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Chapter 6 - Bio 111
Test 2
61
Biology
Undergraduate 3
10/21/2013

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Term
What is energy?
Definition
The capacity to do work.
Term
What is kinetic energy?
Definition
The energy of motion
Term
What is potential energy?
Definition
Stored energy
Term
What are the 4 forms energy can take?
Definition
1.) mechanical
2.) electric current
3.) heat
4.) light
Term
Potential vs Kinetic?
Definition
P - bitch at top of slide.
K - bitch actually sliding.
Term
How is heat energy measured?
Definition
In kilocalories.
Term
What is a calorie?
Definition
The amount of heat required to raise the temp of 1 gram of water by 1 degree Celsius
Term
1 kilocalorie = 1,000 ________ = 1 _________ (dietary)
Definition
calories. Calorie.
Term
Energy flows into the biological world from the ________.
Definition
sun
Term
How do photosynthetic organisms store the energy they receive from the sun?
Definition
As potential energy in chemical bonds.
Term
How can potential energy be transferred?
Definition
By transferring electrons from one molecule to another.
Term
What is oxidation? What is reduction? What is redox?
Definition
O I Loss

R I Gain

Redox = those two coupled together.
Term
What is the first law of thermodynamics?
Definition
Energy cannot be created or destroyed. Energy can only be converted from one form to another. Total amount of energy in the universe remains constant.
Term
Why are energy transfers inefficient?
Definition
Energy is "lost" as heat.
Term
What is the second law of thermodynamics?
Definition
Disorder is more likely than order.
Term
What is entropy?
Definition
Disorder in the universe.
Term
What does the 2nd law actually mean?
Definition
Energy transformations proceed spontaneously to convert matter from more ordered (less stable) to less ordered (more stable) form
Term
According to the 2nd law of thermodynamics, ________ is always increasing.
Definition
Entropy
Term
What is an endergonic reaction?
Definition
A reaction requiring an input of energy.
Term
What is an exergonic reaction?
Definition
A reaction that releases free energy.
Term
If looking at graphs, what does an exo/endo look like?
Definition
Endergonic has the line going above the zero line signifying energy must be used.

Exergonic has the line going below the zero line signifying that energy has been released.
Term
What is activation energy?
Definition
Extra energy required to destabilize existing bonds and initiate a chemical reaction.
Term
What does an exergonic reaction rate depend on?
Definition
The activation energy required. Larger activation energy goes slower vs smaller going faster.
Term
How can rate be increased? (2 ways)
Definition
1.) Increasing energy of reacting molecules (heating)
2.) Lowering the activation energy (catalyst)
Term
What is a catalyst?
Definition
Substances that influence chemical bonds in a way that lowers activation energy.
Term
What does a catalyst NOT do?
Definition
1.) Violate laws of thermodynamics
- Endergonic rxn cannot be spontaneous
2.) Alter the proportion of reactant turned into product.
- Makes rxn faster, does not increase the amount made
Term
What is the energy currency of the cell?
Definition
ATP. Adenosine triphosphate.
Term
What is the structure of ATP?
Definition
A ribose (5 carbon sugar)
Adenine
Three phosphates
Term
Where is the energy stored in ATP?
Definition
The bonds between the three phosphates.
Term
Because phosphates are highly negative, what 3 things does this cause?
Definition
1.) They repel each other
2.) Much energy is required to bond them to each other
3.) Much energy is released when the bonds are broken between them
Term
What does the structure become when ATP is broken down? Is this reaction reversible?
Definition
ATP -> ADP + P1
YES
Term
What is ADP called?
Definition
Adenosine diphosphate
Term
What is P1 called?
Definition
Inorganic phosphate.
Term
What breaks apart the bonds of the phosphate in ATP?
Definition
h2o!
Term
What are enzymes?
Definition
Molecules that catalyze reactions in living cells.
Term
What are enzymes (mostly) structure-wise?
Definition
Most are proteins, some are RNA
Term
What is an enzymes function?
Definition
Lower the activation energy required for a reaction.
Term
Are enzymes changed or consumed by the reaction?
Definition
NO
Term
What do enzymes interact with?
Definition
Substrates
Term
What is a substrate?
Definition
A molecule that will undergo a reaction.
Term
What is an active site?
Definition
Region of the enzyme that binds to the substrate
Term
What does the binding of an enzyme to a substrate cause?
Definition
The enzyme to change shape, producing a better INDUCED FIT between molecules.
Term
Where are enzymes located in the cell?
Definition
Suspended in the cytoplasm, attached to the cell membrane, or attached to organelles.
Term
What is a multienzyme complex?
Definition
Subunits work together to form a molecular machine.
Term
What are the pro's of a multienzyme complex?
Definition
1.) Product can be delivered easily to the next enzyme
2.) Unwanted side reaction can be prevented
3.) All reactions can be controlled as a unit
Term
What is an enzyme's effectiveness effected by?
Definition
It's environment like concentrations of substrate and enzyme factors that can change an enzymes overall shape.
Term
How does temperature effect enzyme activity?
Definition
Enzyme activity can be increased by increasing the temperature to optimal level. Too high and they can denature.
Term
What pH range to enzymes function best at?
Definition
6-8
Term
What is an inhibitor?
Definition
Substance that binds to an enzyme and decreases its activity.
Term
What is a competitive inhibitor?
Definition
Competes with the substrate for the active site.
Term
What is a noncompetitive inhibitor?
Definition
Binds to enzyme at another site other than the active site thus changing the shape which makes the actual enzyme unable to bond.
Term
Allosteric enzymes exists in _______ and ________ forms
Definition
inactive and active
Term
What do noncompetitive inhibitors bind to?
Definition
Allosteric site which acts as the chemical on/off switch
Term
What is an allosteric inhibitor?
Definition
Binds to allosteric site and reduces enzyme activity.
Term
What is an allosteric activator?
Definition
Binds to allosteric site and increases enzyme activity.
Term
What is a cofactor?
Definition
Usually metal ions, found in the active site participating in catalysis.
Term
What is a coenzyme?
Definition
Nonprotein organic molecule, often used as an electron donor or acceptor in redox reaction
Term
What is metabolism?
Definition
Total of all chemical reactions carried out by an organism,
Term
What is anabolic vs catabolic?
Definition
Ana - Use energy to build up molecules
Cat - Harvest energy by breaking down molecules
Term
In a biochemical pathway, the ______ of one reaction is the ________ for the next.
Definition
Product/substrate.
Term
What is feedback inhibition?
Definition
End-product pathway binds to an allosteric site on an enzyme that catalyses first reaction in pathway. Shuts it down so raw materials and energy aren't wasted.
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