Topic 7: Thermodynamics Flashcards
Explain the concept of energy and 2 types of energy
Energy is the capacity to do work
- Potential energy: energy stored in chemical bonds/interactions
- Kinatic energy: energy used in movement or released as heat/radiation
What is bioenergetics?
Bioenergetics is the transfer of potential to kinetic energy and vice versa in living systems
Explain the concept of entropy
Entropy is the degree of disorder
Explain the concept of thermodynamics, kinetics and the difference between them
- Thermodynamics: involves the intrinsic energy level of substrate and products
+ Whether the reaction is favourable or unfavourable
+ Whether the reaction will take place - Kineitcs: involves the rate at which the reaction takes place
+ How quickly the reaction is going to be
Explain the state of equilibrium
Equilibrium is the state at which the concentration of substrates and products don’t change any more. Still, reactions still happen forward and reverse but at same rate and the overall energy is balanced.
What are thermodynamically favorable and unfavorable reactions?
- Favorable reactions: release energy - exergonic
- Unfavorable reactions: require energy - endergonic
When a reaction has reached near equilibrium, how do increasing and decreasing concentration of substrates or products affect the reaction rate?
- Increasing concentration: push the equilibria towards the other side, or such reaction happens at higher rate
- Decreasing concentration: pull the equilibria towards the low concentration side
Do living cells ever reach equilibrium and why?
Living cells never reach equilibrium because new substrates are continuously added while products are constantly used up.
What is activation energy or barrier?
The energy level which reactions have to reach to start producing products.
What is the role of enzyme as biological catalysts and how do they complete their role (mechanisms)?
- Enzymes, as catalysts, help to speed up reaction rate by lowering down the activation barrier.
- It does so by stabilizing transition states (eg. transforming substrates so they resemble transition state earlier in the reaction)
Identify and describe different models for enzyme binding
Characteristics of enzyme binding
- Lock and key model: substrate molecule fits directly to the enzyme
- Induced-fit model: the substrate induces changes of shape in enzyme for ideal binding and activity
- Selection model:
+ 1 type of enzyme can exist in different forms in which only 1 is suitable for specific substrate
+ when binding, the production of suitable enzyme from unsuitable one is favored. - Enzymes are HIGHLY SPECIFIC for their substrates
What are enzymes (nucleic acids, carbohydrates, proteins, etc??) and what is special about the function, size, and ability to be regulated of different enzyme?
- Most enzymes are proteins and there are some enzymes that are proteins and RNA based
- Enzymes vary greatly in function, size and ability to be regulated
How can enzyme be regulated (environment conditions, what can be added for optimal activity, what can activate and inhibit activity)?
- Each enzyme evolves to work best at certain range of temperature and pH
- Many enzymes need additional chemical component (cofactor) - like a metal - to work best
- Can be inhibited or activated by other molecules
+ Inhibition: active site is binded by inhibitors, other sites are binded by inhibitors –> inactive
+ Activation: some compounds bind and help enzymes work better
How are enzymes designed for cellular pathways?
How can mutation affect this?
Enzymes assist in many pathways of different cellular processes.
Mutation affecting enzymes that result in lack of certain compounds and building up of others –> diseases
How are enzymes located in living cells?
- Enzymes are specifically located by compartmentalism
+ inside or outside of cell
+ inside certain cellular compartments
–> specific location of enzymes help to detect certain risks of diseases when detecting enzymes being in the wrong location
