Chemical Basis of Life

Question 1

What are the four types of macromolecules?

Answer 1

Proteins, carbohydrates, lipids, and nucleic acids

Question 2

Where is genetic information usually contained (not place in cell, molecule)?

Answer 2

DNA (sometimes RNA)

Question 3

What is the infectious agent in mad cow disease?

Answer 3

Proteins (PRION’s)

Question 4

Improperly folded _____ protein “infects” folding of normal cellular _____ protein.

Answer 4

PrP^sc, PrP^c

Question 5

PrP^c is mostly ______, while PrP^sc is mostly _______.

Answer 5

Alpha helix, beta sheet

Question 6

Organic molecules are characterized by _______ bonds.

Answer 6

Covalent

Question 7

What are covalent bonds?

Answer 7

Pairs of electrons shared between atoms (# electrons in outer shell is number of bonds atom can form).

Question 8

In non-polar covalent bonds, electrons are ______ shared between atoms

Answer 8

equally

Question 9

In polar covalent bonds, electrons are _______ shared between atoms.

Answer 9

Unequally

Question 10

What are electronegative atoms?

Answer 10

Positively charged nucleus exerts a large attractive force on outer shell electrons (for example, oxygen)

Question 11

What are electropositive atoms?

Answer 11

Less positively charged nucleus exerts smaller attractive force on outer shell electrons (for example, hydrogen).

Question 12

Electronegativity is dependent on what two things?

Answer 12

Number of protons in the nucleus and distance between protons and outer shell electrons.

Question 13

Carbon and ______ have very similar electronegativities, and thus whole molecules composed of them are relatively ________.

Answer 13

Hydrogen, non-polar

Question 14

What are the non-polar functional groups of organic molecules?

Answer 14

Methyl only

Question 15

What are the polar functional groups of organic molecules?

Answer 15

Hydroxyl, carboxyl, amino, phosphate, carbonyl and sulfhydryl

Question 16

Covalent bonds for ______ of organic macromolecules. Non-covalent bonds determine their _______ and their interactions with other molecules.

Answer 16

Backbone, 3-D structures

Question 17

Proteins have a ______ group, a ______ group and a ______ ______.

Answer 17

Amino, carboxyl, side chain

Question 18

When two amino acids connect, the C and N form a ______ bond.

Answer 18

Peptide

Question 19

Primary protein structure consists of _____ _____.

Answer 19

Peptide bonds (form covalent protein backbone)

Question 20

Polar uncharged amino acids

Answer 20

Aspartic, Glutamic, Lysine, Arginine and histadine

Question 21

Polar uncharged amino acids

Answer 21

Serine, threonine, glutamine (gln), asparagine and tyrosine

Question 22

Non-polar amino acids

Answer 22

alanine, valine, leucine, isoleucine, methionine, phenylalanine, and tryptophan

Question 23

Side chains with unique properties

Answer 23

glycine, cysteine and proline

Question 24

R groups participate in __________ bond types that drive protein folding

Answer 24

non-covalent (hydrogen bonds, ionic bonds, van der waals forces)

Question 25

_______ R groups have both acid and base forms in H2O

Answer 25

Polar charged

Question 26

_______ R groups form hydrogen bonds

Answer 26

polar uncharged

Question 27

Secondary protein structure primarily involved folding of protein due to ______.

Answer 27

Hydrogen bonds

Question 28

Beta sheet

Answer 28

H-bonding between strands

Question 29

Alpha helix

Answer 29

H-bonding between turns of the helix

Question 30

PrP^c ARR varient

Answer 30

Resistant, low stability

Question 31

Prp^c AHQ varient

Answer 31

Low suceptibility

Question 32

PrP^c ARQ varient

Answer 32

moderately susceptible

Question 33

PrP^sc VRQ varient

Answer 33

highly susceptible, high stability (H-bond stabilizes beta sheet)

Question 34

Van der Waals interactions are ______ ______ on non-polar molecules.

Answer 34

momentary partial charges

Question 35

Non-polar molecules disrupt ______ between H2O molecules

Answer 35

H-bonding

Question 36

Hydrophobic interactions drive _______ folding of proteins

Answer 36

tertiary level

Question 37

When hydrophobic molecules aggregate together, the entropy in the surrounding water ______.

Answer 37

Increases

Question 38

Which R-groups participate in Van der Waals and Hydrophobic interactions?

Answer 38

Alanine, valine, leucine (non-polars) and glycine and proline (unique properties)

Question 39

pK’ = the pH at which ______ = _____.

Answer 39

conjugate acid, conjugate base

Question 40

pK’ reflects the strength of the _______ relative to H2O.

Answer 40

Conjugate base

Question 41

Which R groups will never form an ionic bond?

Answer 41

glu w/ asp, lys w/ arg or his

Question 42

What is the pH range at which glu and lys can form an ionic bond?

Answer 42

Between 4.25 and 10.53

Question 43

What is the pK’ of asp?

Answer 43

3.86

Question 44

What is the pK’ of glu?

Answer 44

4.25

Question 45

What is the pK’ of lys?

Answer 45

10.53

Question 46

What is the pK’ of arg?

Answer 46

12.48

Question 47

What is the pK’ of his?

Answer 47

6.0

Question 48

What are the basic polar charged amino acids?

Answer 48

Lys, arg and his

Question 49

What are the acidic polar charged amino acids?

Answer 49

asp and glu

Question 50

Soluble acid/base pairs in solution can buffer polar charged groups from ________.

Answer 50

Ionizing effects of H2O