3. Cellular Respiration
Lyase
Cleavage of C-C, C-O and C-N bonds; a double bond is formed
Hexose Monophosphate Shunt, also known as Pentose Phosphate Pathway
Converts glucose into 5 sugars and generates NADPH which is used in reductive biosynthesis of lipids. For most organisms, the pentose phosphate pathway takes place in the cytosol; in plants, most steps take place in plastids
After strenuous격렬한 exercise, a muscle cell would contain increased amounts of all of the following EXCEPT: A. ADP B. CO2 C. Lactate D. Glucose
D. During strenuous exercise, glucose is broken down to pyruvate. Aerobic respiration produces CO2, Anaerobic respiration, which would occur during strenuous exercise, would increase lactate formation. Exercise would also consume ATP, producing ADP and Pi.
Chemiosmosis describes how ATP is generated from ADP. All of the following statements conform to the process as it occurs in mitochondria EXCEPT: A. H+ accumulates in the area between the membrane of the cristae and the outer membrane of the mitochondrion (matrix). B. A voltage gradient is created across the cristae membranes. C. A proton gradient is created across the cristae membranes. D. Electrons flowing through the ATP synthase channel protein provide the energy to phosphorylate ADP to ATP.
D. Protons, not electrons, pass through ATP synthase as they move down the proton gradient. An electrical gradient or voltage is produced by the greater number of positive charges in the intermembrane space relative to the number of positive charges inside the crista membrane.
Explain the process of oxidative phosphorylation
Electrons from NADH and FADH2 pass along an electron transport chain (ETC). The chain consists of proteins that pass these electrons from one carrier protein to the next. Along each step of the chain, the electrons give up energy used to phosphorylate ADP to ATP. NADH generates 3 ATP FADH2 generates 2 ATP
Fatty acid synthesis
Fatty acid synthesis is the creation of fatty acids from acetyl-CoA and malonyl-CoA precursors through action of enzymes called fatty acid syntheses. Occurs in cytosol. Animals cannot convert fatty acids into glucose.
Kinase
Transfer phosphorylgroups
ADP
(Adenosin DiPhosphate) When one phosphate group is removed from ATP by hydrolysis, it becomes more stable molecule, ADP
ATP
(Adenosin TriPhosphate) Unstable molecule because 3 phosphate in ATP are all negative charged and repel one another
△G = negative
-A net release of free energy. -Exergonic -Can occur spontaneously (that is, without an input of energy) Ex). Respiration C6H12O6 + 6O2 -> 6CO2 + 6H20 A breakdown of glucose to CO2 and H2O △G = -686 kcal/mol
The Cori Cycle
-Actively contracting muscle tissue has a higher amount of lactate than resting muscle tissue. -The blood transports lactate to the liver. The Cori cycle allows the conversion of lactate back into glucose, which can be carried back to muscles via blood.
△G = positive
-Free energy must be added to the reaction for it to occur. -Endergonic -non-spontaneous Ex). Photosynthesis 6CO2 +6H2O -> C6H12O6 + 6O2 The making of glucose from CO2 and H2O △G = + 686kcal/mol
Oxidative phosphorylation
-Powered by redox reactions of ETC. -occurs when a phosphate group is added to ADP to form ATP, but the energy for the bond does not accompany the phosphate group. Instead, electrons give up energy for generating ATP during each step of a process, where electrons are transferred from one molecule to another in a chain of reactions. The process of producing ATP from NADH and FADH2.
Glycolysis? Occurs in _____?
1 glucose -> 2 pyruvate, 2NADH, 2ATP are produced. This process occurs in the cytosol
The three boxes represent the three major biosynthetic pathways in aerobic respiration. Name all the allows 1 though 12
1. 2 ATP 2. pyruvate 3. NADH 4. ATP 5. NAD + 6. ADP or FADH2 7. NADH 8. ATP 9. O2 10. ADP or FADH2 11. H2O 12. ATP
The Krebs Cycle
1. 2 Pyruvate -> 2 acetyl CoA 2. Krebs Cycle: 6 NADH, 2 FADH2, 2ATP, and 4CO2 is produced 1 acetyl CoA + OAA -> Citrate -> etc.
Explain steps of glycolysis
1. 2ATP are added 2. 2NADH are produced 3. 4ATP are produced by substrate-level phosphorylation 4. 2 pyruvate are formed Phosphofructokinase (PEK) is an allosteric enzyme. It inhibits glycolysis when cell has enough ATP and does not need to produce anymore
Lactic Acid Fermentation (Yogurt, cheese)
1. 2Pyruvate + (2NADH) -> (2NAD+) + Lactate *Freeing NAD+ allows glycolysis to be continued which produces 2 ATPs for each 2 converted pyruvate. *In human and other mammals, most lactate is transported to the liver, where it is converted back to glucose when surplus (excess of production) ATP is available *Human skeletal muscles carry out lactic acid fermentation when the blood cannot supply adequate oxygen to muscles during strenuous exercise. Latic acid in the muscle cause fatigue and burning. The lactic acid continues to build up until the blood can supply the muscles with adequate oxygen to repay oxygen debt.
What are three steps of aerobic respiration?
1. Glycolysis 2. Krebs cycle (citric acid cycle) 3. Oxidative phosphorylation
What are four distinct areas of a mitochondrion
1. Outer membrane 2. Intermembrane space 3. Inner membrane 4. Matrix
What are the two major process occur in inner membrane of the mitochondria?
1. Oxidative phosphorylation (the electron transport chain, consisting of a series of protein complexes, removes electrons from NADH and FADH2, and transports H+ ions from the matrix to the intermembrane space.) 2. ATP synthase
What are two basic mechanisms of phosphorylation in cells
1. Substrate level phosphorylation 2. Oxidative phosphorylation
What are the two major process occur in the matrix of the mitochondria?
1. The Krebs cycle 2. The conversion of pyruvate to acetyl CoA.
Explain Chemiosmosis in Mitochondria
1. The Krebs cycle produces NADH and FADH2. In addition, CO2 is generated and substrate-level phosphorylation occurs to produce ATP. 2. Electrons are removed from NADH and FADH2. Protein complexes in the inner membrane remove electrons from these two molecules. The electrons move along the electron transport chain, from one protein. 3. H+ ions are transported from the matrix to the intermembrane compartment. 4. A pH and electrical gradient across the inner membrane is created. As H+ are transferred from the matrix to the intermembrane space, the concentration of H+ increases (pH decreases) in the intermembrane space and decreases in the matrix (pH increases). 5. ATP synthase generates ATP. ATP synthase allows the protons in the intermembrane compartment to flow back into the matrix. The protons moving through the channel generate the energy for ATP synthase to generate ATP.
NADH
A coenzyme, an electron carrier when NAD+ combines with two energy rich electrons and H+ (obtained from an intermediate molecule during the breakdown of glucose). As a result, NADH is an energy-rich molecule.
A direct product of beta-oxidation of fatty acids is
A direct product of beta-oxidation of fatty acids is acetyl CoA. Under starvation conditions, fats can be utilized to produce energy for essential bodily functions. Many possible fates await acetyl CoA after being oxidized from fatty acids such as entering the Krebs cycle or proceeding to form ketone bodies.
The three boxes represent the three major biosynthetic pathways in aerobic respiration. What are the names of Pathway A, B, and C?
A. glycolysis B. the Krebs cycle C. Oxidative phosphorylation
AMP
Adenosine monophosphate Allosteric activators such as AMP and ADP bind to the allosteric site. They most likely to stimulate the activity of phosphofructokinase.
Which of the following sequences correctly indicates the potential ATP yield of the indicated molecules from greatest ATP yield to least ATP yield? A. pyruvate, ethanol, glucose, acetyl CoA B. Glucose, pyruvate, acetyl CoA, NADH C. Glucose, pyruvate, NADH, acetyl CoA D. Glucose, FADH2, NADH, pyruvate
B. Glucose produce 36 ATP Pyruvate -> 15 ATP acetyl CoA -> 12 ATP NADH -> 3 ATP FADH2 -> 2 ATP
Draw Free Energy and Activation Energy Diagram and Explain
Before most reactions can occur, activation energy is required to contort (twist) or destabilize the reactants. The necessary activation energy can be lowered by the presence of a catalyst. However, the free energy of a reaction is not changed by the presence of a catalyst.
β-oxidation of fatty acids
Beta-oxidation is the process by which fatty acid molecules are broken down in the mitochondria to generate acetyl-coA, which enters the citric acid cycle, and NADH and FADH2, which are used by the electron transport chain Occurs in the matrix of mitochondria
At levels of atmospheric O2 increase beyond 5%, the amounts of CO2 released increase. This is probably a direct result of A. an increase in glycolytic activity B. a greater availability of appropriate enzymes C. an increase in Krebs cycle activity D. an increase in atmospheric temperature
C. CO2 is produced in the Krebs cycle. The production of CO2, rather than its consumption, indicates that photosynthesis is not occurring, and that the plant activity is taking place at night.
All of the following processes release CO2 EXCEPT: A. the Krebs cycle B. alcohol fermentation C. oxidative phosphorylation D. the conversion of pyruvate to ethanol
C. Oxidative phosphorylation describes the transfer of electrons from NADH and FADH2 to electron acceptors that pump H+ across the inner mitochondrial membrane. Oxygen is required as the final electron acceptor of these electrons.
Al level of atmospheric O2 below 1%, the amount of CO2 released is relatively high. This is probably because A. The Krebs cycle is very active B. O2 is being converted to H2O C. Alcohol fermentation is occurring D. There are insufficient amounts of coenzyme A.
C. When O2 is absent (or very low), anaerobic respiration (alcohol fermentation) is initiated. Alcohol fermentation releases CO2. Production of CO2, rather than its consumption, indicates that photosynthesis is not occurring, and that the plant activity is taking place at night.
What is the chemical equation for the cellular respiration?
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
Phosphatase
Catalyzes the hydrolytic cleavage of a phosphate ester bond
Gluconeogenesis
Gluconeogenesis is a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as pyruvate, lactate, glycerol, glucogenic amino acids, and fatty acids. Occurs in cytosol Similar to glycosis but NOT REVERSE
Anaerobic Respiration, what are two process?, purpose?
If oxygen is not present, no electron acceptor exists to accept the electrons at the end of the electron transport chain. -> Alcohol Fermentation -> Lactic Acid Fermentation Both replenish NAD+ so that glycolysis can proceed once again. Occurs in the cytosol alongside glycolysis
Why prokaryotes are capable of getting a greater amount of ATP per molecule of glucose than eukaryotes can?
In Eukaryotes, pyruvate enters the mitochondrial matrix via active transport but in Prokaryotes, which lack mitochondria, pyruvate does not need to be transported across a membrane.
In respiration, glucose is ________ and thus ________ energy. Oxygen is _____ to form ________.
In respiration, glucose is oxidized and thus release energy. Oxygen is reduced to form water.
Dehydrogenase
Involved in oxidation-reduction reaction
FADH2
Like NADH, is a coenzyme, accepting electrons during a reaction.
NAD+ and FAD
Nicotinamide adenine dinucleotide Falvin ademine dinucleotide are coenzymes that carry protons or electrons from glycolysis and Krebs cycle to ETC. Are both oxidized form
Alcohol Fermentation (Beer, liquor, Wine, etc.)
Occurs in plants, fungi (yeast), and bacteria. 1. 2Pyruvate ->2CO2 + 2 acetaldehyde are produced 2. 2 acetaldehyde + (2NADH) ------> (2NAD+) + 2 ethanol * Freeing NAD+ allows glycolysis to be continued which produces 2 ATPs for each 2 converted pyruvate.
Cytochrome c
One of the carrier proteins in the electron transport chain. It is so ubiquitous among living organisms that the approximately 100-amino-acid sequence of the protein is often compared among species to assess genetic relatedness.
What is the purpose of oxygen in aerobic respiration?
Oxygen accepts electrons at the end of an electron transport chain
___________ is an enzyme involved in the key regulatory step of glycolysis.
Phosphofructokinase
What enzyme inhibits glycolysis?
Phosphofructokinase (PEK) is an allosteric enzyme. It inhibits glycolysis when cell has enough ATP and does not need to produce anymore
Glyoxylate cycle
Plants and some bacteria employ a modification of Krebs cycle called glyoxylate cycle which can produce sugars from Acetyl-CoA
Cellular Respiration
The ATP-generating process that occurs in cells. Energy is extracted from energy-rich glucose to form ATP.
Exergonic
The change from a less stable molecule to a more stable molecule, always release energy ATP -> ADP + Pi
Gibbs Free Energy
The energy in a system that is available for conversions
ATP hydrolysis (what kind of reaction?)
The hydrolysis of ATP (an exergonic reaction) occurs in coupled, with the endergonic metabolic reaction. The coupling usually involves the transfer of energy with one of the inorganic phosphates (Pi) from ATP to one of the reactants.
Chemiosomosis
The mechanism of ATP generation that occurs when energy is stored in the form of a proton concentration gradient across a membrane
Phosphorylation
The process of adding energy and an inorganic phosphate to ADP to make ATP energy + Pi + ADT -> ATP
The first law of thermodynamics
The total amount of energy in the universe remains constant. - Energy cannot be created or destroyed, but it can be converted from one form to another. -These forms of energy include kinetic energy (energy of motion) and potential energy (stored energy)
How many ATP?
Theoretically: 38 ATPs Actually: 30 ATP due to variations in mitochondria efficiencies and competing biochemical processes.
Intermembrane space of mitochondria
This is the narrow area between the inner and outer membranes. H+ ions accumulate here.
The second law of thermodynamics
When energy is converted from one form to another, some energy is "lost" in the form of heat. Further, as additional energy conversions occur, more energy becomes unusable, things become disorganized, and disorder or randomness increases. "Entropy (disorder) increases in the universe"
When NADH donates its electrons to the electron transport chain it becomes ____a___ to ___b_____.
a. oxidized b. NAD+ NADH is oxidized to NAD+ because it loses two electrons with the hydrogen atom.
The NAD+ that is used in Glycolysis comes from two sources: _____a_____, and NAD+ is also recycled from reduction of NADH during the ___________.
a. the anaerobic pathways—alcohol fermentation and lactic acid fermentation b. electron transport chain
During cellular respiration in eukaryotes, pyruvate enters the mitochondrial matrix via _____________.
active transport.
Ubiquinone
also called Coenzyme Q, is a lipid soluble electron carrier in electron transport chain (ETC)
The____________ is the network of organelles and structures, either directly or indirectly connected, that function in the transport of proteins and other macromolecules into or out of the cell.
endomembrane system
In Eukaryotes, glycolysis occurs in _________, Krebs cycle occurs in ______, and ETC occurs in ______________.
glycolysis occurs in cytosol, Krebs cycle occurs in mitochondrial matrix, and ETC occurs in Inner mitochondiral membrane.
In prokaryotes, glycolysis and Krebs cycle occurs in ________
in cytosol Prokaryotes such as bacteria do not have a mitochondria, however they do carryout glycolysis and have their own electron transport system
Substrate Level phosphorylation
occurs when a phosphate group and its associated energy are transferred to ADP to from ATP. The substrate molecule (A molecule with the phosphate group) donates the high energy phosphate group. ex). During glycolysis, 4 ATP are produced by substrate-level phosphorylation (During this process, the enzyme kinase transfers a phosphate from a substrate directly to ADP, forming ATP) ex). Krebs cycle, 2ATP are produced.
During glycolysis an initial net investment of two molecules of ATP is required to ______ a single molecule of glucose to two molecules of pyruvate.
oxidize
The relative permeability of a phospholipid bilayer is influenced by _________List 4 things_______
temperature, cholesterol content, the degree of hydrocarbon tail saturation, and hydrocarbon tail length.
In prokaryotes, Electron Transport Chain occurs in ______
the plasma membrane
