Chaper 9 Flashcards
Define cellular respiration. What does it require? What does it produce?
Cellular Respiration converts the chemical energy off food molecules into chemical energy of ATP.
It requires oxygen.
It produces ATP.
Describe how energy flows through a system.
Energy Flows through a system by:
Solar energy —-> chemical energy of food —>chemical energy of ATP—-> heat
Describe how nutrients cycle through a system.
The products of photosynthesis are the reactants of cellular respiration, and vice versa. Nutrients cycle through a system by cellular respiration and photosynthesis.
Define photosynthesis and cellular respirations/fermentation in terms of energy.
Photosynthesis is the energy acquisition (light energy —> chemical bond energy)
Cellular respiration/fermentation is energy release (chemical bond energy —-> ATP +heat)
Through what process in glucose used to make ATP in aerobic environments? What process is used in anaerobic environments?
Aerobic environment glucose is used in cellular respiration.
Anaerobic environment glucose is used in fermentation.
Carbon atoms of glucose are _____ (reduced/oxidized) to form what byproduct?
oxidized, to form CO2
Oxygen atoms in oxygen are ______ (reduced/oxidized) to form what byproduct?
Reduced, to form H2O
Write out the chemical formula for cellular respiration.
C6H12O6 +6 O2 —> 6 CO2 + 6 H2O + energy
List and describe the four steps of cellular respiration.
1) Glycolysis: glucose is broken down to pyruvate
2) Pyruvate processing: pyruvate is oxidized to form acetyl CoA.
3) Citric Acid Cycle: Acetyl CoA is oxidized to CO2
4) Electron Transport and Chemiosmosis: Compounds reduced in steps 1-3 are oxidized in reactions leading to ATP production.
Define what occurs during glycolysis. Where in the cell does glycolysis occur?
Glycolysis breaks glucose (6 carbon) into two pyrrhic acid molecules (3 carbon). Glycolysis occurs in the cytosol.
List the products (results) of glycolysis.
2 pyruvate molecules
2 molecules of NAD+ are reduced to form NADH
4 molecules of ATP are formed by substrate level phosphorylation
Define substrate-level phosphorylation.
Substrate level phosphorylation occurs when enzymes transfer an inorganic phosphate from a substrate to ADP, forming ATP.
Where is pyruvate transported to after being formed in the cytosol?
It is transported to the mitochondria in the presence of O2.
Define what occurs during pyruvate processing. Where in the cell does this occur?
2 pyruvates (3C) molecules are oxidized to form 2-acety-CoA (2C) molecules. A NAD+ are reduced to form 2 NADH. 2 CO2 molecules are released as waste.
This occurs in the matrix of the mitochondria.
Describe the main process of the citric acid cycle. (Hint: what enters and what exits?)
The acetyl CoA produced in the pyruvate processing enters the citric acid cycle and are oxidized to make 2 molecules of CO2.
Where in the cell does the citric acid cycle take place?
Occurs in the mitochondrial matrix.
What are the three uses of the released potential energy from the citric acid cycle?
1) reduce NAD+ to NADH
2) Reduce FAD+ to FADH2
3) Phosphorylate GDP/ADP to form ATP (depending on the cell)
List the six steps of the citric acid cycle in detail.
1) 2 carbon molecule (acetyl CoA) joins a 4 carbon molecule to form citric acid.
2) 2 CO2 molecules exit as waste
3) Most of energy (from electrons) are captured by NADH
4) Some energy transfers ADP—> ATP
5) Remaining electrons are captured by FADH2
6) Any 4 carbon molecules in citric acid cycle are recycled and join another acetyl CoA forming citric acid.
(Not a question, just information)
Glucose oxidation includes three of the four steps of cellular respiration: glycolysis, pyruvate processing, citric acid cycle
Glucose oxidation (glycolysis, pyruvate processing, citric acid cycle) produces ATP, NADH, FADH, and CO2. How many of each are produced in total?
4 ATP, 10 NADH, 2 FADH2, 6CO2
Where in the mitochondria are the electron transport proteins located?
Located on the cristae (inner membranes of the mitochondria)
NAD+ pick up two____ (electron/hydrogen ion) and one ______ (electron/hydrogen ion) from glucose, and becomes reduced to______.
Electrons, hydrogen ion, reduced to NADH
What facilitates the transfer of electrons as they lose energy?
The electron transport chain facilitates the transfer of electrons as they lose energy.
What is the final result of this transfer of electrons? (Hint: What is the main goal of cellular respiration?)
The transfer of electrons activates electron transport proteins to make ATP.
Name the atom at the end of the electron transport chain that is the final electron acceptor.
The final electron acceptor is Oxygen (O2)
Explain why electrons are moved from one electron acceptor to the next, in regards to how it affects hydrogen ions (H+).
Electrons move from one electron acceptor to the next to an even lower energy state. Energy isn’t lost but used to fuel a hydrogen ion pump. The hydrogen ions are pumped across the membrane, their potential energy is increased because a steep concentration gradient is created.
Explain how the created concentration gradient of hydrogen ions create ATP, including involved enzymes, locations, etc.
The ions flow through the system through the enzyme ATP synthase back to the other side of the membrane. The flow of H+ ions is converted to kinetic energy. The kinetic energy from the hydrogen ion flow allows ATP synthase to make ATP in a process : Chemiosmosis.
Define Chemiosmosis.
Chemiosmosis when H+ flows down the Fo unit, the rotor shaft rotates, increasing the affinity of the ADP to Pi to form ATP.
What type of phosphorylation occurs in the electron transport chain?
Oxidative phosphorylation
What specific membrane protein phosphorylates ADP into ATP?
ATP synthase
Where is the majority of ATP from glucose oxidation occur out of the 4 steps of cellular respiration? How many of the 29 ATP are produced in this step?
ATP synthase produces 25 of the 29 ATP molecules.
What are the two examples of final electron acceptors prokaryotes use in anaerobic respiration?
NO3 - and SO4 2-
What is the downside of using electron acceptors other than oxygen?
They are less electronegative and generate less ATP.
Does fermentation (another anaerobic pathway to produce ATP) require oxygen?
No it does not require oxygen.
Which stage of cellular respiration is fermentation a modification of?
A modified glycolysis stage.
List and describe the two steps of the fermentation process.
Pyruvate —> ethanol or lactic acid
Reduce pyruvate and oxidize NADH to NAD+
How many ATP does fermentation produce? Is it more or less efficient compared with cellular respiration?
2 molecules of ATP , less efficient compared to cellular respiration.
If oxygen is not available, what is pyruvate reduced into? What is the point of this reduction?
Pyruvate is reduced to lactic acid, the purpose is to regenerate more NAD+
What is the downside of creating more electron carriers? (Hint: its a good thing, because it can oxidize more glucose, but too much of a good thing is bad!)
It creates a high concentration of waste products (lactic acid)
Describe lactic acid fermentation.
This occurs in human muscle cells, Pyruvate produced by glycolysis accepts electrons (H+) from NADH —> NAD+ and lactic acid is formed.
Describe alcohol fermentation.
Occurs in yeast, Pyruvate is converted to acetaldehyde and CO2, Acetaldehyde accepts electrons from NADH —> NAD+ and ethanol are produced.
