metabolism- lecture #10 & #11 Flashcards
what is ATP to the cell?
currency $$$
what 3 types of cellular work does ATP perform?
chemical work (endergonic/anabolic reactions)
transport work (movement of materials against the concentration gradient)
mechanical work (muscle contraction)
what is rigor mortis and how does it happen?
Rigor mortis is the stiffening of the muscles, this happens because theres no ATP flow in a dead body
what does energy coupling pair together?
energy coupling pairs endergonic reactions ( non-spontaneous) with exergonic reactions (spontaneous)
what is energy coupling?
energy generated from one reaction is used to drive a second reaction
what is ATP hydrolysis? what happens to energy
exergonic water mediated breakdown
energy/heat is released when ATP turns into ADP
are cell conditions standard and what does it mean for hydrolysis?
no, therefore much more energy is available from the hydrolysis as a result
what kind of charge do phosphate groups have?
negative charge
what does the negative charge of the phosphate mean for energy
repulsion of like charge causes energy release when the bonds are cleaved
what do enzymes work to do and what net reaction is created?
couple exergonic reactions with reactions that require energy (endergonic)
creates a net exergonic reaction
what is the process of enzymes coupling
the product (usually a phosphate group) is picked up and used as a reactant in the second reaction (intermediate)
this raises the energy of the intermediate
how is ATP produced
using energy that arises from catabolic reactions in the cell
do anabolic reactions require or produce ATP? what about catabolic reactions
anabolic: require ATP
catabolic: produce ATP
what happens when a reaction reaches equilibrium? what does delta G look like?
it may no longer be used to perform work
delta G = 0
what does cellular catabolism begin and finish with?
begins with: glucose + O2 (high energy)
finishes with CO2 + H20 (low energy)
metabolic processes must be tightly regulated, regulation may
turn the production of an enzyme off (stop transcription of the gene)
regulate the activity of the enzyme post- production
what is the allosteric site
when the allosteric regulatory molecule (inhibitor or activator) binds somewhere where the active site isn’t, that site is the allosteric site
what happens when an allosteric inhibitor binds to an enzyme?
Allosteric enzymes typically have multiple active sites located on different protein subunits.
When an allosteric inhibitor binds to an enzyme, ALL active sites on the protein subunits are changed slightly so that they don’t work as well.
what happens when an allosteric activator binds to an enzyme
Some allosteric activators bind to locations on an enzyme other than the active site, causing an increase in the function of the active site.
what is an example of an allosteric inhibitor?
ATP
-turns off catabolism (produce)
what is cooperativity?
substrate binds to the active site of an enzyme that has many active sites
what happens when cooperativity happens?
triggers a change in shape of all subunits
increases the catalytic activity of the enzyme
what is an allosteric protein that does not work as an enzyme?
hemoglobin
what does hemoglobin do?
works to transport O2 from the lungs to the tissues to the inside of the red blood cells
as the hemoglobin is going through the body you need to load it with tones of oxygen
how does feedback inhibition work?
the end product of a metabolic pathway acts on the key enzyme regulating entry to that pathway, keeping more of the end product from being produced.
how is feedback inhibition behavior observed?
with allosteric inhibitiors
what is an example of a feedback inhibitor?
amino acid isoleucine
what does compartmentalization of the cell do?
creates order in metabolic pathways
______ of the first reaction will be the ________ for the next reaction
product of the first reaction will be the reactant for the next reaction
what is the origin of chemical energy?
the sun
what can be directly catabolized to release energy?
glucose
what will require some processing before they can be catabolized?
proteins, amino acids, lipids, polysaccharides
what happens when theres oxidation of organic molecules? delta G, activation energy
high energy molecules are broken into low energy molecules
(-)delta G
requires enzymes because of high activation energy
what is a loss of electrons?
oxidation
what is a gain of electrons?
reduction
how is energy in organic molecules released?
via electron transfers from one reactant to another
what is a redox reaction?
oxidation and reduction are always coupled
every H+ that gets moved an e- gets moved
what is the reducing agent?
electron donor
what is the oxidizing agent?
electron acceptor
what is the greediest for electrons?
oxygen
do all redox reactions involve the complete transfer of electrons?
no
are C-H covalent bonds polar or non-polar
non-polar
are C-O covalent bonds polar or non-polar
polar
is oxygen an oxidizing agent or reducing agent?
oxidizing agent
what happens when transferring an electron to oxygen?
releases energy
this energy may be used to perform work in the cell
when giving an electron to a molecule that wants it what type of reaction is that?
spontaneous
heavily reduced organic molecules have what potential energy
large potential energy
how is energy harvested through catabolism? what needs to happen and what does it need?
multiple steps
each step has its own enzyme
why does catabolism of an organic molecule not occur in a single step?
causes explosion
energy would not be harvested
energy would be wasted
do we want enzymes to be controlled? why?
yes, because controlling enzymes means to turn them on and off
if we couldn’t control them we would constantly waste energy
why are multiple steps in a transfer good? analogy
if a teacher hands all the papers to you, its overwhelming
if they give to you one by one (multiple steps) its easier
what is NADH
electron carrier that temporarily holds electrons
reduced version
how many electrons does NADH hold?
2 electrons and H+
what is NAD+?
electrons that travel to go pick up electrons
oxidized version
(empty truck)
process of glucose to H2O (through NAD+)
glucose –> NAD+ –> O2 –> H2O
electrons move from _____ energy end of the chain to the _____ energy end of the chain
high to low
what can FADH2 hold?
2 spots
2H+ and e-
what is aerobic cellular respiration?
requires O2
where does aerobic respiration occur?
glycolysis, intermediate step, TCA cycle and electron transport chain
where does substrate level phosphorylation occur?
glycolysis and TCA cycle
how much ATP does substrate level phosphorylation produce?
4 ATP
where does oxidative phosphorylation take place?
electron transport chain and chemiosmosis
how much ATP does oxidative phosphorylation produce?
28 ATP