BIOCHEM WEEK 4

Question 1

• Fats
• Insoluble in water
• Soluble in nonpolar organic solvents
• Wide structural diversity
• Can be classified based on biochemical function

Answer 1

Lipids

Question 2

Classification of Lipids
BASED ON FUNCTION
• triacylglycerols

Answer 2

Energy storage

Question 3

Classification of Lipids
BASED ON FUNCTION
• phospholipids
• sphingoglycolipids,
• cholesterol

Answer 3

Membrane component

Question 4

Classification of Lipids
BASED ON FUNCTION
• bile acids

Answer 4

Emulsification

Question 5

Classification of Lipids
BASED ON FUNCTION
• steroid hormones,
• eicosanoids

Answer 5

Messenger

Question 6

Classification of Lipids
BASED ON FUNCTION
• biological waxes

Answer 6

Protective coating

Question 7

hydrolysisoccurs & lipids are converted into 2 or more smaller molecules
• Triacylglycerols
• Phospholipids
• Sphingoglycolipids
• Biological waxes

Answer 7

Saponifiable

Question 8

doesnotreact with water
• Cholesterol
• Steroid hormones
• Bile acids
• Eicosanoids

Answer 8

Nonsaponifiable

Question 9

• Naturally occurring monocarboxylic acid • Usually contain
1. Evennumberofcarbons
2. unbranched carbon chain
3. Double bonds in a cis configuration (if present)

Answer 9

Fatty Acid

Question 10

(t or f)

• Fatty acids may be classified based on the presence or absence of carbon-carbon double bonds

Answer 10

true

Question 11

• all C-C bonds are single bonds

Answer 11

Saturated fatty acids

Question 12

• one double bond

Answer 12

Monounsaturated Fatty Acids

Question 13

• >1 double bond

Answer 13

Polyunsaturated Fatty Acids

Question 14

• 2 numbers separated by a colon is used to denote length & number of C-C double bonds
• Carboxyl atom is C1
• Enclosed in parenthesis: Capital delta (Δ) with superscript indicating location of C-C double bonds

Answer 14

Delta Nomenclature

Question 15

• C1 is the carbon atom on the methyl (noncarboxyl) end (ω)
• Family is determined by the location of the C-C double bond closest
to the omega end

Answer 15

Omega Nomenclature

Question 16

• Most abundant type of lipid in the human body
• Lipid formed by esterification of 3 fatty acids to 1 glycerol molecule → triester + 3 H2O
• Location: within fat cells (adipocytes) found beneath the skin, in the abdominal cavity, in the mammary glands, and around various organs
• Simple – identical FAs
• Mixed – >1 type of FA

Answer 16

Triacylglycerols

Question 17

• TAG mixture that is solid or semisolid at room temp
• Saturated fatty acids predominate
• Odorless, colorless, tasteless when pure
• Animal source

Answer 17

FATS

Question 18

• TAG mixture that is liquid at room temp
• MUFAs and PUFAs predominate
• Odorless, colorless, tasteless when pure
• Plant source
• Fish source

Answer 18

OILS

Question 19

(t or f)

• Both the type of dietary fat and amount of dietary fat are important
• Recommendations:
• Limit to 30% of total calories
§ Less than 10% saturated fat
§ Up to 15% monounsaturated fat
§ Up to 10% polyunsaturated fat
• Intake of omega-3 fatty acids – from deep/coldwater fish oils (albacore tuna, salmon, mackerel)

Answer 19

true

Question 20

(t or f)

Fatty acid needed by the body that must be obtained from the diet as the body cannot synthesize them

Answer 20

true

Question 21

• Needed for proper membrane structure
• Starting material for production of longer-chain fatty acids

Answer 21

Linoleic & Linolenic acid

Question 22

eicosanoids

Answer 22

Arachidonic Acid

Question 23

for normal brain & retinal development

Answer 23

EPA & DHA

Question 24

Lipid that contains
§ 1 or more fatty acids
§ Phosphate group
§ Platform molecule – can be glycerol or sphingosine
§ Alcohol attached to phosphate
• Most abundant type of membrane lipid

Answer 24

Phospholipids

Question 25

• Phospholipid that has glycerol as its platform molecule • Lipid that contains § 2 fatty acids § Phosphate esterified to Glycerol § Alcohol esterified to PO4 group • All attachments between its groups are ester linkages • Head + 2 tails structure • Can undergo hydrolysis and saponification in a manner similar to TAGs

Answer 25

Glycerophospholipids

Question 26

• Phospholipid that has sphingosine as its platform • Lipid that contains § Fatty acid § Carbohydrate group – mono or disaccharide § Platform molecule –sphingosine • Head + 2 tails structure • Also undergo hydrolysis and saponification

Answer 26

Sphingophospholipids

Question 27

• monosaccharide (Glucose or Galactose) • Myelin sheath

Answer 27

Cerebrosides

Question 28

• more complex branched chain of up to 7 monosaccharide residues • grey matter & myelin sheath

Answer 28

Gangliosides

Question 29

• C27 steroid molecule • Most abundant steroid in the body – precursor of other steroids • Structure § C3: –OH § C10, C13: –CH3 § C5-C6: = § C17 – 8C side chain • Cell membranes • Brain & nerve tissue • Virtually all fluids • Mostly synthesized by the liver & intestines

Answer 29

Cholesterol

Question 30

a lipid whose structure is based on a fused-ring system that involves three 6-membered rings & one 5-membered ring called the steroid nucleus

Answer 30

steroid

Question 31

is a compact molecule with limited water solubility

Answer 31

Cholesterol

Question 32

Cholesterol • Distributed by protein carriers called

Answer 32

lipoproteins

Question 33

• Oxygenated C20 fatty acid derivative that functions as a messenger lipid • Precursor: Arachidonic Acid • Produced by almost all cells except RBCs • Exert their effects in the tissues where they are synthesized • Prostaglandins • Thromboxanes • Leukotrienes

Answer 33

Eicosanoids

Question 34

Functions • Mediation of inflammation • Production of pain and fever • Regulation of blood pressure • Blood clotting • Control of reproductive functions, e.g. induction of labor • Regulation of sleep-wake cycle

Answer 34

Eicosanoids

Question 35

• C20 structure containing a cyclopentane ring + oxygen- containing functional groups • C8 and C12 become connected to form a ring • Inhibit secretion of gastric acid • Increase protective mucus layer of the stomach • Contract or relax smooth muscle • Raise body temperature • Intensify pain • Enhance inflammatory response • Antithrombotic effect

Answer 35

Eicosanoids

Question 36

• C20 structure containing a cyclic ether ring + oxygen-containing functional groups • C8 and C12 become connected to form a ring • Promote formation of blood clots – released by platelets to promote platelet aggregation

Answer 36

Eicosanoids

Question 37

• C20 structure containing 3 conjugated double bonds and hydroxy groups • Mediate inflammation and hypersensitivity

Answer 37

LEUKOTRIENES

Question 38

• Monoester of long-chain fatty acid + long-chain alcohol • Fatty acids • saturated • 14-36 carbon atoms • Alcohols • saturated or unsaturated • 16-30 carbon atoms • Water-insoluble, water-repellent Functions • Humans & animals –protect hair & skin to keep it pliable & lubricated • Birds – keep feathers water-repellent & minimize loss of body heat • Plants – prevent excessive evaporation and protect against parasitism • Pharmaceuticals, Cosmetics, Polishing

Answer 38

Biological Waxes