LIPIDS Flashcards
(118 cards)
1
Q
Lipids are ____ in water and ____ in non-polar solvents
A
Insoluble; Soluble
2
Q
Type of linkage present in lipids
A
Glyceride linkage
3
Q
How are lipids energy dense?
(kcal)
A
It provides 9kcal/g
4
Q
Why are lipids energy dense?
A
The long fatty acid chains can be separated and used for glycolysis
5
Q
Common animal sources of lipids
A
fatty meats, butter, lard, cheese, whole milk, cream, egg yolk
6
Q
Common plant sources of lipids
A
vegetable oil, nuts, chocolate, avocado, durian, olives, margarine
7
Q
Foods that are purchased and used as fats|
(ex. butter, margarine, cooking oil)
A
visible fats
8
Q
Which part of the egg consists of lipids and which are for proteins
A
egg yolk for lipids (cholesterol), egg white for protein
9
Q
Examples of invisible fats
A
egg yolk, cheese, milk, cream, and salad dressings
10
Q
What is the difference of fats and oils
A
fats: solid at room temp. and came from animal sources
oils: liquid at room temp. and came from plants sources
11
Q
What are the 6 main purposes of lipids
A
- Energy storage
- Transport of fat soluble vitamins
- Supply essential fatty acids
- Protect & support organs and bones
- Insulate from cold temperatures
- Provide satiety
12
Q
Lipid Storage
what is the starting material for fatty acid synthesis
A
acetyl-CoA
13
Q
Lipid Storage
Importance of malonyl-CoA
A
Inhibits fatty acid beta-oxidation to ensure storage of fat
14
Q
Lipid Storage
What is the purpose of inhibiting fatty acid oxidation
(Importance of ensuring fat is stored)
A
To balance energy storage and utilization
Storage: ensure backup energy & prevents wasteful expenditure of energy
15
Q
Lipid Storage
Raw material for synthesis of Malonyl-CoA
A
Acetyl-CoA
16
Q
Lipid Storage
What specific enzyme does malonyl-CoA inhibits
A
carnitine acyl transferase
17
Q
Transport of fat soluble vitamins
What are the fat-soluble vitamins
A
Vit. A, D, E, K
18
Q
Essential fatty acids
What are the essential fatty acids
A
Omega 3 & Omega 6
19
Q
Body Insulation
How does fat insulate the body
A
Cold temperature triggers brown adipose tissue to release stored energy in the form of heat
20
Q
Lipid Family
3 main types of lipids in the body
A
- Triglycerides
- Phospholipids
- Sterols
21
Q
basic structure of triglycerides
A
1 molecule of glycerol with 3 fatty acid chain attachments
22
Q
why are triglycerides considered space saving efficient molecules for storing energy?
A
- energy dense
- Their neutrality and nonpolar characteristics allow them to be stored in anhydrous environment and they will not expand from water uptake
23
Q
How are fatty acids classified?
A
- essentiality
- degree of saturation
- chain length
24
Q
Differentiate essential from non-essential
A
Essential: cannot be synthesized by the body and must be supplied by diet
Non-essential: can by synthesized by the body
25
Difference of omega 3 and omega 6
Omega 3: first double bond located at 3rd carbon from methyl end
Omega 6: first double bond located at 6th carbon from methyl end
26
members of the omega 3 family
1. alpha linolenic acid
2. eicosapentoic acid
3. docosahexaenoic acid
| ALA (18:3)
EPA (20:5)
DHA (22:6)
27
food sources for ALA
flax seed (57%) meal and oils, canola (8%) oils, soybean (7%) oils, walnut, butternuts, red & black currant seeds
28
food sources of EPA and DHA
cod liver oil, fish oil capsules, mackerel, salmon, sardines, bangus, crab, shrimp, oysters
29
Benefits of omega 3 FAs
1. growth and development of fetal CNS and retina
2. CVD: decrease triglycerides
3. precursore for prostaglandins
30
Purpose of prostaglandins
to cause inflammation, pain, and fever as part of the healing process. Can also causes muscle contraction to prevent blood loss
31
what does thromboxane do during the healing process
produced by platelets to stimulate blood clot
32
major food sources of omega 6
vegetable oils (corn, sunflower, cottonseed), salad dressings, margarine
| (common in plants)
33
members of the omega 6 family
1. linoleic acid
2. gamma linoleic acid
3. arachidonic acid
| LA (18:2)
GLA (18:3)
AA (20:6)
34
benefits of omega 6 FAs
1. CVD: associated with decreased levels of LDL and HDL
2. Deficiency: growth retardation, skin lesions, reproductive failure, fatty liver, polydipsia
35
what are the two parent members of the omega 3 and 6 families
Omega-3: alpha linolenic acid
Omega-6: linoleic acid
36
what is the ratio of omega 3 and omega 6
1 omega 3: 4 omega 6
37
why is there a difference in amount of omegga 3 and 6 fatty acids
because omega 3 and omega 6 compete for the same enzyme for elongation
38
Difference of saturated and unsaturated fatty acids
Saturated: all carbons carry the max hydrogens possible; solid at room temp; usually from animal products
Unsaturated: contains double bonds; liquid at room temp; usually from plants
39
common food source of saturated fats
meat, egg yolks, whole milk, whole milk cheeses, cream, ice cream, butter, chocolate, coconut and palm oil
40
2 types of unsaturated fats
monounsaturated and polyunsaturated fats
41
difference of mono and polyunsaturated fat
monounsaturated: one double bond
polyunsaturated: more than one double bond
42
common food source of monounsaturated fats
olive oil, canola oil, avocados, cashew nuts
43
benefit of monounsaturated fats
may raise HDL without raising LDL
44
why is palm oil not environmentally friendly
plantation of palm trees require clearing massive lands leading to deforestations, habitat destruction, etc.
45
consistency or texture of polyunsaturated fats
usually soft or oily
46
examples of polyunsaturated fats
omega 3 and omega 6
47
why is omega 6 not 100% protective
may produce free radicals
| must be taken with antioxidants to prevent this
48
__ is the process of adding hydrogen to polyunsaturated vegetable oils, forming __
Hydrogenation, Trans fats
49
purpose of hydrogenation
solidifying (semi-solid) oils at room temp.
50
why do we want the solid or semi-solid form of fats
prolong shelf life and makes it pliable to use
51
effect of trans fat
raise LDL and total cholesterol
52
common sources of trans fat
baked goods and restaurant foods
53
difference of the categories in classifying fatty acids by chain length
short: <6 carbons
medium: 6-10 carbons
long: 12-24 carbons
54
components of phospholipids
glycerol, fatty acids, choline (or nitrogen-containing compound), and a phosphate group
55
where are phospholipids synthesized
liver
56
functions of phospholipids
1. emulsifies in food industry and body
2. constituent of cell membrane
57
a momdel that describes the structure of the plasma membrane
fluid mosaic model
58
example of sterols
cholesterol
59
functions of sterols
1. starting material for body compounds such as bile, sex hormones, adrenal hormones, vit. D and cholesterol
2. structural component in cell membranes
60
T or F: cholesterol only exists in animal products
true
61
T or F: cholesterol is needed by every cell in the body
true
62
what materials from fats and lipids can be absorbed by the body
| (when dismantled)
monoglycerides, fatty acids, glycerol
63
how are lipids digested in the mouth
1. fat begins to melt in mouth
2. lipase is secreted by salivary glands to start digesting medium and short chain fatty acids (milk)
64
type of lipase secreted by ____ salivary glands
lingual lipase from sublingual salivary glands
65
T or F: fat is digested stomach
true: but only very little amount
66
type of enzyme to digest lipids in stomach
gastric lipase
67
what hormone signals the release of bile from gallbladder
cholecystokinin (cck)
68
what triggers the release of cck to release bile from gallbladder
food containing lipids and proteins detected by the cells on the mucosal lining of the duodenum
69
how does bile help in digestion of lipids
bile acts as emulsifier
70
enzyme to digest cholesterol
cholesterol esterase
71
what is the mode of action of the enzyme to digest cholesterol
hydrolysis
72
enzyme secreted by pancreas for lipid digestion
pancreatic lipase
73
T or F: small intestines release enzyme to digest lipids
True: intestinal lipase
74
product of lipid digestion in mouth
diglycerides and free FA
75
product of lipid digestion in stomach
70% triglyceride, free FA, partially digested fats
76
product of the interaction between fat and bile
emulsified fat
77
product of cholesterol digestion
esters of cholesterol and fatty acids
78
product of lipid digestion in small intestine
monoglycerides, phospholipid fragments, sterols, and free FA
79
how are small units of lipids absorbed in the body
diffuses into intestinal cells into the bloodstream
80
how are larger units of lipids absorbed in the body
they merge into micelles to diffuse into the intestinal cells
81
what happens to large units of lipids once they diffuse into the intestinal cell?
assemble into triglycerides to be packed into chylomicrons which are released to the lymphatic system
| (95-97% of dietary fat)
82
what is the basic unit for lipid catabolism
acetyl CoA
83
what does beta oxidation do
cleaves carbon at a time
84
what are the two molecules and their respective pathways in lipid catabolism
glycerol: glycolysis
fatty acids: beta oxidation
85
process of converting acetyl CoA and glyceraldehyde-3-phosphate to adipose tissue
lipogenesis
86
step before glyceraldehyde-3-phosphate undergoes lipogenesis
conversion to glycerol by removing 2 phosphates
87
what are the two possible products of acetyl CoA when turned into HMG CoA
cholesterol and ketone bodies
88
what happens if ketone bodies accumulate in the body
ketoacidosis (lowering of pH)
89
products of acetyl CoA after turning into malonyl CoA
triacylglycerides and phospholipids
90
what are the components of lipoproteins
triacylglycerols, phospholipids, cholesterol and protein
91
function of lipoproteins
main transport form of fat
92
why are VLDL, LDL, and HDL called density proteins
due to protein content (more protein, higher density)
93
%protein of each lipoprotein
chylomicron (2%)
VLDL (10%)
LDL (25%)
HDL (40%)
94
what do chylomicrons transport and what is the pathway of transport
transport diet-derived triglycerides; from small intestine to liver and other tissues
95
what do VLDL transport and what is the pathway of transport
triglyceride; from liver to body cells
96
what do LDL transport and what is the pathway of transport
cholesterol; from liver to body cells
97
what do HDL transport and what is the pathway of transport
cholesterol; from body cells and blood back to the liver
98
T or F: the density of lipoproteins is proportional to its size
False: the least dense is the chylomicron and is also the largest lipoprotein
99
why is HDL considered "good cholesterol"
HDL can carry cholesterol from the plaque deposits in the arteries
100
why are non-HDL considered "bad cholesterol"
serves as raw material for plaque in blood vessels
101
purpose and mechanism of calcium blockers
relieve pressure by blocking calcium channels into smooth muscle cells, making the muscles contract less
102
lipid functions when stored as adipose tissue
1. insulation
2. support vital organs
3. generate heat
4. energy reserve
103
what happens to lipids when in blood as lipoproteins
1. excreted in feces (small amounts)
2. converted to brain and nerve tissue
3. oxidized for energy
4. synthesized from carbohydrates and proteins
5. stored as energy reserve
104
how much fat do adults need
| (range)
15-30%
105
disadvantage of ketogenic diet
fat heavy diet and onset of gout
106
saturated fats that increase LDL
lauric, myristic, and palmitic acid
107
what are fat replacers
substitute fat in foods to give a similar taste, texture and mouth feel as a full fat food
108
purpose of fat replacers
reduce fat and calories in food
109
types of fat replacers
carbohydrate-based, protein-based, and fat-based
110
examples of carb-based fat replacers
guar gum, polydextrose (Litess), gum Arabic, xanthum gum, carrageenan (an extract from seaweed), dried plum paste, modified food starches, oat fiber, and wheat fiber
111
characteristic of carb-based fat replacer
they have the creaminess of fat
112
where do protein-based fat replacers come from
milk proteint and/or egg white protein
113
characteristic of protein-based fat replacer
give same mouth feel as fats
114
process of making protein-based fat replacers
microparticulaton
115
example of fat-based fat replacers
Caprenin, Benefat, Olean
116
If fat-based fat replacers are made of fat molecules, how does it become a "fat replacer"?
| (for Olestra)
Extra fatty acids are added to increase molecule size, making it too large to be absorbed and simply passes through the intestines to be eliminated as waste
| (Not all fat-based replacers. Some are only partially absorbed.)
117
T or F: all fat replacers are considered safe
True
118
Even though Olestra does contribute to fat and caloric intake, what are its disadvantages
1. Not for people with disorders that interfere with nutrient absorption
2. Reduces absorption of fat-soluble vitamins
3. May cause loose stools and diarrhea
