topic 3 bioenergetics enzymes and metabolism

metabolism

all chemical reactions a cell caries out to survive grow and reproduce

catabolism

from complex to simple releases energy

anabolism

biosyntheic pathway

uses small moleuclare to make larger complex molecules needs/ consumes energy

1st law of thermodynamics

energy cannot be created or destroyed but can be converted from one form to another

what forms of energy do cells use and what conversions are made?

Cells mainly use:

• Chemical energy stored in molecules like glucose and ATP

• Light energy (in photosynthetic organisms)

• Electrochemical energy such as ion gradients across membranes

2nd law of thermodynamics

in the universe as a whole or in any isolated system the degree of disorder only increases

how do cells ensure they are lowering their own entropy while still increasing the entropy of the universe?

Cells lower their own entropy by building and organizing complex structures (like proteins, membranes, and DNA), but they do this by using energy from their surroundings.

oxidation

loss of electrons

often the gain of oxygen or a loss of hydrogen

dehydrogenation reactions

reduction

gain of electrons

often the loss of oxygen or gain of hydrogen

hydrogenation reactions

how can we tell if a reduction or oxidation of a molecule has occured

looking for changes in:

• electrons

• hydrogen

• oxygen

• oxidation number

different forms of carbon

depending on how much it is bonded to:

• hydrogen → more reduced

• oxygen → more oxidized

CH4​→glucose→alcohol→carboxylic acid→CO2​

free energy

changes in free energy reflect how much disorder is generated in the universe by a reaction

activation energy

increase of energy required to overcome an energy barrier before a molecule can undergo a chemical reaction that moves it to a lower energy state

enzyme

catalyst that accelerates a reaction without being changed by the reaction

highly specific in the reaction they catalyze

substrate

molcules an enzyme binds

change in free energy delta G

the amount of disorder created in the universe when a reaction takes place

energetically favourable reactions

increase disorder

negative delta g

spontaneous reactions

catabolism

energetically unfavourable reactions

create order or decrease disorder

positive delta g

never occur spontaneously

anobloism/ biosynthesis

equalibrium

chemical reactions proceed until they reach a state of equalibrium

delta g = 0 the forward and reverse reactions occur at the same rate

how do lving cell expend energy to avoid reaching equalibrium

• exchange materials with the environment

• replenish nutrients eliminate waste products

• products of one reactions become the substrates of the next

k > 1

more product than substrate

the reaction proceeds naturally to make product

k < 1

most substrate than product

the reaction proceeds naturally to make substrate

sequential reactions

changes in free energy are additive

unfavourable reaction is driven by the favourable reaction

which finds each other first substrate or proteins

substrate finds the protein

how are enzymes and substrates stablized?

stablized by weak bonds

hydrogen bonds

van der waals attractions

electrostatic attractions

what causes moleculares to disociate

random thermal motion

what is made energetically unfavourable phosphorylation

atp made unfavourable in what?

what are nadh and nadph

carry high energy electrons and hydrogen atoms

when is nadh used

catbolic reactions

low concentrations in cells compared to nad which is used as an oxidzing agent

when is nadph used?

anabolic reactions

one extra phosphate group gives it a slightly different shape

hgih cocentrations to be used as a reducing agent compared to nadp

what does condensation reactions depend on?

energy is provided by hydrolysis of a nucleoside triphosphate

what are the charasteristics of catabolism

• Releases energy

• Energetically favourable

• Has a negative ∆G

• Increases entropy

  • Spontaneous

what are the characterists of anabolism

• Consumes energy

• Energetically unfavourable

• Has a positive ∆G

• Decreases entropy

• Non-spontaneous

what active carriers carry phosphate?

atp carries

carries electrons and hydrogens

carried by nadh nadph fadh2

carries acetyl group

carried by acetyl coA

carries carboxyl groups

carboylated biotin

carres methyl groups

s adenosylmethionine

gulcose

uridine diphosphate glucose

What structures are commonly found in activated carriers?

nucloetides is apart of there structure

Why do cells avoid reaching equilibrium? How do they avoid reaching
equilibrium?

there is no net change and no usable free energy left to do work.

How is K calculated?

product/reactants