Lecture 6 Flashcards Preview

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Flashcards in Lecture 6 Deck (21):
1

Energy can be stored within _______________
so that it can be used at a later time

chemical bonds

2

What is the first law of thermodynamics?

Energy is not created nor destroyed,
simply transformed

3

Why cells cannot use heat to do work?

But cells are too small to be able to use heat
to do work, instead they rely on the energy
found in chemical bonds

4

What is the second law of thermodynamics?

Disorder
(entropy) in the universe is continuously
increasing

5

which is more stable order or disorder?

disorder

6

what is the free energy?

the energy available to
do work.

7

what is called the reaction where the energy in the bonds of products is lower than energy in bonds of
reactants

exergonic

8

what is called the reaction where the energy in bonds of products is higher than
those of reactants

endergonic

9

what does Exergonic reactions will happen
spontaneously

they increase disorder and endergonic will not, as they increase order.

10

what is activation energy?

the energy required to
destabilize existing bonds in order to start a
chemical reaction

11

what are the two things that can be done to speed up a reaction?

add energy to it, lower the activation energy

12

How does catalysts function?

Catalysts function by stabilizing the
intermediate products or transition state of
the reaction, in doing so they speed up the
reaction.

13

what are enzymes?

Enzymes are macromolecules (generally
proteins, but sometimes RNA) that catalyze
the biological reactions within the cell

14

what does enzymes (3 things)?

Orienting substrates in the the proper fashion
• Bringing reactants close together
• Stressing particular bonds in the molecules

15

what does multienzyme complexes allow (3 things)?

The efficient delivery of products to the next
enzyme
– Prevention of unwanted side reactions
– Reactions can be controlled as one unit

16

how does temperature affects a protein?

slight increases will increase
reaction rates (molecular collisions will
increase so the enzyme is more likely to come
into contact with a substrate), but if the
temperature rises too high, the protein will
denature

17

how does the pH affects a protein?

The cations and anions produced in acidic or
basic conditions will interact with charged or
polar amino acids in the protein. Eventually
the protein may denature.

18

inhibitor binds to the active site

competitive inhibition

19

noncompetitive inhibition, the inhibitor
binds to an allosteric site (not the active
site), changes the shape of the enzyme, thus
inhibiting the binding of the substrate

allosteric inhibitor

20

what does the km do ?

give us an idea about the affinity
between the enzyme and the substrate

21

what is the binding affinity between two molecules?

a measure of how strong their non-covalent
interaction is