Bartling Exam 1 Study Guide

Question 1

What is the solid storage form of lipids found primarily in adipose tissue?

Answer 1

Triglycerides

Question 2

What molecule is central to both carbohydrate and fat metabolism?

Answer 2

Acetyl-CoA

Question 3

Fatty Acid Structure and Physical Properties

Answer 3

Longer chain -> poorer solubility, higher melting point

Less double bonds -> poorer solubility, lower melting point

Question 4

Major class of polar membrane lipids derived from phosphatidic acid

Answer 4

Phospholipids

Question 5

Fatty acids are esterified to what molecule?

Answer 5

Glycerol -> Triglyceride

Question 6

Sphingolipids

Answer 6

2nd largest

Sphingosine backbone, non-saponifiable (amide linkage)

Cell surface recognition sites (RBC type)

Question 7

Bacterial endotoxin

Long O-antigen side chains

Lipid A: hydrophobic anchor- inflammatory response

Answer 7

Lipopolysacharide

Question 8

Cholesterol

Answer 8

• Only in animal fat
• Made in liver
• Controls membrane fluidity
• Storage and transport
• Steroid hormone precursor

Question 9

Steroid Hormones

Answer 9

• No alkyl chain (unlike cholesterol)
• More polarity than cholesterol
• Move through blood stream attached to protein carriers

Question 10

Terpenes

Answer 10

• Simple lipids w/out fatty acid
• 2 isoprenes
• Flavors and odors
• Vitamin precursors

Question 11

How is lipid metabolism regulated?

Answer 11

Controlled by rate of triglyceride hydrolysis in adipose tissue.

Regulated by hormones (insulin, glucagon, epinephrine, cortisol)

Question 12

What is the carnitine shuttle?

Answer 12

Fatty acyl-CoA too large and polar to penetrate inner membrane -> FA transferred to carnitine -> antiport mechanism brings carnitine with FA in

Question 13

Products of beta-oxidation of even-numbered FA?

Answer 13

Fatty Acyl-CoA (with 2 less carbons)

1 mol each of:
Acetyl-CoA
FADH2
NADH

Question 14

Beta-oxidation products of unsaturated FA

Answer 14

Already partially oxidized -> Less FADH2 and less ATP

Question 15

Beta-oxidation products of odd-number FA

Answer 15

Same as even until last rxn -> Propionyl-CoA instead of Acetyl-CoA -> Succinyl-CoA -> TCA cycle

Question 16

Beta-oxidation products of branched FA

Answer 16

Can’t beta oxidase, so alpha oxidation instead -> CO2 and Acetyl OR Propionyl-CoA

Question 17

What is a ketone body?

Answer 17

• Carbonyl w/2 R groups branching off
• Formed during fasting/starvation (rich energy source)
• Spares glucose and degradation of muscle protein for gluconeogenesis

Question 18

Acetyl-CoA Carboxylase

Answer 18

Phosphorylation (glucagon) inhibits, Dephosphorylation (insulin) activates.

Enzymatic and carrier protein function.

Forms Malonyl-CoA from Acetyl-CoA (stage 1 lipogenesis)

Question 19

Malate Shuttle

Answer 19

Transports Acetyl-CoA out through inner mitochondrial membrane by transfer of two-carbon units (citrate out, malate in)

Question 20

Main fat storage info molecule

Protein hormone

Reduces appetite, increases energy expenditure

Answer 20

Leptin

Question 21

Fatty Acid Synthesis Steps

Answer 21

1. Priming of cysteine group with Acetyl-CoA
2. Malonyl-CoA transferred
3. 3-ketoacyl synthase catalyzes rxn of acetyl group and malonyl residue
4. Malonyl-CoA displaces ACLU group
5. Rxn repeated 7X

Question 22

Catalyzes hydrolysis of ester bonds -> glycerol and FA for fuel

Answer 22

Lipase

Question 23

Group of drugs that act to reduce levels of fats (triglycerides/cholesterol) in blood

Answer 23

Statins

Question 24

Bile Acids

Answer 24

• Formed in liver, stored in gallbladder
• Emulsifies fats into micelles
• Derived from cholesterol

Question 25

Carbohydrate Chirality

Answer 25

D- hydroxyl group on R L- hydroxyl group on L Anomeric Carbon- when cyclic sugar is formed through tautomerization -> new asymmetric center

Question 26

Most abundant carbohydrate in nature?

Answer 26

Cellulose (plant cell walls)

Question 27

Starch vs Glycogen

Answer 27

Starch- plants, alpha 1,4 Glycogen- animals, alpha 1,6

Question 28

Amino sugar found in bacterial cell walls and connective tissues as hyaluronate?

Answer 28

Peptidoglycan (murein)

Question 29

Lipids or Carbohydrates more energy?

Answer 29

Lipids. FA are more "reduced" than carbs; FA are no polar and not hydrated by water

Question 30

How many stereoisomers can be made from aldoses?

Answer 30

2^n (number of asymmetric centers)

Question 31

Why has glucose been evolutionary selected as blood sugar?

Answer 31

- It exists in nonreactive, inert, cyclic conformations - Least oxidizable and least reactive with protein - Highest percent of sugar found in cyclic form

Question 32

Relationship between sugars and blood types?

Answer 32

Blood determined by sugars located on head groups. - NAG: A antigen - Gal: B antigen - NAG + Gal : AB antigen - No NAG or Gal: O antigen

Question 33

Polar lipids from phosphatidic acid (Phosphatidylcholine, Phosphatidylserine, etc.) Ester bonds (saponifiable)

Answer 33

Glycerophospholipids

Question 34

Primary starting material of Glycerol-3-phosphate for synthesis of phosphatidic acid

Answer 34

Liver- Glycerol Adipose- Glucose

Question 35

Sphingolipids with covalently bound sugars (blood typing)

Answer 35

Glycolipids/Glycosphingolipids