BIOL150 Chapter Notes -Atp Hydrolysis, Hexokinase, Endergonic Reaction

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grayelephant135

3 Nov 2014

School

University of Waterloo

Department

Biology

Course

BIOL150

Professor

Tristan A F Long

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Phosphorylation for glucose is endergonic its not spontaneous. Hexokinase enzyme holds the molecules in specific positions so that the reaction occurs. The phosphate used by hexokinase it has to get the phosphate from the atp reaction. There are 2 coupled reactions to form glucose-6-phosphate + adp. The kcal value is -4. 0 in the atp hydrolysis with phosphorylation of glucose. 10 million atp molecules per second per cell. Repeated atp hydrolysis powers the change in shape that allow dna helicase to move. Enzymes speed up reactions without themselves being consumed.

Related Questions

Creatine (Cr) is made in the liver and kidneys and then transported to the muscles, where it serves as a high energy storage compound via phosphorylation by creatine kinase. Two forms of this enzyme exist, mitochondrial and cytoplasmic. In mitochondria there is net synthesis of creatine phosphate (CrP). In the cytosol, the phosphate is transferred from CrP to ADP to supply ATP to power the muscles. Table 3.2 of your G&G text lists ÎGËÌ for hydrolysis of creatine phosphate: -43.3 kJ/mol at 25Â°C. creatine phosphate + H2O ----> creatine + Pi

a. Calculate the KeqÍ for this hydrolysis.

c. In mouse muscle cells at 25Â°C, [Cr] is 10 mM, and [CrP] is 20 mM. What concentration of Pi would be needed to maintain this level of phosphorylation by reversal of the hydrolysis reaction? Is this concentration of Pi a reasonable expectation? Why?

d. Coupling ATP hydrolysis (ÎGËÍ-35.7 kJ/mol at 25Â°C) to an unfavorable reaction is often used to drive biochemical reactions. Write the chemical equations for the CrP reverse hydrolysis and ATP hydrolysis and add them together to give the coupled reaction. Then calculate ÎGËÍfor the coupled reaction. Is this reaction favorable? Justify your answer.

e. Considering ÎGÍin the muscle cells rather than under 1M standard state conditions, what ratio of ATP/ADP would be needed inside mitochondria to make the coupled reaction for CrP synthesis produce the concentrations of Cr and CrP observed in mouse muscle? Is this ratio reasonable? Why?

crimsonduck531

1. Consider all the pathways of carbohydrate metabolism discussed in biochemisty. List all the reactions that are:

a. unique to glycolysis (1)

b. unique to gluconeogenesis â give enzyme names (1)

c. shared between glycogen synthesis and glycogenolysis â give enzyme names (1)

2. Consider the enzyme hexokinase.

d. Hexokinase activity is regulated by glucose-6-phosphate by the process of _________________________. (1)

e. The liver isozyme of hexokinase, called glucokinase, is not susceptible to this type of regulation. Explain why this makes sense, considering the role of the

liver in maintaining the glucose balance for the organism. (2)

f. Glucokinase has a much higher Km for glucose than does hexokinase. How does this property help the liver act as a glucose storage organ? (2)

3. Lactate is a waste product in rapidly contracting muscle, but a fuel for resting muscle. Explain, with reference to the metabolic pathways through which lactate proceeds in each

case. (2)

g. When lactate is used as a fuel by muscle, how much ATP can the muscle obtain by complete oxidation of lactate? (1)

byzantiumsquirrel336

Question 1 When energy changes from one form to another, some of the energy that can be used to do work is always lost. The loss of this energy is mostly in the form of _________.
a. heat
b. potential energy
c. kinetic energy
d. light energy
e. mechanical energy

Question 2 Which of the following is exergonic?
a. binding fatty acids and glycerol molecules together to form lipids
b. building proteins from amino acids
c. binding sugars molecules together to form glycogen
d. breaking bonds in starch to release glucose
e. adding a phosphate group to ADP to form ATP

Question 3 The first law of thermodynamics states that:
a. energy can neither be created nor destroyed.
b. the universe is increasing in entropy.
c. all living organisms must eat to derive energy.
d. energy is required to bring molecules into a cell against a concentration gradient.
e. in energy-yielding reactions, matter goes from a more-ordered to a less-ordered state.

Question 4 Which of the following is true of energy?
a. It can be transferred from one form to another with 100 percent efficiency.
b. It can be created.
c. It can be stored in chemical bonds.
d. It can never be stored.
e. It can be released by forming chemical bonds.

Question 5 Metabolism is:
a. the sum of all the energy a cell uses.
b. the sum of all the vitamins a cell contains.
c. the sum of all the enzymes a cell contains.
d. the sum of all the chemical reactions that an organism carries out.
e. the sum of all the ATP a cell contains.

Question 6 Entropy is the measure of ________ in a system.
a. disorder
b. order
c. energy
d. work
e. heat

Question 7 What percentage of the energy stored in glucose are humans cells able to use to do useful work?
a. 37%
b. 100%
c. 15%
d. 52%
e. 48%

Question 8 What is activation energy?
a. the energy gained by living things, allowing them to remain active
b. the energy produced by the breakdown of ATP to ADP.
c. the energy required to initiate or begin a chemical reaction
d. the energy created by enzymes during exergonic reactions
e. the energy lost by living things in the form of heat

Question 9 Which of the following is true of allosteric enzymes?
a. Their activity can be reduced when the product binds the enzyme.
b. Their activity can be reduced when a coenzyme binds to them.
c. Their activity can be reduced when the substrate binds the enzyme.
d. Their activity can be increased when the product binds the enzyme.

Question 10 Which of the following is a true statement about enzymes?
a. They are made of proteins.
b. They are altered by the reactions they catalyze.
c. They increase the energy of activation of chemical reactions.
d. All of the above are true.
e. None of the above is true.

Question 11 What is the energy currency of cells?
a. ADP
b. enzymes
c. glucose
d. vitamins
e. ATP

Question 12 Kinetic energy is ____________, while potential energy is _____________.
a. stored energy; energy that is being used
b. stored energy; energy that can't be used
c. energy that is being used; stored energy
d. energy that can't be used; stored energy

Question 13 The energy released during ________ reactions can be used to drive ________ reactions, and this is called ________ reactions.
a. exergonic; endergonic; coupled
b. endergonic; exergonic; coupled
c. exergonic; endergonic; mutually dependent
d. coupled; mutually dependent; independent
e. endergonic; exergonic; mutually dependent

Question 14 ADP + P + Energy --> ATP Which of the following is a true statement about the chemical reaction above?
a. This is a coupled reaction.
b. This is an exergonic reaction.
c. The product of the reaction contains more energy than that of all of the reactants combined.
d. This is an endergonic reaction.
e. This is an example of a catabolic reaction.

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BIOL150 Chapter Notes -Atp Hydrolysis, Hexokinase, Endergonic Reaction

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