Module 4- Lipid Digestion Flashcards
(162 cards)
1
Q
T or F: lipids are soluble in organic solvents such as ether & chloroform
A
T
2
Q
what are the 2 most important energy sources in the diet?
A
lipids & carbs
3
Q
phospholipids allow the cell membrane to be
A
selectively permeable
4
Q
what are the 4 fat soluble vitamins?
A
ADEK
5
Q
lipids are substrates for
A
cholesterol
6
Q
cholesterol is important in the formation of ( ) hormones
A
sex
7
Q
3 components of lipids
A
C, H, O2
8
Q
why do lipids have more oxygen
A
required for oxidation for energy production
9
Q
what is the simplest lipid
A
fatty acid
10
Q
what is the simplest carb
A
glucose
11
Q
fatty acids are ( ) to make energy
A
oxidized
12
Q
what are the 3 types of simple lipids
A
1) fatty acids
2) tri, di & monoglycerols
waxes
13
Q
sterol vs non-sterol wax ester
A
sterol: precursors for corticosteroids
non-sterol: functional
14
Q
T or F: waxes do not provide energy but they are functional
A
T
15
Q
lipoproteins & their functions (2)
A
lipids conjugated to a protein
- lipid absorption in small intestine & transport into bloodstream
16
Q
what are the 2 ends of a fatty acid & what property do they each give the fatty acid?
A
1) methyl -> CH3
- hydrophillic: attracts water
2) carboxylic -> COOH
- hydrophobic: repels water
17
Q
saturated vs unsaturated FA
A
saturated: no C-C double bonds
unsaturated: 1 or more C-C double bond
18
Q
acetic acid
A
CH3COOH
19
Q
cis vs trans
A
cis: H on same side of C-C double bond
trans: H on different sides of C-C double bonds
20
Q
trans fatty acids are a result of ( ) of cis fatty acids
A
microbial fermentation
21
Q
the presence of a C-C double bond means the fatty acid will be
A
kinked, not linear
22
Q
naturally occurring fatty acids are in the ( ) configuration
A
cis
23
Q
fatty acids that have more than 1 C-C double bond will always be separated by ( ) carbon atoms
A
3
24
Q
C 16: 0
A
palmitic acid
25
C 18: 0
stearic acid
26
C18: 1
oleic acid
27
C18: 3
alpha linoleic acid
28
C18: 2
linoleic acid
29
2 essential fatty acids
1) linoleic acid = C18: 2 delta 9,12
2) a-linoleic acid = C18: 3 delta 9,12,15
30
what 2 desaturase enzymes do animals lack?
delta 12 & delta 15
31
what desaturase enzyme do animals have?
delta 9
32
desaturase enzyme function
inserts a C-C double bond into C9 starting from COOH end
33
T or F: plants can synthesize both essential FA so animals on plant diet get both
T
34
3 symptoms of FA deficiency
1) retarded growth
2) reproductive failure
3) necrosis of tail
35
what 2 beneficial effects do omega 3 fatty acids have on human health?
1) brain development
2) anti-carcinogenic effects
36
what omega FA is linked to negative health impacts?
omega 6
37
what ratio of omega 3 : omega 6 fatty acids reduce negative health impacts?
4:1
38
T or F: lipid content is most plants is relatively high
F
39
major form of lipid storage in plants
triglycerides
40
ideal lipid % in animal feeds
2-3%
41
silages have (%) lipids
2-4
42
T or F: oil seed lipid content is very high
T
43
as animals get older, water ( ) and fat ( )
decreases, increases
44
why will dry cows have a higher adipose tissue reserve compared to lactating animals?
b/c they mobilize adipose tissue during early lactation to support milk production
45
what are the structural lipids in an animal?
phospholipids
46
T or F: storage lipids are variable, not constant
T
47
list 3 major functions of FA in the body?
1) insulation
2) component of steroid hormones
3) fat soluble vitamin absorption
48
2 types/components of lipids
1) fats-> solid at room temp
2) oils -> liquid at room temp
49
difference between fats & oils
chain length & degree of saturation
50
lipids composed of longer chain FA / saturated are ( ) while lipids composed of short chain FA / are unsaturated are ( ) at room temperature
long- solid = fat
short= liquid = oil
51
triglyceride structure
glycerol backbone with 3 FA attached in an ester linkage
52
T or F: the FA attached in a triglyceride can be all the same or different
T
53
what happens to a triglyceride during lipid digestion?
lipase breaks ester linkage to release 3 free FA
54
monoglyceride
1 FA is attached to glycerol backbone
55
phospholipids heads are ( ) while tails are ( )
hydrophillic, hydrophobic
56
2 reasons why phospholipids are important for cell membranes
1) provide structure
2) give it selective permeability
57
cell membrane is composed of a
bilayer of phospholipids
58
why are phospholipids soluble in aqueous environments?
bc hydrophilic ends are in contact with aqueous environment inside & outside the cell
59
lipoproteins have a hydro( ) core
hydrophobic
60
glycolipids contain a ( ) component in their structure
- list an example
carbohydrate such as glucose or galactose
61
2 important glycolipids
cerebrosides & gangliosides
62
what feed source is rich in glycolipids?
grasses
63
what 2 forms can cholesterol exist in?
1) free form
2) cholesterol ester
64
cholesterol is made of a ( ) ring structure
4
65
cholesterol ester function
synthesis of a variety of compounds
66
bile acids functions
digestion of lipids
67
building block of bile acids
cholesterol
68
what is the active form of vitamin D
vitamin D3
69
how are fat soluble vitamins absorbed?
absorbed in micelles
70
primary triglyceride
C18: 2
71
T or F: phospholipids are high in ruminal bacteria
T
72
short, medium & long chain FA lengths
short: 0-8 carbons
med: 10-16 carbons
long: 18+ carbons
73
animal based lipid supplements contain ( ) fats while plant based lipid supplements contain ( ) fats
saturated, unsaturated
74
digestibility of fats and oils is affected by what 2 factors
1) degree of saturation
2) chain length
75
longer FA chain lengths ( ) digestibility
increases
76
what type of lipids are most digestible?
unsaturated
77
why are saturated lipids less digestible than unsaturated?
saturated FA are packed tightly due to kinks = less surface area = less area for enzymes to penetrate = less digestible
78
lipids are added to livestock diets in what form?
oil seeds
79
3 reasons for adding lipids to livestock diets
1) increase palatability
2) alleviate heat stress
3) dust control
80
why would feed intake be greater with higher fat content?
bc fat increases palatability
81
T or F: supplementation of lipids in the diet improves absorption of fat soluble vitamins
T
82
why are essential FA essential?
animals do not have enzymes to synthesis delta 12 & 15
83
T or F: lipids increase biosynthesis of steroid hormones
T
84
90% of lipids in diets fed to livestock are in the form of
triglycerides
85
total dietary lipid content is (%) in monogastric diets after supplemental lipids are added
6-7%
86
primary location of lipid digestion in monogastrics
small intestine
87
serous gland
secretes lingual lipase
88
gastric lipase is secreted by
chief cells in stomach wall
89
one major difference between salivary amylase and lingual lipase
salivary amylase is completely digested once it gets to the stomach but lingual lipase is not
90
emlusification
break large fat globules into fat droplets
91
where does most emulsification take place in monogastrics
duodenum
92
what organ initiates emulsification? how?
muscular contractions of stomach wall break them into fat droplets
93
major substrate for lipid digestion in monogastrics
triglycerides
94
what 2 things are flowing out of monogastric stomach during lipid digestion?
1) intact triglycerides
2) small amounts of di & monoglycerides
95
reason for emlusification
increases surface area for enzyme activity
96
why do oil & water not mix?
fat globules are hydrophobic = limits enzyme penetration
97
where are micelles produced vs stored?
produced: liver
stored: gallbladder
98
how are micelles reabsorbed?
through the ileum
99
pancreatic lipase function
digests triglycerides
100
where is co-lipase produced? what is its function?
produced by pancreas
removes bile salts attached to fat droplets to allow lipase to attach & start digesting the lipid
101
end products of triglycerides
- NEFA
- small amounts of mono & diglycerides
102
T or F: there is complete removal of all 3 FA after triglycerides are digested in monogastrics
F
103
product of phospholipase
lipophospholipids
104
lipophospholipids
phosphate group + 3 FA
105
cholesterol esterase function & products (2)
digests cholesterol esters
free cholesterol & FA
106
core of micelle is made of what 4 things?
1) NEFA
2) monoglycerides
3) cholesterol
4) lipophospholipids
107
T or F: mixed micelles are absorbed
F
108
where does re-synthesis of TG occur?
endoplasmic reticulum
109
what does the disintegration of micelles release?
end products of lipid digestion which will be absorbed
110
chylomicron function
allows micelle to migrate towards cell membrane & allow access into lymphatic system through exocytosis
111
why is the outside of a chylomicron made of phospholipids?
their hydrophillic ends allow it to interact with aqueous environment in bloodstream
112
chylomicron functions (2)
- facilitate absorption of lipids of feed origin
- transport lipids into bloodstream
113
lipoprotein function
transport endogenous lipids that are packaged into VLDLs, LDLs, HDL, etc
114
endogenous lipids
lipids synthesized in liver, skeletal muscle & adipose tissue
115
short chain vs long chain FA absorption
short: absorbed directly into portal system -> liver
long: absorbed into lymphatic system -> peripheral tissues -> thoracic duct
116
2 mechanisms of FA absorption
1) passive diffusion
2) facilitated diffusion
117
facilitated diffusion of FA uses what transporter?
FATP -> fatty acid transport protein
118
how many FATPs are there?
4
119
T or F: absorption of lipids is an energy-independent mechanism
T
120
T or F: glycerol is not used in adipose tissue, it goes to the bloodstream instead
T
121
fatty acyl-Coa is activated in the ( ), then transported into ( ) for ( )
cytosol, mitochondria matrix, oxidation
122
2 ATP =( ) AMP
1
123
beta oxidation of oleic acid
releases acetyl CoA so it can enter TCA cycle
124
most FA have an (even/odd) number of carbon atoms for beta oxidation
even
125
how many cycles of beta oxidation does palmitic acid go through? how many acyl CoA are produced?
8, 8
126
2 examples of when overproduction of acyl CoA can occur?
1) early lactation
2) keto diet
127
what happens with excessive catabolism of adipose tissue?
acyl CoA is used to make ketones bc it exceeded capacity of TCA cycle
128
3 ketone bodies
1) acetone
2) b-hydroxybutyrate
3) acetoacetate
129
what are products of triglycerides used for?
beta oxidation to produce ATP
130
what is the 1st important step in the synthesis of FA?
malonyl CoA
131
what is malonyl CoA important for?
milk synthesis in mammary gland
132
T or F: there is complete degradation of TG into glycerol + 3 FA in ruminants
T
133
saturated vs unsaturated FA in rumen
saturated: no transformation, go to small intestine
unsaturated: undergo transformation through biohydrogenation to convert to saturated FA
134
biohydrogenation
conversion of unsaturated FA to saturated by adding 2 H
135
glycolipid digestion in rumen
instantaneously fermented to produce VFAs
136
T or F: rumen bugs can synthesis sufficient lipids
T
137
what lipids do rumen bugs mostly synthesize?
microbial phospholipids
138
T or F: very little unsaturated FA in diet end up in small intestine
T
139
why do very little unsaturated FA in ruminant diets make it to the small intestine?
b/c most are biodehydrogenated due to activity of microorganisms
140
T or F: FA composition in a pig reflects very closely to the FA composition of the diet, but this does not occur in ruminants
T
141
how does biohydrogenation alter methanogenesis?
reduces methane production bc it is using up H ions in rumen instead of them going towards supporting methane production
142
how to reduce methane production in the diet using lipids?
feed diet high in unsaturated FA
143
T or F: more unsaturated FAs will be in the small intestine than what the ruminant actually consumed
T
144
why will more unsaturated FAs be in the small intestine than in the feed?
b/c of biohydrogenation
145
2 intermediates of biohydrogenation under normal conditions
1) cis-9 trans 11 C18: 2
2) trans-11 C18:1
146
what causes the biohydrogenation pathway to change?
high amounts of linoleic acids
147
2 intermediates formed by the altered biohydrogenation pathway
1) trans 10 cis 12 CLA
2) trans 10 C 18:1
148
anti-lipogenic
suppress lipogenesis in adipose tissue/mammary gland = milk fat depression
149
what are the 2 anti-lipogenic intermediates of biohydrogenation
1) trans 10 cis 12 CLA
2) trans 10 C18:1
150
beneficial effects of cis 9 trans 11
1) reduce blood pressure
2) reduce cancer
3) improve heart health
151
most important animal product source of cis 9 trans 11 for human consumption
milk
152
what animal products have a high level of CLA?
bovine products
153
total fat in ruminant diets should be (%)
6-7
154
4 impacts of too much fat in ruminant diet
1) reduced fiber digestion
2) lower production of VFA
3) reduced DMI & milk yield
4) milk fat depression
155
what 4 things are a mixed micelle composed of
1) free fA
2) monoglycerides
3) diglycerides
4) cholesterol
156
order of lipid digestion in small intestine (4)
1) bile salts
2) co-lipase
3) pancreatic lipase
4) micelles
157
what do micelles transport
microvilli
158
why is fiber digestion decreased with a high fat diet
microbial enzymes cannot access feed due to lipid layer around feed particles
159
T or F: unsaturated FA are toxic to protozoa
T
160
a decrease in protozoa = ( ) in fiber digestion
decrease
161
high fat diet reduces what ratio of VFAs? why?
acetate : propionate
- less acetate due to less fiber
162
T or F: small intestine lipid absorption is the same in ruminants & monogastrics
T
