Lecture 1&2: Kincaid

Question 1

Covalent bonds

Answer 1

Sharing of a pair of electrons

Question 2

Electrostatic. Interactions

Answer 2

A charged group can attract an oppositely charged group

Question 3

Hydrogen bonds

Answer 3

Hydrogen atom covalently bonded to one EN atom is also attracted to another

Question 4

Van dear walls interactions

Answer 4

Results from the asymmetrical distribution of electrons in molecules or atoms

Question 5

Common COVALENT c-c bond distance and energy:

Answer 5

1.54 angstroms; 355 kJ mol-1 (85kcal)

Question 6

Common electrostatic interaction length

Answer 6

3 angstroms; 5.86 kJmol-1

Question 7

Common hydrogen bond length

Answer 7

1.5 -2.6 angstrom; 4-20 kJ mol-1

Question 8

How to combine sugar and amino acid moieties:

Answer 8

Dehydration rxn

Question 9

Which carbon in DNA is “deoxy”

Answer 9

2’ carbon

Question 10

Nuceloside

Answer 10

Sugar+nitrogenous base(NO phosphate group)

Question 11

Adenine and thymine have___ bonds; Guanine and cytosine have ____ bonds.

Answer 11

2; 3

Question 12

Properties of water:

Answer 12

Polarity, cohesion, moderation of temperature, expansion upon freezing, versatility as a solvent

Question 13

Hydrophobic effect

Answer 13

Nonpolar to cluster together to exclude water in aq. Environment

Question 14

Guanine: pKa =9.7 what’s this mean?

Answer 14

Above this pH, you lose H’s…DNA becomes single stranded

Question 15

PH=pKa then:

Answer 15

Protonated = deprotonated

Question 16

PKa =

Answer 16

The susceptibility of proton removal

Question 17

PH is lower than pKa:

Answer 17

Hydrogen bonds remain intact

Question 18

Buffers:

Answer 18

Regulate pH in organisms and in lab; weak acid and its conjugate base

Question 19

Buffers are most effective at pH:

Answer 19

near their pKa

Question 20

Dynamic equilibrium

Answer 20

Rate of the forward reaction = rate of reverse; [ ] of R / P don’t have to be =

Question 21

Catabolic pathways

Answer 21

Release energy by breaking bonds of complex molecules to simpler.

Question 22

Anabolic pathway

Answer 22

Consume energy to build complex molecules from simpler ones.

Question 23

Kinetic energy

Answer 23

Asso. W/ motion

Question 24

Thermal energy

Answer 24

Also. W/ random movements of atoms/molecules

Question 25

Potential energy

Answer 25

Energy in matter that is present d/t location or structure

Question 26

First law thermodynamics

Answer 26

Total energy of a system and environment is constant. “Can’t be created or destroyed”

Question 27

Second law thermodynamics

Answer 27

Entropy of system and environment always increases. Spreading

Question 28

IF disorder increases, why does an organized DNA helix form?

Answer 28

The heat released by helix formation increases the entropy of the surrounding.

Question 29

Free energy:

Answer 29

A living organisms energy that can do work

Question 30

3 types work from cell:

Answer 30

Chemical, transport, mechanical

Question 31

ATP

Answer 31

Cells energy shuttle

Question 32

Phosphates are removed from ATP via

Answer 32

Hydrolysis

Question 33

Can exergonic rxn’s be used to drive end endergonic rxn’s?

Answer 33

Yes

Question 34

Free energy of activation:

Answer 34

Initial energy needed to start a chemical reaction

Question 35

Do enzymes affect the changes in free energy?

Answer 35

NO

Question 36

How do enzymes work?

Answer 36

Lower activation energy

Question 37

How does enzyme active site lower activation energy?

Answer 37

Orienting substrates,straining substrate bonds, making favorable environment, covalently bonding to substrate