BIO 141 - ch 8 - metabolism

catabolic breaks down complex molecules into simpler compounds

• RELEASE energy

anabolic consume energy to build complex molecules from simpler ones.

• NEED energy

Explain the difference between catabolic and anabolic reactions

the study of how energy flows through living organisms

What is bioenergetics

1. energy can be transferred and transformed but it cannot be created or destroyed

2. every energy transfer or transformation some energy is unusable and is often lost as heat

   1. heat cant do any work

   2. every energy transfer / transformation increases the entropy of the universe

Explain the two laws of thermodynamics in relation to biology

kinetic is energy associated with motion

potential is energy that matter posses because of its location or structure

Describe the two types of energy, potential and kinetic

spontaneous occurs

• without energy input - can happen quickly or slowly

nonspontaneous

• needs an input of energy - decrease entropy

Describe the differences between spontaneous reactions and non-spontaneous reaction

free energy is energy that can do work when temperature and pressure are uniform - its the amount of energy a cell can use

gibbs energy = H -TS

G = total energy - unusable energy

G is positive for nonspontaneous - needs energy - endergonic

G is negative for spontaneous - release energy - exergonic

more stable at low G less stable at high G

free energy

• describe

• equation

• pos vs neg / ender vs exergonic

• stable vs unstable

equilibrium is reached when forward and reverse reactions are occurring at the same rate - no work is being done

cells are constantly out of equilibrium due to the constant flow of materials in and out - they are always doing work

• multiple stages of energy, each giving some power at each stage

Explain what is meant by a metabolic dis-equilibrium that is needed to maintain life

• what is happening at equilibrium

• why are cells in dis-equilibrium

energy coupling is the use of an exergonic process to drive an endergonic one.

• most energy coupling in cells is mediated by ATP

ATP releases more energy with the loss of a phosphate than most other molecules could deliver

ATP breaks down and loses one phosphate group and becomes ADP. this releases energy. the phosphate is then transferred to another molecule, making it more reactive or easier to change.

Describe how ATP powers cellular work by coupling exergonic reactions to endergonic reactions through phosphorylation. What is phosphorylation

• hydrolysis of ATP

The transition state is the level a molecule needs to get to to start the reaction

enzymes help the reactant go through its reaction by lowering its activation energy

once enzymes bind to a substrate the active site becomes unstable and the Ea is lowered, allowing for the reaction to speed up

after that the substrate becomes a product and the product is released

Describe the importance of enzymes to living system

• transition state

• activation energy

• binding

• product

The substrate is a molecule the enzyme acts on

once binded to the substrate it forms a enzyme-substrate complex

the active site the area of the enzyme where the substrate can bind

an induced fit brings chemical groups to the active site into positions that enhance their ability to catalyze the reaction. - the enzyme will change its shape to best fit the substrate

Explain how enzymes work

• substrate

• complex

• active site

• induced fit

an inhibited can black the substrate from entering the active site

• completive inhibition - there is a lot of the inhibiter present and it competes with the substrate to bind to an enzyme

• noncompetitive alters / changes the binding site so the substrate is unable to attach. only once the non competitive inhibiter leaves can the substrate bind

allosteric regulation is similar to noncompetitive

• when an activator binds - the substrate is able to bind

• but when the inhibiter the substrate is unable to bind - it makes the cell inactive

feedback inhibition

• the product of an activated substrate becomes an inhibiter

• this process doesn’t make waste project - it repurposes product

Explain how enzymes are regulated by several different mechanism

• competitive

• noncompetitive

• allosteric

• feedback

endergonic

• energy needed

• nonspontaneous

exergonic

• energy released

• spontaneous

endergonic vs exergonic reaction

• energy

• spontaneous vs non

exergonic

• reactions due to their chemical structure have more energy than their products

• through the progress of the reaction energy is released and G is smaller no energy input - this reaction is spontaneous

endergonic

• when reactants energy is lower than the product the only way to get there is with the addition of energy

• Gibbs goes up energy is added - the reaction is non spontaneous

explain this figure

• free energy changes exergonic and endergonic reactions

1. adding ammonia to the acid converts it to glutamine

   1. gibbs is positive = no energy added = nonspontaneous

2. Or you can phosphorilize ATP = attaching a phosphate to the glutamic acid and making the reactant Phosphorylated intermediate plus with P plus ADP = ammonia can be added during the reaction making the product glutamine plus ADP plus P

3. The coupled reaction

   1. reactants are glutamic acid plus ammonia plus ATP = glutamine plus ADP plus P

   2. they net G is negative = nonspontaneous

explain how hydrolysis of ATP drives chemical work when involving glutamic acid

• 2 ways

• what’s the coupled reaction

ATP = ADP plus P

this process can be repeated through catabolism and cellular work

when ATP is used for a reaction what is it concerted to