Unit 5: Intro to Metabolism Flashcards
Sum of all chemical reactions in a organism called:
Metabolism
Metabolic pathway
Begins with a starting molecule that eventually leads to an ending product
What are the 2 metabolic processes, and how do they function? What is difference and similarities between exergonic and endergonic, and some examples?
Catabolic: release energy when complex molecules are broken down and goes from high PE energy compound to low PE product (breakdown, digestion, hydrolysis)
Ex: cellular respiration G = -686 Kcal/mol
Exergonic reaction - spontaneous reaction that proceed with the release of free energy (-G)
*exergonic more FAVORED/downhill - ATP to adp, protein to AA, Glucose to 6CO2
Anabolic: requires energy to put together complex molecules and combines stable, low PE reactants to high PE products (building, synthesis)
Ex: AA to protein, ADP to ATP, photosynthesis = 686 Kcal/mol
Endergonic reaction -non spontaneous reaction that can only proceed with additional energy (+G)
Endergonic Is less favored/UpHill - Adp to ATP, 6CO2
Both exergonic and endergonic require activation energy
What is energy and why do molecules possess energy? What are the two main types of energy/their definition?
Energy: capacity to cause change
Molecules posses energy because of the arrangement electron in the bonds between their atoms
Kinetic: associated with movement
Ex: Heat/thermal = type of kinetic energy, running, throwing
Potential: energy stemming form positioning/location or structure
Ex: standing on diving board = higher potential, standing on ground = lower potential energy, chemical energy = PE available for release in chemical reaction
What is study of energy transformations?
Thermodynamics
What happens in a open system? What happens to a organism in a open system?
Open system: energy and matter can be transferred between the system and its environment
Ex: organism absorb energy (eat food) and release heat
What are the 2 laws of thermodynamics?
1st law - NRG can be transferred and transformed, but can’t be create or destroyed
2nd law - Every energy transfer or transformation increases entropy (state of energy) of the universe
What is entropy?
Entropy: quantity to measure disorder or randomness
*loss usable energy during NRG transfer = universe more disordered = increased entropy
*unusable heat increases entropy
*energy must be constantly added to offset entropy
What is a spontaneous and non spontaneous reaction?
Spontaneous: reaction not requiring NRG, energetically favorable, increases entropy (still requires some activation NRG)
Non spontaneous: energy required, decreases entropy
What is free energy?
Proportion of a systems NRG that can perform work when temps and pressure are uniform (a measure of energy that is available to do work)
What happens when bonds are broken? How is energy released in chemical reaction
Breaking bonds requires NRG, does not release NRG
Bonds broken and new bonds formed and products have less NRG than the reactants had (-G/ free energy) *exergonic reaction
What happens when a cell reaches metabolic equilibrium?
The cell dies
How is disequilibrium maintained?
Products of one reaction do not build up but are instead used in other reactions or expelled as waste out of the cell
Three main types of work in a cell
Chemical: the pushing of endergonic reaction
Transport: the pumping of substances across membrane
Mechanical: contracting muscles, movement
What is energy coupling? How does ATP use energy coupling? What is the key to this energy coupling
Using an exergonic reaction to power a endergonic reaction.
Ex: aid of enzymes = the energy released from ATP hydrolysis is used to drive a endergonic reaction
Key: free energy of endergonic has to be LESS than the NRG released from ATP hydrolysis for the reactions to be couple and eventually make the overall reaction exergonic, formation of phosphorylated intermediate (more reactive)
What are the components of ATP/Adp and elaborate on the phosphate portion
Look at notes for picture. 3 Phosphate groups, ribose (sugar), adenine (NH2, N)
3 phosphate groups have negative charge = instability, high free energy = can be seen as a “compressed spring”
How are bonds of ATP broken down in cellular respiration?
Broken down by hydrolysis (exergonic reaction: G = -7.3) in cellular respiration
Questions about ATP - ADP cycle: how fast does ATP regenerate, where does the NRG to regenerate ATP come from, What is different about ADP, what kind of reaction is the regeneration and breakdown of ATP.
- 10 million molecules of ATP consumed/regenerated in a sec
- NRG comes from exergonic reaction in cellular respiration
- ADP is more stable and less Nrg
- Regeneration = endergonic and uses energy from exergonic reaction , breakdown = exergonic but energy released used in cellular work = endergonic
What is an enzyme, what does it do/not do, and how are they inhibited? What are coenzymes and cofactors?
- A protein that acts as a catalyst (speeds up) to a reaction (reusable)
- Lowers activation energy
- operate at an optimal temp/ph
- highly specific (substrates)
- Does not alter G (free energy)
- inhibited competitively (attaches to site) or allosterically (attaches to another place on enzyme to change its shape)
Coenzyme: organic molecule (vitamins) that aid enzymes in lowering AE
Cofactors: Inorganic helpers (minerals) helping catalytic activity
What is activation energy, what is the supply for activation NRG, and why is it important?
-Initial energy to get into transition state (point of breaking/or building in reaction)
Ex: spark plug for car
- AE often supplied form heat absorbed through surrounding area
- No AE = mostly spontaneous reactions = can not control = loss of internal balance
Can you add heat to speed up reaction (lessen AE)?
-high temps denature proteins and kills cells
-Speed up ALL reactions (even the ones not needed)
What is induced fit?
Amino acid causes enzyme to change shape = fit the substrate more snugly
What are the 4 enzyme mechanisms that lower AE?
- Active site = Template for substrates to join together
- Stress and bends chemical bonds that must be broken
- Active site = environment that is conductive for the reaction to begin
- Directly participates in the active site
4 Factors that affect rate of reaction
Substrate concentration: more substrate = increase rate until enzymes are saturated (full)
Enzyme concentration: more enzyme = increase rate
Temp: Enzyme rate increase until the point of denature (in humans = 37 C) = more cluttered graph
PH: most enzymes work best at ph 7 but it varies from enzymes = more spread out graph
