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BIO Chap 6


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What is energy
The capacity to do work
What is kinetic energy? give an example on the cellular level
The energy ffrom anything that is in motion.
EX: Lysosomes move during the recycling process. They are performing work
What is potential energy? give an example on the cellular level
Stored energy or the potential to do work
EX: Cells store energy obtained through food to use for activities later.
What is the relationship between kinetic and potential energy?
Potential energy is needed for kinetic energy
What is the first law of thermodynamics? Give an example in a living system
Energy can bo transferred and transformed but not created of destroyed.
EX: a plant consume light energy and uses that energy to grow
If energy cannot be destroyed why do living organisms need a constant input of energy?
Our energy is released when we use it to to work. We then need to replenish that energy inorder to perform more work
What is the second law of thermodynamics?
Every energy transformation increases entropy in the universe.
What is entropy
Disorder or randomness
Describe a specific spontaneous event in terms of total energy and entropy changes.
In a spontaneous even, total energy is given up and entropy increases
Edfine free energy , what is the equation and what do the two terms represent
The portion of a systme's energy that can perform work when temperature in uniform throughtout.

Change G= (Change H) - T(Change S)

H: systems total energy
G: Free energy
S: entropy
Describe a specific spontaneous even in terms of the free energy of the initial and final states
In a spontanious reactions, freee energy is given up in the final state
What is Change G and is the value positive or negative in a spontaneous reaction?
This is the difference in the amount of free energy in the final and initial states of a reaction. If it is negative then the reaction is spontaneous
Define exergonic
A net release of energy. Change G is less than 0
Define endergonic
a net absorption of energy. Change G is positive
What is the relationship b/w the change in G of a reaction and it's displacement from equillibrium
When the change in G is = 0, it has reached equillibrium. If a cell has reached metabolic equillibrium it is dead.
What is metabolism
the totality of an organisms chemical reactions
What is catabolism
the breaking down of complex substances to simple products with a net release of energy. This is exergonic and spontaneous
What is anabolism
the building of complex molecules from simpler ones. A net absorption of energy. This is endergonic and nonspontaneous.
What is meant by coupling in refernece to catabolic and anabolic processes?
Catabolism is a spontaneous reaction. When catabolsm finishes, it releases energy. This energy is used to start the reactions of the anabolic pathways. So, one reaction loss of energy is another reactions gain.
What molecule transfers energy b/w catabolic and anabolic reactions
desrcibe the structure of ATP
There are 3 phospates groups attached to the ribose, which is bonded to adenine
what is an enzyme
a catalytic protein
Wht is the activation energy and how does it affect the rate of a reaction
Ther energy for starting a reaction that is needed to break bonds in the reactant molecule. This speeds the rate of reaction.
what is the transition state
This is the point wen the free energy of a reaction is increaseing and has reached the point where it will start to decrease
Why should cells need enzymes
an enzyme speeds a reaction by lowering the activation energy barrier so that the transition state can be reached
What is a substrate
the reactant an enzyme acts on
Describe the induced fit model of substrate binding
as the substrate binds to the protien, the protein induces a change in the shape of the protein that xauses the active site to embrace
list the steps in the catalytic cycle
1. Substrate binds to the active site creating weak
2. Substrate is converted to products
3. Products are released frm enzyme
4. Active site is available for another molecule of substrate
What happens to enzyme activity when substrate concentration increases
There is more of a chance for substrates to bind to enzymes so therefor enzyme activity increases
What happens to enzyme activity when temperature increases
Molecules move more rapidly causing substrate binding to occur more frequently
What happens to enzyme activity when temperature increases dramatically
enzyme activity decreases because the bonds are disrupted by the high temperatures. This causes denaturation
What is the optimum pH for enzyme activity
Where do competitive inhibitors bind on an enzyme
at the active site, permanently blocking any substrates from binding
Where do non competitive inhibitors bind on an enzyme
not at the active site
What happens to an enzyme when a non competitive inhibitor binds to an enzyme
it causes the enzyme to changes shape, making the active site less receptive to the substrates
Competitive inhibitors are _____________ inhibitors
non reversible
non competitive inhibitors are _____________ inhibitors
What type of bond is involved in competitive inhibitor binding
what is an allosteric site
a site on an enzyme remote from the active site. This is where a non competitive inhibitor binds
Catbolism:anabolism :: exergonic:____________
Most cells connot harness heat to perform work because....
termperature is usually uniform throughout the cell
if an enzyme solution is saturate with substrate, the most effective way to obtain an even faster yield of product is to add more ________
how does ATP transfer energy from exergonic to endergonic processes in the cell
BY phosphorylation. The addition of phosphate groups which transfers the energy to endergonic processes by phosphorylating other molecules

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