Metabolic Processes - Chapter 3 - Pop Quiz 1 Flashcards
What is metabolism
the sum of all chemical reactions in the body: anabolic, catabolic, redox
What do all living things require to survive
energy
What is energy
the capacity to do work
what are the two types of energy studied in biology
Kinetic and potential
What is kinetic energy
the energy of motion
what is potential energy
stored energy via the object’s position or arrangement like CHEMICAL BOND ENERGY in ATP bonds
What is the first law of thermodynamics
energy cannot be created or destroyed but can be transformed from one form to another (photosynthesis, light energy from sun into chemical bond energy in sugars)
What is the second law of thermodynamics
Energy cannot be transformed from one form to another without a loss of useful energy. the energy is lost as thermal energy therefore it is no longer available to do work
What is ΔG
Gibbs free energy, the energy available to do work
What is entropy
the release of unusable energy, in the form of random particle motion during any energy transformation
What is a reaction with a net release of free energy
exergonic
what is a reaction that absorbs energy from the sorrounding
endergonic
what is the Gibbs free energy for a exergonic reaction
negative
what is the gibbs free energy for a endergonic reaction
positive
If a reaction is exergonic, what else can be said about it
the reaction is spontaneous
what is bond energy
Bond energy is a measure of the strength or stability of a covalent bond
what is activation energy
the minimum amount of energy that chemical reactants
must absorb to start a reaction
what is a transition state
a temporary condition during a chemical reaction in which the bonds in the reactants are breaking and
the bonds in the products are forming
What can be said about an endergonic reaction
it is non-spontaneous
In an exergonic reaction, compare the chemical potential energy in the reactants vs products
products have less chemical potential energy than reactants
In an endergonic reaction, compare the chemical potential energy in the reactants vs products
products have more chemical potential energy than reactants
In chemical reactions, when does entropy increase
when solids react to form liquids or gasses
liquids react to form gaseous products
the total number of product molecules is greater than reactant molecules
What is a spontaneous change
a change that will, once begun, continue on its own under a given set of conditions (like the burning of a match). DOES NOT require continuous supply of energy
What is free energy
a.k.a gibbs free energy, this is the energy that is not lost during an energy transformation that is available for useful work.
How can gibbs free energy or free energy be calculated
Free energy of products (-) Free energy of reactants
What does a negative free energy value mean
Free energy of products is less than free energy of reactants, downward trending graph
what does a positive free energy value mean
Free energy of products is more that free energy of reactants, upward trending graph
What are coupled reactions (a.k.a energy coupling)
when endergonic reactions are facilitated by free energy from an exergonic reaction
What does a coupled reaction mean in terms of its characteristics
the coupled reactions have a negative free energy value and when coupled, both reactions can occur spontaneously
What is a catabolic pathway
a pathway in which energy is released and complex molecules are broken down into simple molecules (hydrolysis, exergonic reaction, G value negative, spontaneous, cellular respiration)
What is an anabolic pathway
a pathway in which energy is supplied to build complex molecules from simple molecules (dehydration synthesis, endergonic reactions, positive G value, non spontaneous, photosynthesis)
What is ATP
primary source of free energy in living cells
What makes up ATP
Adenine base, five carbon sugar ribose, three phosphate groups
What is ATPase
catalyzes the hydrolysis of the terminal phosphate of the ATP
howmuch energy is produced in the beaking of the high energy phosphate bond in ATP
31 KJ/Mole
What is more stable, ADP or ATP
ADP
instead of releasing free energy as heat in cells, what happens?
the cell couples the hydrolysis of the phosphate groups with another bodily endergonic process that attaches the phosphate group to another molecule
What is attaching a phosphate group to an organic molecule known as
phosphorylation
What does high energy mean in terms of stability
less stable
What is the transfer of one or more electrons from one reactant to another known as
redox reaction
What is the process of losing electrons
oxidation
what is the process of gaining electrons
reduction
If a molecule is oxidized, what type of agent is it
reducing agent
if a molecule is reduced, what type of agent is it
oxidizing agent
What is a coupled redox reaction
Product of one redox reaction is the reactant of the next redox reaction since the electrons move to increasingly stronger electron acceptors (oxidizing agents). this means there is a increasing affinity for electrons as time goes on
what are the three types of work discussed
chemical, mechanical, and transport work
What is released between each step of coupled redox
free energy
What is another way of reduction and oxidation
partially in covalent bonds when the electrons move closer to the more electronegative atom, but not transferred all the way resulting in the effective loss of electrons
what happens when increasing the temperature
method to speed up reaction
what is a common source of activation energy
thermal energy
What do enzymes do
lower activation energy and increase rate of spontaneous reaction
what do enzymes NOT do
alter the products of a reaction, supply free energy to a reaction, cause an endergonic reaction to proceed spontaneously
What must substrate molecules be in for the decrease in activation energy
their transition state
What are the three ways an enzyme catalyzes a reaction
- by bringing 2 substrates into contact by binding them to specific sites allowing them to collide easily so bonds break quickly
- enzymes can bring a substrate into a charged environment and break the bonds in the substrate using repulsion and attraction between ionic groups
- The active site of the enzyme can strain or distort the substrate molecule, which weakens its chemical bonds. This reduces the amount of energy required to break the bonds (induced fit).
What is the main characteristic of C-H bonds
high potential energy
Why are C-H bonds a good source of energy
Electrons in C - H bonds are a good source of energy because of their position and proximity to the relatively small atomic nuclei of carbon and hydrogen atoms
What happens to molecules with oxygen
Less chemical potential energy as the electrons are usually closer to the electronegative oxygen
why is O2 a good electron acceptor in cellular respiration
Since O2 has very high electronegativity, it is an ideal electron acceptor atom in the process of cellular respiration
What is another definition of oxidation
the removal of hydrogen atoms from, or the addition of oxygen atoms to, a molecule or atom is also called oxidation
what is another definition of reduction
the addition of hydrogen or the removal of oxygen is called a reduction
what is produced during the complete oxidation of organic molecules
CO2 and H2O are produced during the complete oxidation of all organic molecules
When glucose is burned during rapid oxidation, what happens
a large amount of waste thermal energy (free energy) is released after an initial large energy of activation is overcome
by a spark or flame, NOT efficent for cells
What do cells use to be more efficient instead of rapid oxidation
cells used controlled oxidation instead by splitting up the process into smaller steps, overcoming significantly smaller activation energies repeatedly via catalysts and body temperature creating modest amounts of energy that can be harnessed better than rapid oxidation
what enzyme catalyzes the reaction when food molecules are oxidized
Dehydrogenase
what does dehydrogenase do in detail
facilitates the transfer of high energy electrons from food to molecules that act as energy carriers or shuttles
What is the most common energy carrier molecule
positively charged coenzyme called nicotinamide adenine dinucleotide (NAD+)
what happens during cellular respiration with food molecules
At various points during cellular respiration, dehydrogenases remove two hydrogen atoms from a substrate molecule, transferring the two high-energy electrons and only one of the protons (H+) to NAD+. The other H+ is released into the cytosol.
What is the main reason for NADH (reduced NAD) to be in the body
drives ATP synthesis as a source of energy
How efficient is the energy transfer between food and NAD+
Efficiency is very high and almost no energy is lost as thermal energy
