Presentation on theme: " 2.a.1 – All living systems require constant input of free energy (8.1-8.3). 4.b.1 – Interactions between molecules affect their structure and function."— Presentation transcript:
2.a.1 – All living systems require constant input of free energy (8.1-8.3). 4.b.1 – Interactions between molecules affect their structure and function (8.4 & 8.5).
The totality of an organism’s chemical processes Concerned with managing the material and energy resources of the cell
Pathways that break down complex molecules into smaller ones, releasing energy Example: Cellular respiration DOWNHILL!
Pathways that consume energy, building complex molecules from smaller ones Example: Photosynthesis, condensation synthesis UPHILL!
Energy cannot be created or destroyed It can be converted from one form to another The sum of the energy before the conversion is equal to the sum of the energy after the conversion
Some usable energy dissipates during transformations and is lost During changes from one form of energy to another, some usable energy dissipates, usually as heat The amount of usable energy therefore decreases
Ability to do work The ability to rearrange a collection of matter Forms of energy: › Kinetic › Potential › Activation
Kinetic: › Energy of action or motion › Ex: heat/thermal energy Potential: › Stored energy or the capacity to do work › Ex: chemical energy
Energy needed to convert potential energy into kinetic energy Potential Energy Activation Energy
The portion of a system's energy that can perform work Known as ΔG
ΔG = Δ H - T Δ S Δ = change (final-initial) ΔG = free energy of a system ΔH = total energy of a system (enthalpy) T = temperature in o K ΔS = entropy of a system
If the system has: › more free energy=less stable (greater work capacity) › less free energy=more stable (less work capacity) › As rxn moves towards equilibrium, ΔG will decrease
These are the source of energy for living systems They are based on free energy changes Two types Two types: exergonic and endergonic
Exergonic: › chemical reactions with a net release of free energy › Ex: cellular respiration › - ΔG, energy out, spontaneous Endergonic: › chemical reactions that absorb free energy from the surroundings › Ex: Photosynthesis › + ΔG, energy in, non-spontaneous
Three phosphate groups and the energy they contain Negative charges repel each other and makes the phosphates unstable › Tail is unstable = more free energy = more instability Works by energizing other molecules by transferring phosphate groups Hydrolysis of ATP = free energy is released as heat (can be adv or not adv)
Energy released from ATP drives anabolic reactions Energy from catabolic reactions “recharges” ATP Very fast cycle › 10 million made per second Coupled RXN
Takes place in cytoplasm and mitochondria Using special process called substrate-level phosphorylation › Energy from a high- energy substrate is used to transfer a phosphate group to ADP to form ATP
Biological catalysts made of protein Speeds up rxn without being consumed Cause the speed/rate of a chemical rxn to increase › By lowering activation energy
AB + CD AC + BD *AB and CD are “reactants” *AC and BD are “products” *Involves bond forming/breaking *Transition state: can be unstable
Lower the activation energy for a chemical reaction to take place Why do we need enzymes? › Cells can’t rely on heat to kick start rxns › Why? Denaturation, heat can’t decipher between rxns › Enzymes are selective! Can only operate on a given chemical rxn Intro to Enzymes movie
Competitive › mimic the substrate and bind to the active site (compete for active site) › Toxins/poisons – Ex: DDT › Can be used in medicine – painkillers, antibiotics Noncompetitive Noncompetitive Noncompetitive Noncompetitive › bind to some other part of the enzyme › Causes active site to change shape Inhibitor video Inhibitor video
Identify forms of energy and energy transformations. Recognize the Laws of Thermodynamics. Recognize that organisms live at the expense of free energy. Relate free-energy to metabolism. Identify exergonic and endergonic reactions. Identify the structure and hydrolysis of ATP. Recognize how ATP works and is coupled to metabolism. Recognize the ATP cycle Relate enzymes and activation energy. Recognize factors that affect enzymes specificity and enzyme activity.. Recognize factors that control metabolism.