Chapter 5 PART 2

Question 1

Lipids

Answer 1

Hydrophobic molecules

Question 2

biologically important lipids

Answer 2

Fats (triacylglycerols)
Phospholipids
Steroids

Question 3

Lipids are hydrophobic because

Answer 3

they consist mostly of hydrocarbons, which form nonpolar covalent bonds

Question 4

They separate from water because

Answer 4

water molecules form hydrogen bonds with each other & exclude fats

Question 5

Lipids are the one class of large biological molecules

Answer 5

that do not form polymers

Question 6

Fats (or triacylglycerols)

Answer 6

are constructed from 2 types of smaller molecules: glycerol and fatty acids linked via an ester linkage

Question 7

Glycerol

Answer 7

is a 3-carbon alcohol with a hydroxyl group attached to each carbon

Question 8

fatty acid

Answer 8

consists of a carboxyl group attached to a long carbon skeleton

Question 9

Saturated Fatty Acids

Answer 9

have the maximum number of hydrogen atoms possible & no double bonds

Question 10

Unsaturated Fatty Acids

Answer 10

have one or more double bonds

Question 11

saturated fats

Answer 11

are solid at room temperature (most animal fats are saturated)

Question 12

unsaturated fats or oils

Answer 12

and are liquid at room temperature (plant fats and fish fats are usually unsaturated)

Question 13

trans fats

Answer 13

partially hydrogenated oils

Question 14

Trans fats raise LDL “bad” cholesterol

Answer 14

& lower HDL “good” cholesterol

Question 15

phospholipid

Answer 15

2 fatty acids and a phosphate group are attached to glycerol

Question 16

Amphipathic

Answer 16

the 2 fatty acids are the hydrophobic tail, but the phosphate group and its attachments (choline & glycerol) form a hydrophilic head

Question 17

phospholipid bilayer

Answer 17

with the hydrophobic tails pointing toward the interior

Question 18

Steroids

Answer 18

are lipids characterized by a carbon skeleton consisting of four fused rings

Question 19

Cholesterol

Answer 19

an important steroid, is a component in animal cell membranes

Question 20

Hormones

Answer 20

are steriods that travel as signaling molecules

Question 21

Proteins account for _______ of dry mass of most cells

Answer 21

50+%

Question 22

Protein functions include:

Answer 22

structural support, storage, transport, cellular communications, movement, and defense against foreign substances

Question 23

Enzymes

Answer 23

are a type of protein that acts as a catalyst to speed up chemical reactions

Question 24

Polypeptides

Answer 24

are unbranched polymers built from the 20 amino acids

Question 25

protein

Answer 25

s a biologically functional molecule that consists of one or more polypeptides

Question 26

Amino acids

Answer 26

are organic molecules with a backbone of carboxyl and amino groups

Question 27

Amino acids are linked by

Answer 27

peptide bonds