Module 6 Part 1: Metabolism

what is metabolism?

the totality of an organisms chemical reactions, including all catabolic and anabolic processes

what are metabolic pathways?

ordered series of chemical reactions that build up or break down molecules.

include catabolic and anabolic pathways

what is a catabolic pathway?

breaking down of complex molecules to simpler compounds and releases energy in the process

what is an anabolic pathway?

the building of complicated molecules and simpler ones by consuming energy

which metabolic pathway is responsible for cellular respiration?

catabolic pathways

what metabolic pathway is responsible for biosynthetic pathways?

anabolic pathways

if small molecules are being assembled into larger ones, which metabolic pathway is this?

anabolic

if large molecules are being broken down into smaller ones, which metabolic pathway is this?

catabolic

which metabolic pathway requires energy input? which releases energy?

catabolic pathways release energy, anabolic pathways require energy

what makes cellular activity possible?

energy and enzymes

what is bioenergetics?

the study of how organisms manage their energy resources; the flow of energy through an organism

what is required to obtain energy?

chemical reactions

what is energy?

the capacity to cause change and do work; move matter against opposing forces

what are the two main types of energy?

kinetic energy and potential energy

what is kinetic energy?

- the energy of motion

- thermal (heat) energy: energy of molecules moving

what is potential energy?

energy stored in position or configuration

includes chemical energy

what is chemical energy?

a type of potential energy where energy is stored in chemical bonds

can energy be transformed from one type to another?

yes

objects that have the potential to move are what kind of energy?

potential energy

objects in motion are what kind of energy?

kinetic energy

which type of energy is more stable?

kinetic energy is more stable

what determines the potential energy in covalent bonds?

the position of the shared electrons and how close they are to the nucleus

what determines the potential energy of a molecule?

the configuration and position of the shared electrons

do longer, weaker bonds with equally shared electrons have high or low potential energy (nonpolar bonds)?

they have high potential energy

do shorter, stronger bonds with unequally shared electrons have high or low potential energy? (polar bonds)

low potential energy

T or F: hydrocarbons have a lot of potential energy

true

how does the transfer of energy allow a car to race on a racetrack?

the potential energy stored in the chemical bonds of gasoline can be transformed into kinetic energy which allows the racecar to move

do polar or nonpolar bonds have higher potential energy and why?

nonpolar bonds have higher potential energy due to their equal electron sharing and being the longest and shortest bonds

in a chemical reaction, do the reactants or products have more potential energy? why?

reactants have more potential energy than the products because the products formed by the reaction have shorter and stronger covalent bonds than reactants.

as a chemical reaction occurs, what happens to the potential energy?

it decreases

in a chemical reaction, the potential energy in reactants is transformed into what kind of energy in products?

kinetic energy (thermal energy or light)

what is thermodynamics?

the study of the energy transformations that occur in a collection of matter

what are the key concepts in thermodynamics?

system, surroundings, closed system, open system

what does system mean in thermodynamics?

signifies the matter under study

what does surroundings mean in thermodynamics?

the rest of the universe; everything outside of the system

what does closed system mean in thermodynamics?

collection of matter isolated from its surroundings

what does open system mean in thermodynamics?

energy and matter can be transferred between the system and its surroundings; living things are open systems

are living things open or closed systems?

open systems

what is the first law of thermodynamics?

- energy is conserved

- energy cannot be created or destroyed

- energy can only be transferred and transformed

what is enthalpy (H)?

the total energy in a molecule

includes potential energy in the bonds of a molecule and the effect of the molecules kinetic energy on surrounding pressure and volume

what is the symbol for enthalpy?

(H)

what is the symbol for changes in enthalpy?

ΔH

what are changes in enthalpy (ΔH) based on?

differences in potential energy

what are exothermic reactions?

- reactions that release heat

-ΔH is negative

- products have less potential energy than reactants

what are endothermic reactions?

- heat energy is taken up during a reaction

- ΔH is positive

- products have higher potential energy than reactants

what type of reactions release heat?

exothermic reactions

what type of reaction is it if ΔH is negative

exothermic

what type of reaction is it if the products have less potential energy than the reactants?

exothermic

what type of reaction is it if heat energy is taken up?

endothermic reaction

in what type of reaction is ΔH positive?

endothermic reactions

in what type of reaction does the product have a higher potential energy than the reactants?

endothermic

what is entropy (S)

the quantitative measure of the amount of disorder

what happens to entropy (S) when the products of a chemical reaction become less ordered (more disordered) than the reactant molecules?

entropy increases and (ΔS) is positive

if (ΔS) is positive what can you conclude about the chemical reaction?

the system is more disordered and the products are more disordered than the reactants. entropy has increased.

what is the symbol for entropy?

(S)

what is the symbol for a change in entropy?

ΔS

what is the second law of thermodynamics?

total entropy always increases in a system that has energy transfers and transformations

the transfer of energy is not completely efficient

with each chemical reaction, some energy is lost in a form that is unusable (such as heat energy)

T or F: a living thing is an ordered collection of matter

true

are living things high or low entropy systems?

they are low entropy systems

how do living things maintain their ordered collection of matter?

creating a net increase in entropy (S) in the universe. living things function as open systems that consume energy and release heat and waste which increases the surrounding entropy.

T or F: when a reaction generates more disorder, entropy increases

true

what is Gibb's Free Energy (G)?

the amount of energy available to do work (aka usable energy)

determines whether a reaction is spontaneous or requires added energy to proceed

what is the symbol for gibbs free energy?

(G)

T or F: not all reactions effect G (gibbs free energy)

false, all chemical reactions affect G

what is the symbol for the change in (G) after a reaction?

ΔG

what is (ΔG)

the change in (G) after a reaction

what determines whether a reaction is spontaneous or requires added energy to proceed?

Gibbs free energy (G)

what is the standard free energy change equation?

ΔG = ΔH - TΔS

ΔH : change in enthalpy

ΔS : change in entropy

T : temperature in degrees Kelvin

ΔG : change in gibbs free energy

the change in gibbs free energy (ΔG) is equal to :

the change in enthalpy and entropy (ΔH - TΔS)

a chemical reaction is spontaneous when

ΔG < 0 exergonic

a chemical reaction is nonspontaneous when

ΔG > 0

- endergonic

if ΔG > 0, the reaction is what?

reaction is nonspontaneous and endergonic

if ΔG < 0, the reaction is what?

reaction is spontaneous and exergonic

if ΔG = 0, the reaction is what?

at equilibrium

if a chemical reaction requires an input of energy, then ΔG is? what type of reaction is this?

ΔG > 0, endergonic

the products have more free energy than the substrates

if energy is released in a chemical reaction, then ΔG is what? what type of reaction is this?

ΔG < 0, exergonic

- the products have less free energy than the substrates

what type of reactions are spontaneous?

exergonic reactions

what type of reaction is nonspontaneous?

endergonic

what are exergonic reactions?

reactions that release free energy and occur spontaneously

(ΔG < 0)

products will have less free energy than the substrates

if products have less free energy than the substrates, what type of reaction is this?

exergonic reaction

what is an endergonic reaction?

reaction that requires an input of energy and is nonspontaneous

(ΔG>0)

products will have more free energy than the substrates

if the products have more free energy than the substrates, what type of reaction is this?

endergonic reaction

what makes an exergonic reaction spontaneous?

because they can occur without the addition of energy

T or F: if a reaction is spontaneous, that means that it occurs quickly

false

in order for most reactions to proceed, what needs to happen?

one or more chemical bonds have to break and others have to form. Substances must collide in a specific orientation to bring electrons involved near eachother

do higher or lower temperatures increase reaction rate?

higher temperature

why does higher temperature increase reaction rates?

because the particles gain kinetic energy which causes them to move faster and collide more frequently

T or F: higher concentration increases the number of collisions in a reaction

true

what are two important factors that speed up chemical reactions?

higher temperature and higher concentration

what is the iodine clock experiment and what did it show?

this was an experiment that tested temperature vs reaction rate and concentration vs reaction rate. it concluded that the reaction rates increased when the temperature of a reaction mixture was higher and the reaction rates increased when the reaction concentrations were higher.

what is energetic coupling?

allows the energy released from an exergonic reaction to drive an endergonic reaction

in cells, what are the two ways that energetic coupling occurs?

through the transfer of electrons and through the transfer of phosphate groups

what are reduction oxidation reactions?

chemical reactions that involve electron transfer

include oxidation and reduction

what does oxidation mean?

the loss of electrons

what does reduction mean?

the gain of electrons

T or F: redox reactions are examples of energetic coupling

true

Redox reactions are an example of energetic coupling. which part is exergonic and which is endergonic?

oxidation is exergonic because it loses electrons and releases energy. reduction is endergonic because it gains electrons and uses energy.

during redox reactions what are the two ways that electrons can be gained or lost?

change in number of electrons in valence shell of atom

electrons transferred as new covalent bonds formed with other atoms

does oxidation or reduction "add H+"? which "removes H+"?

reduction adds H+

oxidation removed H+

Flavin adenine dinucleotide (FAD) accepts two electrons plus two protons to form FADH2. Which is the oxidized form and which is the reduced form?

FAD is the oxidized form and FADH2 is the reduced form