Cell Bio Exam 2

Entropy

thermodynamic quantity that measures the degree of disorder in a system

Living systems maintain order that is trending towards ______

disorder

Enzymes

proteins that catalyze chemical reactions

Metabolism 

the sum of the chemical reactions that take place in the cells of a living organism 

Catabolism

set of reactions that molecules are broken down

Anabolism

set of reactions that molecules are synthesized (built)

Second law of thermodynamics

• disorder can ONLY INCREASE 

• systems change spontaneously

• systems change in ways that increase entropy 

First law of thermodynamics 

energy cannot be created or destroyed, but it can be converted to another form 

Kinetic energy + heat energy

potential energy

Activated carriers

small molecule that stores energy or chemical groups in a form that can be transferred to many different metabolic reactions

Carbon Fixation

the process by which inorganic carbon is converted to organic compounds.

Cells obtain energy by the ______ of organic molecules 

oxidation (loss of electrons)

Cellular respiration

the complex stepwise process by which food molecules are broken down

Oxidation-reduction reactions

chemical reactions involving the transfer of electrons where one substance loses an electron and one substance gains an electron

Is photosynthesis oxidation or reduction?

reduction 

In the reactions involving electron transfer, what gets overall oxidized?

Activated carriers

Chemical reactions proceed in the direction that causes loss of ______

free energy

Free energy

energy that can be used to do work

Activation energy

the energy that must be acquired by a molecule to undergo chemical reaction

Substrate

a molecule on which an enzyme acts to catalyze a reaction

Enzymes can direct molecules along _______

Specific pathways

A reaction is favorable when …

the products have lower free energy than the reactants

Equilibrium

state in which the forward and reverse rats of a chemical reaction are equal so that no net chemical change occurs

Cells rarely allow reactions to reach ____ and are constantly fighting against it

equilibrium=death 

Standard free energy change

the free energy change measured at a defined concentration, temperature, and pressure

Enzyme catalyzed reactions depend on rapid _______

molecular collisions

Diffusion

process by which molecules and small particles move from one location to another by random thermally driven motion

_____ interactions allow enzymes to bind to specific molecules

noncovalent

_____ are responsible for all reversible interactions in the cell and folding of macromolecules 

noncovalent

Affinity constant 

equilibrium constant of binding, larger the constant= more tight binding

The formation of an activated carrier is a _____ reaction

uphill, which means it must be paired to a downhill reaction 

Coupled reaction

linked pair of chemical reactions in which free energy released by one reactions serves to drive the other reaction

______ is the most widely used activated carrier

ATP (uphill reaction)

Transfer of a phosphate is a _____ reaction 

phosphorylation 

What drives the synthesis of many macromolecules by powering the reaction of the subunit attaching to the growing polymer

ATP

____ is the activated carrier of phosphate groups

ATP

NADH and NADPH are activated carriers of _____

electrons 

NADH/NAD+ will come back in ______

cellular respiration

NADPH/NADP+ will come back in ______

photosynthesis

NADH is mostly _____ reactions 

catabolic 

NADPH is mostly _____ reactions

anabolic

Activated carrier that donates the carbon atoms in its readily transferable acetyl group to many metabolic reactions, including the citric acid cycle and fatty acid biosynthesis 

acetyl CoA

A large carrier is easily recognizable by ________

enzymes