Bio 111 Intro to Chem Reactions

requires energy

anything that takes work (transporting molecules, maintaining a constant cellular environment, moving cells and tissues, building macromolecules)

metabolism

set of chemical reactions through which cells covert organic molecules to harness energy

catabolic reactions

start with macromolecules and break them into subunits, destroys, “cats shred apart curtains”

anabolic reactions

build macromolecules from subunits, builds

subunits/monomers

monosaccharides, amino acids, fatty acids, nucleotides

macromolecules/polymers

polysaccharides, protein, triacylglycerides, nucleic acids

forward metabolic reaction

uses dehydration synthesis to join subunits, example of anabolic reaction (building)

reverse metabolic reaction

uses hydrolysis to break macromolecules apart, example of catabolic reaction

what do metabolic reactions do

store and release energy

cellular energy currency

energy is stored and released from the chemical bonds of ATP

ATP

nucleotide; stores a lot of energy in its 3 phosphate groups, which have negative charges and repel, making them easy to break and release all that stored energy

catabolism and ATP

takes the energy that is stored in the big macromolecules and adds ADP + inorganic phosphate to get ATP, so the stored energy is now in ATP

anabolism and ATP

building requires energy, so it breaks down the ATP bonds and puts the released ATP energy into the big macromolecules

energy

capacity to do work

kinetic energy

energy of motion

potential energy

stored energy, related to position

energy in chemical compounds

electrons potential energy is held in bonds a certain distance from the nucleus, the electrons move between energy levels using kinetic energy

energy and gradients

the ions being held on one side of the gradient is potential energy, the ions traveling on the gradient is kinetic energy

Laws of Thermodynamics

what energy follows; these laws apply to the whole universe, not just individual reactions

first law

energy is neither created or destroyed, it is transferred from one form to another (same amount of energy in each form)

second law

disorder (entropy) tends to increase because some energy is always lost in the transfer

entropy

disorder

what does energy being lost mean

that only a subset of the energy we started with is able to be harnessed to do work due to entropy; the amount of usable energy resulting from a reaction will always be less than the total energy available in the starting materials

what is energy often lost to

often lost in the form of heat (because random molecular movement contributes to disorder)

how does cell carry out work

chemical reactions

chemical reactions

connections between atoms are rearranged, they use or release energy

Gibbs free energy (G)

measurable free energy that is available to do work

changeG

change in free energy over the course of a reaction

Gp-Gr= (what does the products minus the reactants equal)

changeG

if the changeG equals a positive number…

there is more energy in the products than the reactants, so it is an endergonic reaction

endergonic reaction

energy input is required because we started with something low in energy, and are making a higher energy product and need to put energy into the product, it is a non-spontaneous reaction

if the changeG equals a negative number…

energy is released, so it is an exergonic reaction

exogonic reaction

energy is released because reactants have more energy than the products, it is spontaneous

anabolic dehydration synthesis

in a forward chemical reaction when the product has greater energy than the reactants (endergonic), it is anabolic

catabolic hydrolysis

in a reverse chemical reaction when the reactants have more energy than the products (exergonic), it is catabolic

what does low energy result in

high disorder/entropy (cleaning a room analogy)

what does high energy result in

low disorder/entropy (cleaning a room analogy)

high disorder

low energy, monomers (less bonds to break for energy)

low disorder

high energy, polymers (because more bonds to break for energy)

changeG in metabolism

reactions are coupled, so entropy is always increasing

coupled reactions

cells use the energy released by exergonic reactions to fuel endergonic reactions

ATP hydrolysis

ATP is broken down by catabolism, and then releases a lot of energy due its unstable bonds, which powers an anabolic reaction, the leftover energy will contribute to entropy