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Chapter 1 BC > Chap 2 > Flashcards

Chap 2 Flashcards

1
Q

Noncovalent interactions

A

Don’t share –transfer

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2
Q

ionic

A

NaCl

electrostatic interactions between permanently charged species, or between the on and a permanent dipole

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3
Q

H-bond (Dipole-dipole): (FON)

A

electrostatic interactions between uncharged, but polar molecules.

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4
Q

covalent integration

A

sharing electrons

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5
Q

Van der walls

do all compounds have them

A

weak interactions between all atoms, regardless of polarity.

Attractive (AT LONGER DISTANCES): dispersion
Repulsive(AT SHOWER DISTANCES): steric
-both depend on distance, when too close they become steric ( this static ,run away) etc
- any two atoms in close proximity

all atoms have vanderwals

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6
Q

Hydrophobic effect

A

: associated with the ordering of water molecules around non-polar substances.

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7
Q

hydrogren bond

A

Strong dipole-dipole or charge-dipole interactions that arise between an acid (proton donor) and a base (proton acceptor). They are the strongest when the bonding molecules are oriented to maximize electrostatic interaction. So ideally, 3 atoms involved are all in one line.

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8
Q

why are G-C base pairs harder to pull apart then A-T

A

The hydrogen bonds holding two strands together can be pulled apart (unzipped) because hydrogen bonds are weak.

GC base pairing is considered stronger than AT pairing for two reasons. AT has TWO characteristically strong hydrogen bonds, one N-H…..O and one N-H…..N.

GC has THREE bonds, three characteristically strong: two N-H….O and one N-H….N.
–So more energy is required to break this bond OF GC

However GC bonds are also stabilized further due to their higher tendency to pi-stack and use the LDF forces to stabilize the rings within their structure when arranged like this.

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9
Q

IMPORTANCE OF HYDROGEN BONDS

EXTREMELY IMP.

A 
The unique properties of water
Structure and function of proteins
Structure and function of DNA
Structure and function of polysaccharides
Binding of a substrate to enzyme
Binding of hormones to receptors
Matching of mRNA and tRNA
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10
Q

water geometry

LOW OR HIGH BP,MP

A

The geometry is a distorted tetrahedron.

HIGH BP AND MP

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11
Q

is H2O Bronstead-Lowry acid (proton donor) or base (proton acceptor)

A

Oxygens electronegativity induces a net dipole moment. For this reason, H20 can serve as BOTH a Bronstead-Lowry acid (proton donor) or base (proton acceptor)

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12
Q

Water is a poor solvent for .

A

Water is a poor solvent for nonpolar substances like nonpolar gases, aromatic moieties, and aliphatic chains (long hydrocarbon chains- fast/lipids).

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13
Q

Water is a GOOD solvent for .

A

charged and polar substances like amino acids and peptides, small alcohols, and carbohydrates.

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14
Q

AMPHIPATHETIC

A

BOTH POLAR AND NON POLAR REGIONS

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15
Q

one of the main factors behind: protein folding, protein- protein association, formation of lipid micelles, binding of steroid hormones to their receptors?

A

The Hydrophobic effect

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16
Q

Adding hydrophobic molecules to water ___ the entropy of the system

A

DECREASES

Each lipid molecule forces surrounding h20 molecules to become highly ordered.

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17
Q

The hydrophobic effect also favors ligand( STEROIDS) binding WHICH IS

A

binding sites in enzymes and receptors are often hydrophobic. Such sites can bind hydrophobic substrates and ligands such as steroid hormones.

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18
Q

As the substrate comes in closer proximity to the enzyme, the entropy __ as the enzyme displaces ordered h20 molecules from the substrate, thereby increasing the entropy of the system.

A

INCREASES

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19
Q

buffers help keep pH in a

A

in a discrete range. Different buffer systems have different ranges.
Maintaining intracellular pH is vital to all cells. Enzyme catalyzed reactions have specific pH to function optimally.

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20
Q

he ability for polar substances to dissolve depends on

A

H bond donors and acceptors

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21
Q

is Water part of protein structure

A

Yes

22
Q

where is water bound in port channel?

A

Water is bound in a proton channel of the membrane protein cytochrome f, which is part of E-trapping machinery of photosynthesis.

23
Q

he presence of ___ allows for proton hopping.

A

water

24
Q

Do two non polar molecules in a solution have any speed affinity ?

A

NOO, two non polar molecules in a solution DO NOT have any speed affinity THHEY GO TOGETHER BECAuSE OF ENTROPy IN A AQUEOUS SOLUTION !

25
Q

What cause non polar molecules to go together in a solution

A

ENTROPY

26
Q

Is disorder favored in hydrophobic effect?

A

YES

entropy is favored
entropy is positive

27
Q

IS low entropY theordynamically favorable or unfavorable?

A

UNFAVORABLE!

LOW ENTROPY IS NOT FAVORABLE IN WATER

28
Q

HYDROPHOBIC SUBSTANCES HAVE ___SOLUBILITY

A

LOW!!

THEY DO NOT DISSOLVE

29
Q

ARE POLAR HEAD GROUBS EXPOSED IN HYDROPHOBIC EFFECT

A

YES! Only polar head groups are exposed and make energetically favorable H-bonds with h20.

30
Q

INITIALLY WHEN LIPID MOLECULES ARE DISPERSED IN WATER FORCES SURROUNDING H2O TO BECOME

A

HIGHLY ORDER= DECREASING ENTROPY=SYSTEM IS NOW UNFAVORBALE

31
Q

WHEN LIPID MOLECULES ARE TOGETHER IT MINIMIZES___

A

ORDER MAKING IT FAVORED

THERE IS LESS ORDER OF WHATER BETWEEN LIPID MOLECULES BECAUSE THEY ARE NOW TOGETHER

32
Q

MICELLES

A

WHEN ALL THE HYDROPHOBIC MOLECULES ARE AGGREGATED FROM WATER ENTROPY INCREASES

33
Q

3 CONTRIBUTERS OF BUFFER SYSTEMS IN VIVO

A

-Bicarbonate buffer system ( BLOOD PLASMA): buffers to blood
CO2 + H20←→H2CO3←→ CO2 + H20
-Histidine, efficient buffer at neutral pH
-PHOSPHATE

34
Q

WATER IS NOT ONLY A SOLVENT IT IS A

A

SUBSTRATE– SEEN IN HYDROLYSIS

35
Q

Why do nonpolar moieties aggregate in water?

A

The hydrophobic effect is the observed tendency of nonpolar substances to aggregate in aqueous solution and exclude water molecules.

36
Q

Water can become so heavily attracted to a different molecule, like

A

Water can become so heavily attracted to a different molecule, like salt (NaCl), that it can disrupt the attractive forces that hold the sodium and chloride in the salt molecule together and, thus, dissolve it.

37
Q

hydrophobic rxn are ____ driven

A

entropy

38
Q

what are one of the main factors behind protein folding , formation of lipids micelles, binding of steoird hormones their recptors

A

hydrophobic effect

39
Q

Hydrophobic rxn is or is not the result of attractive force between two nonpolar molecules

A

IS NOT!!!!

40
Q

water near hydrophobic solutes are

A

highly ordered, forming cages around hydrophobic alkyl chains –

41
Q

because water around hydrophobic substance is highly ordered this means entropy is LOW which is Favorable or unfavorable

A

UNFAVORABLE

42
Q

adding hydrophobic molecules increases or decreases entropy of system?

A

DECREASES– each lipid forces h20 to become highly ordered around it

43
Q

what would happen if you added amphipathtic molecule to water?

A

the nonpolar regions would aggregate ( gather) so the h20 around would be less ordered =INCREASES ENTROPY

ONLY POLAR heads are exposed making energy favorable H-bonds with h2o

44
Q

Why do nonpolar ends aggregate

A

Because entropy of the system INCREASES IF ess water cages form —NOTHING TO DO WITH NONPOLAR BEING ATTRACTED TO NONPOLAR

45
Q

HYdrophobic effects favors ligand binding, binding sites in enzymes/recptors are __

A

hydrophobic

46
Q

As a substrate comes closer proximity to the enzyme , entropy increases as the enzymes_

A

displaces ordered h20 molecules from the substrate, increases entropy of the system

47
Q

the ability for polar substance to dissolve depends on

A

h bond donors and acceptors

48
Q

maintaing normal ph in the blood is essential for

A

cells to carry out their fuction, ezymes catalyzed rxn have a specific ph yo function

49
Q

what is a micelle

A

In aqueous solution, molecules having both polar or charged groups and non polar regions (amphiphilic molecules) form aggregates called micelles. In a micelle, polar or ionic heads form an outer shell in contact with water, while non polar tails are sequestered in the interior.

-spontaneously forms through phospholipids

50
Q

ATP can be hydrolysized to

A

ADP or AMP, atp hydrolysis is exergonic

51
Q

why is hydroysis favored

A

ATP is a covalent bond , atp concentration is higher than adp in the cell

52
Q

how does atp hydrolysis drive a rxn

A

when atp is hydroylzed, P(phosphate) is removed and stuck to an enzyme which causes actication= the 2 neg charges change conformation which drive rxn!

Chapter 1 BC (4 decks)

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