energy and metabolism Flashcards
What is energy?
The capacity to cause change
exists in various forms
What is Kinetic energy associated with?
It is associated with motion
What is potential energy?
It is energy that matter possesses because of its location or structure
What are the three types of systems?
- isolated system
- closed system
- open system
what is an isolated system?
unable to exchange energy or matter with its surrounding - contains all of the energy it has or needs
what is a closed system?
cannot exchange matter but can exchange energy - can gain or lose energy
what is an open system?
energy and matter can be transferred between the system and its surroundings
What is thermodynamics?
It is the study of energy transformations - specifically focused on maxim of power (ability to do work) and heat generated in the process
How many laws govern thermodynamics and which two are we specifically focusing on?
There are 4 main laws and we are focusing on two:
- First law of thermodynamics (principal of conservation of energy)
- Second law of thermodynamics
what is the First law of thermodynamics (principal of conservation of energy)
energy of the universe is constant - energy can be transferred/transformed but it cannot be created or destroyed
what is the Second law of thermodynamics
every energy transfer / transformation increases entropy (disorder) of the universe- waste energy goes to increasing entropy
diffusion- entropy- disorder and chaos
What are spontaneous processes?
they occur without energy input- they can happen quickly or slowly
for a process to occur without energy input, it must increase the entropy of the universe.
what is a metabolic pathway?
a metabolic pathway begins with a specific molecule and ends with a product
Associated each step is a specific enzyme (protein—catalyst) it can change energy inputs
What are two unique metabolic pathways?
- Catabolic pathways
2. Anabolic pathways
what is a Catabolic pathways?
release energy by breaking down complex molecules into simpler compounds (creates entropy)
cellular resperation- break down of glucose in the presence of oxygen is a pathway of catabolism
what is a Anabolic pathways
consume energy to build complex molecules from simpler ones (increasing order)
synthesis of protein from amino acids is an example of anabolism
What is free energy?
energy that can do work when temperature and pressure are uniform
what is the outcome for a negative Delta-G
It is spontaneous (what else does this mean?) entropy increases
what is the outcome for a positive Delta-G
is not spontaneous so entropy decreases
What is free energy a measure of?
a measure of a systems instability, its tendency to change to a more stable state
What happens during spontaneous change (2 things)?
Free energy decreases and the stability of a system increases
What is equilibrium?
it is a state of maximum stability- it is done and there is no more free energy
What is a defining feature of life?
is that metabolism is never at equilibrium- that would be death because blood cells could no longer function
Two types of reactions in metabolism, what are they?
- Exergonic reaction
2. Endergonic reaction
what is a Exergonic reaction
proceeds with a net realize of free energy and is spontaneous
what is a Endergonic reaction
absorbs free energy from its surroundings and is nonspontaneous
What is an activation energy barrier?
It is the initial energy needed to start a chemical reaction which is called free energy/ activation, or activation energy (Ea)
How is Activation energy usually supplied?
Often supplied in the form of thermal energy that the reactant molecules absorb from their surroundings
What role do enzymes play in the Ea
enzymes catalyze reactions by lowering the activation energy barrier
Enzymes do not affect the change in the free energy instead they hasten reactions that would eventually occur
What is a catalyst?
is a chemical agent that speeds up a reaction without being consumed by the reaction
What is the substrate?
The reactant that an enzyme acts on is called the enzyme’s substrate
How is an enzyme - substrate complex formed?
The enzyme binds to its substrate forming an substrate complex
the region catalyzed by each enzyme is a very specific - structure begins function (lock and key)
What is the active sight?
is the region on the enzyme where the substrate binds
What is the induced fit?
of a substrate brings chemical groups of the active sight into positions that enhance their ability to catalyze the reaction
snaps it and locks it in place- induced fit
challenges structure - once connected the name changes
How does an enzyme reduce the Ea barrier? in an enzymatic reaction, the substance binds to the active site of the enzyme and the active site can lower and Ea barrier by: (4 ways)
- orienting substances correctly
- straining substate bonds
- providing a favorable microenvironment - changing pH
- covalently bonding to the substance
