Energy and Metabolism Flashcards

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1
Q

What is thermodynamics?

A

Branch of chemistry that focuses on energy changes

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2
Q

What is energy?

A

The capacity and ability to do work

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3
Q

What are the two main states of energy?

A

Kinetic energy and potential energy

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4
Q

What is kinetic energy?

A

Energy of motion

ex: Moving down a slide (doing work)

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5
Q

What is potential energy?

A

Stored energy

ex: At the top of the slide (stationary energy)

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6
Q

What is the most convenient way to measure energy?

A

Heat is the most convenient form of measuring energy.

1 calorie = heat required to raise a gram of water by 1 degree celsius.

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7
Q

What is a kilocalorie?

A

Most common unit of energy used in biology. Calorie on food labels with a capital C. (1000 calories)

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8
Q

What is the ultimate source of energy?

A

The sun is the ultimate source, as energy flows into the biological world from the sun.

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9
Q

What is bioenergetics?

A

How the flow of energy is described.

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10
Q

How is the sun’s energy captured?

A

Through photosynthesis, chlorophyll containing organisms capture the potential energy of the sun and store the energy in the form of chemical bonds.

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11
Q

What is oxidation?

A

Atom or molecule loses an electron.

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12
Q

What is reduction?

A
  • Atom or molecule gains an electron.
  • Have higher energy than oxidized form due to carrying high energy electrons. (more unstable)
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13
Q

What are the laws of energy?

A
  • Energy cannot be destroyed or created.
  • Energy can only change from one form to another.
  • Total amount of energy in the universe remains constant.
  • During each energy conversion, some energy is lost as heat.
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14
Q

What is entropy?

A

Entropy is the measure of disorder of a system that is continuously increasing as energy transformations proceed, going from more ordered/less stable to a less ordered/more stable form.

ex: Ice is more ordered → heat breaks down the h-bonds → changes ice to liquid form (more stable but less order) = highest entropy

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15
Q

What energy is available to do work?

A
  • Not every chemical energy in bonds is available for work.
  • Gibbs Free Energy (G) = energy available to do work.
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16
Q

How is Gibbs free energy (G) calculated (energy available to do work)?

A

G = H-TS

  • H = enthalpy (energy in molecule’s chemical bonds)
  • T = absolute temperature (K)
  • S = entropy, unavailable energy.
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17
Q

What is endergonic?

A
  • Not spontaneous absorption of energy from its surroundings in chemical reaction.
  • Less free energy in reactant than products, therefore requires input of energy.
  • Positive change in free energy.
  • H (enthalpy) is higher, or S (entropy) is lower
  • ex: Active transport, cell movement, anabolism
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18
Q

What is exergonic?

A
  • Spontaneous release of energy to surroundings in chemical reaction.
  • Does not require continuous energy supply but requires activation energy.
  • More free energy in reactant than products.
  • Negative change in free energy.
  • H (enthalpy) is lower, or S (entropy) is higher
  • ex: Cell respiration, catabolism
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19
Q

What is activation energy?

A
  • The energy needed to break existing bonds.
  • Larger activation energy proceed more slowly.
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20
Q

How can rate of exergonic reaction be increased?

A
  • Heating reacting molecules to increase energy
  • Lowering activation energy using catalysts
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21
Q

What is the role of catalysts?

A
  • Make chemical bonds unstable to allow reactions take place.
  • Lower activation energy becomes lower.
  • Do not change thermodynamics.
  • Do not alter ratio of reactants that turn into products.
  • Speed up rate of reaction.
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22
Q

What is ATP?

A

The primary energy currency used by cells that is readily available. (Adenosine Triphosphate)

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23
Q

What is ATP made up of?

A
  • Ribose (five carbon sugar)
  • Adenine
  • Chain of three phosphates = energy is stored

Unstable in phosphate chains because all negative charges causing them to repel each other.
Easier to break bonds due to instability.
Not able to store long-term due to instability
(Cells only store ATP for a few seconds worth)

24
Q

What are enzymes?

A

Biological catalysts that are mostly made from proteins, and some RNA. They reduce activation energy to allow reaction to proceed

25
Q

Enzymes are not changed or consumed in reaction.

A

True

26
Q

Why are shapes of enzymes important?

A

Enzymes have specific shapes as they bind to substrates cause them to be more stable.

27
Q

What is an active site?

A

The area where the enzyme and substrate meet, a pocket or cleft for substrate binding.

28
Q

What is an induced fit?

A

Precise fit of substrate into active site.

29
Q

What is distortion in enzymes?

A

Distortion of moving substrate into enzyme, moves bonds that lower activation energy.

30
Q

What is a substrate?

A

A molecule that enzymes react with like macromolecules.

  • ex: Lactaste (enzyme) = Lactose (substrate)
  • ex: Amylase (enzyme) = Starch (substrate)
31
Q

What are the forms of enzymes?

A

Enzymes can be suspended in cytoplasm or attached to cell membranes and organelles

32
Q

What is a molecular machine?

A

Several enzymes/subunits working together, operating as one.

33
Q

What are the enzymes in a molecular machine?

A

Multienzyme complexes

34
Q

How does a molecular machine work?

A

Enzymes create products, that become the substrate for another enzyme within the complex like a cycle.
Products delivered easily to next enzyme while preventing unwanted side reactions.

  • ex: Pyruvate dehydrogenase: 60 subunits of protein working in assembly line
35
Q

What are nonprotein enzymes?

A

Riboszymes are catalyzed in cells by RNA itself.

36
Q

What are the two kinds of ribozymes?

A

Intramolecular catalysis and Intermolecular catalysis

37
Q

What is intramolecular catalyst?

A

Intra = within (catalysts RNA within itself)

38
Q

What is intermolecular catalysis?

A

Inter = between (catalysts on other RNA molecules)

39
Q

What are enzymes influenced by?

A

Chemical or physical condition can affect enzyme’s 3D shape which changes rate.

40
Q

What are inhibitors?

A

Enzymes are regulated by inhibitors that are substances that bind to enzymes to prevent or decrease its activity

41
Q

What are the two types of inhibitors?

A

Competitive inhibitor and non-competitive inhibitor.

42
Q

What is a competitive inhibitor?

A

Competes with substrate for active site. (direct)

43
Q

What is a non-competitive (allosteric) inhibitor?

A

Binds to site on enzyme that is other than the active site.

Results in enzyme shape to change as it blocks enzyme from binding with substrates and change active site from enzyme shape change. (indirect)

44
Q

What are allosteric enzymes?

A

Enzymes that exist in inactive and active forms.

Noncompetitive inhibitors bind to allosteric site.

45
Q

What are allosteric inhibitors?

A

Binds to allosteric site to reduce enzyme activity.

46
Q

What are allosteric activators?

A

Binds to allosteric site to increase enzyme activity.

Enzyme in default state cannot catalyze, but activator changes active site to receive substrate.

47
Q

What are co-factors?

A

Molecules that assist enzymes in carrying activity. Often found in active site.

  • ex: metal ions like zinc, maganese (when people take supplements)
48
Q

What are coenzymes?

A

Cofactors are non-protein organic molecules.

  • ex: vitamins
49
Q

What is metabolism?

A

Metabolic activities (anabolic + catabolic) that is the total sum of all chemical reactions carried out in the body.

50
Q

What are anabolic reactions (anabolism)?

A

Expending energy to build up molecules like monomers to build polymers.

51
Q

What are catabolic reactions (catabolism)?

A

Harvesting energy by breaking down molecules.

52
Q

What are biochemical pathways?

A

When reactions occur in a sequence as a product of one becomes a substrate for the next.

53
Q

What is feedback inhibition?

A

End product is in less quantity before biochemical pathway processing, increases concentration of end product. More products = increase probability to bind to allosteric site that changes enzyme to not be able to bind normal substrates. (Hits a cap)what

54
Q

What is the First Law of Thermodynamics?

A

Energy cannot be created or destroyed; it can only be converted from one form to another

55
Q

What is the Second Law of Thermodynamics?

A

During each energy conversion, some energy is lost as heat as energy is transformed.

When energy changes from one form to another form, or matter moves freely, entropy (disorder) increases.

  • ex: Hot things always cool unless you do something to stop them