BIO 190A EXAM 2

__________ is the ability to promote change or do work.

Energy

There are 2 general forms of energy: __________ and potential energy.

kinetic energy

There are 2 general forms of energy: kinetic energy and __________.

potential energy

The __________ states that energy cannot be created or destroyed, but can be transferred or transformed.

first law of thermodynamics

The __________ states that an energy transfer or transformation increases the disorder of a system.

second law of thermodynamics

The second law of thermodynamics states that an energy transfer increases the __________ (degree of disorder) of a system.

entropy

Total energy = __________ energy + unusable energy.

usable

Total energy = usable energy + __________ energy.

unusable

The __________ is the usable energy, the amount of energy available to do work.

free energy (G)

We can determine whether a reaction will occur spontaneously by evaluating the __________ that occurs as a result of the reaction.

free-energy change (ΔG)

In an __________, the products have less free energy than the reactants.

exergonic reaction

In an exergonic reaction, the products have __________ free energy than the reactants, so free energy is released.

less

In an __________, free energy must be added during the reaction.

endergonic reaction

In an endergonic reaction, the products have __________ free energy than the reactants.

more

Many reactions that cells must accomplish are __________.

endergonic

Energy released from __________ is used to drive other endergonic reactions.

ATP hydrolysis

A spontaneous reaction is not necessarily a __________ reaction.

fast

__________ are protein catalysts in living cells that increase the rates of chemical reactions.

Enzymes

An initial input of energy, the __________, is required to start a reaction.

activation energy (EA)

The activation energy needed to achieve the __________ is a barrier to the formation of products.

transition state

Enzymes __________ the activation energy barrier.

lower

The __________ is the location in an enzyme where the reaction takes place.

active site

__________ are the reactants that bind to the active site.

Substrates

The enzyme undergoes conformational changes upon substrate binding, which is called __________.

induced fit

__________ is the attraction of an enzyme for a substrate.

Affinity

For a given concentration of enzyme, as substrate concentration is increased, reaction velocity increases until it __________.

plateaus

__________ is the maximal rate of the reaction.

Vmax

__________ is the substrate concentration where velocity reaches half of its maximal rate.

KM

KM is the substrate concentration where velocity is __________.

half the max

Cells often use __________ to regulate enzyme activity.

reversible inhibitors

__________ bind noncovalently to the active site.

Competitive inhibitors

Competitive inhibitors bind noncovalently to the __________.

active site

__________ bind to a distinct regulatory site that is different from the active site.

Noncompetitive inhibitors

Noncompetitive inhibitors bind to a distinct regulatory site, called an __________, that is different from the active site.

allosteric site

Some enzymes require non-protein molecules or ions to function, such as __________, coenzymes, and prosthetic groups.

cofactors

Some enzymes require non-protein molecules or ions to function, such as cofactors, __________, and prosthetic groups.

coenzymes

Some enzymes require non-protein molecules or ions to function, such as cofactors, coenzymes, and __________.

prosthetic groups

__________ along with pH and ionic conditions influences enzyme structure and function.

Temperature

Temperature, __________, and ionic conditions influence enzyme structure and function.

pH

In living cells, chemical reactions often occur in a series of coordinated steps called a __________.

metabolic pathway

__________ break down larger molecules into smaller ones.

Catabolic reactions

Catabolic reactions are typically __________.

exergonic

__________ synthesize larger molecules from smaller ones.

Anabolic reactions

Anabolic reactions are typically __________.

endergonic

As a larger molecule such as glucose is broken down, energy is often stored in an __________ such as ATP or NADH.

energy intermediate

In general, a substance that has been oxidized has __________ energy stored in its bonds.

less

A substance that has been reduced has __________ energy stored in its bonds.

more

Cells use __________ in many important redox reactions, including the breakdown of food molecules.

NAD+/NADH

The regulation of catabolic and anabolic pathways occurs at the __________, cellular, and biochemical levels.

genetic

The regulation of catabolic and anabolic pathways occurs at the genetic, __________, and biochemical levels.

cellular

The regulation of catabolic and anabolic pathways occurs at the genetic, cellular, and __________ levels.

biochemical

__________ is a process by which living cells obtain energy from organic molecules.

Cellular respiration

The aerobic respiration of glucose involves __________ metabolic pathways.

4

__________ is the first stage of cellular respiration.

Glycolysis

Overall, in glycolysis 1 molecule of glucose is transformed into 2 molecules of __________.

pyruvate

In glycolysis, a net of __________ is generated per glucose.

2 ATP

In glycolysis, a net of __________ is generated per glucose alongside ATP.

2 NADH

__________ is the second stage of cellular respiration.

Pyruvate oxidation

In pyruvate oxidation, 2 pyruvate yield a total of 2 __________.

acetyl CoA

In pyruvate oxidation, 2 pyruvate yield 2 acetyl CoA, 2 NADH, and 2 __________.

CO2

The __________ is the third stage of cellular respiration.

citric acid cycle

Processing 2 acetyl groups in the citric acid cycle yields a total of __________ CO2.

4

Processing 2 acetyl groups in the citric acid cycle yields a total of __________ NADH.

6

Processing 2 acetyl groups in the citric acid cycle yields a total of __________ FADH2.

2

Processing 2 acetyl groups in the citric acid cycle yields 2 ATP via __________.

GTP

The final stage of cellular respiration, __________, uses high-energy electrons stored in NADH and FADH2.

oxidative phosphorylation

Oxidative phosphorylation uses high-energy electrons to generate an __________.

H+ gradient

The enzyme __________ uses the H+ gradient to synthesize ATP.

ATP synthase

The __________ consists of a group of protein complexes and small organic molecules.

electron transport chain (ETC)

The electron transport chain is embedded in the __________.

inner mitochondrial membrane

Oxygen receives electrons at the end of the electron transport chain, making it the __________.

final electron acceptor

Some of the energy released as electrons move is used to pump H+ across the membrane, establishing an __________.

H+ electrochemical gradient

The H+ gradient is a source of __________ energy.

potential

The flow of H+ through the ATP synthase enzyme causes __________ that result in the synthesis of ATP.

conformational changes

__________ refers to the chemical synthesis of ATP as a result of pushing H+ across a membrane.

Chemiosmosis

Cells rarely achieve the maximal amount of ATP because NADH is also used in __________ pathways.

anabolic

Because the H+ gradient is used for other purposes, the actual ATP yield is about __________ ATP.

25

__________ can be considered a rotary machine with moving parts powered by an energy source.

ATP synthase

ATP synthase can be considered a __________ with moving parts powered by an energy source.

rotary machine

As proteins and fats are broken down into smaller molecules, components can enter __________ or the citric acid cycle.

glycolysis

As proteins and fats are broken down into smaller molecules, components can enter glycolysis or the __________.

citric acid cycle

An environment that lacks oxygen can be described as __________.

anaerobic

Under anaerobic conditions, E. coli produces the enzyme __________.

nitrate reductase

Under anaerobic conditions, nitrate reductase uses __________ as the final electron acceptor.

nitrate (NO3-)

One strategy to produce ATP under anaerobic conditions is to make ATP only via __________.

glycolysis

Under anaerobic conditions, NADH builds up and __________ decreases.

NAD+

NAD+ must be regenerated under anaerobic conditions to keep __________ running.

glycolysis

__________ production in muscle is a fermentation process that oxidizes NADH to NAD+.

Lactic acid

__________ production in yeast is a fermentation process that oxidizes NADH to NAD+.

Ethanol

Lactic acid and ethanol production are both examples of __________ processes that regenerate NAD+.

fermentation

The process of __________ captures light energy and uses this energy to synthesize carbohydrates.

photosynthesis

Energy from light drives photosynthesis, which is an __________ reaction.

endergonic

Organisms that produce their own organic food from inorganic sources are categorized as __________.

autotrophs

Organisms that must consume organic molecules from their environment are categorized as __________.

heterotrophs

Life is primarily driven by the photosynthetic activity of __________, algae, and cyanobacteria.

plants

Life is primarily driven by the photosynthetic activity of plants, __________, and cyanobacteria.

algae

Life is primarily driven by the photosynthetic activity of plants, algae, and __________.

cyanobacteria

__________ are organelles that carry out photosynthesis.

Chloroplasts

Chloroplasts contain the photosynthetic pigment __________.

chlorophyll

The __________ involve a series of energy conversions starting with light energy.

light reactions