Bio exam 3

Metabolism, cellular respiration, photosynthesis

Energy use by living things demonstrates the

First law of thermodynamics

According to the first law of thermodynamics, the…

Energy of the universe is constant

The first law of thermodynamics is also called the…

Principle of conservation of energy

Thermodynamics is the study of

Energy transformations in a collection of matter

The conversion of energy to thermal energy released as heat by living things demonstrates the

Second law of thermodynamics

According to the second law of thermodynamics, every energy transfer or transformation increases…

The entropy of the universe

According to the second law of thermodynamics, Entropy is a measure of…

Molecular disorder or randomness

During every energy transfer or transformation, some energy is converted to…

Thermal energy and lost as heat, becoming unavailable to do work

Living organisms increase the disorder of their…

Surroundings through their metabolism

Ex. The breakdown of food releases heat and small molecules, such as CO2

An isolated system, such as the liquid in a thermos bottle, is unable to

Exchange energy or mater with its surroundings

In an open system, energy and matter can be

Transferred between the system and its surroundings

Organisms are open systems; they absorb…

Energy from light or food and release heat and metabolic wastes, such as CO2, to the surroundings

Every energy transfer or transformation increases the

Entropy (disorder) of the universe

Metabolism is the

Totality of an organisms chemical reactions

Metabolism is an

Emergent property of life that arises from orderly interactions between molecules

In a metabolic pathway,

A specific molecule is altered in a series of steps to produce a product

Each step in a metabolic pathway is catalyzed by

A specific enzyme, a macromolecule that speeds up a specific reaction

Catabolic pathways release energy by

Breaking down complex molecules into simpler compounds

Cellular respiration is the

Breakdown of glucose in the presence of O2

Cellular respiration is an example of

A pathway of catabolism

Anabolic pathways consumer energy to

Build complex molecules from simpler ones

The synthesis of protein from amino acids is an example of

Anabolic pathway

Catabolic pathways are described as

Downhill reactions

Anabolic pathways are described as

Uphill reactions

Living things use energy released from the downhill reactions of catabolic pathways to power…

The uphill reactions of anabolic pathways

Bioenergetics is the study of

How energy flows through living organisms

Energy, the capacity to cause change, can be used to

Do work—move matter against opposing forces, such as gravity and friction

Living cells must transform energy from one form to another to

Do the work of life

Kinetic energy is energy associated with

Motion

Moving objects perform work by

Imparting motion to other matter

Thermal energy is the kinetic energy associated with

Random movement of atoms or molecules

Thermal energy in transfer from one object to another is called

Heat

Potential energy is energy that

Matter possesses because of its location or structure

Molecules possess energy due to

The arrangement of electrons in bonds between their atoms

Chemical energy is

Potential energy available for release in a chemical reaction

Complex molecules, such as glucose, are high in

Chemical energy because energy is released as they are broken down to simpler products

Energy can be

Converted from one form to another

The kinetic energy of muscle movement is transformed into

Potential energy as the diver climes higher above the water

The potential energy is then transformed to

Kinetic energy as the diver falls back down to the water

Processes that increase the entropy of the universe can occur

Spontaneously

Spontaneous processes occur without…

Energy input; they can happen quickly or slowly

Processes that decrease entropy are…

Non-spontaneous; they require an input of energy

Cells create ordered structures from…

Less organized starting materials

Ex. Simple molecules are ordered into amino acids, which are assembled into ordered polypeptides

Complex, ordered structures are also produced from…

Simpler starting materials at the organismal level

The increase in order within living systems is balanced by…

The catabolic breakdown of organized forms of matter, releasing heat and small molecules

At a larger scale, energy flows in to…

Ecosystems as light and exits as heat

Entropy (disorder) may decrease in a particular system, such as an organism, as long as the…

Total entropy of the system and surroundings increase

Biologists follow the energy and entropy changes during chemical reactions to determine whether they require…

An input of energy or occur spontaneously

Gibbs free energy, G, can be…

Simplified and referred to as free energy

Free energy is the portion of a…

Systems energy that can do work when temperature and pressure are uniform throughout the system, as in a living cell

Change in free energy during a reaction is related to…

Temperature and changed in enthalpy and entropy

🔺G = 🔺H - T🔺S

• 🔺G =

• 🔺H =

• 🔺S =

• T =

• 🔺G = change in free energy

• 🔺H = change in enthalpy (total energy)

• 🔺S = change in entropy

• T = temperature in Kelvin (K)

The 🔺G for a process can be used to…

Determine whether it is spontaneous or not

🔺G is

Negative for all spontaneous processes

🔺G is zero or..

Positive for non-spontaneous processes

Every spontaneous process decreases the

Systems free energy

Spontaneous processes can be harnessed by the…

Cell to perform work

🔺G represents the…

Difference between free energy of the final state and free energy of the initial state

🔺G = G final stage - G initial state

If a reaction has negative 🔺G, the system loses…

Free energy and becomes more stable

Free energy can be thought of as measure of a…

Systems stability; unable systems (higher G) tend to become more stable (lower G)

Equilibrium is the point at which forward and reverse reactions occur at the…

Same rate, describes a state of maximum stability

Systems never spontaneously…

Move away from equilibrium

A process is spontaneous and can perform…

Work only when it is moving toward equilibrium

The concept of free energy can be applied to the…

Chemistry of life’s processes

Chemical reactions can be classified based on their…

free-energy changes

An exergonic reaction (“energy outward”) proceeds with a…

Net release of free energy to the surroundings

An endergonic reaction (“energy inward”) absorbs…

Free energy from the surroundings

In exergonic reactions, the products store…

Less free energy than the reactants

Since 🔺G is negative, exergonic reactions occur…

Spontaneous

Spontaneous means that…

A reaction is energetically favorable, not that it will occur rapidly

The magnitude of 🔺G determines the…

Maximum amount of work an exergonic reaction can perform

in endergonic reactions, the products store…

More free energy than the reactants

Since 🔺G is positive, endergonic reactions are…

Non-spontaneous

The magnitude of 🔺G determines the quantity of…

Energy required to drive an endergonic reaction

Reactions in a closed system, such as an isolated hydroelectric system, eventually…

Reach equilibrium and can then do no work

The chemical reactions of metabolism are reversible but never reach…

Equilibrium in a living cell

Like an open hydroelectric system, cells allow…

Materials to flow in and out

The flow of materials prevents…

Metabolic equilibrium, enabling cells to continue doing work

Like a multi-step open hydroelectric system, a catabolic pathway in a cell releases…

Free energy in a series of reactions

A cell does 3 main kinds of work:

• Chemical work

• Transport work

• Mechanical work

Chemical work in a cell is…

Pushing endergonic reactions

Transport work in a cell is…

Pumping substances across membranes against the direction of spontaneous movement

Mechanical work in a cell is…

Such as beating cilia or contracting muscle cells

Cells manage energy resources to do work through…

Energy coupling, the use of an exergonic process to drive an endergonic one

Most energy coupling in cells is mediated by…

ATP

ATP (adenosine triphosphate) is composed of…

Ribose (a sugar), adenine (a nitrogenous base), and three phosphate groups

In addition to energy coupling, ATP functions as…

One of the nucleoside triphosphate used to make RNA

Energy is released from ATP when the…

Terminal phosphate bond is broken by hydrolysis, the addition of a water molecule

The energy does not come directly from the phosphate bonds m, but from the…

Chemical change to a state of lower free energy in the products

ATP releases more energy with the loss of a…

Phosphate than most other molecules could deliver

Repulsion between the negative charges of the 3 phosphate groups creates…

A lot of potential energy

The triphosphate tail is the…

Chemical equivalent of a compressed spring

Cellular work is consists of…

Mechanical, transport, and chemical work

Cellular work is powered by…

ATP hydrolysis

Overall, the couples reactions are…

Exergonic

Phosphorylation is the transfer of a…

Phosphate group from ATP to another molecule

Phosphorylation is typically used to…

Power endergonic reactions

The recipient molecule, a phosphorylated intermediate, is more reactive (less stable, with more free energy) than the…

Original molecule

Transport and mechanical work in a cell are also nearly always powered by…

ATP hydrolysis

ATP hydrolysis causes a change in…

Protein shape and binding ability