1. Concept 8.1: An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics
  1. ______is the totality of an organism’s chemical reactions
  2. Metabolism is an emergent property of life that arises from interactions between molecules within the cell
  3. A metabolic pathway begins with a specific molecule and ends with a product
  4. Each step is catalyzed by a specific

______

  1. ______pathwaysrelease energy by breaking down complex molecules into simpler compounds
  1. ______respiration, the breakdown of glucose in the presence of oxygen, is an example of a pathway of catabolism
  1. ______pathwaysconsume energy to build complex molecules from simpler ones
  1. The synthesis of ______from amino acids is an example of anabolism
  1. ______is the study of how organisms manage their energy resources
  1. ______is the capacity to cause change
  2. Energy exists in various forms, some of which can perform work
  3. Kinetic energy is energy associated with

______

  1. Heat (thermal energy) is kinetic energy associated

with______movement of atoms or molecules

  1. Potential energy is energy that matter possesses

because of its location or ______

  1. ______energyis potential energy available for release in a chemical reaction
  2. Energy can be converted from one form to another
  1. ______is the study of energy transformations
  2. A closed system, such as that approximated by liquid in a thermos, is isolated from its surroundings
  3. In an open system, energy and matter can be

______between the system and its surroundings

  1. Organisms are ______systems
  1. The First Law of Thermodynamics
  2. According to the first law of thermodynamics, the

energy of the universe is ______:

  1. Energy can be transferred and transformed, but it cannot be created or destroyed
  2. The first law is also called the principle of conservation of energy
  1. The Second Law of Thermodynamics
  2. During every energy transfer or transformation, some energy is unusable, and is often lost as

______

  1. According to the second law of thermodynamics:
  2. Every energy transfer or transformation increases

the______(disorder) of the universe

  1. Cells create ordered structures from less ordered materials
  2. Organisms also replace ordered forms of matter and energy with less ordered forms
  3. Energy flows into an ecosystem in the form of light and exits in the form of heat
  4. The evolution of more complex organisms does not violate the second law of thermodynamics
  1. Entropy (disorder) may ______in an organism, but the universe’s total entropy

______

Lecture Questions 8.1 Metabolism, Energy, and Life

  1. Explain the role of catabolic and anabolic pathways in cellular metabolism.
  1. Explain the first and second laws of thermodynamics in your own words.
  1. Concept 8.2: The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously
  2. Biologists want to know which reactions occur

______and which require input of energy

  1. To do so, they need to determine energy changes that occur in chemical reactions
  1. A living system’s ______energyis energy that can do work when temperature and pressure are uniform, as in a living cell
  2. Free-Energy Change,______
  3. The change in free energy (∆G)during a process is related to the change in enthalpy, or change in total energy (∆H), change in entropy (∆S), and temperature in Kelvin (T):
  1. ______
  1. Only processes with a ______∆G are spontaneous
  1. Spontaneous processes can be harnessed to perform work
  1. Free energy is a measure of a system’s instability, its tendency to change to a more stable state
  2. During a spontaneous change, free energy

______and the stability of a system

______

  1. ______is a state of maximum stability
  2. A process is spontaneous and can perform work only when it is moving toward equilibrium
  1. The concept of free energy can be applied to the chemistry of life’s processes
  2. There are 2 metabolic reaction types:
  1. An ______reaction proceeds with a net release of free energy and is spontaneous
  1. An ______reaction absorbs (stores) free energy from its surroundings and is nonspontaneous
  1. Reactions in a closed system eventually reach equilibrium and then do no work
  2. Cells are ______in equilibrium; they are open systems experiencing a constant flow of materials
  3. A defining feature of life is that metabolism is never at equilibrium
  4. A catabolic pathway in a cell releases free energy in a series of reactions

Lecture Questions 8.2 Free Energy

1. Write and define each component of the equation for free-energy change.

  1. Concept 8.3: ATP powers cellular work by coupling exergonic reactions to endergonic reactions
  2. A cell does three main kinds of work:
  3. Chemical
  1. ______
  2. Mechanical
  1. To do work, cells manage energy resources by energy

______, the use of an exergonic process to drive an endergonic one

  1. Most energy coupling in cells is mediated by

______

  1. ATP (adenosine triphosphate) is the cell’s energy shuttle
  2. ATP is composed of ribose (a sugar), adenine (a nitrogenous base), and three phosphate groups
  3. The bonds between the phosphate groups of ATP’s tail can be broken by hydrolysis
  4. Energy is released from ATP when the terminal phosphate bond is broken
  5. This release of energy comes from the chemical change to a state of lower free energy,

______from the phosphate bonds themselves

  1. The three types of cellular work (mechanical, transport, and chemical) are powered by the hydrolysis of ATP
  2. ATP drives endergonic reactions by

______, transferring a phosphate group to some other molecule, such as a reactant

  1. The recipient molecule is now phosphorylated
  1. ATP is a renewable resource that is regenerated by addition of a phosphate group to adenosine diphosphate (ADP)
  2. The energy to phosphorylate ADP comes from

______reactions in the cell

  1. The chemical potential energy temporarily stored in ATP drives most cellular work

Lecture Questions 8.3 ATP Power

  1. Explain how ATP performs cellular work.
  1. Concept 8.4: Enzymes speed up metabolic reactions by lowering energy barriers
  1. A ______is a chemical agent that speeds up a reaction without being consumed by the reaction
  1. An ______is a catalytic protein
  2. Hydrolysis of sucrose by the enzyme

______is an example of an enzyme-catalyzed reaction

  1. Every chemical reaction between molecules involves bond breaking and bond forming
  2. The initial energy needed to ______a chemical reaction is called the free energy of activation, or activation energy (EA)
  3. Activation energy is often supplied in the form of

______from the surroundings

  1. Enzymes catalyze reactions by lowering the EA barrier
  2. Enzymes do not affect the change in free energy (∆G); instead, they hasten reactions that would occur eventually
  3. The reactant that an enzyme acts on is called the enzyme’s

______

  1. The enzyme binds to its substrate, forming an enzyme-substrate complex
  1. The ______siteis the region on the enzyme where the substrate binds
  1. ______fitof a substrate brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction
  1. In an enzymatic reaction, the substrate binds to the active site of the enzyme
  1. The active site can lower an EA barrier by
  1. Orienting substrates correctly
  1. ______substrate bonds
  2. Providing a favorable microenvironment
  1. ______bonding to the substrate
  1. An enzyme’s activity can be affected by
  2. General environmental factors, such as

______and pH

  1. Chemicals that specifically influence the enzyme
  1. Effects of Temperature and pH
  2. Each enzyme has an optimal temperature in which it can function
  3. Each enzyme has an optimal pH in which it can function
  4. ______arenonprotein enzyme helpers
  5. Cofactors may be inorganic (such as a metal in ionic form) or organic
  6. An organic cofactor is called a ______
  1. Coenzymes include ______
  1. ______inhibitorsbind to the active site of an enzyme, competing with the substrate
  1. ______inhibitorsbind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective
  2. Examples of inhibitors include toxins, poisons, pesticides, and antibiotics

8.4 Protein Enzymes Regulate Metabolic Pathways

  1. Explain the induced-fit model of enzyme function.
  1. Explain how substrate concentration affects the rate of an enzyme-catalyzed reaction.
  1. Concept 8.5: Regulation of enzyme activity helps control metabolism
  2. Chemical chaos would result if a cell’s metabolic pathways were not tightly regulated
  3. A cell does this by switching on or off the genes that encode specific enzymes or by regulating the activity of enzymes
  1. ______regulationmay either inhibit or stimulate an enzyme’s activity
  2. Allosteric regulation occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site
  3. Most allosterically regulated enzymes are made from polypeptide subunits
  4. Each enzyme has active and inactive forms
  5. The binding of an activator stabilizes the

______form of the enzyme

  1. The binding of an inhibitor stabilizes the

______form of the enzyme

  1. ______is a form of allosteric regulation that can amplify enzyme activity
  2. In cooperativity, binding by a substrate to one active site

stabilizes______conformational changes at all other subunits

  1. Allosteric regulators are attractive drug candidates for enzyme regulation (much more specific)
  2. Inhibition of proteolytic enzymes called caspases may help management of inappropriate inflammatory responses
  3. In ______inhibition, the end product of a metabolic pathway shuts down the pathway
  4. Feedback inhibition prevents a cell from wasting chemical

resources by synthesizing more ______than is needed

  1. Structures within the cell help bring order to metabolic pathways
  2. Some enzymes act as structural components of membranes
  3. In eukaryotic cells, some enzymes reside in specific organelles; for example, enzymes for cellular

respiration are located in ______

Lecture Questions 8.5 The Control of Metabolism

  1. Describe how allosteric regulators may inhibit or stimulate the activity of an enzyme.