Exam 3

How many carbons does formate have?

1

How many carbons does acetate have?

2

How many carbons does propionate have?

3

How many carbons does butyrate have?

4

How many carbons does valerate have?

5

How many carbons does caproate have?

6

How many carbons does octanate have?

8

How many carbons does decanoate have?

10

How many carbons does laurate have?

12

How many carbons does myristate have?

14

How many carbons does plamitate have?

16

How many carbons does stearate have?

18

How many carbons does archadonate have?

20

Draw a triacylglycerol

Saturated fats =

no double bonds

Unsaturated fats =

have double bonds (they are not saturated with carbons)

What is a monounsaturated fat?

1 carbon to carbon double bond

What is a polyunsaturated fat?

more than 1 carbon to carbon double bond

Draw 18:1 omega 3

Draw 18:1 omega 6

Draw 18:3 omega 9,6,3 as a trans fat

Draw 18:3 omega 9,6,3 as a cis fat

Draw linolenic acid

has 3 double bonds (18:2 delta cis 9,12,15)

Draw linoleic acid

has 2 double bonds (18:2 delta cis 9.12)

Liquidity ______ with an increase in chain lengths

decreases

Liquidity _____ with cis double bonds

increases

Liquidity _______ with trans double bonds

decreases

Bile salts are beneficial for docking

co-lipase

Bile salts _______ and __________

neutralize chyme

lipid emulsifying

Enzymes produced in the active form are called

zymogens

What does gastric lipase do?

cleaves short/medium chain fatty acids from carbons 1 and 3

What is in the pancreas during lipid digestion?

pancreatic alpha amylase

co-lipase

pro-pancreatic lipase

pro-phospholipase A2

trypsinogen

What does enteropeptidase do?

breaks peptide bonds between amino acids

What does lingual lipase do?

cleaves short/medium chain fatty acids from carbon 3 in glycerol

Draw 20:4 cis omega 3,6,9,12

Name 20:4 cis omega 3,6,9,12 in delta nomenclature

20:4 cis delta 8,11,14,17

What is the lipoprotein that carries lipids from intestines to body?

chylomicron

What apolipoprotein distinguishes a chylomicron?

Apo B48

What is the difference between lipoprotein and apolipoprotein?

Lipoproteins are complex particles that transport lipids (cholesterol and triglycerides) through the blood, acting as the "vehicle". Apolipoproteins are the specific proteins that form the outer shell of these particles, acting as the structural "driver" and organizer, guiding metabolism and receptor binding

What apolioprotein is important for lipid uptake into skeletal muscle?

Apo CII

What enzyme does Apo CII interact with?

lipoprotein lipase

What is the “equation” for beta oxidation cycles?

number of carbons/2 - 1

How many FADH2, NADH2, and acetyl CoA are leftover in beta oxidation?

7 FADH2

7 NADH2

8 Acetyl CoA

How many FADH2, NADH+H+, and GTP are leftover in the TCA cycle?

1 FADH2 per 1 Acetyl CoA * 8 Acetyl CoA = 8 FADH2

3 NADH+H+ per 1 Acetyl CoA * 8 Acetyl CoA = 24 NADH+H+

1 GTP per 1 Acetyl CoA * 8 Acetyl CoA = 8 GTP

How many ATP per palmitate are between beta oxidation and the TCA cycle?

15 FADH2 * 1.5 ATP/FADH2 = 22.5 ATP

31 NADH+H+ * 2.5 ATP/NADH2 = 77.5 ATP

8 GTP * 1 ATP/GTP = 8 ATP

22.5 + 77.5 + 8 = 108 ATP/Palmitate

Ketogenesis

occurs in liver only

occurs in mitochondria

acetyl CoA → Acetoacetate or B-OH butyrate

FA synthesis

occurs in liver

occurs in cytosol

citrate → FA (fatty acid)

Explain/diagram the entry of fatty acids into the mitochondria.

What pathways occur in the cytosol of the cell?

glycolysis

lipogenesis

FA synthesis

glycogenesis

What pathways occur in the mitochondria?

ketogenesis

beta oxidation

Lipolysis

occurs in cytosol

TAG (triacylglycerol) → 3 FAs (fatty acids) + glycerol

Beta oxidation

occurs in mitochondria

FA (fatty acid) → Acetyl CoA

Lipogenesis

occurs in cytosol

3 FA (fatty acids) + glycerol → TAG

Ketolysis

occurs in mitochondria

Acetoacetate or B-OH butyrate → acetyl CoA

What (organ) are ketones made?

liver

What is more acidic propionate or stearate and why?

propionate

fewer carbons; the hydroxyl group that is giving up the hydrogens makes up a bigger proportion of the total molecules in the solution. this means there are more hydrogens that can be donated

Saturated fats

have no double bonds

Unsaturated fats

have double bonds

meaning they are NOT saturated with hydrogens

Lipids are

waxy or oily substances; soluble in non-polar solvents

Functions of lipids

energy dense

insulators

good for forming membranes

C=O is what type of group?

carboxyl

CH3 is what type of group?

methyl

What enzyme breaks down carbohydrates in the mouth?

salivary alpha amylase

Fatty acids are stored as….

triacylglycerols (also known as triglycerides)

Double bonds cause ____ in fatty acids which influence ______

“kinks”

membrane fluidity

Cis double bonds ____ bends in fatty acids while trans do not

induce

Short/easy description of digestion/absorption of lipids

(1) Lipid digestion begins in the mouth with lingual lipase, which targets short- and medium- chain fatty acids.

(2) Gastric lipase in the stomach continues lipid digestion, functioning optimally at pH ~3

(3) The pyloric sphincter regulates stomach emptying; fat sensing triggers hormones (e.g., C P-1, CCK) that delay emptying

(4) In the small intestine, bile (bile salts, cholesterol esters, phospholipids) emulsifies fats to facilitate enzymatic digestion by pancreatic lipase and colipase

Pro-pancreatic lipase breaks down what?

lipids (triacylglycerols)

Pro-phospholipase A2 breaks down

phospholipids

Trypsinogen is an enzyme that breaks down what?

proteins

What happens when lipids are emulsified?

a micelle is created which has a bunch of triglycerols in the middle

Where are bile salts produced?

made in the liver by cells called cholangiocytes

they are stored in the gallbladder

Where in the body do chylomicrons go?

lymphatic system then they enter the blood at the thoracic duct

What are high density lipoproteins (HDLs)?

they are produced by the liver and scavenge fat so there is not too much fat in your blood, then they bring it back to the liver

they are protein dense

What does a lipoprotein lipase do?

removes lipids from lipoproteins

When do you want your adipose tissue to take up lipids?

after consuming a meal

Examples of zymogens

trypsinogen, pro-pancreatic lipase, pro-phospholipase A2

they are produced to inactive to prevent self-digestion

What does enteropeptidase do?

it activates trypsinogen to trypsin

What is the role of trypsinogen?

It is a zymogen (produced in their inactive form) and it is first acted on by enteropeptidase to form trypsin

This trypsin can then self-activate more trypsinogen

When does the pancreas release insulin?

during the fed state

When is adipose tissue releasing fats?

during the fasted state

When is adipose tissue taking up fats?

during the fed state

Glucose induces insulin release but it can only occur in response to

eating a high protein meal

this is because of histidine, arginine, and lysine are positively charged and when they enter the cell, they make the inside of the cell less negative. This causes depolarization which stimulates insulin release

What has to be on the cell surface of adipose tissue in order to take up fatty acids and glycerol?

LPL (lipoprotein lipase)

What does pancreatic lipase do?

removes fatty acids from triacylglycerols, producing fatty acids and monoacylglycerols

What transporter are fatty acids absorbed through?

CD36

What does LPL (lipoprotein lipase) do?

hydrolyzes triglycerides in chylomicrons to fatty acids and glycerol for uptake by skeletal muscle and adipose tissue

Ketogenesis occurs in the brain during what state?

the fasted state

Fatty acids enter mitochondria as

fatty acyl CoA interacting with CPT1, converting to fatty acyl carnitine

Fatty acyl carnitine is transported into the mitochondria via

CACT and reconverted to a fatty acyl CoA by CPT2

In fasting or ketogenic diets, excess acetyl-CoA from beta-oxidation cannot enter the TCA cycle due to

low OAA availability

Acetyl-CoA converts to

ketone bodies

acetoacetate and B-OH butyrate

When do we make ketones?

fasted state

Name this fatty acid (include cis/trans in the name) using the n/Ω nomenclature.

18:3 _{Ωcis 3,6,9}

Name this same fatty acid using the Δ nomenclature (include cis/trans in the name)

18:3 _{Δcis 9,12,15}

What essential fatty acid is this? (HINT: 18:3 _{Ωcis 3,6,9} OR 18:3 _{Δcis 9,12,15})

linolenic acid

Which lipid is more likely to be solid?

16:1 or 16:4

16:1

they both have the same chain length (16 carbons) but the difference is the amount of double bonds. the fewer the double bonds = straighter chains = tighter packing = more solid

Which lipid is more likely to be solid?

20:1 cis n(Ω)-6 or 20:1 trans n(Ω)-6

20:1 trans n-6

this is because trans fats are more linear (ie. they just have a regular double whereas cis fats have the trapezoid shape) and this allows them to be more tightly packed

Which lipid is more likely to be solid?

butyrate or octanoate

octanoate

has more carbons

Name this fatty acid (include cis/trans in the name) using the Ω nomenclature.

18:2 _{Ωcis 9,12}

also known as linoleic acid