Energy and enzymes Flashcards
Define: Metabolism
The sum of the processes in the buildup and destruction of protoplasm.
Specifically: the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated
It consists of anabolism (constructive metabolism) and catabolism (deconstructive metabolism)
Explain why adenosine triphosphate (ATP) is sometimes called the “currency of the cell”.
ATP is a molecule which is produced for the purposes of briefly storying energy. Just as we use money to pay for things, the cell uses ATP as a standardized way to transfer energy
Define: cellular respiration
The process by which cells get their energy from ATP
A set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
Define: cellular respiration
The process by which sugar (glucose) is broken down, energy is released and captured in the form of ATP and stored (briefly) in the cell to be used as energy.
A set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
The overall chemical reaction is:
What are the 4 steps of cellular respiration?
- Glycosis
- Link reaction
- Krebs cycle
- Electron transport chain
Explain the steps required in photosynthesis for plants to convert sunlight into energy
Plants use the energy of sunlight to convert carbon dioxide gas into sugar molecules. If the energy is not immediately required, the plant can store these sugars in the form of starch.
Photosynthesis takes place in many small steps, but its overall reaction is just the cellular respiration reaction flipped backward
Metabolic pathways can be broadly divided into two categories based on their effects. Name the categories and explain their relationship and key differences.
Anabolic pathway: Involves constructing larger molecules our of smaller ones. Energy is required.
Catabolic pathway: Involves breaking down molecules into smaller ones. Energy is released.
Anabolic pathways create complex molecules using the energy from catabolic pathways.
Which type of protein is required to catalyze metabolic reactions?
Enzymes
What is the first law of thermodynamics?
Adapted from the law of conservation of matter, the first law of thermodynamics states that energy can neither be created or destroyed, only transferred from one type of energy to another.
ΔU=Q-W
It states that the change in the internal energy ΔU of a closed system is equal to the amount of heat Q supplied to the system, minus the amount of work W done by the system on its surroundings.
What is the second law of thermodynamics?
The second law refers to the directionality of entropy.
It is the general principle which places constraints upon the direction of heat transfer and the attainable efficiencies of heat. Heat (kinetic energy) can only transfer The entropy (disorder) of the universe (closed system, not interacting with its surroundings) only increases and does not decrease.
What are the 2 main types or categories of energy?
Kinetic energy = movement energy
Includes radiant, thermal, sound, electrical (light), and mechanical (motion) energy
Potential energy = stored energy
Includes: Gravitational, elastic, chemical (nuclear) and magnetic
We use heat to do work, but heat can also cause entropy.
Why does adding heat to a system increase entropy?
Heat is a transfer of energy, it increases the kinetic energy of a system. Only some of that energy can be used to do work, and some of it will be released into the system as kinetic energy which increases the overall entropy of the universe.
Entropy is not purely defined by the possible spaces that particle can take up, but everything you can use to predict what’s going to happen next to the system including velocity. heat = larger number of potential velocities.
What impact does the second law of thermodynamics say kinetic energy will have on closed systems?
Increase in kinetic energy on a closed system increases the randomness of where particles can end up, thus increasing entropy.
Since every energy conversion results in some form of unusable energy (like heat), the entropy of the universe (the closed system that contains us) is always increasing.
What are the 3 types of systems in thermodynamics?
- Open: can exchange both energy and matter with its surroundings (a saucepan boiling water with no lid)
- Closed: can only exchange energy with its surrounding, not matter) (Put a very tight lid on the saucepan)
- Isolated: can not exchange matter or energy with it’s surroundings (perfect ones rarely exist, but an insulated drink cooler is conceptually similar - items inside can exchange energy to cool down the drink, ice melts, but very little energy exchange with the outside environment)
What type of thermodynamic system are humans?
Open system.
Humans take in chemical energy from food, do work and release heat and waste products back into the environment
A plant converts sunlight into energy stored in organic molecules, then uses these molecules to do work. What types of energy are being transferred?
The plant converts the radiant energy from the sunlight into chemical energy (sugar) to be converted into kinetic energy to grow, reproduce etc.
Negentropy occurs all the time. Processes that build and maintain highly organised bodies of living things are happening all the time and decreasing entropy. Why doesn’t this lead to a decrease in entropy in the universe?
In every transfer of energy that is happening during the work of local negentropic processes, only some of that energy is used for the work it’s self , while lots of it is lost as heat energy.
This increases the kinetic energy of the universe and contributes to overall entropy.
What doe Gibbs free energy formula assume must occur in order to predict whether a reaction will be spontaneous or not?
It assumes that pressure and temperature will stay constant.
What does ΔG (delta G) represent in the Gibbs free energy equation?
ΔG = represents Gibbs free energy and refers to the change in free energy of a system as it goes from some initial state, such as all reactants, to some other, final state, such as all products.
This value tells us the maximum usable energy released (or absorbed) in going from the initial to the final state.
In addition, its sign (- = spontaneous, += not spontaneous) tells us whether a reaction will occur spontaneously, that is, without added energy.
What is the formula for Gibbs free energy?
ΔG = ΔH - TΔS
Gibbs free energy = Change in enthalpy (heat energy) - Temperature X Entropy (disorder in a system)
What does the formula for Gibbs free energy tell us?
The equation ΔG = ΔH - TΔS tells us how much energy will be in a system after a reaction takes place.
If the reaction was spontaneous, there will have been more entropy (energy released as heat into the universe) and there for less energy in the system.
If the reaction was not spontaneous and required energy to be added to take place, there will be more energy in the system at the end of the rection.
What does ΔH (delta H) represent in the Gibbs free energy equation?
∆H is the enthalpy change.
Enthalpy in biology refers to energy stored in bonds, and the change in enthalpy is the difference in bond energies between the products and the reactants. A negative ∆H means heat is released in going from reactants to products, while a positive ∆H means heat is absorbed. (This interpretation of ∆H assumes constant pressure, which is a reasonable assumption inside a living cell).
What does ΔS (delta S) represent in the Gibbs free energy equation?
∆S is the entropy change of the system during the reaction. If ∆S is positive, the system becomes more disordered during the reaction (for instance, when one large molecule splits into several smaller ones). If ∆S is negative, it means the system becomes more ordered.
What does T (temperature) represent in the Gibbs free energy equation?
Temperature (T) determines the relative impacts of the ∆S and ∆H terms on the overall free energy change of the reaction. (The higher the temperature, the greater the impact of the ∆S term relative to the ∆H term.) Note that temperature needs to be in Kelvin (K) here for the equation to work properly.
