Exam 1 Flashcards
What is the definition of metabolism?
Sum of all chemical reactions occurring in a living organism
What does it mean if there is no energy change in a chemical reaction?
Nothing happens
What are chemical reactions in living organisms catalyzed by?
Enzymes
What are enzymes attempting to drive the reaction towards?
Equilibrium
As enzyme catalyzed reactions proceed towards equilibrium what happens?
They release energy
What happens when a reaction is farther from equilibrium?
It releases more energy/the more energy it can release
What can the energy released in a chemical reaction be used for?
to do work, the remainder is unavailable
In our muscles what is the energy that is not captured to do work released as?
Heat
What is bioenergetics?
The study of the transformation of energy in living organisms
What 4 things can energy be used for?
Anabolic part of metabolism, contraction, transport process, control mechanism
What is the first law of thermodynamics?
In any physical or chemical change the total amount of energy in the universe remains constant, although the form of energy may change
What is the second law of thermodynamics?
In all natural processes the entropy of the universe increases
What does thermodynamics focus on?
The difference between initial and final states (changes delta)
What is entropy?
randomness or disorder
What is enthalpy (delta H)?
the change in energy of the reactions when turned into products
How is enthalpy change measured?
As the total heat energy change (delta H)
What is an exothermic reaction? What is it the negative value of?
When heat energy is given off in a reaction. delta H
What limits can an endothermic reaction take place in? What is it the positive value of?
Can only occur with the input of energy or take up heat from surroundings. Positive value for delta H
What is entropy change (delta S) a quantitative expression of?
The randomness or disorder in a system. Any change in the randomness of the system is the entropy change (delta S)
What is entropy change a measure of? What does this tell us?
a measure of energy dispersal. Tells us that energy wants to move from where it is concentrated to where it is dispersed or spread out
When does Delta S have a positive value?
Delta S has a positive value when the randomness increases
What is free energy change (delta G)?
The maximum energy available from a reaction or process that can be harnessed to do something useful
Of the total energy released in a reaction or process not all of it is available to _____
Do something useful
What are 3 useful things that can be done with bioenergentics?
Muscle contracting and lifting a load, moving ions across a membrane against their concentration gradient, synthesizing proteins from amino acids
When free energy is released delta G is _____ and is called _____
Negative, exergonic
Between an exergonic and endergonic reaction which is favored, which is spontaneous (can occur by itself), and is delta G positive or negative?
Exergonic: delta G -, spontaneous, favored
Endergonic: delta G +, not spontaneous, not favored
What do delta G, delta H, T, and delta S stand for?
delta G = free energy change, delta H = enthalpy change, T = absolute temp (Kelvin C+273=K), Delta S = entropy changes
What does delta G < 0 mean? _____ of the _____ is lower than the _____ of the _____
Free energy of the products is lower than the free energy of the reactants, exergonic
What is the formula for free energy changes?
Delta G = Delta H - T Delta S
When delta G > 0 is this reaction favored?
It is favored in the opposite direction even though it is endergonic
What does it mean when delta G = 0?
There is no free energy change
Is equilibrium static?
No, it is dynamic
What can’t we measure in regards to quantifying free energy? What can we measure?
We cannot measure exact values associated with an initial and final state of a reaction in terms of enthalpy, entropy, and free energy. We can measure energy changes over the course of a reaction as changes in enthalpy, entropy, and free energy.
- The farther the reaction is from equilibrium, the _____ the value of delta G (as a _______ value)
- Larger and negative
- From an energy perspective, when the reaction begins which values will be large and which will be small?
- A and B will be large, C and D will be small
- The natural logarithm and delta G will be ____ and _____ at the start of the reaction
- Large and negative
- What happens to the values of A and B and C and D as the reaction proceeds toward equilibrium? What will happen to delta G
- A and B will decrease and C and D will increase. Delta G will decrease but remain negative
What is the delta G naught value determined by?
- It is determined by the value for the equilibrium constant
- What does the delta G naught reflect?
- Reflects the energy generating potential for the reaction
- Why doesn’t the delta G naught value for a reaction define the actual energy change for the reaction inside a cell?
- Because it depends on the relative concentrations of reactants and products
- What do cells exploit energy from to synthesize ATP?
- Sunlight or food
- What is the base of adenine?
- Nitrogen
- What is ribose made up of?
- 5 carbon carbohydrate
- Hydrolysis of what linkages releases high amounts of energy?
- Phosphoanhydride
- When can ATP be hydrolyzed?
- At either linkage but not both at the same time
- Hydrolysis between the __ and ___ group is more common
- Beta and gamma
- What does hydrolysis of linkage between beta and gamma phosphoryl groups yield?
- ADP + Pi
- What does hydrolysis of linkage between beta and alpha phosphoryl groups yield?
- AMP + inorganic pyrophosphate
- What is catabolism?
- Degradation of large molecules into smaller molecules
- What are the 2 functions of catabolism?
- Produce raw materials for the synthesis of macromolecules (anabolism), and release energy, part of which is used to synthesize ATP
- What type of process is anabolism? What is the definition?
- Biosynthetic process, form molecules from smaller molecules
- What are 3 examples of anabolism?*****
- Cell growth and division, replace damaged molecules, create energy deposits
- Is a substance oxidized or reduced when it loses or accepts one or more electrons?
- Oxidation is losing, reduction is gaining
- Catabolic process usually involve oxidations of ________ this is known as _______
- Metabolites, dehydrogenations
- Anabolic processes usually include reductions of _________ by the addition of __ this is known as _______
- Metabolites, H, hydrogenations
- How are electron gain and loss connected in redox reactions?
- Directly connected
- When does most of the energy needed by our bodies to grow and survive arise? What does it do first, then eventually?
- When electrons on fuel molecules are transferred. First to coenzymes in dehydrogenation reaction then eventually to oxygen we breathe
- What are the 3 coenzymes?
- NAD, NADP, FAD
- What 3 main features do enzymes share?*****
- They increase reaction velocities, they have high specificity, their catalytic power is regulated
- What is the difference between a reversible and irreversible reaction? Which has a large energy change? Which is an equilibrium reaction? Which is more common?
- Irreversible only goes one way, irreversible, reversible, reversible
- What is the average rate?
- Change in the concentration of a reactant (substrate) or product divided by the time within this change is accomplished
- What does an enzyme increase in a reaction?
- Rate
- The increase in V attributable to an enzyme indicates _____
- Its catalytic power
- Free energy of activation is always _____
- Always positive
- When the value of delta G++ is higher what happens to the activation of the substrates, and what happens to the speed of the reaction?
- The harder the activation and the slower the reaction
- When enzymes bind substrate at an active site what does this expedite?
- Expedites the formation of the transition state which lowers delta G++
- Enzymes increase reaction rate without doing what?
- Without altering outcome of reactions
- What 5 factors affect rate of enzyme reactions?
- Substrate concentration, enzyme concentration, temperature, pH, ionic strength
- _____ is higher as _____ is increased
- Initial velocity, substrate
- What type of increase is a low S?
- Linear increase
- What happens with a higher S?*****
- V flattens out approaching a maximum velocity (Vmax)
- When V max is reached what does increasing S not produce?
- Will not produce an increase in the rate of reaction
- What is each enzyme molecule working as fast as it can to do?
- Converting S to P
- What is Michaelis constant?
- If you determine Vmax, divide it in half, then determine what S will produce one half Vmax, we get a concentration known as Michaelis constant (Km)
- How is Km defined?
- The substrate concentration needed to produce one half the maximal velocity of an enzyme catalyzed reaction
- What does the line weaver burk plot allow for?
- Allows for accurate determination of the kinetic parameters of an enzyme catalyzed reaction
- Pertaining to the line weaver burk plot, what are values determined from?
- Values are determined from intercepts on the horizontal and vertical exes
- When enzyme reaction follows Michaelis-Menton kinetics _____ over the range of substrate concentrations the L-B plot is _____
- Hyperbolic, linear