enzymes are involved in the CAC
9 in the matrix Mitochondrion.
What are the 9 steps that occur in the Citric Acid Cycle?
1) First enzyme is used to combine Acetyl CoA w/ Oxaloacetate to form Citrate
2-3) H2O removed from Citrate & reattached to a diff location of the molecule.
4-5) NAD+ = NADH & CoA is attached.
6) CoA removed, ATP is formed through Direct Transfer Kinase.
7) FAD+ = FADH
8) Water Removed
9) NAD+ = NADH, Oxaloacetate regnerated.
Why is the CAC called a Cycle? And how many cycles must occur?
-Oxaloacetate is involved in the first step then regenerated in the last
-Occur 2 times to completely break down glucose.
What is the Substrate of CAC
2 Acetyl CoA (Per glucose)
What are the Products of CAC?
1 CoA (per Acetyl CoA) & 2CO2
Is the CAC a Pathway or Complex? & Does it need O2
A Metabolic Pathway & yes it does or it inhibits it.
What is the Net energy molecules produced in CAC
2 ATP
6NADH
2FADH2
In total of 2 Acetyl CoA
What is the Electron Transport Carrier, & where does it happen?
-Transfers the E- from the NADH & FADH2 to form ATP.
The matrix
In the Cristae (H+ pumps, ATP synthase, E- carriers)
What direction does the H+ gradient go? And why is it important?
-H+ from matrix to the inner compartment.
-When the H+ goes through the pump then hits the ATP synthase, it then makes ATP (Inner membrane)
What Element is the final electron acceptor in the ETC? And does the element become when it collects the last E-
O2, becomes H20
In the ETC, how much ATP does every NADH & FADH.
NADH: 3 ATP.
FADH: 2 ATP.
What Stages uses Substrate-Level Phosphorylation and what is the ATP production?
Glycolysis: 2ATP,
CAC: 2 ATP
Total 4 ATP
What Stages use Oxidative Phosphorylation & # of ATP production
Glycolysis: 2NADH = 6 ATP
Intermediate: 2 NADH= 6 ATP
CAC: 6 NADH = 18 ATP
2FADH2= 4ATP
IN total: 34 ATP
How much does 1 Glucose make in ATP production?
38 ATP, (Realistically (Net) 30 ATP because some of that used to transport molecules from the cytosol to Mitochondria.
When there is Low/ to close to none Oxygen for Cellular Respiration, how much is the ATP production
2 ATP per glucose,
-Converts Pyruvate to Lactate. (Lactate Dehydrogenase).
What are the other Fuel Molecules that is Oxidized in Cellular Respiration?
Fatty Acids and Amino Acids.
What is Beta-Oxidation (C.R)
-Fatty Acids that are enzymatically changed 2 Carbon units at a time to form CoA
-Needs O2
What are Ketoacids? (C.R)
Byproduct of fatty acid metabolism in CR
What happens to the AA in C.R?
-The body starts to break down the protein/ or muscles in body for fuel.
-So the AA w/ Amine group (-NH2) is removed by Urea.
