Chapter 6 - Cellular Energy Flashcards

1
Q

What is energy in motion?

A

Kinetic energy

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2
Q

What is energy called that is not being used but could be?

A

Potential energy

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3
Q

What is the measurement of heat called?

A

Thermodynamics

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4
Q

What is the unit of heat?

A

Kilocalorie (Kcal)

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5
Q

How many kcals is equal to 1000 calories?

A

1 kcal

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6
Q

How man calories does it take to heat 1 gram of water to 1 degree Celsius?

A

1 calorie

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7
Q

What is oxidation?

A

The loss of an electron by an atom or molecule.

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8
Q

What is reduction?

A

The gain of an electron by an atom or molecule.

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9
Q

What reactions always take place together?

A

Oxidation and reduction because every electron that is lost by one atom is gained by another atom.

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10
Q

What is short for Oxidation-reduction reaction?

A

Redox reaction

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11
Q

What does the first law of thermodynamics state?

A

Total energy of the universe is constant. Living systems cannot create the energy needed for life but must acquire it in some way.

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12
Q

Why is energy always constant?

A

Energy continuously flows through the biological world in one direction with new energy from the Sun entering the system to replace energy that was lost dissipated as heat.

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13
Q

What is the second law of thermodynamics?

A

The transformation of potential energy into heat; disorder is continually increasing in the universe as energy changes occur, so disorder is more likely than order.

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14
Q

What measures the disorder of a system?

A

Entropy which is a measure of how much energy in a system has become so dispersed that it is no longer available to do work.

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15
Q

Energy available to work is called:

A

Free energy which is used to break and form other chemical bonds.

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16
Q

What is the difference between endergonic reactions and exergonic reactions?

A

Endergonic is any reaction that requires input and exergonic is any reaction that releases the excess free energy as heat.

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17
Q

What is activation energy?

A

energy that must be processed by a molecule for it to undergo a specific chemical reaction

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18
Q

What is ATP composed of?

A

a 5-carbon sugar, ribose, the nitrogenous base adenine, and a chain of three phosphates.

19
Q

How does ADP form?

A

through the hydrolysis process which results in adenosine diphosphate (ADP) plus an inorganic phosphate (Pi).

20
Q

When ADP forms how much energy is released?

A

7.3 kcal of energy

21
Q

Why don’t endergonic reactions proceed spontaneously?

A

Their products possess more free energy than their reactants

22
Q

In what ways can the rate of reactions be increased?

A

Two ways: by either increasing the energy of the reacting molecules OR by lowering the activation energy

23
Q

What is a catalysis?

A

The process by which chemical subunits of larger molecules are held together and positioned by enzymes that stress their chemical bonds.

24
Q

True or False: A catalysis will affect the reactants and products.

A

False: a catalysis only speeds up the reaction. It will never affect the reactants or products.

25
Q

What macromolecules are enzymes typically?

A

Proteins

26
Q

True or False: Enzymes are consumed after usage.

A

False: It increases the rate of reaction without being consumed

27
Q

Are some enzymes something else other than proteins?

A

Yes: they can be RNA molecules as well.

28
Q

How does an enzyme work to speed up a reaction?

A

It brings two substrates together in the correct orientation or by stressing chemical bonds of a substrate, and then it lowers the activation energy required for new bonds to form.

29
Q

What is an active site?

A

The region of an enzyme surface to which a specific set of substrates binds, lowering activation energy required for a particular chemical reaction and so facilitating it.

30
Q

True or False: Shape does not matter for an enzyme to work effectively.

A

False: while an enzyme can slightly adjust its shape to perfectly fit a substrate it is used for that specific substrate and will not work correctly without a perfect fit. Shape matters.

31
Q

What is the assembly of several enzymes called?

A

Multienzyme complex

32
Q

True or False: Multienzyme complexes use different steps in a sequence of reactions to increase effectivity.

A

True

33
Q

What are benefits of a multienzyme?

A

The product of one reaction can be delivered to the next enzyme without releasing it to diffuse away. Unwanted side effects are prevented. All of the reactions are controlled as a unit.

34
Q

What is required by an enzyme to function?

A

Cofactor: one or more nonprotein components. Many cofactors are metal ions

Coenzyme: a nonprotein organic molecule such as B vitamin. Often act as a donor or acceptor of electrons.

35
Q

What can cause an enzyme to denature?

A

too low or too high of temperature and pH.

36
Q

What does it mean when something is ‘optimum?’

A

It means it is the perfect temperature or pH balance for a maximum reaction rate.

37
Q

What is an inhibitor?

A

A substance that binds to the enzyme and decreases its activity

38
Q

What is the difference between a competitive inhibitor and a noncompetitive inhibitor?

A

A competitive inhibitor competes with substrates for the same active site.

A noncompetitive inhibitor binds to an enzyme in a location other than the active site changing the shape of the enzyme and making it unable to bind with the substrate.

39
Q

What is an allosteric site?

A

A part of an enzyme away from its active site. It serves as an on/off switch for the function of the enzyme.

40
Q

What is an allosteric inhibitor and an allosteric activator?

A

Exactly as it sounds. They bind to the allosteric site and work as an on (activator)/off (inhibitor) switch.

41
Q

What is metabolism?

A

The sum of all chemical processes occurring within a living cell or organism.

42
Q

What is the difference between anabolism and catabolism?

A

Anabolism is where chemical reactions expend energy to build up molecules.

catabolism is where reactions harvest energy by breaking down moleules.

43
Q

What is feedback inhibition?

A

The end-product of the pathway binds to an allosteric site on the enzyme that catalyzes in the pathway.