Cellular Respiration
Account for the 36 ATP molecules produced from the complete oxidation of the glucose molecule.
2 ATP from glycolysis 2 ATP from Krebs ~ 32 ATP from ETC
Use the diagram below to answer the questions that follow: Outer membrane Inner membrane Cytoplasm Matrix Intermembrane space Crista Site of glycolysis Site of krebs cycle High H+ Location of ATP synthase molecules Location of electrons transport chain
A Outer membrane C Inner membrane F Cytoplasm D Matrix B Intermembrane space E Crista F Site of glycolysis D Site of krebs cycle B High H+ E Location of ATP synthase molecules C Location of electrons transport chain
What is the role of ATP synthase complexes in cellular respiration?
ATP synthase complexes are the protein enzymes that actually make ATP from ADP and inorganic phosphate.
What are the advantages and disadvantages of fermentation?
Advantages Can make ATP energy in the absence of oxygen Disadvantages Can only make 2 ATP by substrate-level phosphorylation, wheras oxidative phosphorylation can male up to 16 times more (32 ATP) from a single molecule of glucose
How is aerobic respiration different from anaerobic respiration (fermentation
Aerobic means "with oxygen", the process of using oxygen to reduce glucose and make ATP. Anaerobic means "without oxygen", and so there is no oxidative phosphorylation process to make ATP
Why is glycolysis thought to be one of the earliest of all biochemical processes to have evolved
Ancient prokaryotes are thought to have used glycolysis to make ATP long before oxygen was present in Earth's atmosphere
What are the roles of NAD+ and FAD+ in cellular respiration
As electrons are stripped from the glucose, each electron travels with a hydrogen ion (H+). The hydrogen atoms are not directly transferred to oxygen, but instead are first passed to an electron carrier, either the coenzyme NAD+ or FAD++
b) Alcoholic fermentation is utilized by what organisms?
Bacteria and yeast (for brewing, winemaking, breadmaking)
Write the chemical equation for cellular respiration
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
What are the products of cellular respiration
Carbon dioxide, water
What are the reactants of photosynthesis
Carbon dioxide, water
Define the following terms and tell which reaction (photosynthesis or cellular respiration) is? Exergonic
Chemical reaction that releases energy...Cellular respiration
Define the following terms and tell which reaction (photosynthesis or cellular respiration) is? endergonic
Chemical reaction that requires an input of energy...Photosynthesis
What is chemiosmosis and how is it generated?
Chemiosmosis is the process in which energy stored in the form of a hydrogen ion (H+) gradient across a membrane is used to drive cellular work such as the synthesis of ATP. It is generated by the electron transport chain.
Where in the cell does photosynthesis occur
Chloroplast
What is the role of dehydrogenases in cellular respiration?
Dehydrogenases remove a pair of hydrogen atoms (2 electrons and 2 protons) from glucose, thereby oxidizing it.
What happens during fermentation when oxygen is not available to accept the electrons from the electron transport chain?
Fermentation is an extension of glycolysis that allows continuous generation of ATP by the substrate level phosphorylation of glycolysis. For this to occur there must be a sufficient supply of NAD+ to accept electrons during the oxidation step of glycolysis. The two fermentation pathways recycle NAD+ from NADH, thus restoring the cell's pool of NAD+, an oxidizing agent.
Cellular respiration is described as a stepwise redox reaction...What substance is oxidized?
Glucose -> Carbon dioxide
What are the products of photosynthesis
Glucose, oxygen
What are the reactants in cellular respiration
Glucose, oxygen
What phase of cellular respiration is included in fermentation?
Glycolysis generates 2 ATP whether oxygen is available or not.
d) Lactic acid fermentation is utilized by what organisms?
Human muscle cells, bacteria and fungi (for making cheese and yogurt)
What is the main reason that energy is harvested into ATP molecules gradually in phases in cellular respiration? What happens to most of the energy released?
If energy is released from fuel all at once, it cannot be harnessed efficiently for constructive work. If a gasoline tank explodes, it cannot drive a car very far. Cellular respiration does not oxidize glucose in a single explosive step, but by a series of smaller steps that extracts energy slowly and efficiently.
Some desert animals such as the kangaroo rat never have to drink water. Explain how kangaroo rats can obtain the water they need to survive from the dry seeds they eat.
Kangaroo rats obtain the water they need from the digestion of seeds through the process of cell respiration. Water is produced at the end of the electron transport chain when oxygen, as the final electron acceptor, is reduced.
As electrons are transported through the electron transport chain they lose potential energy. This energy is used to do what work
Make ATP from ADP and P
Define the following terms and tell which reaction (photosynthesis or cellular respiration) is? Anabolic
Metabolic process by which larger molecules are synthesized from smaller ones...photosynthesis
Define the following terms and tell which reaction (photosynthesis or cellular respiration) is? Catabolic
Metabolic process that breaks down large molecules into smaller ones...Cellular respiration
Indicate if each of the following is true of: Substrate- level phosphorylation or oxidative phosporylation. Accounts for 90% of ATP production in aerobic respiration
O
Indicate if each of the following is true of: Substrate- level phosphorylation or oxidative phosporylation. Couples the addition of a phosphate to ADP with the exergonic slide of electrons down the electron transport chain
O
Indicate if each of the following is true of: Substrate- level phosphorylation or oxidative phosporylation. Produce ATP by adding a phosphate to ADP
O
Indicate if each of the following is true of: Substrate- level phosphorylation or oxidative phosporylation. oxygen used as the terminal electron acceptor
O
Cellular respiration is described as a stepwise redox reaction...What substance is reduced?
Oxygen -> water
Indicate if each of the following is true of: Substrate- level phosphorylation or oxidative phosporylation. Involves the direct transfer of a phosphate form an intermediate molecule to ADP
S
What is meant by oxidative phosphorylation
Process by which ATP production is tied to an electron transport system that uses oxygen as the final acceptor/ energy released by the electron transport chain to make ATP from ADP
In general, describe what happens during photosynthesis
Process by which light energy is converted to chemical energy
Explain why respiration is considered exergonic.
Respiration is exergonic because energy is released when large high-energy molecules (glucose) are broken down into smaller molecules.
By the end of the krebs cycle, what has become of the six carbon atoms in the glucose molecule?
The 6 carbon atoms in glucose become 6 carbon dioxide molecules by the end of the Krebs cycle.
Describe in detail what happens in the electrons transport chain. What happens to the electrons and H+?
The electron transport chain is a collection of proteins in the inner mitochondrial membrane. The folding of the inner membrane to form cristae increases its surface area, providing space for thousands of copies of the chain in each mitochondrion. During electron transport along the chain, electron carriers alternate between the reduced and oxidized states as they accept and donate electrons. Each component of the chain becomes reduced when it accepts electrons from its "uphill" neighbor, which has a lower affinity for electrons (is less electronegative). It then returns to its oxidized form as it passes electrons to its "downhill", more electronegative neighbor.
What happens to the amount of potential energy of electrons as they shift from carbon and hydrogen toward oxygen in cellular respiration....How is the energy used
The electron transport chain is an energy converter that uses the exergonic flow of electrons from NADH and FADH2 to pump H+ across the membrane.
What happens to the amount of potential energy of electrons as they shift from carbon and hydrogen toward oxygen in cellular respiration
The electrons lose potential energy as they "fall" down the electron transport chain, just as a ball loses potential energy as it rolls downhill. The energy released does not make ATP directly
What is the major function of the krebs cycle?
The major function of the Krebs cycle is to transfer most of the chemical energy from the breakdown of pyruvate (through acetyl CoA) to NAD+ and FAD during redox reactions.
What is the energy released in cellular respiration used for?
This released energy is used to drive the reaction that synthesizes ATP from ADP.
Considering both the transition reaction and the krebs cycle together how many of each molecule lusted below are produced per glucose molecule a) NADH b) FADH2 c) CO2 d) ATP
a) 2+6= 8 b) 2+4=2 c) 6 d) 2
List the four phases of cellular respiration
a) Glycolysis - oxidation of glucose to pyruvate b) Transition reaction - oxidation of pyruvate to acetyl CoA c) Krebs cycle d) Oxidadtive phosphorylation - electron transport and chemiosmosis
Phase 2 : the transition reaction - the oxidation of pyruvate a) Occurs where? b) Starts with? c) Produces? d) Yields how much ATP?
a) cytoplasm b) pyruvate c) acetyl- CoA d) 0
Phase 1: glycolysis Label the diagram by filling in the boxes with the correct molecule a) Where does this process occur? b) What molecule does it start with? c) Which step(s) show the transfer of a phosphate form ATP to an intermediate? d) Which step shows a reduction reaction? e) Which step shows the splitting of a 6-c compound into two 3-c PGALs? f) Which steps are included in the energy-investment phase? g) Which steps are included in the energy-yielding phase? h) How many ATP molecules, per glucose, are used in this series of reactions? i) How many NADH, per glucose, are produced? j) How many ATP, per glucose, are produced
a) cytosal b) glucose c) 1,3 d) 5 e) 4 f) 1,3 g) 6,9 h) 2 i) 2 j) 4
In summary glycolysis: a) Occurs where? b) Starts with? c) Ends with? d) Yields how much ATP (net)? e) Produces ATP through what process?
a) cytosal b) glucose c) pyruvate d) 2 e) substrate phosphorylation
Phase 4: the electron transport chain a) Occurs where? (be specific) b) Starts with? c) Produces? d) Yields how much ATP? e) Produces ATP through which process?
a) inner mitochondrial membrane-cristae of the mitochondria b) NADH and FADH2 c) NAD+, FAD+, ATP d) 32 e) Oxidative phosphorylation
Phase 3: the krebs cycle (aka citric acid cycle) a) Occurs where? b) Starts with? c) Produces? d) Yields how much ATP? e) Produces ATP through what process?
a) mitochondrial marix b) acetyl-CoA c) CO2, NADH, FADH2, ATP d) 2 e) Substrate level phosphorylation
a) Alcoholic fermentation converts glucose to
ethanol (alcohol)
In general, describe what happens during cellular respiration
extracts the chemical energy stored in food (glucose) and uses it to generate ATP energy for cellular work.
define reduction
gain of electrons
c) Lactic acid fermentation converts glucose to
lactic acid
define oxidation
lose of electrons
What is the final electron acceptor in the electron transport chain
oxygen
What reactant is not utilized during the glycolysis stage but must be available for cellular respiration to follow?
oxygen
What is meant by substrate- level phosphorylation
process in which ATP is formed by transferring a phosphate from a metabolic substrate to ADP/ the mode of ATP synthesis when an enzyme transfers a phosphate group froma substrate molecule to ADP