Lecture 7- intro to metabolism and energy

Question 1

metabolism=

Answer 1

all of a cell’s chemical reactions

Question 2

anabolism=

give example

Answer 2

rxn that requires energy to organize the cell (building and moving away from chaos/ disorder)
eg. DNA replication

Question 3

catabolism=

Answer 3

rxn that release energy from breakdown of nutrients

Question 4

ATP from ____ rxns drive the energy needs of ___ rxns

Answer 4

catabolic

anabolic

Question 5

energy=

Answer 5

capacity to cause change or the capacity to work

Question 6

2 main energy types:

Answer 6

1. Potential energy: stored energy due to position or composition (or both)
2. Kinetic Energy: energy due to movement (every molecule has a certain degree of kinetic energy)
   - eg diffusion

Question 7

thermodynamics=

*note: cell is a(n) ____ system

Answer 7

• the study of energy transformations

- open

Question 8

first law of thermodynamics

Answer 8

energy cannot be created nor destroyed (only converted/ transformed from one form to another)

Question 9

second law of thermodynamics

Answer 9

entropy of the universe is always increasing

entropy= measure of disorder

Question 10

____ is the most disordered form of energy

Answer 10

heat

Question 11

rxns will be spontaneous if the disorder of the universe is _____ (inc/decreased).
Why?

Answer 11

• increased

- therefore system becomes more stable (less likely to change)

Question 12

free energy=

Answer 12

portion of a system’s energy that’s available to perform work

Question 13

systems with high free energy (complex/ organized) have ____ (high/low) entropy

Answer 13

low

Question 14

systems with low free energy (disordered/ random) have ____ (high/low) entropy

Answer 14

high (therefore less energy available to do work)

Question 15

rxns with a negative delta G are ____(spont or not).
= _________ (ender/exergonic)
- example

Answer 15

spontaneous
exergonic
-ex. cellular respiration

Question 16

rxns with a positive delta G are ____(spont or not).
= _________ (ender/exergonic)
- example

Answer 16

non-spontaneous
endergonic
-ex. photosynthesis

Question 17

energy from exergonic rxns are used to power endergonic rxns= ___ ______

Answer 17

energy coupling

Question 18

-

Answer 18

C5

• charge repulsion
• steric hinderance

Question 19

the 3rd phosphate in ATP has a ___ energy bond

Answer 19

high

everyone hates the 3rd phosphate!

Question 20

Hydrolysis of ATP –> ADP + Pi can do 13kcal of work ie delta G=

Answer 20

the delta G is -13kcal/mol under ideal conditions

Question 21

often the 3rd phosphate of ATP is transferred to a reactant. Why?

Answer 21

the addition of a phosphate makes the reactant more reactive/ spontaneous

Question 22

ATP can be regenerated during _____ _____

Answer 22

cellular respiration

Question 23

Cells couple ATP hydrolysis to power ___ rxns

Answer 23

endergonic

Question 24

enzymes=

Answer 24

biological catalysts that provide an alternate energy path for a rxn to proceed with a lower activation energy

• fxn in both endergonic and exergonic rxns
• highly regulated in the cell

Question 25

enzymes decrease the ___ ____ but do NOT change ____

Answer 25

activation energy

delta G

Question 26

• enzymes bind and act on ____ (which they are very specific to)
• enzymes have an ____ ___ (binding site of substrate- catalysis)
• active/ catalytic site has ___ and ______ compatibility with substrate

Answer 26

• substrates
• active site
• geometric and chemical

Question 27

catalysis=

Answer 27

reactants converted to products

- often proceeded by enzyme induced fit

Question 28

Enzymes lower Ea for a rxn by:

List 5 different ways

Answer 28

1. bringing reactants closer together
2. active site contains a unique chemical enviro favorable for rxn
3. physically stress bonds to be broken
4. covalently stabilize rxn intermediate
5. place substrates in correct orientation (panda example!)

Question 29

Certain chemicals selectively inhibit the action of specific enzymes. What are the 2 types of enzyme inhibitors?

Answer 29

1. Competitive inhibitors

2. non- competitive inhibitor

Question 30

Competitive inhibitors=

- can be outcompeted by:

Answer 30

inhibitor that binds the active site but does not participate in a rxn
- increase [substrate]

Question 31

Non-Competitive inhibitors=

Answer 31

inhibitor that binds a site on the enzyme that is not the active site and blocks enzyme activity
- changes shape of active site