Chapter 9 Review

Question 1

Three roles of lipids

Answer 1

• Form bilayers that make up biological membranes
• Have hydrocarbons that serve as energy stores
• Many intra- and intercellular signaling

Question 2

Lipids are soluble in _______ solvents.

Answer 2

Organic

Question 3

Lipids make:

Answer 3

• Fats
• Oils
• Some vitamins
• Some hormones
• Nonprotein membrane components

Question 4

Define fatty acids

Answer 4

Carboxylic acids with long- chain hydrocarbon side groups. Most are found in the esterified form.

Question 5

Lipids ______ polymerize. Stick together due to ________, this __________ it.

Answer 5

can’t ; entropy, which increases it.

Question 6

Fluid Mosaic Model

Answer 6

• Membrane is not rigid and does not have a fixed orientation.
• Contains glycoproteins
• Contains integral proteins

Question 7

Glycoproteins

Answer 7

Membrane protein with oligosaccharides (carbohydrates) attached. On the extracellular side.

Question 8

Integral Proteins

Answer 8

Amino acids on the surface of the membrane with lipids–> hydrophobic –> polar residues. Go all the way through the membrane.

Question 9

Glycolipid

Answer 9

Lipid with carbohydrate attached. Extends into the extracellular area.

Question 10

Fatty acids will connect to the ______ of the triglycerols.

Answer 10

R-group

Question 11

Saturated Fats

Answer 11

• NO double bonds present, completely reduced (packed with H atoms).
• This causes them to pack closer together. Less reactive, higher melting point
• Highly flexible and can assume a large range of conformations

Question 12

Unsaturated Fats

Answer 12

Has at least one double bond present. Cis-formation –> causes kink in the chain and multiple unsaturated fats can’t pack close together like saturated fats can. Lower melting point due t the reduced van der Waals forces

Question 13

Glycerophospholipid head is made of

Answer 13

A phosphatic acid head and two fatty acid tails

Question 14

Why are glycerophospholipids bent?

Answer 14

• Not saturated

- Double bond adds kink, which adds rigidity

Question 15

How does phospholipase breakdown a lipid?

Answer 15

It binds close to the membrane and “chops” off the tail through hydrolyzation. It catalyzes the hydrolytic reactions.

Question 16

The fluidity of lipids ______ with the increase in degree of unsaturation.

Answer 16

Increases

Question 17

Triacylglycerols (aka triglycerides)

Answer 17

• A lipid in which three fatty acids are esterified to a glycerol backbone.
• Nonpolar
• Water insoluble
• Fatty acid triesters of glycerol
• Function as energy reservoirs
• Most ABUNDANT class of lipids
• Provide more energy than glycogen

Question 18

Triacylglycerols

Answer 18

Long-term energy storage

Question 19

Glycogen

Answer 19

Short-term energy storage

Question 20

Glycerophospholipids are a major lipid component of ________.

Answer 20

Biological membranes

Question 21

Plasmalogens

Answer 21

• a type of phosphoglyceride.
• The first carbon of the glycerol has a hydrocarbon chain attached via an ether.
• Central carbon (C2) has a fatty acid linked by an ester.
• The third carbon links to an enthanolamine or choline by means of a phosphate ester.
• Important component of muscles and nerves.

Question 22

Vitamins stay in the membrane except vitamin _____.

Answer 22

D

Question 23

The only water soluble vitamin

Answer 23

Vitamin C

Question 24

Vitamin essential for blood clotting

Answer 24

Vitamin K

Question 25

Vitamin important for picking up wavelengths in the eye.

Answer 25

Vitamin A

Question 26

Why is only having one tail not go for phospholipid heads?

Answer 26

- They form spheres: * Allows water gaps * Not good, entropy decreases * Allows the cells' insides (the HYDROPHOBIC REGION) the potential of coming into contact with water

Question 27

If hydropathy is positive

Answer 27

hydrophobic

Question 28

If hydropathy is negative

Answer 28

hydrophilic

Question 29

Phospholipases do what?

Answer 29

Hydrolyze Glycerophospholipids

Question 30

Integral Proteins are ________ membrane associated.

Answer 30

Tightly

Question 31

Gangliosides

Answer 31

- Mostly makeup cell-surface membranes | - Make up 6% of brain cell lipids

Question 32

- Act as specific receptors of certain pituitary glycoprotein hormones ( their complex carbohydrate heads act as the receptors). - Receptors of certain bacterial protein toxins - Could be specific determinants of cell-cell recognition

Answer 32

Gangliosides

Question 33

Gangliosides are important for:

Answer 33

- Cell growth - Cell differentiation - Carcinogenesis

Question 34

Steroids are _______-fused nonpolar rings.

Answer 34

four

Question 35

The most abundant steroid in animals and a big portion of it makes animal plasma membranes.

Answer 35

Cholesterol

Question 36

Polar OH group means

Answer 36

weak ampihilic nature

Question 37

The four-fused ring system of steroids

Answer 37

- adds a greater rigidity | - can be esterified to long-chain fatty acids

Question 38

Vitamin D is a ________.

Answer 38

Steroid

Question 39

Fat-soluble vitamins include

Answer 39

- Vitamin A - Vitamin K - Vitamin E

Question 40

Transverse Diffusion

Answer 40

The transfer of a lipid across a bilayer. Extremely rare. Requires hydrated, polar head group to pass through the hydrocarbon core of the bilayer

Question 41

Lateral Diffusion

Answer 41

The pairwise exchange of neighboring phospholipid molecules in the same bilayer half.

Question 42

Chaotropic Agents

Answer 42

- Disrupt the water structure | - Reduces the hydrophobic effect (which is responsible for stabilizing the association of the protein with the membrane)

Question 43

Beta-barrel structures are

Answer 43

antiparallel beta sheets that roll up

Question 44

Porins

Answer 44

- Channel-forming proteins in the outer membrane of gram-negative bacteria. - Beta-barrels make these. - Permit the entry of smaller polar solutes