TAMU BIOL 111: Chapter 6 Exam 2 (Fletcher)

Define Metabolism

totality of reactions in your body that involves energy

Define Metabolic Pathway

A series of reactions controlled by enzymes

What are the two Metabolic Pathways?

Catabolic & Anabolic

Catabolic Pathway

Breaks down complex molecules & RELEASES energy, H2O IN

Anabolic Pathway

Builds up, energy in, H2O OUT

What kind of metabolic pathway is Carbohydrate Metabolism?

Catabolic, because it is RELEASING energy

What kind of metabolic pathway is photosynthesis?

Anabolic, because it REQUIRES energy

Potential Energy

Stored energy that has the potential to move

Kinetic Energy

In motion

Free Energy

The available energy to do work (usable energy)

Activation Energy

The energy required for a reaction to start

-HEAT is the main source

When Delta G is favorable...

G is negative, stable, & spontaneous

When Delta G is unfavorable...

G is positive, unstable, & NON spontaneous

When Delta G is at equilibrium...

forward and reverse rates are equal, delta G=0, no work can be done

Endergonic Reactions

Absorb free energy, NON spontaneous, positive delta G

Exergonic Reactions

Release free energy, spontaneous, negative delta G

1st Law of Thermodynamics (Law of Conservation of Energy)

Energy cannot be created or destroyed

2nd Law of Thermodynamics

Entropy of a system is always increasing

Define spontaneous

A process that occurs by itself without outside intervention

Define Entropy

the measure of disorder or randomness in a system

Define Free Energy

Gibbs Free Energy, G, is used to describe the capacity of a system to do work

Endergonic is to Exergonic as ______ is to ______

Anabolism, Catabolism

What process can occur without the net influx of energy from other processes?

Photosynthesis

What is this formula---> C6H12O6 + 6O2 → 6CO2 + 6H2O

cellular respiration

If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of product is to:

Add more of the enzyme

Some bacteria are metabolically active in hot springs because:

Their enzymes have high optimal temperatures

What factors can affect enzyme activity?

Temperature, pH, inhibitors

Which of the following is an example of potential energy rather than kinetic energy?

A. water rushing over Niagara Falls

B. light flashes emitted by a firefly

C. Hydrolysis

D. a molecule of glucose

D. a molecule of glucose

In this equation: ΔG = ΔH - TΔS... What is ΔG?

The change in free energy

What is most similar in structure to ATP and why?

an RNA nucleotide

-Both have 5 Carbon sugar - pentose

-Both contain a phosphate

-Both contain adenine

What is the name of the thermodynamic barrier that must be overcome before products are formed in a spontaneous reaction?

Activation Energy

Which condition may be overcome by increasing the substrate concentration in an enzymatic reaction with a fixed amount of enzyme?

Competitive Inhibition

What are the requirements for metabolism to occur?

Reactants, Enzymes

Metabolism

All of the chemical reactions that occur within an organism

metabolic pathway

Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product.

catabolic pathways

Metabolic pathways that release energy by breaking down complex molecules into simpler compounds.

catabolic example

cellular respiration

anabolic pathways

consume energy to build complex molecules from simpler ones

anabolic example

photosynthesis

Energy

the ability to do work

kinetic energy

energy of motion

potential energy

stored energy

energy transformation

A change from one form of energy to another

open system

A system in which matter can enter from or escape to the surroundings.

closed system

A system in which no matter is allowed to enter or leave

which systems are humans?

open systems because they absorb light and chemical energy. They also release heat and metabolic waste products.

first law of thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

second law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

Entropy

A measure of disorder or randomness.

what increases entropy?

When a substance is broken down into parts, the entropy increases.

Entropy also increases when temperature increases

An exemption to this rule is when a gas is produced from nongaseous reactants

free energy

energy that is available to do work

spontaneous energy

process that occurs without the input of free energy

releases free energy while moving to a lower, more table state.

Negative G

spontaneous, exergonic

free energy decreases, stability of a system increases

Positive G

nonspontaneous, endergonic

less stable

nonspontaneous reaction

a chemical reaction that does not favor the formation of products at the stated conditions

Exergonic

releases energy

Endergonic

requires energy

Structure of ATP

adenine, ribose, 3 phosphate groups

Phosphorylation

The metabolic process of introducing a phosphate group into an organic molecule.

energy coupling

The use of an exergonic process to drive an endergonic one.

Enzymes

Catalysts for chemical reactions in living things

enzyme function

speed up chemical reactions

enzyme structure

Globular proteins that have a functional region known as an active site

ADP structure

ADP is basically the same as ATP. It has an Adenine molecule and 2 (instead of 3) phosphate groups.

activation energy

Energy needed to get a reaction started

activation barrier

The energy required to start a chemical reaction by reaching the transition state.

What affects enzyme activity?

temperature, pH, and regulatory molecules

Denaturation

loss of normal shape of a protein due to heat or other factor

cofactors and coenzymes

two types of activators( ways to turn on enzymes)

competitive inhibitor

A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.

noncompetitive inhibitor

A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.

Disulfiram

Used in tx of alcohol cessation.

Inhibits acetaldehyde dehydrogenase-->increased acetaldehyde when drinking (toxic)-->N/V-->incentive not to drink

allosteric regulation

When a protein's function at one site is affected by the binding of a regulatory molecule to a separate site.