Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NUTR2101 > Lipids > Flashcards

Lipids Flashcards

1
Q

Lipids

A

diverse group of organic substances commonly associated on the basis of:
insolubility in water
solubility in fat solvent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

triglycerides

A

most common form of lipid in food and the body ( made from glycerol backbone and 3 fatty acids of similar or different kind or lengths.
dietary: fats or oils.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Other dietary lipids ( not triglycerides)

A

cholesterol, phytosterols, FFA, phospholipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Esterification

A

joining 3 fatty acids to a glycerol unit= results in triglyceride

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

De-esterification

A

(=lipolysis of adipose tissue stores) release of fatty acids from glycerol; results in free fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

re-esterification

A

reattaching FA to glycerol (e.g. during absorption)

after absorption in the enterocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

diglyceride

A

2 FA with glycerol molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

monoglyceride

A

1 FA with a glycerol molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fat or oil

A

Fat = solid
oil= liquid
(different structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Long chain fatty acid

A

12 or more carbons
( beef pork lamb most plant oils)
- re-esterified in enterocytes and combine to cholesterol and proteins to form chylomicrons and enter lympathic system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Medium chain fatty acid

A

6-11 Carbon
( coconut and palm kernel oil)
- absorbed directly into blood stream- taken to liver bound to albumin
- more readily used as Energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Short chain fatty acids

A

6 carbon long
produced when bacteria in the gut ferments fibre.
- absorbed directly into blood stream- taken to liver bound to albumin
- more readily used as Energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fatty acids

A

saturated and unsaturated fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Unsaturated FA

A

Poly or mono unsaturated = how many double bonds their are.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Saturated FA

A

Single bond b/w carbons all hydrogen positions are filled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

unsaturated FA

A

double bonds b/w some carbons

Mono or poly ( cannot be synthesised)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Transfats

A

partial hydrogenation of poly unsaturated FA- through food processing or naturally occurring in ruminant food.
= more ridgit position
= fat more compact
(hydrogens on opposite sides)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

PUFA

A

poly unsaturated FA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Nomenclature of PUFA

A
  1. omega system
    total number: total number of double bonds n-position of 1st closest to the methyl end
  2. delta system
    indicates pos of all double bonds
    total number : number of bonds delta position of bonds from carboxyl end.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Essential FA

A

: omega 3 and omega 6 FA
must be consumed in the diet: body lacks enzymes
that can incorporate bonds.
linoleic acid ( precursor for omega 6FA)
Alpha linoleic acid (precursor for omega 3)
omega 3 FA
gamma linoleic acid
arachnoid acid
important component structure of call membranes: DHA and EPA
precursor of eicosanoids ( hormones like molecules)
omega 3 and omega 6 use the same enzymes to produce them.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Function of Fats

A
  1. provides energy consumes in compact form 37KJ
  2. insulates and protects the body
  3. forms structure of cell membrane (strengthen and fluidity)
  4. assist in fat soluble vitamins absorption and transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

phospolipid

A

emulsifier
cell membrane
hydrophobic and hydrophilic ends

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Sterols

A

= ring structures
= cholesterols in animals and phylosterols in plants
cholesterols is a precursor of sex and adrenal hormones, vit D, bile salts, involved in cell membrane stability, part of lipoproteins.
sources: synthesis in liver, adrenal glands, intestines and gonads= circulating + dietary sources.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Cholesterol production

A

Cholesterol in the body is produced through a system- the starting molecule is Acetyl CoA (circulating cholesterol) = endogenous synthesis in liver, adrenal glands, intestines and gonads.
insulin promotes the synthesis
cholesterol inhibits SREBP enzyme that then down regulates the system
statins down regulate
stimulated by high glucose levels and high dietary FA (?)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Cholesterol absorption / regulation

A 
absorb 50-60% 
Via NPC1L1 (carrier protein) 
Ezitimibre= blocks NPC1L1

fibre promotes the excretion of bile and decreases the amount of circulating cholesterol by forcing the body to use cholesterol to make more bile.

beta glucans (in oats) prevents recycling of bile- blocks reabsorption= excrete more bile.

drugs: Stains and ezetimbre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

DHA:

A

during pregnancy and fatal life
= normal development and function of retina
= normal development and maturation of nervous syste.
life
= regulation of nerve transmission and communication
= important signalling for gene expression

27
Q

Omega 3 FA

A 
DHA and EPA 
soft response: produce eicosanoids 
that dilate BV and lower blood pressure 
promote anti inflammatory response 
- response via prostaglandins and thromboxjnes
28
Q

Omega 6 FA

A

influence BV to constrict and increase blood pressure

promote pro- inflammatory response via prostaglandins and thromboxane

29
Q

Fat digestion

A

mouth: lingual lipase: de-esterification
stom: gastric lipase from chief cells
SI: CCK triggers bile and pancreatic enzymes secretion
bile and lectin emulsifies fats to convert them into smaller droplets (micelles with larger SA)
Pancreatic lipase (act on triglycerides = mono glycerides and FFA) and co-lipase act on micelles
phospholipids = FFA and glycerol by phospholipase A2
cholesterol esters = cholesterol an FFA by cholesterol esterase.
( distal duodenum and jejunum) micelles are absorbed through brush border enzymes- empty contents into the enterocytes
long chain FA: re-esterified and combine with cholesterol and proteins= form chylomicrons enter lymphatic system
short chain and medium FA: absorbed directly via portal vein - taken to liver bound to albumin

30
Q

long chain FA

A

Absorbed into lymphatic system

31
Q

SHort chain FA

A

absorbed into BS

32
Q

entrohepactic circulation

A

= the recycling of bile salts and the role of fibre in regulating blood cholesterol
90% of bile is reabsorbed

33
Q

Fat transport

A

lipoproteins: lipid core + shell composed of specific apoldprotein- phospholipids and cholesterol.
4:
chylomicrons; transport fat through the lymphatic system.
From SI to liver.
VLDL: triglycerides: carries lipids from liver to cells
LDL: cholesterol from liver to cells (endocytosis) - excess oxidised in blood
HDL: helps remove and excrete cholesterol- carries it to liver

34
Q

Cholesterol uptake

A

via LDL receptors
with abundant receptors are blocked for reduced uptake- LDL build up in the blood - oxidised and taken up by macrophages- becomes foam cells- these cells become trapped in the walls of BV and contribute to atherocserosis.
more receptors are made if intracellular levels are low.

35
Q

Plant sterols

A

chemically similar to dietary cholesterol- but cannot be converted into steroids in the body
40+ types
reduced the amount of cholesterol absorbed- incorporated into micelles during absorption= lowers the amount of dietary cholesterol in micelles.= bind to same receptors.
found in whole grains fruit, veg, legumes
absorbed via NPC1L1

36
Q

Lipids

A

= fats and oils
fat- high saturated= solid at room temp
oils- high unsaturated= liquid at room temp

37
Q

Recommended fat intake

A

25-30 % of estimated E requirements

38
Q

What are the most common types of lipids found in food?

A

triglycerides.

39
Q
  • Definition pertaining to triglycerides formation and breakdown.
A

esterification: joining 3 fatty acids to a glycerol unit
de-esterification: lipolysis of adipose tissue stores: release FA from glycerol: resulting in FFA
re-esterification: reattaching FA to glycerol (absorption)

40
Q
  • How are trans fat found in food created?
A

through partial hydrogenation of polyunsaturated FA. = more ridgit and compact.

41
Q

• What did the PREDIMED study demonstrate?

A

The PREDIMED study demonstrated that the TMD was better then the Traditional western diet.
long term affects of the long effect of the TMD
- the benefits of TMD for CVD (reduced incidence)

The PREDIMED study results demonstrate that a high-unsaturated fat and antioxidant-rich dietary pattern such as the MeDiet is a useful tool in the prevention of CVD.

42
Q

How does TMD compare to other currently trending diets?

A 
Atkins: 
high fat low carb high protein 
Ketogenic: 
high fat low protein low carb 
typical american: 
low fat, high carb, high protein
43
Q

• What are the sources of circulating cholesterol?

endogenous synthesis and regulation mechanisms

A

endogenous synthesis

promoting the excretion of bile: fibre reduces the amount of circulating cholesterol

44
Q

• What are the sources of circulating cholesterol?

endogenous synthesis and regulation mechanisms

A

endogenous synthesis: production of cholesterol with acetyl CoA as the starting molecule. in liver, adrenal glands, intestines and gonads.

high glucose levels stimulates cholesterol synthesis.
high insulin levels promotes endogenous synthesis.
high levels of circulating cholesterol inhibit- through SCAP
glucagon inhibits
statins and drugs inhibits enzyme in cholesterol synthesis.
promoting the excretion of bile: fibre reduces the amount of circulating cholesterol

HDL- cells- liver
LDL- liver to cells

45
Q

• How does atherosclerosis develop?

A

Damage to endothelium- macrophages activated to consume and remove high levels of cholesterol in BS - become foam cells which become embedded in endothelial wall- body protect and surround them by plaque- build up creates a blockage. = hardening in arterial wall= hypertension

risk factors: high blood glucose (damaging to endothelium), smoking, physical inactivity, obesity, diabetes, low HDL, high level of LDL in blood

46
Q

• Describe the role of EFA’s in the inflammatory response

A

FAF are precursors of eicosanoids: hormone like molecules.
Omega 3 and omega 6 compete to produce them- use same enzymes.
Omega 6:
influence BV to constrict and increase Blood pressure.
promote pro inflammatory response.
Omega 3:
Influence dilation of BV and lower BP
inflammatory response.
omega 6: omega 3 ratio
Inflammatory : anti-inflammatory

47
Q

What is the lipid hypothesis?

A
  1. “Dietary cholesterol and saturated fat raise blood
    cholesterol
  2. High blood cholesterol is associated with atherosclerosis,
    and the incidence of coronary heart disease
  3. Therefore saturated fat and cholesterol in the diet
    increase the risk of CVD”
  4. was in rabbits- vegetarian= not applicable.
    increased sugar consumption
    been proved wrong.
48
Q

• How is cholesterol uptaken in the cells?

A
  1. receptor pathway: endocytosis of LDL- broken down and utilised. Excess not taken up may become oxidised in the blood.
    High cholesterol= LDL receptors synthesis is blocked
    low “ = more LDL receptors are made
    2, scavenger pathway: removes oxidised LDL that can burrow under endothelium. can build up over time to form plaque. taken up by macrophages become foam cells
  2. HDL’s pick up cholesterol throughout the periphery and returns it to the liver for disposal and recycling.
49
Q

• What is an apo-lipoprotein?

A

in lipoproteins: lipid core+ shell composed of specific apolipoprotein, phospholipid and free cholesterol.
4 types:
1. chylomicrons : dietary fats from SI to liver. ( long chain FA)
2. VLDL lipids from liver to cells
3. LDL: liver - cells cholesterol
4. HDL: cells - liver cholesterol

50
Q
  • What are plant sterols? How can they reduce dietary cholesterol absorption?
A

Chemically similar to dietary sterols but cant be converted to steroids in the body. 40+ types
incorporated in micelles during absorption- bind to same receptors- reduce the amount of dietary cholesterol that is absorbed.
found in whole grains, fruits, veg, legumes.
also absorbed via NPC1L1. released back into the limen via proteins ADCGS. travel to colon for excretion.

51
Q

• What is the difference between MCT and LCT metabolism?

A

Medium chain triglycerides Vs long chain
med are more readily utilised for energy production
higher ketone body production.
produce Acetyl CoA faster. short chains are absorbed directly into the BS via portal vein.
long chains- re-esterified and combine to cholesterol an d protein to form chylomicrons- travel via lymphatic system.

52
Q

• What is measured when blood cholesterol blood is measured?

A

measuring the different types of cholesterol.

53
Q

What are EFAs? What is their characteristic?

A

_ body cannot produce. lack enzyme to make precursors. must be consumed in the diet. two classes:
Omega 6 and Omega 3.
important component structure of cell membranes: DHA And EPA.
precursor of eicosanoids
Polyunsaturated FA

54
Q

• What are 6 enzymes involved in the digestion of lipids?

A
  1. lingual lipase
  2. gastric lipase
  3. pancreatic lipase
  4. phospolipase A2
  5. Cholesterol Lipase
  6. Bile Salts ( CKK) - emulsifies fat
55
Q

Examples of EFA . What are the precursors?

A

omega 6 precursor: linoleic acid
omega 3 precursor: alpha linoleic acid.

examples: LA, DHA, EPA, GLA, ALA,

56
Q

ENTEROHEPATIC CIRCULATION

A

ENTEROHEPATIC CIRCULATION – THE RECYCLING
OF BILE AND ROLE OF FIBRE IN REGULATING
BLOOD CHOLESTEROL

57
Q
  • Precursor of cholesterol synthesis? What are key players in the synthesis?
A

Acetyl CoA + acetoacetyl CoA.

HMG CoA reductase.

58
Q
  • How can oats reduce circulating cholesterol?
A

Contain Beta glucans- macrophage activation
end up excreting more cholesterol- increase the production of bile. prevents recycling of bile
bind to bile acids- increase excretion.

59
Q

What are the dietary guidelines for fat intake for the general healthy adult population?

A

AMDR: 25-30% of TFI

o.2% TFI low density omega 3.

60
Q
  • Lipids are transported in the circulation via lipoproteins. Describe the characteristics, composition and role of the four main lipoproteins
A
  1. chylomicrons: transport fat through the lympatic system.
    SI– Liver 2-7% cholesterol.
  2. VLDL: triglycerides- carries lipids from liver to cells
  3. LDL: cholesterol from Liver to cells
  4. HDL : cholesterol from cells to liver.

= lipid core + shell composed of specific apolipoprotein, phopolipids and free cholesterol.

61
Q
  • What is an example of a rich food source for each of the types of fatty acids?
A

long chain: 12+ beef, pork, lamb + most plant oils
short chain: 6-11 Carbons coconut and palm kernel oil
medium chain: less then 6
3% of fat in butter.

62
Q
  • What are the chemical characteristics and specific physiological function of dietary fatty acids?
A 
FA 
saturated 
unsaturated 
trans 
poly 
mono
63
Q

• Describe the digestion, absorption and transport of dietary triglycerides

A

triglycerides: most common form form of lipids in food and the body. 3 fatty acids + glycerol unit.
Triglycerides in micelles are broken down into
monoglycerides and free fatty acids by pancreatic
lipase
short/med chains FA- directly into BS
long/ + mono glycerides- absorbed through brush border enzymes. re formed as triglycerides.

64
Q

FA

A 
chain of carbons+ carboxyl group. 
half hydrophobic (chain)  half hydrophilic (head)

NUTR2101 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions