Chapter 8 Flashcards

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1
Q

Metabolism

A

the totality of an organism’s chemical reactions; transforms matter and energy

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2
Q

metabolic pathways

A

a series of chemical reactions occurring within a cell that are essential for its survival.

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3
Q

catabolic pathways

A

Break down complex molecules into simple building blocks and release energy.

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4
Q

anabolic pathways

A

Build up complex molecules from simple molecules and require energy.

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5
Q

what do catabolic pathways do with energy

A

release energy

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6
Q

what do anabolic pathways do with energy

A

consume energy

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7
Q

kinetic energy

A

energy doing work (generally energy in motion)

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8
Q

types of kinetic energy that are important to living organisms.

A

heat (thermal) and light (electromagnetic)

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9
Q

thermal (heat) energy

A

associated with random movement of atoms or molecules

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10
Q

electromagnetic (light) energy

A

movement of photons

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11
Q

potential energy

A

Stored energy that matter possesses because of its location or structure

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12
Q

how is energy stored

A

it can be stored as chemical energy

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13
Q

Why do organic molecules provide a rich source of energy?

A

Organic molecules have a lot of potential energy because they are easily broken.

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14
Q

Explain why ATP represents usable potential energy for a cell.

A

ATP is easily broken because the bonds of the ATP tail can be broken by hydrolysis.

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15
Q

What are the two laws of thermodynamics?

A
  1. states that the energy of the universe is constant. Energy can be transferred and transformed, but it cannot be created or destroyed. (law of conservation)
  2. states every energy transfer or transformation increases the entropy and heat of the universe.
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16
Q

Explain the concept of entropy. How does it relate to chemical reactions?

A

Entropy is the measure of molecular disorder or randomness. An increase in entropy favors the spontaneous chemical reaction; a decrease favors the nonspontaneous reaction.

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17
Q

What is enthalpy? How does it relate to change in free energy levels?

A

Enthalpy is a measure of energy in a thermodynamic system. Relates to free energy levels If a reaction is spontaneous. The change in enthalpy is the difference in bond energies between products and reactants.

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18
Q

Exergonic chemical reaction

A

energy is released (spontaneous)

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19
Q

endergonic chemical reaction

A

energy is required (nonspontaneous)

20
Q

free energy

A

Energy that can do work when temperature and pressure are uniform as in a living cell.

21
Q

Explain how the free energy equation (ΔG=ΔH-TΔS) predicts whether a particular reaction is endergonic or exergonic.

A

if you have negative G it is going to be an exergonic reaction because of the release of energy. Positive G (added on energy) endergonic reaction.

22
Q

are catabolic pathways endergonic or exergonic?

A

exergonic

23
Q

are anabolic pathways endergonic or exergonic?

A

endergonic

24
Q

energy coupling

A

The use of an exergonic reaction of ATP hydrolysis to drive an endergonic reaction

25
Q

The structure of ATP

A

ATP is composed of ribose (sugar) adenine (nitrogenous base) and three phosphate groups.

26
Q

Explain how ATP supplies energy to make endergonic reactions occur.

A

ATP drives endergonic reactions by phosphorylation, transferring a phosphate group to some other molecule.

27
Q

What properties does ATP possess that make it valuable to a cell?

A
  • transport
  • mechanical
  • chemical
28
Q

transport (ATP)

A

changes transport carrier protein shape.

29
Q

mechanical (ATP)

A

bonds to other proteins and has a hydrolysis causing movement.

30
Q

chemical (ATP)

A

conversions are coupled with ATP hydrolysis.

31
Q

Why is the cycle of ATP breakdown and regeneration important to cells?

A

Energy released by breakdown reaction in the cell is used to phosphorylate ADP regenerating ATP. Regeneration is important in cells because a working muscle recycles a whole pool of ATP in less than a minute.

32
Q

What are enzymes? How do they function?

A

Enzymes speed up metabolic reactions. They do this by lowering the energy of activation.

33
Q

Describe how enzymes interact with their specific substrate molecules.

A

The enzyme binds to its substrate which makes the enzyme-substrate complex.

34
Q

Substrates

A

The reactant on which an enzyme works.

35
Q

Active sites

A

the region on the enzyme where the substrate binds

36
Q

Induced fit

A

brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction

37
Q

Products

A

the end result

38
Q

How do enzymes affect the energetics of chemical reactions?

A

Enzymes lower the activation energy that is needed, making reactions happen at a lower temperature that they could without the enzyme. This speeds up the rate of reaction.

39
Q

What physical factors affect enzyme activity?

A

temperature and pH

40
Q

In what two basic ways can enzyme activity be regulated?

A
  • competitive inhibitors

- noncompetitive inhibitors

41
Q

Competitive inhibitors

A

bind to the active site of an enzyme, competing with the substrate (Preventing the substrate from bonding)

42
Q

Noncompetitive inhibitors

A

bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective (preventing the substrate from bonding)

43
Q

Explain what feedback inhibition is and how it works.

A

a metabolic pathway is switched off by the inhibitory binding of its end product to an enzyme that acts early in the pathway. -> prevents the cell from wasting chemical resources

44
Q

What are cofactors and coenzymes?

A

Cofactors are nonprotein enzyme helpers. Cofactors may be inorganic or organic. A coenzyme is an organic cofactor.

45
Q

What is allosteric regulation of enzymes?

A

when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site.

46
Q

How does cooperativity influence the function of an enzyme?

A

Cooperatively is a form of allosteric regulation that can amplify enzyme activity