Chapter 6: How Cells Utilize Energy Flashcards
What is the function of catabolic reactions?
Ch 6.3
Break down of larger molecules into smaller ones (EXERGONIC)
Ch 6.3
What is the function of anabolic reactions?
Ch 6.3
Synthesis/Building of larger molecules from smaller ones (ENDERGONIC)
Ch 6.3
How do catabolic reactions create ATP ?
Ch 6.3
By recycling organic molecules
Ch 6.3
What is the removal of electrons called ?
Ch 6.3
Oxidation Reaction
Ch 6.3
What is it called when an electron of one molecule is transferred to another?
Ch 6.3
Reduction-Oxidation (REDOX) Reactions
Ch 6.3
What is the reaction where electrons are added ?
Ch 6.3
Reduction Reaction
Ch 6.3
TRUE or FALSE: Oxidation reactions has more energy stored within its cellular bonds than reduction reactions
Ch 6.3
FALSE; Oxidation reactions have less energy within their cellular bonds in comparison to reduction reactions
Ch 6.3
What is the function of NAD+/NADH in redox reactions?
Ch 6.3
Break down of “food” molecules
example: glucose & fat molecules
Ch 6.3
What are the 3 ways Metabolic Pathways are regulated ?
Ch 6.3
GENETIC, CELLULAR, BIOCHEMICAL
Ch 6.3
Define genetic metabolic pathway regulation.
Ch 6.3
Gene regulation; increase or decrease in gene expression
Ch 6.3
Define cellular metabolic pathway regulation.
Ch 6.3
Cells integrate signals from their environment and adjust metabolic activity accordingly
Define biochemical metabolic pathway regulation.
Ch 6.3
Feedback inhibition; a product of a pathway binds a pathway enxyme at an allosteric site and decreases production of enzymes as needed
Allosteric Site: Where molecules are allowed to start/stop enzyme activity
Which is oxidated and which is reduced?
Ae- + B → A + Be-
Ch 6.3
A is Oxidated, B is Reduced
Oxidated: Electron Removal ; Reduction: Addition of Electron
Define Cellular Respiration
Ch 6.4
The process in which living cells obtain energy from organic molecules to make ATP
What’s the difference between kinetic and potential energy?
Ch 6.1
kinetic energy is associated with movement (such as a baseball bat from one location to another) , while potential energy is the energy that is stored in an object or substance (such as the location of an arrow when a bow is drawn).
What is the first law of thermodynamics?
Ch 6.1
Energy cannot be created or destroyed.
What is the second law of thermodynamics?
Ch 6.1
Any energy transformation from one form to another increases the degree of disorder of a system, which is called entropy.
Describe the relationship between entropy and energy disorder.
Ch 6.1
If an energy system is more disordered, entropy increases. As energy becomes evenly distributed, the energy is less ale to promote change.
Which do you think has more entropy, a NaCl crystal at the bottom of a beaker of water, or the solution that would be formed after the Na+ and Cl forming the crystal have dissolved in the water?
Ch 6.1
The solution has more entropy because a salt crystal is very ordered whereas the ions in the solution would be much more disordered.
T or F: Entropy is a main component of usable energy.
Ch 6.1
FALSE: entropy is a main component of UNUSABLE energy
Describe what exergonic reactions are. What are some characteristics of an exergonic reaction?
Ch 6.1
If a chemical reaction has a NEGATIVE free-energy change, then the products have LESS free energy than the reactants, and therefore free energy is RELEASED during product formation. It IS spontaneous; meaning it is slow and occurs on its own.
Describe endergonic reactions. What are some characteristics of endergonic reactions?
Ch 6.1
When a chemical has a POSITIVE free energy change, and it requires the ADDITION of free energy. It is NOT a spontaneous reaction.
Most reactions that cells must accomplish are _________. In order for them to overcome this problem, one strategy is to couple ________ reactions with them. If they are coupled together, the __________ reaction will proceed spontaneously.
Ch 6.1
1) endergonic
2) exergonic
3) endergonic
Identify which image is endergonic and which one is exergonic.
Ch 6.1
Left: exergonic
Right: endergonic
The hydrolysis of ATP is an example of an ____________ reaction. The energy released from ATP hydrolysis is used to drive other ___________ reactions.
Ch 6.1
1) exergonic
2) endergonic
T or F: A spontaneous reaction is a fast reaction.
Ch 6.2
FALSE: Not necessarily.
Define activation energy.
Ch 6.2
input of energy in a chemical reaction that allows molecules to cause a rearrangement of bonds.
This is an image of the steps of an enzyme catalyzed reaction. The example here shown involves the enzyme hexokinase, which binds ATP and glucose. The products are glucose-6-phosphate and ADP. Briefly describe each step.
Ch 6.2
1) substrates (ATP and glucose) bind to the enzyme (hexokinase)
2) enzyme undergoes conformational change, binding the substrates more tightly
3) substrates are converted to products
4) products (ADP and glucose-6-phosphate) are released, and enzyme is ready to be reused! :D
During which step is the activation energy lowered?
Ch 6.2
Step 2 when the substrates undergo induced fit.
Define affinity.
Ch 6.2
The attraction of an enzyme for a substrate.
Define Vmax and Km.
Ch 6.2
Vmax is the maximal rate of a reaction.
Km is the substrate concentration where velocity is half the max.
Define and compare competitive and noncompetitive inhibitors.
Ch 6.2
Competitive inhibitors raise Km for the substrate without affecting the Vmax; bind noncovalently to the active site which compete with the substrate in binding to the enzyme
Noncompetitive inhibitors lower the Vmax for the reaction without affecting the Km; binds noncovalently to an enzyme at a location outside the active site, called an allosteric site.
What factors influence enzyme structure and function? What are the optimal requirements in order for enzymes to properly function?
Ch 6.2
1) Temperature, pH, and ionic conditions.
2) Optimal temp is 37 degrees celsius or 98.6 degrees Fahrenheit. For pH, it depends on the type of enzyme.
What are the two general functions of catabolic pathways?
Ch 6.3
1) to recycle the components of organic molecules
2) to obtain energy for use in endergonic reactions
What is chemical energy?
Ch 6.1
A form of potential energy stored in chemical bonds.
Define aerobic respiration.
Ch 6.4
A type of cellular respiration in which O2 (oxygen) is consumed and CO2 (carbon dioxide) is released.
When glucose is broken down via oxidation, __________ is released, but some of this energy is lost as _____. However, most of this energy is used to make 3 energy intermediates: _____, _____, and ________.
Ch 6.4
1) free energy
2) heat
3) ATP, NADH, FADH2
Cellular respiration is a process that involves four metabolic pathways: glycolysis, pyruvate breakdown, the citric acid cycle and oxidative phosphorylation. Which of these processes does NOT produce ATP?
Ch 6.4
the breakdown of pyruvate
Define glycolysis. Bonus: Draw it
Ch 6.5
Glycolysis involves the breakdown of glucose, a simple sugar, into two molecules of a compound called pyruvate.
What are the 3 phases of glycolysis?
Ch 6.5
energy investment phase, cleavage phase, and the energy liberation phase
During glycolysis, ATP is used during the ______ phase, and ATP is synthesized during the ______ phase.
Ch 6.5
energy investment; energy liberation
T or F: ATP, NADH, and pyruvate are products of glycolysis, while CO2 is NOT a product of glycolysis.
True :D
What is the chemical composition like during glycolysis? That is…what is being transformed, and what is being produced?
Ch 6.5
Overall, 1 molecule of glucose is transformed into 2 molecules of pyruvate, and a net of 2 ATP and 2 NADH are generated
Where is glycolysis located in the cell?
Ch 6.5
the cytoplasm
Where is the breakdown of pyruvate located in the cell?
Ch 6.6
Glycolysis produces pyruvate in the cytosol, then is transported into the mitochondrial matrix
What molecule is removed from pyruvate?
Ch 6.6
CO2 (carbon dioxide)
T or F: Pyruvate is oxidized by an enzyme complex called pyruvate dehydrogenase.
Ch 6.6
True :D
What is the chemical composition like during the breakdown of pyruvate? What is being transformed and what is being produced?
Ch 6.6
a molecule of CO2 is removed, then the remaining acetyl group is attach to an organic molecule called coenzyme A (CoA) and then acetyl CoA is produced. 1 NADH is produced for each pyruvate.
T or F: ATP, NADH, acetyl group attach to CoA, and CO2 are ALL products of the breakdown of pyruvate.
Ch 6.6
FALSE; ATP is NOT a product of the breakdown of pyruvate
What are the products of the citric acid cycle?
Ch 6.7
4 CO2, 6 NADH, 2 FADH2, GTP and CoA
Briefly explain what happens during the citric acid cycle.
Ch 6.7
An acetyl group is removed from acetyl CoA and attached to oxaloacetate to make citrate. Then, 4 CO2 molecules, 6 NADH, 2 FADH2 and 2 ATP are made. Then the cycle begins again.
During the citric acid cycle, what happens to carbon?
Ch 6.7
carbon is oxidized to make NADH and FADH2.
During the first 3 stages of glucose metabolism, the oxidation of glucose yields __ molecules of CO2, __ molecules of ATP, __ molecules of NADH, and __ molecules of FADH2.
Ch 6.8
6; 4; 10; 2
Define oxidative phosphorylation.
Ch 6.8
The process in which NADH and FADH2 have electrons removed and become oxidized to generate a H+ gradient
Where does oxidative phosphorylation occur in the cell?
Ch 6.8
electron transport chain (ETC) inside the mitochondrial matrix
At the end of the chain is _______, which is the most electronegative component and the final electron acceptor.
Ch 6.8
oxygen
What are the reasons that the maximum amount of ATP may not always be produced through oxidative phosphorylation?
Ch 6.8
some NADH might be used to synthesize organic molecules AND the mitochondria may use some of the H+ gradient for other purposes
What are the two distinct events that occur in oxidative phosphorylation?
Ch 6.8
1) electron transport chain and
2) ATP synthesis
At the end of oxidative phosphorylation, about how much ATP can be synthesized? How much is USUALLY synthesized?
Ch 6.8
1) 30-34 ATP
2) less than 25, which is still greater than the amount that is generated in glycolysis or the citric acid cycle
Why do cells rarely achieve the maximal amount of ATP?
Ch 6.8
1) NDH is also used in anabolic pathways
2) H+ gradient is also used for other purposes
The source of energy that directly drives the synthesis of ATP during oxidative phosphorylation is _______
Ch 6.8
the H+ gradient
Fatty acid tails have _______ acetyl units removed, which bind to _____ and enter the citric acid cycle.
Ch 6.9
two-carbon; CoA
The advantage of connecting metabolic pathways for carbohydrate, protein, and fat metabolism is that ________________.
Ch 6.9
the same enzymes are used to break down different starting materials
Define anaerobic.
Ch 6.10
the term is used to describe an environment that lacks oxygen
What are the 2 mechanisms that have allowed organic molecules WITHOUT oxygen?
Ch 6.10
1) anaerobic respiration
2) fermentation
One strategy to produce ATP under anaerobic conditions is to make ATP only via _________.
Ch 6.10
glycolysis
Under anaerobic conditions, _______ builds up and _______ decreases.
Ch 6.10
1) NADH
2) NAD+
What are some examples of fermentation processes that oxidize NADH to NAD+ (that allow glycolysis to continue)?
Ch 6.10
lactic acid production in muscle and ethanol production in yeast
Define fermentation.
Ch 6.10
the breakdown of organic molecules without net oxidation
