Chapter 1: Foundations of Biochemistry

Question 1

Who is the father of biochemistry?

Answer 1

Albert Lehninger

Question 2

What are Albert Lehninger’s significant contributions?

Answer 2

that the citric acid cycle occurs in mitochondria, mech for oxidative phosphorylation, mitochondrial structure/function, bioenergetics

Question 3

What does biochemistry study?

Answer 3

the chemistry responsible for accelerating reactions, organizing metabolism and signaling in cells, and storing and transferring information

Question 4

What are the four building blocks of biochemistry?

Answer 4

sugars (monosaccharides), lipids (fatty acids), amino acids, nucleotides

Question 5

Can biological molecules have more than one functional group?

Answer 5

Yes! Most biological molecules have several functional groups

Question 6

What is a structural isomer? Are there differences in properties?

Answer 6

the same atoms but different order of bonding, different properties

Question 7

What is a stereoisomer? Are there differences in properties?

Answer 7

molecules with the same chemical bonds but different configuration, different properties

Question 8

What is an enantiomer? Are there differences in properties?

Answer 8

mirror imaged stereoisomer, have identical physical properties and react identically with achiral reagents, BUT may ave different biological activity

Question 9

What is a diasteromer?

Answer 9

not mirror imaged stereoisomer, have different physical and chemical properties

Question 10

What are the two types of diastereomers?

Answer 10

cis and trans geometric isomers

Question 11

What does cis mean?

Answer 11

all groups are on the same side

Question 12

What does trans mean?

Answer 12

all the groups are on the opposite side

Question 13

Can cis geometric isomers rotate to be trans geometric isomers?

Answer 13

No! there is no freedom of rotation due to double carbon bond

Question 14

How are the interactions between biomolecules specific?

Answer 14

macromolecules have unique binding pockets, thus the binding of chiral biomolecules is stereospecific

Question 15

How does the enzyme hexokinase exhibit stereospecifcity?

Answer 15

the enzyme is specific for D-glucose (produced in the body), not L-glucose (made in the lab); this glucose must fit into a pocket of the enzyme and interact via noncovalent interactions

Question 16

If lexapro is an enantio-pure drug and citalopram is a racemic mixture, what drug is stronger?

Answer 16

lexapro

Question 17

What is a eutomer?

Answer 17

the active isomer

Question 18

What is a distomer?

Answer 18

the inactive isomer

Question 19

Half of all drugs and nearly 90% of recently approved drugs are?

Answer 19

racemic mixtures

Question 20

Why are modern drugs usually racemic mictures?

Answer 20

cheaper, little to no greater therapeutic benefit

Question 21

In what general cases would only one enantiomer in a drug be required?

Answer 21

when the other enantiomer is toxic to the body, when the other enantiomer causes undesirable side effects

Question 22

What is the 1st law of thermodynamics?

Answer 22

energy can neither be created nor destroyed

Question 23

What is the 2nd law of thermodynamics?

Answer 23

a chemical or physical process goes spontaneously in the direction of greater disorder/entropy

Question 24

What is it called when a reaction breaks down something? Does is produce or consume energy?

Answer 24

catabolic, energy-producing

Question 25

What is it called when a reaction synthesizes something? Does is produce or consume energy?

Answer 25

anabolism, energy-consuming

Question 26

What three things must living systems do to maintain organization?

Answer 26

extract usable energy, release useless energy, and increase entropy in the universe

Question 27

What do all reactions go towards?

Answer 27

equilibrium

Question 28

What is ΔG at equilibrium?

Answer 28

0

Question 29

What can ΔG tell us about a reaction?

Answer 29

which direction the reaction will go as it reaches equilibrium

Question 30

Can ΔG tell us how fast a reaction will proceed?

Answer 30

No!

Question 31

What is ΔG(knot)?

Answer 31

ΔG at standard conditions of 1 M reactions and products, 25°C, 1 atm, and pH 0

Question 32

What are some things that you can do to speed up a reaction?

Answer 32

increase temperature, increase reactant, decrease product, lower activation barrier, couple the reaction to a fast one

Question 33

What is used instead of ΔG(knot) in biochemistry?

Answer 33

ΔG(knot)(prime)

Question 34

What does ΔG(knot)(prime) indicate?

Answer 34

that the reaction is at the biochemical standard state of pH 7, [H2O] = 55 M

Question 35

What does it mean if the Keq is above 1.0?

Answer 35

ΔG is negative and the reaction proceeds forward

Question 36

What does it mean is the Keq is 1.0?

Answer 36

ΔG is zero and the reaction is at equilibrium

Question 37

What does it mean if the Keq is below 1.0?

Answer 37

ΔG is positive and the reaction proceeds in reverse

Question 38

Why can individual steps in a pathway not be favorable, but the overall pathway is?

Answer 38

ΔGs are additive in multistep pathways, the overall pathway must have a -ΔG

Question 39

What can enzymes not do?

Answer 39

alter ΔG or go against equilibrium

Question 40

What are the advantages of an enzymatic catalyst?

Answer 40

acceleration under mild conditions, high specificity, possibility for regulation, coupling reactions to ATP hydrolysis, avoids side reactions, substrate channeling

Question 41

Why are chemical couplings so important?

Answer 41

they allow for otherwise unfavorable reactions by making the overall ΔG negative

Question 42

What are the two steps of ATP group transfer?

Answer 42

1) ATP transfers phosphate to substrate, raising its energy (group transfer) 2) the phosphate leaves the substrate, making it go back to a lower energy state

Question 43

What is a metabolic pathway?

Answer 43

a pathway that produces energy or valuable materials

Question 44

What is a signal transduction pathway?

Answer 44

a pathway that transmits information

Question 45

Where is the most common point of regulation?

Answer 45

at the first enzyme in a pathway