Chapter 9 Flashcards
What is considered the “useable” form of energy for cells?
ATP
Where do the high energy organic molecules (food) originally come from?
Organisms may obtain food through photosynthesis (autotrophs) or by consuming other organisms (heterotrophs)
Are cellular respiration, anaerobic respiration, and fermentation considered catabolic or anabolic processes?
Catabolic
What are the three major catabolic pathways?
cellular respiration, anaerobic respiration, and fermentation
Which catabolic pathways produce ATP?
All three pathways (cellular respiration, anaerobic respiration, and fermentation) produce ATP, but in different amounts
Know the overall chemical equation for cellular respiration
C6H12O6 + 6O2 —> 6CO2 + 6H2O + Energy
Is glucose the only molecule that can be broken down during cellular respiration?
No, other organic molecules too
Why is glucose the most commonly used organic molecule met when tracking cellular respiration?
Since glucose is the preferred energy molecule for most organisms
The energy released during glucose oxidation (cellular respiration) is used to make what molecule?
ATP
Approximately, what percentage of the energy released during glucose oxidation is used to make ATP? What happens to the rest of the energy?
40% goes to ATP production
60% lost as heat
Which type of organisms can undergo cellular respiration?
prokaryote/eukaryote; all living organisms essentially
How do cells obtain the O2 used for cellular respiration?
photosynthesis
What happens to the CO2 that is produced during cellular respiration?
It is released
Be able to identify a redox reaction (i.e. which molecule is being oxidized? which is being reduced? which is the reducing agent? which is the oxidizing agent?)
Transfer of electrons through Oxidation and Reduction.
Oxidation - loses electrons and becomes oxidized
Reduction - gains electrons, becomes reduced. (electron donor - reducing agent. Electron receptor - oxidizing agent)
How much energy in kcals is released during the oxidation of one mole of glucose?
686 kcal/mole
Is cellular respiration endergonic or exergonic?
exergonic
Is cellular respiration spontaneous or non-spontaneous?
spontaneous
Does NAD+ become reduced or oxidized during cellular respiration?
Reduced
Does NADH become reduced or oxidized during cellular respiration?
Oxidized
What is the name of an enzyme that removes hydrogens and electrons from organic molecules and transfers them to NAD+?
Dehydrogenase
Which macromolecule class does NAD+ belong to?
nucleotide
Which stage of cellular respiration is NADH used?
Oxidative phosphorylation
Why is glucose catabolized in a series of small steps rather than one big step?
Catabolic pathways release stored energy by breaking down complex molecules (exergonic reactions)
What are the three major stages of cellular respiration?
Glycolysis, Pyruvate Oxidation and Citric Acid Cycle, and Oxidative Phosphorylation
Which stages produce ATP?
Glycolysis, Citric Avid Cycle, and Oxidative Phosphorylation
Which stage produces the most ATP?
Oxidative phosphorylation
What cellular location does glycolysis take place?
in cytoplasm of cell
Is glycolysis an aerobic or anaerobic process?
anaerobic
Is the ATP made during glycolysis made by substrate level phosphorylation or oxidative phosphorylation?
substrate level phosphorylation
What are the requirements for glycolysis to occur?
glucose, 2 ATP, 2 NAD+, and 4 ADP
What is the difference between the energy investment and the energy payoff phases of glycolysis?
energy investment - energy is used.
energy pay off - energy released
What are the products of glycolysis?
Net gain of 2 ATP, 2 NADH, and 2 pyruvate
How many carbons does the starting molecule have in glycolysis and how many carbons does the final product of glycolysis have?
6 carbon into two 3 carbon molecules called pyruvate
What is the purpose of phosphorylating some of the glycolysis intermediates?
can be used to make glucose, amino acids, cholesterol, fatty acids, glycerol, nucleic acids
Which enzyme is responsible for phosphorylating glycolytic intermediates and ADP during glycolysis?
Glucose
How many enzymes are involved in glycolysis?
10
What cellular location does pyruvate oxidation occur?
inside mitochondrion
What are the two pathways that pyruvate may undergo after it is synthesized?
During aerobic conditions: the pyruvates enter the mitochondrion where it is oxidized to form acetyl CoA
During anaerobic conditions: the pyruvate remains in the cytoplasm and is fermented into other organic molecules
What dictates which pathway it will undergo?
anaerobic or aerobic (O2)
Which enzyme is responsible for oxidizing pyruvate?
Pyruvate dehydrogenase or ? Coenzyme A ?
What are the products of pyruvate oxidation?
2 acetyl CoA
2 CO2
2 NADH
Which molecule links glycolysis to the citric acid cycle?
Acetyl CoA
What cellular location does the citric acid cycle take place?
Inside mitochondrion
What is the starting molecule for the citric acid cycle and how many carbons does it possess?
Acetyl CoA-2
The citric acid cycle begins with the combining of a two carbon molecule and a four carbon molecule to form a six carbon molecule. This six carbon molecule is ultimately converted back into the same four carbon molecule which completes the cycle. The two carbons that are removed from this six carbon molecule leave as which molecules?
CO2
What are the products produced per turn of the citric acid cycle?
1 ATP, 3 NADH, 1 FADH2, and 2 CO2
How many turns of the citric acid cycle will occur from one molecule of glucose?
2
How many enzymes are required to carry out the citric acid cycle?
8
What cellular location does oxidative phosphorylation occur?
inside mitochondria
What are the two processes included in oxidative phosphorylation? What specific location do each of the processes take place?
Electron transport - inner membrane
Chemiosmosis - matrix
Are these aerobic or anaerobic processes?
aerobic
What are the precursor molecules for oxidative phosphorylation?
NADH, FADH2, O2
What makes up the electron transport chain?
a series of four multiprotein complexes (numbered I-IV) embedded in the inner membrane of mitochondria
What is the source of the electrons that are transported through the electron transport chain?
The NADH and FADH2 formed during glycolysis and the citric acid cycle are oxidized resulting in electrons
Electron transport causes a release of energy. What is this energy used for?
used to pump H+ from the mitochondrial matrix to the intermembrane space through transport proteins
Does the electron transport chain directly make ATP?
No
What is the final electron acceptor at the conclusion of the electron transport chain?
O2
What molecule is formed when O2 is reduced by hydrogen protons and electrons?
H2O
How is ATP synthesized during oxidative phosphorylation?
ATP synthase then utilizes the energy from the proton motive force to make ATP
How many ATP are made during oxidative phosphorylation?
28
Which electron carrier pumps more H+ into the intermembrane space? Why?
Electron transfer in the electron transport chain releases energy that is used to pump H+ from the mitochondrial matrix to the intermembrane space through transport proteins
What is the difference between aerobic respiration and anaerobic respiration?
aerobic requires oxygen, anaerobic does not
naerobic respiration uses an electron transport chain with a final electron acceptor other than O2 (occurs in some bacteria only)
What cellular location does fermentation occur?
cytoplasm
Is fermentation aerobic or anaerobic?
anaerobic
How is ATP formed during fermentation?
Fermentation allows for ATP production (via glycolysis only) during anaerobic conditions (provides a way for cells to survive temporarily under anaerobic conditions)
What specific role does fermentation play in making sure that glycolysis can continue?
the NADH that is formed during glycolysis must be oxidized in order to replenish NAD+ levels
What are the two main types of fermentation?
- Which one has two steps?
- Which one involves reducing pyruvate?
- Which one produces CO2?
Alcohol and Lactic acid fermentation.
Alcohol has 2 steps
Lactic acid reduces pyruvate
Alcohol produces CO2
How are molecules other than glucose (fats, proteins, other carbohydrates, etc.) catabolized?
Catabolic pathways funnel electrons from many kinds of organic molecules into cellular respiration
How can the body use glycolytic and citric acid cycle intermediates other than for ATP production?
The body uses small molecules to build other substances
-can be used to make glucose, amino acids, cholesterol, fatty acids, glycerol, nucleic acids
How are glycolysis and the citric acid cycle regulated?
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