Biology 1002B Lecture Notes - Lecture 9: Thermogenin, Uncoupling Protein, Pyruvate Dehydrogenase Kinase

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greenduck439

20 Apr 2016

School

Western University

Department

Biology

Course

Biology 1002B

Professor

Beth Mac Dougall- Shackleton

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Document Summary

1: location, products, distribution in nature and purpose of pathways such as glycolysis, ca cycle, respiratory electron transport etc. There is a lot of potential energy in glucose because there are a lot of c- h bonds. Cellular respiration is exergonic and catabolic. Phosphofructokinase activity is also sensitive to the levels of citrate which is the first product of the citric acid cycle. If the products of the citric acid cycle are in high demand, then citrate should not accumulate in the cell. It may also indicate that citrate is not required as a carbon skeleton for anabolic reactions. Glycolysis: glycolysis takes place in the cytosol. It"s purpose is to take glucose and turn it into two molecules of pyruvate. Purpose: to break down glucose into 2 pyruvate molecules with free energy that can enter the matrix. Takes place in the mitochondrial matrix. Links glycolysis and the citric acid cycle.

Related Questions

Phosphofructokinase (PFK1) is a glycolytic enzyme that catalyzes the irreversible transfer of a phosphate from ATP to fructose -6-phosphate to form fructose-1, 6- bisphosphate.

fructose-6-phosphate + ATP --> fructose-1,6-bisphosphate + ADP

PFK1 is the key regulatory enzyme for glycolysis. When ATP levels are high in the cell, the cell no longer needs metabolic energy production to occur. In the case of these high energy levels, PFK1's activity is inhibited by allosteric regulation by ATP, which essentially closes the valve on the flow of carbohydrates through glycolysis.

Recall that allosteric regulators bind to a different site on the enzyme rather than the active (catalytic) site. ATP binds to the regulatory site and decreases PFK1 activity. ATP bound in the regulatory site acts as a modulator by lowering the affinity of PFK1 for its substrate, fructose-6-phosphate. AMP on the other hand, which is generated when the cell is in a low energy state binds to allosteric site and increases enzyme activity.

7. The enzyme PFK1 is an example of a non-regulatory enzyme or regulatory enzyme?

8. How is PFK regulated?

A. It is not regulated because it is a non-regulatory enzyme

B. allosteric enzyme regulation

C. covalent enzyme regulation

D. or proteolytic cleavage enzyme regulation?

9. What is the substrate and to which site on the enzyme does it bind? Which compounds are the positive and negative effectors?

10. In which conformational state would the enzyme be when negative inhibitors bind and in which conformational state would the enzyme be when positive inhibitors bind?

11. PFK1 is a heterotropic or homotropic regulatory enzyme?

12. Draw (or insert the picture from your course packet available on Canvas) the graph that corresponds to this reaction. Your graph should include the activity of PFK without bound effectors, with bound positive effector, and with bound negative effector. Label (or describe) each line to distinguish these along with which molecules are positive and negative effectors.

13. How does Vmax and K0.5 change with the positive and negative effectors?

3) The hydrolysis of sucrose to glucose and fructose is exergonic. However, if you dissolve sucrose in water and keep the solution overnight at room temperature, there is no detectable conversion to glucose and fructose. Why?

Select one:

a. The change in free energy of the reaction is negative.

b. The activation energy of the reaction is high.

c. The free energy of the products is higher than the free energy of the reactants.

d. This is a condensation reaction.

e. The change in free energy of the reaction is positive.

5) Competitive inhibition differs from non-competitive inhibition in that the ___1___ site is where we see competitive inhibition, while the non-competitive inhibitor __2___.

1. a. allosteric b. non-active c. active d. hydrophillic e. hydrophobic

2.
a. binds to the active site, thus blocking it
b. binds outside the active site, changing the shape of the enzyme
c. binds outside the active site, and blocks the active site

6) Phosphofructokinase is an enzyme, and as such it __1___ of the reaction. It is part of glycolysis, and is an example of an enzyme controlled by inhibition, as high levels of citrate (an intermediate further down the catabolic pathway) turns the enzyme off
(1)Select one:
a. lowers activation energy
b. lowers the ÎG
c. raises the Free Energy
(2)Select one
a. non-competitivenegative feedback
b. irreversible competitivereversible competitive.

15)The reactions in the pathways of glycolysis and the citric acid cycle harvest the high-energy electrons stored in glucose. Therefore, these pathways _______________.

Select one:

a. take place in animal cells, but not in plant cells
b. are catabolic pathways
c. are anabolic pathways
d. involve the reduction of glucose and its metabolic intermediates

21) In an exergonic chemical reaction, the products have less free energy than the reactants (-ÎG). Endergonic reactions require an input of energy (+ÎG). The addition of starting materials and the removal of end products prevent metabolism from reaching final equilibrium. Instead, the cell exists in a state of dynamic equilibrium.

Select one:
True
False

greyferret515

A catabolic pathway would predictably result in the
A) reduction of a sugar.
B) synthesis of a macromolecule.
C) breakdown of a macromolecule.
D) breakdown of an atom.
2.
The drug Ritonavir is used to treat people with HIV/AIDS. It worksby binding to the active site of HIV-1 protease, an enzyme used bythe AIDS virus to create new proteins for production of newviruses.Once bound, the HIV-1 protease cannot produce proteins.Ritonavir can be classified as a(n)
A) competitive inhibitor.
B) allosteric inhibitor.
C) activator.
D) non-competitive inhibitor.
3.
During cellular respiration, __________ is the final electronacceptor that allows the regeneration of the cellâs supply of NAD+.In fermentation, ____________ is the final electron acceptor forNAD+ regeneration.
A) pyruvate / lactic acid
B) pyruvate / oxygen
C) ethanol / CO2
D) oxygen / pyruvate
4.
Which of the following clues would tell you if a cell isprokaryotic or eukaryotic?
A) whether or not the cell carries out cellular metabolism
B) the presence or absence of ribosomes
C) whether or not the cell is partitioned by internalmembranes
D) whether or not the cell contains DNA
5.
Phosphofructokinase (PFK) is an allosteric enzyme that regulatesglycolysis. When cellular concentrations of ATP and citrate become__________, this enzymeâs activity decreases. When cellularconcentrations of AMP become ________, the enzyme isactivated.
A) high / high
B) high / low
C) low / high
D) low / low
6.
______________ is an enzyme that can utilize the free energy in thehydrogen gradient (voltage) produced between the inner and outermembrane of the mitochondrion. The enzyme uses this energy toproduce ________.
A) ATP synthase/ ATP
B) PFK/ ATP
C) PFK/ glucose
D) ATP synthase/ ADP
7.
ATP is able to do cellular work because it
A) has a high energy phosphate bond that can be hydrolyzed torelease energy.
B) converts light energy into chemical bond energy.
C) contains the sugar ribose, which can provide additional energyfor a cell.
D) its hydrolysis is endergonic.
8.
A solution of starch at room temperature does not readily decomposeto form a solution of simple sugars because
A) the starch solution has less free energy than the sugarsolution.
B) the activation energy barrier for this reaction cannot besurmounted.
C) the hydrolysis of starch to sugar is endergonic.
D) starch hydrolysis is nonspontaneous.
9.
A person exposed to toxins would have more activity in their___________compared to an unexposed person.
A) lysosomes
B) Golgi bodies
C) rough endoplasmic reticulum
D) smooth endoplasmic reticulum
10.
Which of the following statements about fermentation is true?
A) The function of fermentation is to regenerate the fermentingcells' supply of NAD+.
B) Fermentation allows a fermenting cell to gain more energy perglucose molecule than a non-fermenting cell.
C) Fermentation produces either lactic acid or ethanol that thefermenting cell can use as an energy source.
D) Fermentation is a universal process that occurs in all cells andall organisms.
11.
A glucose molecule is completely broken down to carbon dioxide andwater in glycolysis and the citric acid (Krebs) cycle, but togetherthese two processes yield only a few molecules of ATP. Whathappened to most of the energy that the cell obtains from theoxidation of glucose?
A) It was lost as heat.
B) It is stored in the carbon dioxide and water molecules releasedby these processes.
C) It is stored in the ATP that was formed by glycolysis and thecitric acid cycle.
D) It is stored in NADH and FADH2
12.
The First Law of Thermodynamics states that
A) entropy tends to increase in a system.
B) entropy tends to decrease in a system.
C) energy cannot be created nor destroyed.
D) the quality of energy in the universe is decreasing.
13.
The endosymbiotic theory states that _______________ evolved as aresult of a symbiotic relationship between different types ofbacteria. _____________ is thought to be the selective factor thatmade this symbiosis advantageous.
A) mitochondria / A change in the Earthâs atmosphere from anaerobicto aerobic
B) endoplasmic reticulum / A decrease in the amount of foodavailable in the environment
C) chloroplasts / A change in the Earthâs atmosphere from aerobicto anaerobic
D) lysosomes / A decrease in the amount of food available in theenvironment
14.
A mutation in a fruit fly affects one of the proteins that pumphydrogen ions across the inner mitochondrial membrane; thismutation makes that particular protein function less efficiently.When comparing aerobic cellular respiration in this fly with awild-type fly, you would predict that the mutant fly would
A) produce less ATP than a wild-type fly.
B) show no difference in ATP production when compared to awild-type fly.
C) produce more ATP than a wild-type fly.
D) not be able to produce any ATP via aerobic cellularrespiration.
15.
Proteins that are destined to be exported from the cell have unique_________________ that are recognized by signal recognitionparticles and thus moved to the _________________ duringtranslation.
A) phosphofructokinases / nucleus
B) codons / rough endoplasmic reticulum
C) signal recognition sequences / rough endoplasmic reticulum
D) signal recognition sequences / free ribosomes
16.
During the Krebs cycle
A) NADH is oxidized.
B) ATP is produced.
C) pyruvate is produced.
D) Acetly CoA gains a carbon to form pyruvate.
17.
Why does the oxidation of organic compounds by molecular oxygen toproduce CO2 and water release free energy?
A) Electrons are being moved from atoms that have a lower affinityfor electrons (such as C) to atoms with a higher affinity forelectrons (such as O).
B) The electrons have a higher potential energy when associatedwith water and CO2 than they do in organic compounds.
C) The covalent bond in O2 is unstable and easily broken byelectrons from organic molecules.
D) The covalent bonds in organic molecules and molecular oxygenhave more kinetic energy than the covalent bonds in water andcarbon dioxide.
18.
In a chemical reaction, if ?G is negative, it means that thereaction is
A) exergonic, and work needs to be done for the reaction toproceed.
B) exergonic, and work can be done with energy released from thereaction.
C) endergonic, and work needs to be done in order for the reactionto proceed.
D) endergonic, and work can be done with energy released from thereaction.
19.
The energy for an endergonic reaction comes from a(n) ___________reaction.
A) ADP + P --> ATP
B) endergonic.
C) exergonic.
D) anabolic
20.
Glycolysis
A) involves catabolic reactions and ATP is produced.
B) involves anabolic reactions and ATP is produced.
C) involves catabolic reactions and creates energy.
D) involves anabolic reactions and creates energy.

Biology 1002B Lecture Notes - Lecture 9: Thermogenin, Uncoupling Protein, Pyruvate Dehydrogenase Kinase

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