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Nutrient Metabolism > Test 2 > Flashcards

Test 2 Flashcards

1
Q

Lipid definition

A

substances that are generally insoluble in water, but soluble in organic solvents

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2
Q

Simple lipids

A

fatty acids, tri,di, and mono-acylglcerols, waxes (sterol esters, nonsterol esters, etc)

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3
Q

Compound lipids

A

phospholipids, glycolipids, lipoproteins

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4
Q

derived lipids

A

hydrolysis of lipids in group 1-2

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5
Q

ethyl alcohol

A

one lipid classification
-similar as lipid metabolism

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6
Q

Short chain FA

A

2-4
won’t be found in diet
from gut bacteria

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7
Q

medium chain FA

A

6-10 C, not found in diet

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8
Q

Long chain FA

A

12-24, found in diet

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9
Q

Why do most FA have even number?

A

most generated from acetyl coA (2 C chain)

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10
Q

FA are amphipathic

A

true

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11
Q

monounsaturated FA

A

one double bond between carbon usuall non-essential but may be 1/3 of total FA intake such as oleic acid

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12
Q

Polyunsaturated FA

A

multiple double bonds (up to six)

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13
Q

Which FA will be solid at room temperature?

A

Saturated FA

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14
Q

Polyunsaturated FA are trans or cis form?

A

Cis

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15
Q

Where does Trans fat come from?

A

Created industrially in partial hydrogenation of plant oils -higher melting point for baking and extends shelf-life

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16
Q

Omega 6 FA

A

Linoleic Acid (18:2)
essential

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17
Q

Omega 3 FA

A

alpha-Linolenic Acid (18:3)
essential

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18
Q

**What are the most prevalent saturated FA in average US diet?

A

Palmitic and stearic acid

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19
Q

Where does beta-oxidation happen?

A

Mitochondria

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20
Q

Where is FA stored?

A

cytosol

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21
Q

What helps transfer FA from cytosol to mitochondria?

A

Acyl-CoA (requires 2 ATP)
-transport of acyl-CoA into mitochondria via an acyl-carnitine intermediate

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22
Q

**What is formed when FA are oxidized in the mitochondria?

A

acetyl CoA

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23
Q

FA synthesis

A

uses acetyl CoA (in mitochondria) to make FA in cytosol

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24
Q

how does acetyl CoA move from mitochondria to cytosol?

A

Oxaloacetate to citrate which can pass membranes then reverts back to oxaloacetate…

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25
Q

Key enzyme that controls FA synthesis

A

acetyl-CoA carboxylase

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26
Q

Most carboxylation uses what as a coenzyme?

A

Biotin

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27
Q

**What is the primary FA synthesized that can then undergo elongation and/or unsaturation to yield other FA?

A

palmitate (16:0)

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28
Q

If fat is entirely excluded from the diet what happens?

A

-retarded growth
-dermatitis
-kidney lesions
-early death

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29
Q

Why is omega-6 (linoleic acid) essential?

A

Our body cannot produce it and uses it to produce arachidonic acid

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30
Q

What is omega-3 (alpha linolenic acid) a precursor for?

A

n-3 PUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)

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31
Q

**Which fatty acid is considered essential and must be consumed by the diet?

A

alpha-linolenic acid
linoleic acid

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32
Q

Significance of arachidonic acid

A

Precursor to eicosanoids
-prostoglandins
-thromboxanes
-leukotrienes

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33
Q

Eicosanoids produce a wide range of biological effects on….

A

inflammatory responses
pain and fever
reproductive function
regulating blood pressure
platelet aggregation
thrombosis

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34
Q

Dietary sources of PUFA

A

animal fats are largely saturated, pig/poultry have less saturated FA and some PUFA, fish and plant oils are highly unsaturated

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35
Q

Fish vs plant omega 3

A

fish = EPA/DHA
plant = ALA (short chain omega 3)

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36
Q

Glycerol can be used directly in every tissue except..

A

adipose

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37
Q

What do adipocytes use for triacylglycerol synthesis?

A

dihydroxyacetone phosphate from glycolysis

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38
Q

When used for energy, FA are released as free FA by lipases (A1-3) in adipose tissue cells, then transferred by what protein to other tissue cells for oxidation?

A

albumin

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39
Q

cholesterol is stored in cells has

A

cholesterol esters

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40
Q

The majority of cholesterol is endogenous

A

true (about 2/3)

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41
Q

How much cholesterol in our body per day

A

1 g/day

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42
Q

Nearly all tissues can synthesize cholesterol from…

A

acetyl coA

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43
Q

What is the rate controlling enzyme in cholesterol synthesis?

A

HMG-CoA reductase

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44
Q

**Humans build about ____ mg of cholesterol each day.

A

700 mg

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45
Q

Cholesterol is important membrane structure and precursor for the synthesis of:

A

-steroid hormones
-bile acids
-adrenocortical hormones
-vitamin D

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46
Q

Primary bile acids come from….

A

cholesterol in the liver

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47
Q

Primary bile acids:

A

chenodeoxycholic acid (45%)
cholic acid (31%)

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48
Q

How are secondary bile acids formed?

A

primary bile acidds are acted upon by gut bacteria to form secondary bile acids

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49
Q

Secondary bile acids

A

deoxycholate, lithocholate (from chenodeoxycholate)

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50
Q

Where in small intestine is dietary TAG mostly digested?

A

upper jejunum (70-90%)

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51
Q

Can intact TAG be absorbed?

A

No; only hydrolytic TAG such as MAG and FFA

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52
Q

***What is the most active site of lipid digestion?

A

Upper jejunum

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53
Q

All lipids in the body are transported by 5 lipoproteins:

A

chylomicrons transport exogenous dietary lipids
-VLDL
-IDL
-LDL
-HDL

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54
Q

***The main function of lipoproteins is

A

To act as the carrier of lipids

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55
Q

***The main component of a HDL molecule is protein…

A

True

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56
Q

major function of chylomicrons

A

deliver dietary triacyglycerols to tissues and dietary cholesterol to the liver

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57
Q

Apolipoproteins of chylomicrons

A

apoB-48, apoA

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58
Q

LDL is often termed “bad cholesterol” b/c it has been linked to atherogenic fatty plaque formation…

A

true

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59
Q

Trans FA are now considered more atherogenic than saturated FA b/c they…

A

elevate serum LDL while decreasing HDL

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60
Q

Antiatherogenic Mechanisms of n-3 PUFA

A

-interfere w/platelet aggregation by inhibiting thromboxane production
-reduction of proinflammatory leukotrienes
-reduction of serum triacylglycerols

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61
Q

How much ALA will convert to EPA and DHA?

A

<5%

62
Q

Statins

A

fungal HMG-CoA reductase inhibitors –>increased cellular uptake of LDL

63
Q

Nicotinic acid (niacin)

A

reduces plasma VLDLs and LDLS by inhibiting hepatic VLDL secretion and FFA release from adipose tissue

64
Q

olistat

A

derivative of lipstatin, potential inhibitor of gastric and pancreatic lipase

65
Q

**The MOA of Orlistat

A

-to inhibit lipase activity

66
Q

Rate limiting step in FA synthesis

A

-acetyl-CoA carboxylase (ACC)

67
Q

ACC is inhibited by

A

palmitoyl-CoA and other long-chain acyl-CoAs

68
Q

ACC is activated by…

A

citrate

69
Q

Regulation of Lipid Metabolism
-other major target other than ACC

A

carnitine palymitoyl=CoA transferase-I
-prevents against FA oxidation

70
Q

**Which hormone is considered to be an antagonist of lipolysis?

A

Insulin

71
Q

From overflow of acetyl CoA (from fat catabolism) the liver cells can create…

A

ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone)

72
Q

**Excessive ketone bodies may be accumulated due to reduced supply of cellular glucose and a concomitant _____ in FA oxidation.

A

increase

73
Q

Two major pathways of oxidation of ethyl alcohol

A

-ADH- alcohol dehydrogenase (major)
-MEOS- microsomal ethanol oxidizing system (minor)

74
Q

**What is the legally intoxicated amount of alcohol in the bloodstream?

A

-less than 10%
(it’s 0.08)

75
Q

Ethanol intoxication causes cellular imbalance of NADH/NAD+

A

-in mitochondria leads to FA synthesis
-in cytosol leads to TAG synthesis

results in fatty liver syndrome

76
Q

Epigenetics

A

modification of gene expression by mechanisms other than in the underlying DNA sequence (nutritional factors)

77
Q

Nutrigenomic

A

nutrition interacts with genetics to influence health

78
Q

**About ____ of the dry weight of a typical human cell is protein

A

one half

79
Q

**Enzymes

A

decrease transition (activation) energy

80
Q

Collagen is made up of

A

tropocollagen

81
Q

Tropocollagen is made up of…

A

3 peptide chains that are cross-linked triple helix

82
Q

Which AA does collagen have a large amt of?

A

glycine and proline

83
Q

2 AA unique to collagen

A

Hydroxylysine
hydroxyproline

84
Q

5 classes of plasma proteins by electrophoresis:

A

-albumin
-alpha1-globulins
-alpha2-globulins
-beta-globulin s
-gamma globulins

85
Q

55% of total plasma proteins

A

Albumin

86
Q

**Albumin functions:

A

-nonspecific transport protein (ex FA, CA, Zn, Vitamin B6)
-contribution to osmotic pressure of the blood

87
Q

**Major role of alpha1-globulin

A

inhibit certain blood protease, contains alpha1-antitrypsin
-inhibitor of elastase that degrades elastin

88
Q

***alpha2-globulins

A

ceruloplamin (copper transport protein)
haptoglobulin (binding free hemoglobin)

89
Q

**The most important beta-globulin protein

A

transferrin and LDL apoprotein

90
Q

***gamma globulins

A

immunoglobulins or antibodies

91
Q

5 classes of immunoglobulins

A

IgG-70% (repeated exposure), can cross placenta
IgA-can secrete in milk (passive immunity)
IgM-largest, responds first
IgE-responsible for allergy
IgD

92
Q

Protein domain

A

large functional sequences of AA that have unique three-dimensional shape

93
Q

more than ____ human diseases can be traced to production of abnormal proteins

A

1500

94
Q

Which AA are absolutely essential?

A

lysine
threonine
histidine

95
Q

3 classes of AA

A

glucogenic
ketogenic
glucogenic and ketogenic

96
Q

ketogenic AA

A

lycine, leucine

97
Q

**A deficiency in which AA will result in Kwashiorkor, even though the diet may contain a large amount of protein?

A

Tryptophan

98
Q

Three phases of protein digestion

A
  1. gastric (10-15%)
    -pepsin hydrolyzes proteins to polypeptides
  2. Intestinal (most important)
  3. Brush Border
99
Q

Partially digested chyme in duodenum stimulates the release of…

A

secretin, CCK, and enteropeptidase

100
Q

Proteins use ____ to absorb into enterocytes

A

Sodium-potassium pump

101
Q

Which immunity function is associated with a significant uptake of intact protein in the small intestine?

A

Passive immunity during infancy

102
Q

At least ____ transporters have been found for extraintestinal AA absorption

A

4

103
Q

Two diseases related to low-tryptophan levels

A

Hartnup-cell can’t uptake
Kwashiorkor-not enough

104
Q

***A patient came to the ER complaining of severe abdominal pain. Labs revealed elevated dibasic AA in the urine. The patient’s pain subsided a few hours later after he passed a kidney stone. The most likely diagnosis is:

A

Cystinuria

105
Q

AA Pool

A

AA not used by the intestinal cells are transported to the portal vein

106
Q

**What % of AA are used to rebuild tissue protein?

A

75%

107
Q

The remainder of AA are used for

A

synthesis of glucose, ketones, various products

108
Q

What is the primary site for AA uptake?

A

liver

109
Q

What % of AA will be catabolized in liver?

A

60%

110
Q

Where are branched chain AA metabolized?

A

muscle

111
Q

3 branched chain AA

A

leucine, valine, isoleucine

112
Q

1st step in catabolism of AA

A

removal of AA via either deamination or transamination

113
Q

Which vitamin is required for this step?

A

B6

114
Q

Most transamination transfer AA into….

A

glutamate—which is then deaminated into ammonia

115
Q

In humans, the major route of nitrogen transfer from AA into ammonia involves which of the following pairs of enzymes?

A

Glutamate dehydrogenase and transaminases

116
Q

**Where is urea synthesized?

A

Liver (majority) and kidneys

117
Q

Intestine AA catabolism

A

absorption
-oxidize glutamine as their major source of energy
-synthesize and release citrulline

118
Q

Skeletal Muscle AA catabolism

A

BCAAs are transaminated into glutamate

119
Q

Ammoniagenic organ

A

kidney

120
Q

Primary function of protein

A
  1. replace body proteins
  2. synthesize N-containing products
121
Q

Primary function of protein

A
  1. replace body proteins
  2. synthesize N-containing products
122
Q

How much of total body protein is turned over each day?

A

about 1-2% (30-40g)

123
Q

A deficiency in which AA will result in negative N balance, even though the diet may contain a large amount of protein?

A

Tryptophan

124
Q

RDA allowance for protein is based on amt needed to maintain

A

Nitrogen balance

125
Q

How much additional protein needed during pregnancy? Lactation?

A

30, 20

126
Q

most common form of malnutrition

A

protein-calorie malnutrition

127
Q

amt of protein required for hospitalized patient formula

A

protein intake (g/24 hr) = (g urinary urea + 4) x 6.25

128
Q

Marasmus

A

not enough protein/or food
-progressive wasting and emaciation

129
Q

***Pellagra-like symptoms may be induced by which condition?

A

-incomplete dietary protein such as corn protein
-inherited defects in neutral amino acid transporter
-niacin deficiency

130
Q

Can FA be used to make glucose?

A

no

131
Q

Fat gain from CHO and/or protein is due to

A

sparing lipolysis rather than direct lipogenesis

132
Q

Fed state

A

last 3 hrs after meal

133
Q

Post absorptive state

A

3-18 hrs after meal

134
Q

Fasting state

A

18 hrs to 2 days w/o additional food intake

135
Q

***How long does it take for a fasting state?

A

Up to 48 hours

136
Q

Most liver glycogen is synthesized via

A

gluconeogenesis

137
Q

Two organs that highly depend on glucose for energy

A

Red blood cells
Brain

138
Q

During the post absorptive state, what is the major provider of glucose to the blood?

A

hepatic glycogenolysis

139
Q

Nearly all liver glycogen and most muscle glycogen can be depleted within…

A

24-36 hrs

140
Q

***How long do hepatic glycogen stores last before exhaustion is reached?

A

24-36 hrs

141
Q

AA from muscle breakdown provide the chief substance for which metabolic process during fasting state?

A

gluconeogenesis

142
Q

A protein-sparing shift in metabolism from gluconeogenesis to lipolysis occurs during which state?

A

starvation state

143
Q

A protein-sparing shift in metabolism from gluconeogenesis to lipolysis occurs during which state?

A

starvation state

144
Q

Metabolic syndrome requires 3 of the 5

A

-elevated waist circum.
-elevated triglycerides
-reduced HDL
-elevated blood pressure
-elevated fasting glucose

145
Q

Red muscle

A

Type 1, high level mitochondria, aerobic….slow twitch

145
Q

Red muscle

A

Type 1, high level mitochondria, aerobic….slow twitch

146
Q

4 major sources of energy during exercise

A

-muscle glycogen
-plasma glucose
-plasma FA
-intramuscular TAG

147
Q

**During EX, which contributes only minimally to the amt of ATP used by working muscles?

A

Amino Acids

148
Q

**The predominant use of plasma free fatty acids for energy is at a low to moderate intensity ex and the prominant use of glucose is at high intenesity ex.

A

True

149
Q

**What is the most important factor influencing the duration of endurance performance?

A

muscle glycogen stores at the start of exercise

150
Q

**BMI is one way to estimate

A

appropriate weight for height

151
Q

**In the reference man and woman, what % of body weight is fat?

A

15, 27

Nutrient Metabolism (2 decks)

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