Test 2 (ch. 6-7)

Bioenergetics

how energy flows through living systems

Metabolism

all the chemical reactions that take place inside cells

Metabolic pathway

a specific series of interconnected biochemical reactions that convert a substrate into a final product

Anabolism

building pathways (requires energy)

Catabolism

breaking down pathways (producing energy)

Kinetic energy

energy associated with objects in motion

Kinetic energy

energy associated with objects in motion

Potential energy

energy associated with the potential to do work

Chemical energy

type of potential energy that exists within chemical bonds and is released when those bonds are broken

Free Energy

measurement used to quantify the amount of energy transferred when chemical bonds are broken and others are created during a reaction

Exergonic

reactions that release free energy (spontaneous)

Endergonic

reactions that require an input of free energy (non-spontaneous)

Thermodynamics

refers to the study of energy and energy transfer in physical matter

Energy System

the physical matter involved, and the environment that are apart of thermodynamics

Entropy

amount of randomness or disorder within a system

Activation Energy

small amount of energy input required in order for chemical reactions to occur

Catalyst

substance that helps chemical reactions to occur (Catalysis)

Enzyme

special molecules that catalyze biochemical reactions

Substrate

chemical reactants to which an enzyme binds

Denaturation

alternation of natural properties of an enzyme that renders it weak or ineffective

Cofactor

inorganic helper ions such as (Fe2+) or magnesium (Mg2+)

Coenzyme

organic helper molecules such as vitamin C

Cellular Respiration

producers and consumers are able to extract the energy from the bond in glucose and convert it into a form that all living things can use, ATP

Oxidation

strip an electron from an atom in a compound

Reduction

add an electron to another compound

Chemiosmosis

free energy generated from the redox reaction (the chemical energy stored in the bonds) is used to move hydrogen ions across a semipermeable membrane (the mitochondrial membrane)

Aerobic

does use oxygen

Anaerobic

does not use oxygen

Fermentation

when cells use an organic molecule other than oxygen as an electron except to recycle NAD+

Anabolic reactions

building (requires energy)

Catabolic reactions

breaking down (producing energy)

Photosynthesis is what type of reaction

anabolic

Cellular respiration is what type of reaction

catabolic

Relationship between kinetic energy and potential energy

if released potential energy could be transferred into kinetic

Example of relationship between kinetic and potential energy

• wreaking ball

  • suspended in sky = potential

  • swinging = kinetic

How is Chemical Energy related to potential energy

it is a type of potential energy (within chemical bonds)

Common High-Energy molecules used to transfer chemical energy

• ATP (adenosine triphosphate)

• NADH (nicotinamide adenine dinucleotide)

• NADPH (nicotinamide adenine dinucleotide phosphate)

Free energy related to exergonic reactions

products of reaction have less free energy than the reaction causing energy to be released during reaction

Free energy related to endergonic reactions

products of a reaction have more free energy than the reaction causing free energy to be added during reaction

Anabolic require what reactions

endergonic reactions (they require energy)

Catabolic require what reactions

exergonic reactions (they release energy)

1st & 2nd Laws of Thermodynamic applied to biological systme

govern the transfer of energy in and among all systems in the universe

Biological systems open or closed

open (energy can be transferred between the system and its surroundings)

1st Law of Thermodynamics

energy transfer (in the entire universe) is not efficient/ more energy lost the more random the system

Form of energy lost from every transfer of energy

heat energy

Main energy currency

ATP

Why do cells need ATP

energy in its bonds have potential for quick bursts of transferable energy that can be harnessed to perform cellular work

Basic molecular structure of AMP

• molecule of adenine (nitrogenous base)

• ribose molecule (5 carbon-ribose)

• single phosphate group

How is AMP different from ADP or ATP

• AMP - one phosphate groups

• ADP - two phosphate groups

• ATP - three phosphate groups

Which bond in ATP stores the Majority of Transferable Chemical energy

third phosphate group

Hydrolysis reaction

one molecule breaks apart to form multiple smaller molecules

Products of Hydrolysis reaction of ATP to ADP

ADP and 1 inorganic phosphate group

Reactants of hydrolysis reaction of ATP to ADP

ATP and water

Phosphorylation

binding a phosphate group to a molecule

Dephosphorylation

unbinding a phosphate group from a molecule (releases energy)

Energy Coupling Applied to Dephosphorylation of ATP

cells couple the exergonic reactions of ATP hydrolysis with endergonic reactions, thus allowing them to proceed

Energy Coupling

occurs when the energy produced by one reaction or system is used to drive another reaction or system

In human and animals cells, what pump is ATP usually spent powering

Na+/K+ pump

Why is ATP so unstable

the phosphate groups are negatively charged and repel each other

Regeneration of ATP from ADP

endergonic reaction

Substrate-level phosphorylation

energy from dephosphorylation is used in the same reaction to phosphorylate a different molecule

90% of ATP is regenerated from what process

Oxidative phsophorylation

Where does Oxidative phosphorylation occur in eukaryotic cells

mitochondria

Where does Oxidative phosphorylation occur in prokaryotic cells

plasma membrane

oxidative phosphorylation relies on what transport process

chemiosmosis

What factors determine the rate of an enzymatic reaction

activation energy

Higher activation energy results in what kind of rate

slower rate

Source of activation energy in most chemical reactions

heat energy

why does increased temperature increase the rate of reactions

speeds up the motion of molecules, causing them to collide with more force and more frequency

Why can cellular reaction not use heat energy from their surrounding as activation energy

activation energies are too high

How does an enzyme catalyze a reaction

enzymes bind to the reactant molecules and hold them in a way to make the chemical bond-breaking and bond-forming process easier

Active site

place on the enzyme where the substrate binds

What properties give an active site its specificity

unique combination of R-groups present at active site

Active Sites Effects of having a a high level of specificity

vulnerable to environmental influences that alter its structure and make it ineffective

Environmental changes that might denature an enzyme

temperature

Lock and Key model

the idea that the enzyme’s active site and substrate fit together perfectly in one step

Induced Fit model

the enzyme and substrate are specific to each other but also undergo changes in their conformation upon binding

Enzymes once they catalyzed a reaction

they release its products

Competitive Inhibition

the inhibitor molecule is similar enough to the substrate that it can bind to the active site and block the substrate form binding

Non-Competitive Inhibition

inhibitor molecule binds to the enzyme in a location other than the active site (substrate won’t work even if in active site)

Allosteric Inhibition

changes the active site so substrates bind less efficiently

Allosteric Activation

changes the active site so substrates bind more efficiently

Coefactors

inorganic helper ions like iron (Fe2+) or (Mg2+)

Coenzymes

organic helper molecules such as vitamin C

Cofactors and Coenzymes assist in the Regulation of Enzymatic Reactions

some enzymes won’t work well or at all unless also bonded by specific non-protein helper molecules

Compartmentalization

enzymes are required only for certain cellular processes and can be housed separately inside structures along with their substrates

Compartmentalization used by eukaryotic cells to regular chemical reactions

metabolic enzymes in the mitochondria; or digestive enzymes in lysosomes

Feedback inhibition

the use of reaction products to regulate its own further production

Example of Feedback Inhibition

• ATP is an allosteric inhibitor that will prevent more from being made

• ADP is an allosteric activator that will cause more ATP to be made

Redox Reaction

oxidation and reduction reactions occur together

How do cells harness transfer energy through redox reactions

uses oxidation to remove an electron and reduction to move that electron to a second compound

Potential chemical energy when electrons are removed

decreases potential energy

Potential chemical energy when electrons are added

increases potential energy

Electroncarriers

pick up electrons from one molecule and from them off with another (NAD/FAD)

Group of Molecules most Electron Carriers derived from

B vitamin group

NAD

nicotinamide adenine dinucleotide

What does NAD come from

Vitamin B3 (niacin)

NAD oxidized form

NAD+

NAD Reduced form

NADH

FAD

flavin adenine dinucleotide