BIOLOGY 151 Lecture Notes - Lecture 14: Exergonic Reaction, Atp Hydrolysis, Endergonic Reaction

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2 Mar 2016

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An endergonic reacion can be coupled to an exergonic reacion. Enzymes do not change the change in (delta) g. they reduce the energy required to get the reacion going. Lowering acivaion energy- straining bonds in reactants to make it easier to achieve transiion state. Some enzymes have charged areas- the charges rearrange the charges in the molecule, reducing the acivaion energy. Enzyme binds to substrate- substrate binds to enzyme at acive site. Acive site formaion- related to 3d shape of protein- the sequences are far away but the amino acids fold together to bring the two together, Nucleic acid molecules can also fold into complex shapes and have catalyic ability. Acive site- main place where reacion takes place. Enzyme-substrate complex- formed when enzyme and substrate bind. Endergonic reacions- products are higher energy than reactants. Enzymes afected by environment- most enzymes funcion at a narrow range of temp and ph. Concentraion of enzyme and substrate afects rate of an enzyme-catalyzed reacion.

Related Questions

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

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.

greychimpanzee211

Which of the following is FALSE with respect to coupledreactions?

	they occur in ALL cells (bacteria, plants, animals, etc.)
	enzymes are typically involved
	endergonic reactions power exergonic reactions
	the coupled reaction has a ?G value that is negative
	none of the above (i.e., all of the above are TRUE)

Which of the following reactions is LEAST likely to bespontaneous? One with a:

	very large increase in entropy and a very large decrease inenthalpy
	very large increase in entropy and a very small increase inenthalpy
	very small decrease in entropy and a very large decrease inenthalpy
	very small increase in entropy and a very small decrease inenthalpy
	very small decrease in entropy and a very small increase inenthalpy

Energy of activation refers to the:

A)	?G of a reaction
B)	difference in energy between the transition state and theproduct
C)	difference in energy between substrate and product
D)	net change in free energy
E)	energy input needed to reach the transition state

Homeostasis refers to maintaining a relatively constantenvironment, and is achieved to a large extent by how enzymes areregulated. For example, when the end product of a pathway regulatesan enzyme that acts early in the same pathway, the effect is mostoften:

	stimulation if an anabolic pathway, and inhibition if acatabolic pathway
	inhibition if an anabolic pathway, and stimulation if acatabolic pathway
	stimulation, whether an anabolic or catabolic pathway
	inhibition, whether an anabolic or catabolic pathway

Enzymes function by:

	decreasing the free energy level of the reactants
	decreasing the free energy level of the transition state
	increasing the free energy level of the reactants
	changing delta G from positive to negative
	changing delta G from negative to positive
	increasing the free energy level of the products
	decreasing the free energy level of the products

6.	When carbohydrates are oxidized, the C

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BIOLOGY 151 Lecture Notes - Lecture 14: Exergonic Reaction, Atp Hydrolysis, Endergonic Reaction

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