Biology Ch 8

the totality of an organism's chemical reactions

begins with a specific molecule, which is then altered in a servies of defined steps, resulting in a certain product. Each step of the pathway is catalyzed by a specific enzyme.

A molecule →Enzyme 1 = Reaction 1 → B Molecule → Enzyme 2 = Reaction 2 → C Molecule → Enzyme 3 = Reaction 3 → D Product

breakdown pathways

consume energy to build complicated molecules from simpler one

the study of how evnery flows throught living organisms

break down complexes and realease energy and build compounds to store energy when in excess....downhill and uphill avenues of the matabolic map

• capacity to cause change
• some forms of energy can be used to move matter against forces (gravity, friction)
• energy exists in various forms and the work of life depends on the ability of cells to transform energy form one form to another

energy of motion - can be transfered from one object to another - pool player

kinetic energy associates with the random movement of atoms or molecules

energy that matter possesses because of its location or structure

potentioal energy available for release in a chemical reaction

• study of energy transformations that occur in a collection of matter
• 1) system - matter under study
• 2) surroundings - everything outside the system
• 3) isolated systems - unable to exchange energy with its surroundings (liquid in a bottle)
• 4) open system - able to exchange energy with its surroundings

• the energy of the universe is constant
• Energy can be transferred and transformed byt it caoont be created or destroyed (also know as the principle of censervation of energy)

measure of disorder or randomness

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

any process that occurs on its own with out input of energy, will increase the entropy of the universe - water flowing downhill, a car rusting, animal giving off heat and CO2

• a process that can occur without an input of energy
• for a process to occur spontaneously it must increase the entropy of the universe

prosess that cannot occur without the input of energy

• "energy outward"
• net release of free energy because the chemical mixture loses free energy
• exergonic reactions are those that occur spontaneously

• "energy inward"
• absorbs free energy from its surroundings
• stores free energy in its molecules - nonspontaneous

• systems at equilibrium have no free energy - not capable of doing work - dead
• a living cell is not a equilibrium - constant flow of materials in and out of the cell keeps the metabolic pathwas from ever reaching equilibrium - cell continues to work throughout its life

• chemical work - pushing of endergonic reactions - nonspontanious - uphill - making polymers from monomers
• Transport work - pumping substances across cell membranes against direction of spontaneous movement
• Mechanical work - contraction of muscle cells, movement of chromosomes during cellular respiration

• the use of an exergonic process to drive an endergonic one
• ATP mediates most energy couplings and acts as the immediate source of energy that powers cellular work

• adenosine triphosphate
• contains:
• ribose (5C) sugar with the nitrogenous base adenine
• chain of three phosphate groups bonded to it
• 

• Reactants =ATP + 1 molecule of water
• Products = ADP + free phosphate + energy
• energy release comes from the chemical change to a state of lower free energy

when ATP is hydrated and a phosphate group comes off and it added to some other molecule - the recipient of the phosphate group is phosphorylated

a cells proteins harness energy released by ATP hydrolysis to perform the three types of cellular work - chemical, transport, and mechanical

• partial degradation of sugars without the use of oxygen
• (catabolic process)

oxygen is consumed as a reactant along with organic fuel

without oxygen - some prokaryotes harvest chemical energy without any oxygen

includes both aerobic and anaerobic processes but usually refers to the aerobic process