Chapter 8

what is energy

systems ability to do work and the capacity to cause change

what are the 2 major states of energy

kinetic and potential

what is kinetic energy

acitive energy and energy used during work

what is potential energy

stored energy that may perform work

what are the six forms of energy

radiant, thermal, chemical, electrical, sound , mechanical

what is radiant energy

visible light, x rays, gamma rays etc. Solar energy

what is thermal energy

Energy from movement of atoms and molecules in a
substance. more movement means more heat

what is chemical energy

Energy storage in chemical bonds (potential energy)
§ Reactions (kinetic)

what is electrical energy

Delivered by electrons
§ E.g. Movement of the electron through a wire (kinetic)

what is sound

Longitudinal waves
§ Produced when a force causes an object or substance to vibrate

what are the two mechanical energies

object position (potential), tension, compressed springs Mechanical energy (kinetic) movement like wind

what law does an organisms transform matter and energy and metabolism

laws of thermodynamics

what is the first law of thermodynamics

the energy of the universe is constant: Energy can be transferred and transformed, but it cannot be created or destroyed.

what is the second law of thermodynamics

Every energy transfer or transformation increases the entropy (disorder) of the universe

3 rules for living organisms

Need energy for metabolic reactions. Canʼt create energy. Must obtain energy from the environment (photosynthesis or feeding).

what are the three features cells possess

A ability to store and transmit information, plasma membrane, ability to harness energy from the environment.

what is metabolism

totality of an organism’s chemical reactions

what is a metabolic pathway

begins with a specific molecule and ends with a product
Each step is catalyzed by a specific enzyme

what 2 groups can the metabolic pathway be divided into

Anabolic and Catabolic

what is a catabolic pathway

release energy by breaking down molecules into simpler compounds, producing energy and building blocks for the synthesis of new molecules. usually hydrolysis reactions

what is a anabolic pathway

consume energy to build complex molecules from
simpler ones to create energy storage or structural molecules (proteins). usually dehydration synthesis reactions

what are three examples of work cells do

proetein synthesis, movement of cell, reproduction of cell

how is potential energy determined in a cell

position of shared electrons in covalent bonds

how is the amount of potential energy determined in a cell

how far away the electron is from the nucleus, farther away=more potential energy

what happens when old bonds are broken

energy is required

what happens when new bonds are formed

energy is released

what is free energy

determine whether or not reactions occur spontaneously. is energy that can do work when temp and pressure are uniform

what is delta G

change in free energy

which processes were spontaneous

negative delta G were spontaneous

what happens during spontaneous change

free energy decrease and stability of system increase

what would happen to a cell if EQ was reached

cell dies no free energy

what is an exergonic reaction

net release of free energy and is spontaneous

what is an endergonic reaction

absorbs free energy from surroundings and is not spontaneous

are anabolic reaction ender or exergonic

endergonic

are catabolic reactions ender or exergonic

exergonic

what is energy recoupling

free energy released from one reaction is used to drive another

what are two ways cells typically perform energy recoupling

transferring phosphate groups or transferring electrons

what do anabolic reactions require

require energy from catabolic energy to synthesize more complex organic molecules

where is the available energy in ATP held in

bonds connected by phosphate groups

at physiological ph how do the phosphate groups behave

negativly charged and repel each other

what type of reaction with ATP and water is what does it form

exergonic release energy ( -delta G and spontaneous), forms ADP and P1 meaning more entropy and delta s positive

how does the the substrate change shape

Energy released during ATP hydrolysis is transferred to a substrate by
phosphorylation.

what is a redox reaction

transfer of electrons during chemical reactions releases energy stored in organic molecules

what happenes in oxidization

a substance loses electrons, or is oxidized.

what happens in reduction

reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced).

what is the electron donor

reducing agent

what is the electron acceptor

oxidizing agent

what are the two electron carriers acting as oxidizing agents in cellular respiration

Flavin adenine dinucleotide (FAD)
Nicotinamide adenine dinucleotide (NAD+ )

how does temp affect reaction rate

low temp slower reaction, higher temp faster reaction

how does concentration affect reaction rate

higher concentration fast reaction, lower concentration slower reaction

what is needed for reactions to take place

some or all the chemical bonds in the reactants must be broken so that new
bonds, those of the products, can form.

what is the transition state

molecule must be contorted (deformed or bent) into an unstable state. high energy

what does a low activation energy equal to

faster reaction

what are enzymes able to do

reduce the activation energy by stabilizing the
transition state.

what are enzyme made of

.protein catalyst

what are enzymes specific to to

to a particular chemical reaction.

how do substrates bind to enzymes active site

Substrates bind via hydrogen bonding or other interactions with amino
acid residues in the active site.

what is induced fir

enzymes undergo a conformational change when the
substrates are bound to the active site

how does the speed of an enzyme catalyzed reaction go

increases linearly

what is an ezymes function dependant on

Temperature
o pH
o Interactions with other molecules
o Modifications of its primary structure

what is the effect of temp on enzymes

temp rises, reacting molecules have more kinetic energy,
increasing chances of a collision between enzyme and substrate molecules, increases in reaction rate

effect of ph of enzyme activity

Each enzyme has an optimal pH at which it can function

what is a apoenzyme

protein in enzyme

what is a competitive inhibitor

bind to the active site of an enzyme, competing with the substrate

what is a non competitive inhibitor

bind to another part of an enzyme (allosteric site), causing the
enzyme to change shape and making the active site less effective or completely inactive

what is feedback inhibition

occurs when an enzyme in a pathway is inhibited by the final product of that pathway