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biol150 > Chapter 6 > Flashcards

Chapter 6 Flashcards

1
Q

Define energy

A

The ability to do work or cause change

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1
Q

Potential vs Kinetic Energy
Include examples

A

Potential: The energy that a substance possesses due to its structure or location (water level with a dam, boulder at the top of a hill, a stretched rubber band)
Kinetic: energy associated with movement (stream of water, boulder moving down hill)

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2
Q

Discuss how the first and second laws of thermodynamics apply to metabolic reactions

A

First law: energy can be neither created nor destroyed; Energy “generated” in any system is energy that’s been transformed from one state to another (chemically stored energy transformed to heat)
Second law: efficiencies of energy transformation never equal 100%; all processes lose energy, typically as heat, and are not reversible unless the system is open and the lost energy is resupplied from the environment; conversion to heat is the ultimate fate of chemical energy

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3
Q

Distinguish between exergonic and endergonic reactions

A

Exergonic: release energy to the environment; spontaneous; catabolic
Endergonic: require energy input from the environment and are not spontaneous; anabolic

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4
Q

Describe how cells use the energy of ATP to drive endergonic reactions

A

ATP donates its phosphate group to another molecule via. phosphorylation; the phosphorylated molecule is at a higher-energy state and is less stable than its unphosphorylated form, this added energy allows the molecule to undergo its endergonic reaction

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5
Q

Distinguish between catabolic and anabolic reactions

A

Catabolic: breakdown of complex molecules into simpler ones and release energy
Anabolic: the synthesis of complex molecules from simpler ones and requires energy

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6
Q

Explain how enzymes increase the rates of chemical reactions

A

Enzymes speed up the rate by lowering the activation energy required for reactants to come together and react.

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7
Q

Discuss how enzyme specificity and the role of enzymes in metabolic reactions

A

Enzymes are highly selective and only fit to specific substrates; shape of the active site determines which substrate(s) the enzyme can act on
Help in the formation of macromolecules
Help in the conversion of a molecule from one form to another form
Aid in the breakdown of large molecules to smaller ones
Minimize the toxicity of substances
Can be reused when going from substrate to substrate

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8
Q

Energy (potential vs kinetic)

A

Potential: energy possessed by a body virtue of its position or state; stored energy and is completely independent of its environment
Kinetic: energy possessed by a body by virtue of its movement; relative to the state of other objects in its environment

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9
Q

First and Second Laws of Thermodynamics

A

First: “law of conservation of energy” Energy cannot be created or destroyed, but can be transformed from one type to another. Metabolic processes of cells transform chemical potential energy of molecular bonds to useful forms of energy
Second: Transfer of energy from one form to another increases the entropy (degree of disorder) of a system. As entropy increases, less energy is available for cells to do work

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10
Q

Chemo/Photo Auto/Heterotroph

A

chemotroph: organism that obtains energy by the oxidation of electron donors in their environments
Phototroph: organisms that carry out proton capture to produce organic compounds (carbohydrates) and acquire energy
Autotroph: organism that is able to form nutritional organic substances form simple inorganic substances such as carbon dioxide
Heterotroph: organism that cannot produce its own food and must obtain it by eating other plants or animals

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11
Q

Gibbs Free Energy

A

The amount of a system’s energy that is available and can be used to promote change or do work

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12
Q

Reactions

A

Reactions may involve molecules attaching to each other to form larger molecules, molecules breaking apart to form two or more smaller molecules, rearrangements of atoms within molecules, or the transfer of electrons from one atom to another
A sum total of all chemical reactions that occur within an organism is the metabolism

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13
Q

Products

A

What is created in a reaction

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14
Q

Entropy

A

The degree of disorder of a system

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15
Q

Enthalpy

A

Total energy of a system

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16
Q

Metabolism

A

The sum of all bodily activities and chemical reactions that occur within an organism to maintain life. Also, a specific set of chemical reactions that occur at the cellular level

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17
Q

Catabolism

A

The process of breaking down large molecules into smaller ones to release energy for the body
is exergonic, meaning it releases heat and works via hydrolysis and oxidation

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18
Q

Anabolism

A

The synthesis of complex molecules in living organisms from simpler ones together with the storage of energy
is endergonic

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19
Q

Reduced

A

the gain of electrons by a substance or the loss of oxygen from a substance

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20
Q

Oxidized

A

the loss of electrons from a substance or the gain of oxygen by a substance

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21
Q

Work

A

usable energy

22
Q

Endergonic

A

require energy input from the environment and are non-spontaneous

23
Q

Exergonic

A

release energy to the environment and are spontaneous

24
Q

Endergonic vs Exergonic

A

Endergonic: require energy input form the environment and are non-spontaneous; anabolic
Exergonic: release energy to the environment and are spontaneous; catabolic

25
Q

Coupled Reaction

A

A phosphate is directly transferred from ATP to glucose in a process called phosphorylation (this coupled reaction proceeds spontaneously because the net free-energy change is negative)

26
Q

ATP

A

A molecule that is a common energy source for all cells

27
Q

Enzyme

A

proteins that act as critical catalysts to speed up thousands of different reactions in a cell

28
Q

Allosteric site

A

A site on the enzyme where a molecule can bind noncovalently and affect the enzyme’s function

29
Q

Competitive vs noncompetitive inhibition

A

Competitive: decreases the number of enzyme molecules available to bind the substrate by binding to the active site of the enzyme
Noncompetitive: binds to the enzyme at a point other than the active site and does not prevent the substrate from binding to the enzyme

30
Q

Active Site

A

The region of an enzyme where substrate molecules bind and undergo a chemical reaction

31
Q

Catalysis

A

The process of change in rate of a chemical reaction by adding a substance known as a catalyst. Catalysts are not consumed by the reaction and remain unchanged afterward

32
Q

What does a negative delta G value tell us? A positive?

A

Negative: the reaction can occur without any energy input/spontaneous
Positive: non-spontaneous

33
Q

What’s the difference between allosteric and competitive regulation of enzymes?

A

Allosteric: a site on an enzyme where a molecule can bind noncovalently and affect the enzyme’s function
Competitive: a molecule that binds noncovalently to the active site of an enzyme and inhibits the ability of the substrate to bind

34
Q

How does ATP contribute to work in a cell?

A

ATP is the energy for the cell and powers cellular processes by transferring a phosphate group to another molecule (phosphorylation)

35
Q

Explain the difference between potential and kinetic energy and give examples of each.

A

Potential: stored energy/location (rock on top of a waterfall; rubber band stretched)
Kinetic: energy stored in moving objects (rubber band being launched)

36
Q

What is the first law of thermodynamics?

A

A fundamental principle of nature that says energy is never lost or gained, only changed

37
Q

Explain how enzymes are used to increase the rate of a chemical reaction

A

Enzymes increase the rate of a chemical reaction by reducing the activation energy needed to make the reaction get started, binding two substrates together in the right orientation, and creating an environment inside the activation site that’s favorable to the reaction (ex. One that’s slightly acidic or non-polar)

38
Q

How does the structure of an enzyme affect its function in a cell?

A

The shape determines the shape of its active site, which is where it binds with the substrate molecules. If the enzyme changes its shape due to factors like heat, pH, or chemical conditions, the active site may not fit with the substrate anymore. This can disrupt the enzyme’s ability to catalyze reactions

39
Q

Use the terms anabolism and catabolism to describe the ATP cycle

A

The ATP cycle is a process in which cells combine anabolic reactions with catabolic reactions to form an efficient energy cycle. Catabolic reactions transform chemical fuels into cellular energy, which is then used to initiate the energy-requiring anabolic reactions

40
Q

Compare and contrast competitive and non-competitive inhibition

A

Competitive: decreases the number of enzyme molecules available to bind the substrate by binding to the active site of the enzyme
Noncompetitive: binds to the enzyme at a point other than the active site and does not prevent the substrate from binding to the enzyme

41
Q

Describe the structure of an ATP molecule and where the energy is stored

A

Energy is stored in the three phosphate bonds of the ATP molecule. The energy is stored in the pyrophosphate bond, which lies between the last two phosphate groups. When the bonds are broken, energy is released

42
Q

Why does ADP have less potential energy than ATP?
a. Because ATP has ribose as a sugar and ADP has deoxyribose.
b. Because ATP has only one phosphate group.
c. Because ATP had adenine and ADP does not.
d. Because ATP has three phosphate groups and ADP has two

A

D) because ATP has three phosphate groups and ADP has two

43
Q

A biologist working in a lab adds a compound to a solution that contains an enzyme and its substrate.
This compound binds to the enzyme and decreases the rate at which the enzyme converts substrate to
product. However, this decrease can be overcome by increasing the concentration of substrate to the
reaction mix. Therefore, which of the following is most likely true of the compound?
a. The compound is an allosteric activator.
b. The compound is an allosteric inhibitor.
c. The compound is an inhibitor that binds to the active site of the enzyme.
d. The compound is a catalyst for the reaction

A

c. The compound is an inhibitor that binds to the active site of the enzyme

44
Q

The initial input of energy in chemical reactions is
a. The transition state
b. Activation energy
c. Entropy
d. Enthalpy
e. Free energy

A

b. Activation energy

45
Q

The second law of thermodynamics states that energy can be –
a. Created
b. Destroyed
c. Lost as heat
d. All of the above
e. None of the above

A

e. None of the above

46
Q

A reaction with a negative ∆G is –
a. Exergonic
b. Entropic
c. Endergonic
d. Enthalpic
e. Energertic

A

a. Exergonic

47
Q

The reactant molecules in enzymatic reactions are the —
a. Specificity
b. Product
c. Active site
d. Substrate
e. Coenzyme

A

d. Substrate

48
Q

Which of the following is an example of kinetic energy?
a. A sugar molecule in the stomach.
b. A glucose molecule in a leaf.
c. A glucose molecule in a muscle.
d. A Starch molecule in a potato.
e. A contracting muscle

A

e. A contracting muscle

49
Q

Oxidation is the ____________ and reduction is the ________.
a. loss of electrons, gain of electrons
b. gain of protons, loss of protons
c. loss of protons, gain of protons
d. loss of electrons, gain of protons

A

A) loss of electrons, gain of electrons

50
Q

The First Law of Thermodynamics states that energy can be –
a. Created
b. Destroyed
c. Converted
d. Lost
e. None of the above

A

c. Converted

51
Q

A reaction with a positive ∆G is –
a. Exergonic
b. Entropic
c. Endergonic
d. Enthalpic
e. Energertic

A

c. Endergonic

52
Q

A catalyst speeds up chemical reactions. How do catalysts do this?
a. Decreasing entropy
b. Altering ∆G
c. Consuming reactants
d. Lowering activation energy
e. Making different products

A

d. Lowering activation energy

biol150 (15 decks)

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