Quiz #1

Question 1

Covalent bond

Answer 1

electrons are shared in orbitals; strong

Question 2

Ionic bond

Answer 2

electrons are transferred from one atom to another (resulting in electrostatic attraction between oppositely charged ions); strong

Question 3

Hydrogen bonds

Answer 3

electrostatic attraction between slightly positively charged H (in -OH and -NH) and slightly negatively charged O or M atom

Question 4

Van der Waals interactions

Answer 4

transient electrostatic attraction between two atoms, each is in a nonpolar covalent bond

Question 5

Electronegativity

Answer 5

the attractive force that an atomic nucleus exerts on the electrons of another atom

Question 6

Methyl (functional group, compound class, example)

Answer 6

CH3; alkyl; alanine

Question 7

Methyl (properties)

Answer 7

nonpolar; important modification of proteins and cytosine nucelotide

Question 8

Hydroxyl (functional group, compound class, example)

Answer 8

OH; alcohol; ethanol

Question 9

Hydroxyl (properties)

Answer 9

polar; hydrogen bonding; often participates in condensation reactions; required for phosphorylation of proteins

Question 10

Sulfhydryl (functional group, compound class, example)

Answer 10

SH; mercaptoethanol; thiols

Question 11

Sulfhydryl (properties)

Answer 11

polar; can form disulfide bridges to stabilize protein structures

Question 12

Aldehyde (functional group, compound class, example)

Answer 12

COH; acetaldehyde; aldehyde

Question 13

Aldehyde (properties)

Answer 13

polar; very reactive; energy-releasing reactions

Question 14

Keto (functional group, compound class, example)

Answer 14

CO; acetone; ketones

Question 15

Keto (properties)

Answer 15

polar; important in carbohydrates and in energy reactions

Question 16

Carboxyl (functional group, compound class, example)

Answer 16

COO-; acetic acid; carboxylic acid

Question 17

Carboxyl (properties)

Answer 17

charged; acidic; ionizes in living tissues; reacts with amino group to form peptide bond

Question 18

Amino (functional group, compound class, example)

Answer 18

NH2; methylamine; amine

Question 19

Amino (properties)

Answer 19

charged; basic; accepts H+ in living tissues to form NH3+; reacts with carboxyl group to form peptide bond

Question 20

Phosphate (functional group, compound class, example)

Answer 20

PO2(OH)2; 3-phophoglycerate; organic phopshates

Question 21

Phosphate (properties)

Answer 21

charged; acidic; ionizes in living tissues; enters into condensation reacts, often with inorganic phosphate; when bonded to another phosphate, hydrolysis is extremely exergonic

Question 22

When characterizing bonds or molecules as polar or nonpolar, what characteristics should you look for?

Answer 22

Electronegativities; dipoles

Question 23

Water is critical to life as we know it. We described three properties of water that all have biological consequences. Describe each.

Answer 23

Hydrogen bonds between water molecules: liquid water is very stable, takes lots of energy to break water molecules; need to break all H bonds to change state of matter

“Universal solvent”: polarity of water; slight positive and negative interacts with solute; solute is distributed

Aqueous solutions and pH

Question 24

Water is called the “universal solvent.” What does that mean?

Answer 24

It’s polar; another charged solute will be pulled apart by the water.

Question 25

Integral membrane proteins

Answer 25

Found in the membrane; exposed hydrophilic and hydrophobic regions

Question 26

Anchored proteins

Answer 26

Covalently attached to lipids in the bilayer; hydrophobic lipid group inserts into the bilayer

Question 27

Peripheral Proteins

Answer 27

Not embedded, interacts with integral proteins or phospholipids; polar or charged regions that interact with heads of phospholipids

Question 28

Transmembrane integral proteins

Answer 28

Type of integral protein spanning the entire bilayer; hydrophilic and hydrophobic domains

Question 29

Simple diffusion

Answer 29

No cellular energy required; small, non polar, uncharged, hydrophobic molecules

Question 30

Facilitated diffusion

Answer 30

No cellular energy required; channel protein/carrier protein; large, polar, charged, hydrophilic molecules

Question 31

Active transport

Answer 31

Cellular energy required; needs ATP; sodium-potassium pump

Question 32

Amino acids with electrically charged hydrophilic side chains

Answer 32

Arginine, histidine; lysine (+) Aspartic acid; glutamic acid (-)

Question 33

Amino acids with polar but uncharged side chains (hydrophilic)

Answer 33

Serine; Threonine; Asparagine; Glutamine; Tyrosine

Question 34

Amino acids with nonpolar hydrophobic side chains

Answer 34

Alanine; Isoleucine; Leucine; Methionine; Phenylamine; Tryptophan; Valine

Question 35

Special cases

Answer 35

Cysteine; Glycine; Proline