CAS BI 105 Lecture Notes - Lecture 8: Competitive Inhibition, Exergonic Reaction, Turnover Number

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14 Dec 2017

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Metabolism is the sum of all chemical reactions within an organism. Chemical reaction involve making a molecule or breaking a molecule. Chemical work is the making and breaking of chemical bonds. Kinetic works it the movement of ions, molecules and large stuff (like proteins) in and out the cell. Energy can be: kinetic energy of motion, potential stored energy. 3: chemical potential energy in food thermal heat (reactions often lose energy in the form of heat) There are constant changes of energy from one form to another. It is governed by two laws: energy is never created or destroyed, it is only converted, every energy transfer increases entropy (biological messiness). In fact, a system is going to tend towards disorder. Entropy is going to result in unusable energy (molecules called intermediates). If you break a bond and release energy: exergonic reaction (catabolism). If you make a new bond and energy is required: endergonic reaction (anabolism).

Related Questions

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

Question 1

Plasma membranes are selectively permeable. This means that

	A.	glucose cannot enter the cell.
	B.	the plasma membrane allows some substances to enter or leave a cell more easily than others.
	C.	plasma membranes must be very thick.

Question 2

Oxygen molecules O₂ crosse a plasma membrane by

	A.	passive transport
	B.	osmosis
	C.	active transport

Question 3

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

		A. energy and channel proteins; against (up)
		B. transport proteins that make channels ; down
		C. energy ; down

Question 4

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will

		A. move to the side with lower water concentration
	B.	move to the side with higher water concentration
	C.	move to the side with lower solute concentration

Question 5

Kinetic energy differs from chemical energy in that

	A.	chemical energy is a particular form of kinetic energy.
	B.	kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules.
	C.	kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement.

Question 6

When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction.

	A.	exergonic; endergonic
	B.	endergonic; exergonic
	C.	spontaneous; exergonic

Question 7

When an enzyme catalyzes a reaction

		A. it raises the activation energy of the reaction.
		B. it lowers the activation energy of the reaction.
		C. it is used once and discarded.

Question 8

Which of the following statements regarding enzyme function is false?

		A. An enzyme's function depends on its three-dimensional shape.
		B. Enzymes are very specific for their substrates.
		C. Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction

As entropy increases there will be more useful energy to doâworkâ. True or false?

False. As entropy increases, there will generally be less usefulenergy to do work. We can think of entropy as usually being presentin the form of heat energy. Imagine a car motor, which attempts toturn chemical potential energy into kinetic energy (movement). Lessefficient motors will get hotter for the same amount of fuelconsumed. When you drive a car you hope that most of the fuelenergy is converted into kinetic energy and not lost as heat(entropy). The hotter the car (and thus the more entropy) the lessefficient the ability to do âworkâ (the moving of the vehicle).

True. As entropy increases, there will generally be more usefulenergy to do work. We can think of entropy as usually being presentin the form of heat energy. In most biological and mechanicalsystems it is heat energy which is captured to do useful 'work'.Heat energy, the random movement of molecules, and increases inentropy are central to doing useful work.

Biological systems sometimes appear on the surface to break theSecond Law of Thermodynamics â by seemingly increasing the order inthe overall system. They donât. Why?

a. Earth (and living things on it) are not a closed system. Thesun's constant input of energy in the form of photons is harnessedby living things to create internal order within themselves. Butwithout such a constant input of energy, most biological systems onearth would break down.

b. The Second Law tells us that no natural process can occurunless it is also associated with an increase in the entropy of theuniverse. A living organism (such as an animal or plant) brings inmatter and energy from its environment and uses this to creategreater order within its body: the processes of life. But it isimportant to keep in mind that all animals and plants are also partof a larger system of the environment around them. While creating asmall âpocketâ of order, the processes of life (metabolism,movement, etc..) releases heat into the environment â thusincreasing the entropy of the universe and following the2^nd law.

c. Living things, by harnessing energy to create order (withinand around themselves) actually create a paradox in questionssurrounding the first and second laws of thermodynamics andseemingly violate many previously held assumptions.

d. Both a and b above are correct.

When plants capture energy in the photons of sunlight andconvert that energy into the chemical bonds of organic molecules,are they creating new energy?

No, the energy is being transferred from one form into another.But no new energy is being created.

No, the overall total energy is decreasing over time.

Yes, by capturing photons, the plants are creating newenergy.

Yes, by capturing photons, the plants are creating new energy -of a different wavelength.

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CAS BI 105 Lecture Notes - Lecture 8: Competitive Inhibition, Exergonic Reaction, Turnover Number

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