The roles of ATP in living cells and the mechanisms of production of ATP Flashcards
What is anabolism?
- simple molecules put together to form complex molecules
- complex molecules will then be stored as energy
- think A = Adding molecules together
What do anabolism terms end in?
- genesis
- e.g. glycogenesis (glucose to glycogen)
What is an example of anabolism?
- glycogenesis (glucose into glycogen)
What is catabolism?
- breakdown of complex molecules into simple molecules
- think C for catabolism = Cut up molecules
What is an example of catabolism?
- glycogen to pyruvate
What do all terms used to describe catabolism end in?
- lysis
what is catabolims and anabolims together referred to as?
- metabolism
When catabolic reactions something is released and captured and used later in anabolic reactions, what is this?
- adenosine triphosphate (ATP)
If organisms do not work to produce energy what will happen to them?
- they will die
What are a few examples of how energy is requried in the body?
- muscle contraction
- ions/molecules transport across membranes
- biosynthesis of essential metabolites, growth and replace damaged cells
- thermoregulation
Energy in the body, called free energy must come from somewhere, where is this?
- nutrients that we consume.
What is Gibbs Free Energy?
- thermodynamic calculation
- used to calculate the maximum reversible work that may be performed by a thermodynamic system at a constant temperature and pressure.
There are 3 parts to Gibbs Free Energy, what is enthalpy?
- the heat content of the reacting system
- referred to as H
There are 3 parts to Gibbs Free Energy, what is entropy?
- the randomness or disorder in a system
- referred to as S
There are 3 parts to Gibbs Free Energy, what is Gibbs Free Energy?
- energy capable of doing work at constant temperature and pressure
- referred to as G
In cells what does the change in enthalpy (/_H)_ relate to?
- types and numbers of chemical bonds broken and formed
In cells if the change in enthalpy (_/_H) is positive (+ve) is this an endothermic or exothermic reaction? A positive change in energy indicates that energy is required to produce something. Ball rolling down or up a slide for example:
- ball rolling down = reduced enthalpy (energy released from glucose through breaking the bonds of glucose)
- ball rolling back up = increased enthalpy (energy required to make bonds, such as glucose to glycogen)
- endothermic (anabolism = adding/building)
- energy has to be invested to make new bonds
In cells what does the change in entropy (_/_S) refer to?
- describes the formation of large complex molecules from smaller molecules or vice versa
- (e.g. DNA formation/protein formation)
In cells a postive (+ve) change in entropy (_/_S) refer to what?
- when randomness increases (i.e. breaking up a big molecule to smaller molecules)
- breaking fown glucose into ATP
What is the formula for determining change in gibbs free energy?
- _/_G = _/_H - T x _/_S
- _/_G = Change in Gibbs Free Energy
- _/_H = Change in enthalpy
- _/_S = Change in entropy
When we are looking at Gibbs Free Energy, if a random reaction is to occur, what must the _/_G (Change in Gibbs Free Energy be?
- negative (i.e. energy is released by the reaction)
- also referred to as an exergonic reaction
- catabolic reactions release energy
What is an exergonic reaction in thermodynamics?
- a chemical reaction where the change in the free energy is negative (there is a net release of free energy)
- reactants are turned into products
Following an exergonic reaction in thermodynamics, do products or reactants have more energy?
- reactants
- reactants become more stable than the reactants
- formation of product is “downhill” (spontaneous)
An example of an exergonic reaction is breaking down (burning) glucose into pyruvate, is this a anabolic or catabolic reaction?
- catabolic
- releasing energy
What is an endergonic reaction?
- reactants are turned into products
- glucose into glycogen is an example
In an endergonic reaction energy is invested to turn reactants into products, such as the formation of glucose into glycogen. Are the reactants or the products more stable?
- reactants are more stable
Why is coupling of reactions important in metabolism?
- endergonic reactions can be driven in the forward direction by coupling it to an exergonic reaction
- anabolic reactions can drive catabolic reactions
Coupling of reactions is important in metabolism. Endergonic reactions can be driven in the forward direction by coupling it to an exergonic reaction (catabolic reactions can drive anabolic reactions). An example of this is:
- coupled with a exergonic reaction (catabolic)
- ATP + H2O = ADP + Pi
- this provides _/_G of -30.5 kJ/mol
- -30.5 - 13.8 = -16.7 meaning reaction will occur as _/_G is negative and it will be spontaneous
What is the principle of coupling reactions?
- couple a reaction that requires energy with one that produces energy
- catabolic = produces energy
- anabolic = requires energy
In thermodynamics the hydrolysis of ATP is able to drive the an unfavourable reaction, which is essentially one where Gibbs Free Energy is not negative. What does the hydrolysis of ATP do then to help?
- releases free energy
- energy released ensures Gibbs Free Energy is negative
Adenosine triphosphate has 3 phosphate groups, hence the tri in its name. If it has one or two phosphate groups attached, what are these called?
- one = adenosone monophosphate
- two - adenosine diphosphate
Adenosine triphosphate has 3 phosphate groups. What are the names of these phosphate bonds moviong away from the adenosine?
- first = alpha
- second = beta
- third = gamma
Adenosine triphosphate has 3 phosphate groups. The generation of energy from ATP is driven by breaking the bonds between the alpha (1st), beta (2nd) and gamma (3rd) phosphates. Which bond is generally broken providing the majority of energy for the cell?
- gamme bond
What is phosphorylation?
- adding a phosphate group to a molecule
What is substrate level phosphorylation (SLP)?
- adding a phosphate group direclty to ADP
- phosphate provided by a substrate
- ADP + phosphate group = ATP
Substrate level phosphorylation (SLP) involves adding a phosphate group direclty to ADP from a substrate, which then forms ATP. What is required for this process to take place?
- soluble enzymes and chemical intermediates
What is an enzyme?
- biological catalysts that accelerate the rate of chemical reaction
- creates a new pathway for the reaction; one with a lower activation energy
In the image below, the _/_G requires an enzyme to accelerate the rate of reaction to get it over the hump. What is the energy known as that the enzyme will release that will determines if the substrate is able to spontaneously roll down the hill becoming the products?
- Ea = activation energy provided by enzymes
Do enzymes influence the Gibbs free energy (_/_G) of a reaction as depicted in the image below?
- no _/_G remains constant
- enzymes lower the activation energy
Are enzymes able to react and act alone or do they require something else?
- they require co-factors