AP BIOLOGY Chapter 8 Metabolism

consume energy to build molecules FIRST The _____ Law of Thermodynamics states that energy can be transformed and transferred by NEVER created or destroyed Anabolic pathways consume energy to build molecules release energy by breaking down molecules The measure of disorder or randomness (symbolized by S) → entropy

SECOND The _______ Law of Thermodynamics states that every energy transfer or transformation increases the entropy of the universe. Chemical reactions with a NEGATIVE free energy (- Δ G) are ____________ endergonic exergonic exergonic

Most enzymes belong to which group of macromolecules? Chemical reactions with a POSITIVE free energy (+ Δ G) are ____________ endergonic exergonic Most enzymes belong to which group of macromolecules? Molecules that speed up chemical reactions are called ____________ endergonic proteins catalysts

→ Energy associated with moving objects is called _______ energy Catabolic pathways consume energy to build molecules release energy by breaking down molecules Chemical energy is a form of ___________ energy kinetic potential kinetic → potential

Reactions that release free energy are called ______________ exergonic endergonic The hydrolysis of ATP is a ________ ΔG reaction. Catalytic proteins that speed up chemical reactions in living things are called ____________ exergonic negative enzymes

Reactions that absorb free energy are called ______________ exergonic endergonic Chemical reactions with a NEGATIVE free energy (- Δ G) are ____________ spontaneous nonspontaneous Region on an enzyme where regulatory molecules can bind = ______________ endergonic spontaneous Allosteric site

spontaneous nonspontaneous Chemical reactions with a POSITIVE free energy (+ Δ G) are ____________ spontaneous nonspontaneous The initial investment of energy for starting a chemical reaction is called the _______________ The place on an enzyme where the substrate attaches = _____________ nonspontaneous Activation energy OR Energy of activation active site

spontaneous nonspontaneous Chemical reactions with a NEGATIVE free energy (- Δ G) are ____________ spontaneous nonspontaneous Which kinds of bonds hold the substrate to the active site of an enzyme? Nonprotein “helpers” for catalytic activty are called ______________ spontaneous Weak interactions like hydrogen & ionic bonds cofactors

If a cofactor is an organic molecule it is called a ____________ Which kind of food molecules often act as coenzymes? A molecule that mimics a substrate, binds to the active site, and reduces the activity of an enzyme is called a(n) _______________ inhibitor. coenzyme vitamins COMPETITIVE

is called _____________ NONCOMPETITIVE ______________ inhibitors slow down enzymatic reactions by binding to a site other than the active site and causing a change in the enzyme’s shape In ___________ inhibition, a metabolic pathway is switched off by the binding of its end product. The change in the shape of the active site of an enzyme after the substrate attaches so that it binds more snugly is called _____________ FEEDBACK INDUCED FIT

When the binding of one substrate molecule primes an enzyme to accept additional substrate molecules more readily it is called ______________ COOPERATIVITY

The arrow in the diagram is showing the _________________ of this reaction. ACTIVATION ENERGY

The arrow in the diagram is showing the ______________________ of this reaction. CHANGE IN FREE ENERGY (ΔG)

+ This reaction has a ___ Δ G because the energy of the products is greater then the reactants

- This reaction has a ___ Δ G because the energy of the products is less then the reactants

How would adding an enzyme change the graph of this reaction? Enzymes lower the activation energy of chemical reactions but don’t change the energy of the products

Cells manage their energy resources by using the energy from exergonic (-ΔG) reactions to drive endergonic (+ΔG) reactions in a process called ____________________ ADP + Pi → ATP This is a __ ΔG reaction. Energy coupling +

Is respiration spontaneous or not? Cellular respiration uses glucose, which has a high level of free energy and releases CO2 and H2O which have low levels of free energy. Is respiration spontaneous or not? Is it exergonic or endergonic? spontaneous exergonic

How does the 2nd LAW of thermodynamics help explain the diffusion of a substance across a membrane? The 2nd Law is the tendency toward randomness. Having equal concentrations on both sides of a membrane is more random than unequal concentrations. Diffusion from high concentration to low INCREASES THE ENTROPY as mandated by the 2nd law

If living things take simpler substances and build them into complicated systems (increase entropy), why does this NOT VIOLATE the 2nd LAW of thermodynamics ? Living things are OPEN systems and must constantly take in energy and materials from outside to maintain the increase in entropy