Ch. 8 Review

Question 1

What is metabolism?

Answer 1

all of the cells chemical reactions (biochemistry)

Question 2

What are the metabolic pathways? What do they do?

Answer 2

anabolic- building of cells (growing)
catabolic- break down of nutrients

Question 3

Need ______ to do ________

Answer 3

Catabolism, anabolism

Question 4

What are the laws of thermodynamics? How do they relate to cells?

Answer 4

1. Energy can only be TRANSFORMED
2. disorder (S) of the universe increases

Cells must conform to BOTH

Question 5

What is disorder (S)?

Answer 5

entropy, which is always increasing

Question 6

what is the difference between enthalpy and entropy?

Answer 6

enthalpy- total heat content of a system

entropy- total disorderliness of a system

Question 7

How much USABLE energy do we have?

Answer 7

Free energy which is the energy of the system that can do work (at uniform temp)

Question 8

Define exergonic and endergonic reactions

Answer 8

exergonic- negative ΔG, ΔH decrease, ΔS increase
MORE stable, favorable rxn, SPONTANEOUS

endergonic- positive ΔG, ΔH increases, ΔS decreases
LESS stable, unfavorable rxn, NONSPONTANEOUS

Question 9

In an endergonic reaction _______ are less stable than _______

Answer 9

products, reactants

Question 10

If the system is at equilibrium? How does this relate to cells?

Answer 10

1. ΔG=0
2. system has MAX stability
3. does no work

Cells are NEVER at equilibrium, they are dynamic, equilibrium= cell death

Question 11

Hydrolysis is an _______ rxn

Answer 11

exergonic

Question 12

Dehydration synthesis is an ________ rxn

Answer 12

endergonic

Question 13

Catabolism is _______, anabolism is ______

Answer 13

exergonic, endergonic

Question 14

What is ATP?

Answer 14

Adenosine Triphosphate
1. nucleotide used to make RNA
2. BASE is adenine
3. three phosphates
4. Ribose
ENERGY RICH

Question 15

Where does the energy from ATP come from?

Answer 15

By releasing a terminal phosphate making ADP

*remember phosphate groups are negatively charged, the 3 phosphates are covalently bonded, when the break apart a lot of energy is released

Question 16

ATP is broken by

Answer 16

Hydrolysis

Question 17

What is the ATP breaking equation

Answer 17

ATP + H2O –> ADP + Pi + Energy
= -7.3kcal/mol

Question 18

ATP hydrolysis is _____ in endergonic reactions

Answer 18

COUPLED

ex. glutamic acid and ammonia anabolism

Question 19

What in the cells are endergonic?

Answer 19

chemical work (anabolism)
transport work (vesicles)
mechanical work (flagella, cilia, pseudopodia, muscle contraction, cell division)

Question 20

What in the cells are exergonic?

Answer 20

cellular respiration
fermentation

Question 21

Breaking bonds ________, forming bonds ________

Answer 21

requires, releases

Question 22

All reactions require _______ even exergonic ones

Answer 22

bond breaking and forming

Question 23

Is ATP enough to break bonds?

Answer 23

NO, breaking bonds TAKES energy

Question 24

All reactions have a _______

Answer 24

Energy barrier which makes reactions SLOW

Question 25

How can we speed up life reactions?

Answer 25

Catalysts in the form of ENZYMES

Question 26

Why can't heat be a catalyst for cells?

Answer 26

1. causes denaturing proteins 2. no specificity

Question 27

Why do we use enzymes?

Answer 27

1. they do not damage the cells 2. they are SPECIFIC

Question 28

Catalysts effect the _______ of reaction, and they are ______ consumed

Answer 28

rate, not

Question 29

How does an enzyme overcome Ea without adding heat?

Answer 29

Enzymes reduce Ea

Question 30

Is ∆G affected by enzymes?

Answer 30

NO

Question 31

Enzymes cannot make an _______ reaction _________

Answer 31

unfavorable, favorable

Question 32

Enzymes are also (4)

Answer 32

1. reusable 2. work in both directions 3. can be regulated (turned on/off) 4. are typically PROTEINS

Question 33

True/False Enzymes create endergonic reactions to exergonic reactions?

Answer 33

FALSE

Question 34

What are the ways enzymes reduce Ea (3)?

Answer 34

1. orients two substrates 2. puts stress on bonds 3. creates a microenvironment

Question 35

What are the things that affect the RATE of an enzyme-catalyzed reaction (6)?

Answer 35

1. [substrate]= greater concentration of substrate means greater reaction rate 2. [enzyme]= greater concentration of enzyme increases reaction rate 3. temperature = higher temperature, faster reaction -every enzyme has an optimal temperature 4. pH= varies depending on enzyme - every enzyme has optimal pH 5. binding of regulatory molecules 6. localizing (proximity of enzyme to a pathway) ex. organelles localize

Question 36

Of the things that effect enzyme rate, which change concentrations and which alter shape?

Answer 36

Concentration- enzyme and substrate concentrations 3-D shape- temperature, pH, binding of regulatory molecules

Question 37

Localizing in enzymes (3)

Answer 37

1. in organelles 2. as membrane proteins 3. in multi-enzyme complexes

Question 38

Enzymes can be stronger due to what type of covalent bonds?

Answer 38

disulfide bonds

Question 39

If you denature an enzyme with heat, once it cooled can it be reused?

Answer 39

Yes, only if it refolds perfectly without sticking to other molecules

Question 40

What helps refold enzymes

Answer 40

chaperones

Question 41

What are the types of regulatory molecules?

Answer 41

Competitive inhibitors- binds to the active site Noncompetitive inhibitors- binds to the allosteric site

Question 42

Competitive inhibitors

Answer 42

- inhibitor blocks the substrate - inhibitor vs. substrate concentration determines who binds

Question 43

Noncompetitive inhibitors

Answer 43

- [inhibitor] does not matter - changes shape of the active site - allosteric regulation can turn the enzyme on/off

Question 44

Competitive inhibitors ________ by concentration, noncompetitive inhibitors ________ by concentration

Answer 44

can be countered, cannot be countered

Question 45

Do all enzymes have an active site? Do all enzymes have an allosteric site?

Answer 45

Yes, No relatively few enzymes are needed to turn on/off

Question 46

Feedback inhibition involves

Answer 46

Turning off the enzyme with the product of the reaction ex. threonine and isoleucine production