1What are lipids generally insoluble in?
Water
2Why is there a problem with lipids being insoluble in water?
Majority of the body and the contents of the GI tract are made of water
3How do lipids try to avoid water?
They try to stick together, increasing their surface area
4What are lipids known for?
An important source of energy, diet, and storage
5What makes up the cell membrane?
The lipid bilayer and microbial phospholipids (MPL)
6Why must the body consume essential fatty acids?
Because the body cannot generate them
7What does the body use essential fatty acids to synthesize?
Hormones
8What do lipids do to feed palatability?
Increase the palatability of feed
9What happens when there are too many lipids in feed?
They decrease the palatability
10What is a fatty acid?
Straight chain of hydrocarbons that terminate in a carboxyl group
11What is the base structure of lipids?
Fatty acids
12What is a carboxyl group?
CH3 - (CH2)n - COOH
13What is special about saturated fatty acids (SFA)?
They do not contain any C=C double bonds, containing all of the hydrogens they can possibly contain
14What does having more hydrogens in a fatty acid cause?
More energy
15What is the structure like in a saturated fatty acid?
A striaght carbon chain
16What is special about unsaturated fatty acids (UFA)?
They contain one or more C=C double bonds
17What is the result of having double bonds in a UFA?
For every one double bond, two hydrogens are missing
18What is the structure like in an unsaturated fatty acid?
Not every straight due to kinks at the double bonds - can either be cis or trans with the hydrogens of the double bond
19What is a monounsaturated fatty acid (MUFA)?
Only one C=C double bond, so it is missing 2 hydrogens
20What is a polyunsaturated fatty acid (PUFA)?
More than one C=C double bond
21What are the two types of fatty acids?
Saturated and unsaturated
22What determines fluidity in fatty acids?
C=C double bonds
23What happens the melting point of a UFA if there are more C=C double bonds?
The melting point will decrease
24What is oil?
A type of lipid that is liquid at room temperature and has many double bonds
25What is fat?
A type of lipid that is solid at room temperature and has very few double bonds
26How does the omega naming system work for fatty acids?
Starts counting from the methyl end of the fatty acid and assumes that the double bonds are separated by three carbons (n-7 means db at C7)
27How does the delta naming system work for fatty acids?
Starts counting from the carboxyl end of the fatty acid (delta^9 means db at C9)
28How do we store lipids?
Triglycerides/triaglycerol (TAG)
29About what percentage of lipids we (humans/pigs) consume are TAG?
95%
30Which parts of a phospholipid are hydrophobic?
Sn1 and Sn2
31Which part of a phospholipid is hydrophilic?
The polar headgroup P (Sn3)
32What type of enzyme is lingual lipase?
Mammalian (ME)
33What is lingual lipase?
A mammalian enzyme produced by the salivary glands in nonruminants
34Where is the only place lingual lipase can be produced?
The mouth
35What does lingual lipase do?
Helps lower the pH in the stomach and hydrolizes the FA at the Sn3 position of TAG
36Where does lingual lipase function in nonruminant animals?
The mouth and stomach
37Where does lingual lipase function in ruminant animals?
Ruminant animals do not have lingual lipase
38What happens in the mouth of a nonruminant?
Physical emulsification of TAG, which increases the surface area, allowing lingual lipase to hydrolize it into DAG + an FFA
39What is DAG?
Diaglycerol - a hydrolized TAG at the Sn3 position
40What is being digested in the mouth of a nonruminant?
A minimal amount of TAG
41What is being secreted by the mouth of a ronruminant?
Lingual lipase
42What happens in the stomach of a nonruminant?
Physical emulsification of TAG so that gastric lipase and some lingual lipase can hydrolize the Sn3 position and turn it into DAG
43What is being secreted by the stomach of a nonruminant animal?
Gastric lipase
44What cells make gastric lipase?
Chiet cells
45What is special about the survival skills of lingual lipase and gastric lipase?
They are stable and functional at a low pH
46What is gastric lipase?
An ME in the stomach that acts on the short chain FA at the Sn3 position, hydrolizing it into DAG
47What is produced continuously in the stomach of a nonruminant?
Gastric lipase
48As fat intake increases, what happens to gastric lipase?
Production of GL increases
49What is absorbed in the stomach of a nonruminant?
Nothing
50Where does the digestion and absorption of TAG, DAG, and FFAs occur in nonruminants?
The small intestine
51What are the three phases that occur in the small intestine of a nonruminant (in order)?
Emulsification, enzymatic digestion, and absorption
52What is emulsification?
Increasing the SA of a fat droplet by turning it into many small fat droplets
53What are the two types of emulsification?
Physical and chemical
54What is physical emulsification?
Mixing that occurs in the stomach and as food enters the duodenum
55What is chemical emulsification?
Occurs in the proximal small intestine when bile is mixed with digesta at the duodenum, coating the fat droplets
56Where is bile made and stored?
Made in the liver and stored in the gallbladder
57What is bile synthesized from?
Cholesterol
58What is unique about the make-up of bile?
It has both a hydrophobic region and a hydrophilic region allowing it to interact with hydrophobic lipids and the aqueous environment
59What is pancreatic lipase?
A ME that hydrolizes fatty acids from the Sn1 and Sn3 positions, but requires colipase for optimal activity
60Which enzyme requires colipase for optimal activity?
Pancreatic lipase
61What positions of TAG does pancreatic lipase interact with?
Sn1 and Sn3
62What is colipase?
A protein produced by the pancrease in its inactive form, procolipase, that is then activated to colipase by trypsin and creates a binding site for pancreatic lipase
63How is colipase able to interact with fat droplets?
It has a hydrophobic region
64What happens during enzymatic digestion in the small intestine?
Pancreatic lipase hydrolizes TAG into DAG, then hydrolizes DAG into MAG, all with the help of colipase
65What activates procolipase into colipase?
Trypsin
66What is absorbed into the enterocyte in the small intestine of a nonruminant?
MAG and 2 FFAs along with some bile
67What is micelle?
A fat droplet that contains FFA and MAG, cholesterol, and ADEK
68What do micelles fromed in bile acid allow for?
Transport across the apical membrane into the enterocyte
69What does AcylCoA Synthetase do?
An enzyme that reforms TAG in the enterocyte
70How does AcylCoA Synthetase reform TAG?
By adding one FFA and removing an H2O molecule to make DAG, then repeating the process on DAG to make TAG
71What is a glycolipid?
A lipid that contains a sugar at Sn1 and is commonly found in grasses and plants as a primary lipid source for grazing animals
72What are phospholipids?
Primary sources of lipids digested in the small intestine of ruminants that can from microbes (MPL)
73What happens to fatty acids with less than (or equal to) 10 carbons in an enterocyte?
They move through the enterocyte into the blood, and in the blood they bind to albumin and go to the liver
74What is albumin?
A transport protein in the blood
75What happens to fatty acids with more than (or equal to) 12 carbons in an enterocyte?
They under go intracellular TAG reformation
76What can AcylCoA Synthetase not bind to?
Fatty acids with less than (or equal to) 10 carbons
77What happens to the TAG that is reformed within the enterocyte of a nonruminant?
It goes to the ER to aquire B-48, then it gets sent to the GA to aquire carbohydrates (thus turning it into a chylomicron), and then sent out of the cell into lymphatic circulation
78What kind of fatty acids make up TAG in nonruminant animals?
Unsaturated and Saturated
79What kind of fatty acids make up TAG in ruminant animals?
Only saturated fatty acids
80What is the proper name for B-48?
Apolipoprotein
81What is B-48?
A protein that stabilizes a lipoprotein as it moves through circulation, confers speciality (like a name tag) which tells the liver to leave it alone, then enables lipoprotein lipase to hydrolize TAG into DAG and FFA outside of the enterocyte on the surface of muscle and adipose cells
82What is a chylomicron?
A complete fat particle that is exocytosed into lymphatic circulation and then slowly moves through the blood stream
83What is the make-up of a chylomicron?
82% TAG, 7% phospholipid, 2% cholesterol, 9% protein, and some ADEK
84What does adsorb mean?
To become stuck
85What does desorb mean?
To become released from
86What is lysolecithin?
A phospholipid that desorbs saturated fatty acids from feed particles in ruminants
87Which animal secretes lysolethicin in the small intestine?
Cowsuminants
88What is an additional product that is absorbed only in the small intestine of a ruminant?
MPL (microbial phospholipid)
89What happens to a chylomicron once it leaves the enterocyte?
It flows through lymphatic circulation into the blood where it is brought to either a muscle or adipose cell and hydrolized by lipoprotein lipase into DAG and FFA (which goes into the cells), creating a chylomicron reminant
90What is lipoprotein lipase?
An enzyme that hydrolizes the TAG in a chylomicron into DAG and FFA, also creating a chylomicron reminant as an additional product
91What are DAG and FFA used for in muscle and adipose cells?
Energy and TAG synthesis (which is also just storage)
92What products go to the liver?
VFAs, fatty acids with less than (or equal to) 10 carbons, and a chylomicron reminant (all animals)
93What happens to the products sent to the liver in lipid digestion?
They are metabolized and used for energy and storage (all animals)
94What is a chylomicron reminant?
A chylomicron devoid of TAG
95If a ruminant and nonruminant were eating the same food, which would absorb more SFAs?
The ruminant
96Why is the passage of time more important in pigs than in cows?
Cows have continuous digestion in the rumen while pigs only eat a few meals a day like humans
97What is the primary lipid consumed in the rumen of ruminants?
Glycolipid
98What is difficult to digest in ruminants?
TAG
99About what percentage of TAG makes up a ruminants diet?
5%
100What is the primary lipid digested in the small intestine of ruminants?
Phospholipids due to MPL synthesis in the reticulorumen
101What are the steps of microbial utilization in the rumen and large intestine?
1) Hydrolisis
2) Hydrogenation
3) Microbial Phospholipid Synthesis
102What occurs during hydrolisis in the rumen and large intestine?
The hydrolisis of TAG into glycerol and 3 FFA, then glycolipid is broken down into glycerol, sugar, and 2 FFA, then phospholipid are hydrolized into glycerol, its polar head group, and 2 FFA
103What is lipase?
A BE that hydrolizes TAG into glycerol and 3 FFA (uses 3 H2O to do so)
104What is galactolipase?
A BE that hydrolizes a glycolipid (using 3 H2O) into glycerol, sugar, and 2 FFAs
105What is phospholipase?
A BE that hydrolizes a phospholipid (using 3 H2O) into glycerol, a polar head group, and 2 FFA
106What is the only difference between enterocyte interactions within a ruminant and nonruminant?
A ruminant will have lysolethicin and SFA in its fat particle that enters the cell and glycerol will be absorbed with FA>12C instead of MAG
107How many H2O particles does AcylCoA Synthetase need to make TAG in the ruminant enterocyte?
3
108How many H2O particles does AcylCoA Synthetase need to make TAG in the nonruminant enterocyte?
2
109What happens to glycerol and sugars during hydrolisis in microbial ulilization?
They are fermented into VFA, CO2, and CH4
110What is the speed at which hydrolisis occurs during microbial utilization?
Rapid and complete
111What is the speed at which hydrogenation occurs during microbial utilization?
Slow and incomplete
112What is hydrogenation during microbial utilization?
When UFAs are hydrogenized into SFAs by hydrogenase
113What is hydrogenase?
A BE that uses H2 to turn UFAs into SFAs
114Why are UFAs hydrogenized into SFAs
They are toxic to cellulolytic cells and decrease methane production, which in turn decreases SCHO digestion, then acetate decreases, then CH4 decreases
115How do double bonds within fatty acids affect energy in animals?
The more double bonds, the less energy there is
116What arrives to the small intestine from the reticulorumen?
SFAs attached to the feed particle and MPL
117What kind of enzyme is tryspin?
Proteolytic
118Why do UFAs decrease methane production?
Because they are hydrogen sinks and are toxic to cellulolytic microbes
119For every double bond broken in a fatty acid what happens to CH4?
It decreases by 0.5
120If you feed a nonruminant UFAs, what will be deposited into their fat cells?
UFA
121If you feed a ruminant UFAs, what will be deposited into their fat cells?
SFA
122What is a possible way to prevent microbes from hydrogenizing UFA?
Coating it in fat or Calcium soap so the microbes cannot access them
123Which animal digests lipids the fastest?
Pigs
124Where is colipase more active?
In a pig
125Which animal has a slower Kp of lipids?
Cows
126What are the products of absorption in a cow?
VFAs (from glycerol and sugar fermentation)
127What is TAG made up of?
Glycerol back bone and SFA or UFA
128If SFAs were fed which animal would get the most energy out of it?
Cow = Pig
129If UFAs were fed, which animal would get the most energy out of it?
Cow > Pig
130How do horses differ from pigs?
They are practically the same but have more glycolipids
131Why is fat harder to absorb in the rumen?
Because the small intestine hasn't helped with absorbing the fats yet