Chapter 5- Biological Macromolecules

Question 1

Functional groups that compose proteins

Answer 1

amine group, central hydrocarbon, carboxyl group, and R group.

Question 2

zwitterionic

Answer 2

• has both charges

- doubly ionized form at neutral pH values

Question 3

How many different amino acids?

Answer 3

20 different types

Question 4

amino acid families

Answer 4

• depends on their side chains*
• uncharged polar
• polar, acidic (negative)
• polar, basic (positive)
• nonpolar

Question 5

cysteine

Answer 5

• side chain has a reactive sulfhydryl group

- disulfide bonds help stabilize a protein structure

Question 6

disulfide bonds

Answer 6

• help stabilize a protein structure
• can be a component of tertiary structure if it is intrachain.
• can be a component of quaternary structure if it is interchain.

Question 7

macromolecule polymerization

Answer 7

• dehydration synthesis polymerizes molecules together.

- hydrolysis synthesis (condensation) breaks polymers down.

Question 8

peptide bonds

Answer 8

• chains of amino acids

Question 9

polypeptides

Answer 9

• multiple peptide bonds connected through dehydration synthesis.
• has polarity
• has a “N” terminus where the free amine group is
• has a “C” terminus where the free carboxyl group is
• The N- terminus is a function of amino acid #1

Question 10

Protein functions

Answer 10

• regulate
• signal
• structure
• transport
• movement
• catalysis

Question 11

Proteins sequences

Answer 11

• primary
• secondary
• tertiary
• quaternary

Question 12

protein primary structure

Answer 12

• The sequence of amino acids
• Polypeptide backbone
• average polypeptide has 300-500 amino acids

Question 13

protein secondary structure

Answer 13

• the alphacarbons in the polypeptide backbone allow a high degree of rotation & flexability.
• the amino acid backbone has many polar functional groups
• H bonds within the polypeptide
• can make an alphahelix or beta sheet
• the turns or random coil form depends on the primary structure.

Question 14

protein tertiary structure

Answer 14

• overall conformation created from interaction with R groups
• primary is stabilized by hydrophobic effect
• hydrophobic core with nonpolar chains
• polar side chains on outside from H bonds with water

Question 15

protein quaternary structure

Answer 15

• multiple polypeptides create one functional protein

- usually held together by noncovalent bonds

Question 16

denaturation

Answer 16

• proteins unfolding

- heat, pH changes, ionic strength changes, anything that disrupts the noncovalent bonds holding structures.

Question 17

lipids

Answer 17

Composed of two molecules

• Fatty acids
• Glycerol

Question 18

Fats

Answer 18

• storage of energy

- insulation and protection

Question 19

Fatty acids

Answer 19

• saturated

- unsaturated

Question 20

saturated fat

Answer 20

• do not have double bonds between carbons

- solid at room temp.

Question 21

monounsaturated fat & polyunsaturated fat

Answer 21

• double bond causes molecule to bend
• bent molecule causes “kink” and it cannot stack
• liquid at room temp.

Question 22

triglycerides

Answer 22

• fats

- glycerol with 3 fatty acids joined by dehydration synthesis.

Question 23

membrane lipids

Answer 23

• major component of cell membranes

- phospholipids

Question 24

phospholipids

Answer 24

• composed of 3 molecule parts: fatty acids, glycerol, polar group “polar head group”
• also goes under dehydration synthesis
• amphiphilic
• almost all have at least one unsaturated bond

Question 25

steroids

Answer 25

- carbon skeleton with 4 fused rings - cholesterol is the most common in humans - gives structure to membranes - precursor to hormones - mostly insoluble in water - emulsifier in human bile