Chapter 2: Cellular Respiration Flashcards
Photoautotrophs
Organisms that can build all the organic compounds required for life from simple inorganic materials, using light in the process.
Heterotrophs
Organisms that feed on other organisms to obtain chemical energy.
Chemoautotrophs
Organisms that can build all the organic compounds required for life from simple inorganic materials without using light energy.
Aerobic Cellular Respiration
Harvesting energy from organic compounds using oxygen.
Obligate Anaerobes
Organisms that cannot live in the presence of oxygen and obtain energy by oxidizing inorganic substances.
Obligate Aerobes
Organisms that obtain energy by oxidizing organic substances using oxygen.
Facultative Anaerobes
Organisms that obtain energy by oxidizing inorganic substances with or without oxygen.
Substrate-level Phosphorylation
Mechanism forming ATP directly in an enzyme-catalyzed reaction.
Oxidative Phosphorylation
Mechanism forming ATP indirectly through a series of enzyme-catalyzed redox reactions (oxidation and reduction) involving oxygen as the final electron acceptor.
The final product from the electron transport chain that contains most of the electrons in which of the following?
Water
In which of the following forms is energy immediately made available for use by living cells?
ATP
The major advantage of aerobic respiration to humans is that we…
Obtain more usable energy by aerobic respiration.
At the end of glycolysis, most of the energy originally found in glucose is located in the molecules of…
Pyruvate
Differences between aerobic and anaerobic respiration.
Aerobic has a higher energy efficiency and anaerobic has a lower one. The products of Aerobic are water and carbon dioxide where the products of anaerobic are lactate or ethanol and carbon dioxide.
Explain how fats can be used to release free energy to help with our metabolic needs.
- fats cannot be used directly to produce energy for a cell.
- First, fat must be hydrolyzed into glycerol and fatty acids. The glycerol can enter glycolysis after either being converted to glucose (via gluconeogenesis) or changed into dihydroxyacetone phosphate (DHAP).
- The fatty acids are broken down to two-carbon units (acetyl-CoA) in a process called β-oxidation, which can be fed directly into krebs cycle.
Briefly explain how ATP is formed from NADH by the electron transport chain and chemiosmosis.
Electrons from NADH are passed to the enzyme NADH dehydrogenase, which is embedded in the inner mitochondrial membrane. The hydrogen that is released from the NADH is pumped to the intermembrane space, thus establishing a proton and pH gradient. The electrons move from electron carrier to electron carrier in the intermitochondrial membrane in a series of redox reactions and ultimatley combine with oxygen and protons at the cytochrome oxidase complex to form water, As electrons move along this pathway more protons, from the dissosiation of FADH2 are pumped from the matrix to the intermembrane space adding to the proton and pH gradient. The protons from the intermembrane space return to the matrix via special ATP synthase molecules embedded in the inner mitochondrial membrane. As they do, they help to catalyze the formation of ATP from ADP and P.
Pyruvate (pyruvic acid) is an interesting molecule because there are so many possibilities for what can happen to it. Describe what the various fates of pyruvate are and under what circumstances these different pathways are used.
.
Aerobic respiration involves which of the following?
The release of energy in cells with an adequate supply of oxygen.
The following molecules can be found at various stages during cellular respiration:
I. acetyl-CoA
II. Carbon Dioxide
III. Glucose
IV. Glyceraldehyde
V. Pyruvate
Which of the following sequences represents the above molecules in order from the largest to the smallest amount of chemical energy?
Glucose, Glyceraldehyde, Pyruvate, acetyl-CoA, Carbon Dioxide
In which of the following situations would you LEAST expect to find anaerobic respiration occuring?
a) a vat in which beer is being manufactured
b) a human brain engaged in writing this test
c) The inside of a bacterium living inside a human intestine
d) a runner’s leg muscle during a 400-m dash
e) the sediments at the bottom of a pond
A human brian enganged in writing this test.
During cellular respiration, the oxygen we inhale ends up in the carbon dioxide we exhale.
False. During cellular respiration the oxygen we inhale ends up in the water we exhale or cecrete.
Overall, glycolysis is an endergonic process.
False, it is an exergonic process.
Electrons combine with oxygen and protons at the end of the electron transport chain.
True
The following reaction takes place in animal cells but not in plant cells:
C6H12O6 + 6 O2 6 CO2 + 6 H2O
False
Pyruvate is a three-carbon compound that is converted into acetyl-CoA in the mitochondrial matrix before entering the Krebs cycle.
True
NADH is reduced by the first protein complex of the electron transport chain.
False. NADH is oxidized by the first protein complex of the electron transport chain.
If a poison blocks the flow of protons through ATP synthase, the Krebs cycle will continue, but glycolysis will not.
False. If a poison blocks the flow of protons through ATP synthase, the Krebs cycle stops, but glycolysis will continue.
Only the amino group of amino acids can be used for energy.
False. The amino group is first removed from the amino acid as waste and the rest of the amino acid is modified prior to entering glycolysis or the Krebs cycle.
In oxidative phosphorylation, 2 NADH and 1 FADH2 theoretically produce 8 ATP.
True
Fermentation oxidizes NADH to NAD+ so that glycolysis can continue.
True
Maximum oxygen consumption, VO2 max, increases as people grow older.
False. Maximum oxygen consumption, VO2 max, decreases as people grow older.
The complete oxidation of glucose to carbon dioxide and water has a G of 2870 kJ/mol glucose. Aerobic respiration captures about 930 kJ of this energy. What happens to the rest of the energy?
It is lost as heat and an increase in entropy.
In glycolysis, glucose must first be activated. Which of the following does this require?
two molecules of ATP
Why is anaerobic respiration less efficient than aerobic respiration?
a. Fewer molecules of ATP are produced per glucose processed.
b. Glucose is not completely oxidized to CO2 and H2O.
c. The potential energy of NADH is not transferred to ATP.
d. The electron transport system is not used.
All of the Above
Which of the following is a product of lactate fermentation?
NAD+
When the supply of acetyl-CoA exceeds the demand for energy, some of the acetyl-CoA can be diverted toward the synthesis of which one of the following?
fatty acids
Cyanide poisoning occurs because cyanide binds cytochrome oxidase, preventing it from transferring electrons to the final electron acceptor of the mitochondrial electron transport chain. What is that acceptor molecule?
O2
If the ATP level of a cell becomes too high, ATP can bind to phosphofructokinase and block the formation of fructose 1,6-bisphosphate. This is an example of which of the following?
feedback inhibition
