AP Biology Chapter 8*** Flashcards
Metabolism is an _____ _____ of life that arises from orderly interactions between molecules
emergent property
what is a major pathway of catabolism?
cellular respiration…in which the sugar glucose and other organic fuels are broken down in the presence of oxygen to carbon dioxide and water
metabolism as a whole manages the ____ and ____ ____ of the cell
- material
- energy resources
what is an example of anabolism?
the synthesis of an amino acid from simpler molecules
true or false: energy released from downhill reactions of catabolic pathways can be stored and then used to drive the uphill reactions of anabolic pathways
TRUE
what is energy used for
can be used for doing work..that is, to move matter against opposing forces, such as gravity and friction
how can moving objects perform work?
by imparting motion to other matter
what is an isolated system?
is unable to exchange either energy or matter with its surroundings
what is a open system?
energy and matter can be transferred between the system and its surroundings
are organisms open or isolated systems?
open systems..they absorb energy
during every energy transfer or transformation, some energy becomes ______
unavailable to do work…more usable forms of energy are at least partly converted to heat, which is the energy associated with the random motion of atoms or molecules
when a bear eats a salmon what happens with this energy?
some energy ( a small amount) converts into the motion of the brown bear and most of it is lost as heat, which dissipates rapidly through the surroundings
a system can put heat to work only when….
there is a temp difference that results in the heat flowing from a warmer location to a cooler one…
if temp is uniform (like in a cell) then the only use for heat energy generated during a chemical reaction is to warm a body of matter, such as an organism
a logical consequence of the loss of usable energy during energy transfer or transformation is….
that each such event makes the universe more disordered
how can a process occur on its own without outside help?
it must increase the entropy of the universe
a process that cannot occur on its own is called….
nonspontaneous
true or false? cells create ordered structures from less organized starting materials
true
how can the entropy of a particular system decrease?
when the total entropy of the universe increases
—thus organisms are islands of low entropy in an increasingly random universe
what is another name for free energy?
gibbs free energy
what is the equation to find the change in free energy
G= free energy H=enthalpy T=temp in Kelvin (K= C + 273) S=change in entropy (delta)G= (delta)H - T* (delta)S
if the result of the free energy equation results in a negative G what does this mean?
What if it results in a positive G?
- means spontaneous
+ means nonspontaneous
every spontaneous process decreases the system’s ___ ____, and processes that have a positive or zero (delta)G are never _____
- free energy
2. spontaneous
we can think of free energy as….
a measure of a system’s instability-its tendency to change to a more stable state
a higher S means…
a lower S means…
- stable systems
1. unstable systems
as a reaction proceeds toward equilibrium…
the free energy decreases
any change from the equilibrium position will have a _____ G and will not be _____
- positive
2. spontaneous
because a system at equilibrium cannot spontaneously change, it can do no….
work
a process is ____ and can perform work only when it is moving towards equilibrium
spontaneous
what does the delta G for an exergonic reaction mean?
the max amount of work the reaction can perform
delta G is ____ for exergonic reactions
negative
the greater the decrease in ____, the greater the amount of ___ that can be done
- free energy
2. work
the phrase “energy stored in bonds” is shorthand for …
the potential energy that can be released when new bonds are formed after the original bonds break…as long as the products are of lower free energy than the reactants
delta G is ____ for endergonic reactions
positive…this reaction is nonspontaneous and the magnitude of G is the quantity of energy required to drive the reaction
true or false: the fact that metabolism never reaches equilibrium is a defining feature of life
true
how is the cell never at equilibrium?
constant flow of materials in and out of the cell keeps the metabolic pathways from ever reaching equilibrium
a cell does 3 main kinds of work:
- chemical work- pushing of endergonic reactions that would not occur spontaneously, such as the synthesis of polymers from monomers
- transport work- the pumping of substances across membranes against the direction of spontaneous movement
- mechanical work- such as the beating of cilia, contraction of muscle cells, and the movement of chromosomes during cellular reproduction
what is ATP responsible for?
mediating most energy coupling in cells, and in most cases it acts as immediate source of energy that powers cellular work
-also makes RNA
what is the structure of ATP
contains the sugar ribose, with the nitrogenous base adenine and a chain of 3 phosphate groups bonded to it
how can the bonds between the groups of ATP be broken down
by hydrolysis
the phosphate bonds of ATP are sometimes referred to as high energy phosphate bonds…what does high energy mean
the reactants (ATP and water..when it comes to hydryolysis) themselves have high energy relative to the enrgy of the products (ADP and inorganic phosphate)
why is ATP useful to the cell?
the energy it releases on losing a phosphate group is somewhat greater than the energy most other molecules could deliver
when ATP is hydrolyzed the release of free energy does what
heat up its surroundings