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DHN 510 > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

What is a monosaccharide?

A

One sugar unit. Includes glucose, galactose, fructose, and lactate (not dietary).

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2
Q

What is a disaccharide?

A

Two sugar units. Includes maltose, sucrose, and lactose.

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3
Q

What are the two monosaccharides that makeup maltose?

A

Glucose + Glucose. Broken down by digestive enzyme maltase. Sourced from starches.

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4
Q

What are the two monosaccharides that make up sucrose?

A

Glucose + fructose. Broken down by digestive enzyme sucrase. Sourced by table sugar

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5
Q

What are the two monosaccharides that make up lactose?

A

Glucose + galactose. Broken down by the digestive enzyme lactase. Sourced by milk sugar.

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6
Q

What are oligosaccharides?

A

Short chain (3-10) of monosaccharide units joined by covalent bonds. Includes inulin and oligofructoses as well as stachyose and raffinose.

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7
Q

What are polysaccharides?

A

Long chain (greater than 10) of monosaccharide units. Includes starch, glycogen, and fiber.

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8
Q

What are glycosidic bonds?

A

Types of covalent bonds that link carbohydrates to other molecules.

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9
Q

What are the characteristics of the two starches, amylose and amylopectin?

A

Amylose is a linear starch with only alpha-1,4- glycosidic bonds. Amylopectin is a branched starch with alpha-1,4 and 1,6 bonds.

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10
Q

Where are starches found?

A

Only in plant food.

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11
Q

Where is glycogen found?

A

Only in animal food.

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12
Q

Are starches more branched than glycogen?

A

No, glycogen is more branched than starch.

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13
Q

What are the two types of fibers?

A

Soluble fiber can be dissolved in water like gum. Insoluble fiber can not be dissolved in water including cellulose and hemicellulose.

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14
Q

Where is fiber found?

A

Only in plant foods.

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15
Q

What types of fiber does an apple contain?

A

The fleshy part is soluble while the skin is insoluble fiber

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16
Q

What are the 3 different fates of glucose when the body is in a FED state?

A
  1. Becomes pyruvate after going through glycolysis
  2. Becomes nucleotides in the pentose phosphate pathway
  3. Becomes glycogen after going through glycogenesis.
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17
Q

What are the 2 ways glucose is made when the body is in a FASTED state?

A
  1. Glucose is made by the breakdown of glycogen through glycogenolysis
  2. Glucose is made from pyruvate through the process of gluconeogenesis.
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18
Q

What are the 5 types of enzyme groups?

A

Kinase, isomerase, mutase, transferase, and dehydrogenase.

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19
Q

What is the function of the enzyme group called kinases?

A

Kinases phosphorylate things by transferring a phosphate group from ATP.

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20
Q

What is the function of the enzyme group called isomerases?

A

Isomerases rearrange groups on a molecule to create an isomer of it.

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21
Q

What is the function of the enzyme group called mutases?

A

Mutases move functional groups from one position to another within the same molecule.

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21
Q

What is the function of the enzyme group called transferases?

A

Transferases move a functional group from one molecule to another.

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22
Q

What is the function of the enzyme group called dehydrogenases?

A

Dehydrogenases remove hydrogens from molecules while adding to a cofactor like NAD+.

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23
Q

What is glycolysis?

A

The metabolic pathway that converts carbohydrates in the form of glucose into pyruvate.

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24
Q

What is the NET energy of ATP only through glycolysis?

A

2 ATP

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25
Q

Is glycolysis aerobic or anaerobic?

A

It can be run under both conditions. The most energy-efficient form is under aerobic conditions.

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26
Q

Why does glycolysis occur in the cell?

A

Cytosol

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27
Q

What is step #1 of glycolysis?

A

Glucose -> Glucose-6-phosphate by hexokinase (muscle and brain) or glucokinase (liver and pancreas). 1 of 3 regulated steps in glycolysis that requires ATP.

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28
Q

What is step #2 of glycolysis?

A

Glucose-6-phosphate -> fructose-6-phosphate by phosphohexose isomerase.

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29
Q

What is step #3 of glycolysis?

A

Fructose-6-phosphate -> fructose-1,6-bisphosphate by phosphofructokinase-1. This step is the rate-limiting step of all glycolysis. Require ATP.

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30
Q

What is step #4 of glycolysis?

A

Fructose-1,6-bisphosphate -> dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P) by enzyme aldolase. G3P moves on in glycolysis, whereas DHAP is a dead end. DHAP can be converted into G3P through the enzyme triosephosphate isomerase.

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31
Q

What is step #5 of glycolysis?

A

Glyceraldehyde-3-phosphate -> 1,3-bisphosphoglycerate by enzyme glyceraldehyde phosphate-3-dehydrogenase. This step produces an NADH.

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32
Q

What is step #6 of glycolysis?

A

1,3-bisphosphoglycerate -> 3-phosphoglycerate by enzyme phosphoglycerate kinase. This step produces ATP.

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33
Q

What is step #7 of glycolysis?

A

3-phosphoglycerate -> 2-phosphoglycerate by enzyme phosphoglycerate mutase.

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34
Q

What is step #8 of glycolysis?

A

2-phosphoglycerate -> phosphoenol pyruvate (PEP) by enzyme enolase

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35
Q

What is step #9 of glycolysis?

A

Phosphoenol pyruvate (PEP) -> pyruvate by enzyme pyruvate kinase. This is the 3rd of 3 regulated steps in glycolysis. It produces ATP.

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36
Q

Where and how does galactose get into glycolysis to form pyruvate?

A

Galactose is converted to glucose-6-phosphate in order to enter into glycosidic pathway.

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37
Q

Where and how does fructose get into glycolysis to form pyruvate?

A

In muscle, fructose enters as fructose-6-phosphate. In liver, the process is more complex

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38
Q

Where and how does lactate get into glycolysis to form pyruvate?

A

Lactate produced in muscle during anaerobic exercise will be transported to the liver to participate in gluconeogenesis to produce glucose to be exported to other body tissues that need it. (Cori Cycle)

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39
Q

Where and how does glycerol get into glycolysis to form pyruvate?

A

The glycerol kinase enzyme uses ATP to change glycerol into glycerol-3-phosphate. Then the enzyme glycerol phosphate dehydrogenase releases glycerol as the backbone of the fatty acid chain. It enters glycolysis as DHAP that needs to be converted to G3P by the enzyme triosephosphate isomerase.

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40
Q

What complex converts pyruvate (3C) to acetyl CoA (2C)?

A

PDH Complex

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41
Q

What are the 3 enzymes involved in the PDH complex

A
  1. Pyruvate dehydrogenase
  2. Dihydrolipoyl transacetylase (DLAT)
  3. Dihydrolipoyl dehydrogenase (DLD)
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42
Q

What vitamins and nutrients serve as coenzymes in the PDH complex?

A

Thiamin used for TPP
Riboflavin used for FAD
Niacin used for NAD
Pantothenic acid use for CoA
Mg2+ used for lipoic acid

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43
Q

What circumstances could lead to deficiencies in previously listed vitamins like thiamin, riboflavin, niacin, and more?

A

Malnutrition and alcoholism.

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44
Q

Is the PDH complex aerobic or anaerobic?

A

Aerobic

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45
Q

Where does the PDH complex occur?

A

Mitochondria

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46
Q

What is the NET ATP made through the PDH complex reaction?

A

Two molecules of pyruvate enter into the PDH complex to produce two acetyl CoAs. This step produce one NADH each time. Each NADH will result in about 3 ATP once in electron transport chain. This calls for a NET ATP production of 6 ATP.

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47
Q

(T/F) Amylopectin contains only alpha-1,4 glycosidic bonds.

A

False

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48
Q

(T/F) Glucose is the only sugar that can enter glycolysis.

A

False

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49
Q

Which molecule is a critical metabolic intermediate of all three macronutrients?

A

Acetyl-CoA

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50
Q

Conversion of pyruvate to Acetyl CoA by the pyruvate dehydrogenase complex is __________.

A

Necessary to convey the carbon atom from glycolysis to the citric acid cycle.

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51
Q

Niacin is critical for the cofactor _______.

A

NAD+

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52
Q

Thiamin is a critical vitamin needed for the production of ________.

A

TPP

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53
Q

Riboflavin is a critical vitamin needed for the production of _________.

A

FAD

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54
Q

Pantothenic acid is a crucial vitamin needed for the production of ________.

A

CoA

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55
Q

Mg2+ is a crucial coenzyme for the production of __________.

A

Lipoid acid

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56
Q

Under anaerobic conditions, pyruvate cannot be converted to __________ and instead accumulates as ___________ in the muscle.

A

Acetyl CoA; Lactic acid

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57
Q

Lactate can then be converted into glucose via the _________ cycle.

A

Cori

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58
Q

How much energy does it require to convert lactate to glucose via the Cori cycle?

A

6 ATP.

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59
Q

What is gluconeogenesis?

A

This is the synthesis of glucose from non-carbohydrate precursors.

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60
Q

Where does gluconeogenesis take place?

A

Primarily in the liver.

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61
Q

Why is glucose (carbohydrates) so important?

A

The brain uses glucose as its primary fuel source and we must keep that running. A total of 160 grams of glucose is needed by the whole body and 120 grams of that is used by the brain. Red blood cells also use glucose as fuel.

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62
Q

What are the three non-carb precursors that can enter the gluconeogenic pathway?

A
  1. Lactate- formed by skeletal muscle when the rate of glycolysis exceeds the rate of oxidative metabolism
  2. Glycerol- released via hydrolysis of triacylglyerides from adipose tissue
  3. Amino Acids - breakdown of body protein.
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63
Q

Are glycolysis and gluconeogenesis on at the same time?

A

In the same cells these two processes will not occur at the same time. However, in a fasted state, the liver could be producing glucose and sending that out to other organs that are putting it through glycolysis to make energy.

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64
Q

What regulates the pathways of glycolysis and gluconeogenesis?

A
  1. Specific enzymes (allosteric regulation by ATP/AMP/ADP
  2. the concentration of glucose, lactate, and other precursors.
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65
Q

Does gluconeogenesis require energy?

A

Yes! Very energetically costly

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66
Q

What is the Krebs cycle/ Citric acid cycle/ TCA cycle?

A

The goal of this cycle is to produce coenzymes NADH and FADH2 that will carry hydrogen atoms and those high energy bond to the electron transport chain where they can be oxidized for energy.

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67
Q

What is step #1 of the Krebs cycle?

A

Oxaloacetate + Acetyl CoA -> Citrate

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68
Q

What is step #2 of the Krebs cycle?

A

Citrate -> isocitrate

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69
Q

What is step #3 of the Krebs cycle?

A

isocitrate -> alpha-ketoglutarate

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70
Q

What is step #4 of the Krebs cycle?

A

Alpha-ketoglutarate -> succinyl CoA

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71
Q

What is step #5 of the Krebs cycle?

A

Succinyl CoA -> succinate (creates GTP from GDP)

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72
Q

What is step #6 of the Krebs cycle?

A

Succinate -> fumarate

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73
Q

What is step #7 of the Krebs cycle?

A

Fumarate -> malate

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74
Q

What is step #8 of the Krebs cycle?

A

Malate -> oxaloacetate

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75
Q

1 NADH=

A

3 ATP

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76
Q

1 FADH2=

A

2 ATP

77
Q

How many NET ATP are created from 1 turn of the Krebs cycle?

A

12 per cycle

78
Q

Where does the Krebs cycle take place?

A

Mitochondria

79
Q

What is glycogenesis?

A

Process in which glucose is used to create glycogen where 1/3 is stored in the liver and the other 2/3 is stored in skeletal muscle.

80
Q

What are the important steps of glycogenesis?

A

Start with glucose. Glucose is converted to glucose-6-phosphate and then that is converted to glucose-1-phosphate.
G1P is then converted to UDP glucose via the enzyme UDP-glucose pyrophosphatase. Glycogenin then brings in some glucose primers to add onto UDP-glucose.
The enzyme glycogen synthase then transfers glycosyl residues from UDP glucose to glycogen.

81
Q

What is the importance of glycogenin in glycogenesis?

A

This enzyme catalyzes the priming step by adding a priming chain of glucose to UDP-glucose.

82
Q

What is the importance of glycogen synthase in glycogenesis?

A

Glycogen synthase moves the rest of the glucose molecules onto the primer. Stimulated by insulin.

83
Q

What is glycogenolysis?

A

The process by which glycogen is broken down to form glucose.

84
Q

What are the important steps of glycogenolysis?

A

Enzyme glycogen phosphorylase cleaves the 1,4 glycosidic bonds until 4 glucose residues remain on glycogen and de-branching enzyme cleaves 1,6 glycosidic bonds. Glucose-1-phosphate is created and turned into glucose-6-phosphate. That is then dephosphorylated by glucose-6-phosphatase to glucose.

85
Q

Why is the dephosphorylation of glucose-6-phosphate so important?

A

If the glucose still had a phosphate attached to it, it would not be allowed the leave the compartment it was originally phosphorylated in. The only reason we are breaking down glycogen now is to supply the rest of body with glucose so it needs to be able to leave.

86
Q

How is the enzyme glycogen phosphorylase regulated in glycogenolysis?

A

Regulated by allosteric and phosphorylation. The active form is phosphorylated, while the inactive form is the opposite. Epinephrine in the muscle and glucagon in the liver tells kinase to phosphorylate the glycogen phosphorylase.

87
Q

What are the three main lipids that humans consume?

A

Triglycerides, phospholipids, and sterols (cholesterol)

88
Q

A fatty acid is a straight hydrocarbon chain with a _____________ end and a _________ on the other end.

A

Carboxylic acid; methyl

89
Q

What is the degree of the length of fatty acids?

A

4 to 24 carbons in length

90
Q

Most fatty acids exist in the cis-isomer configuration, but some exist in the trans-isomer state. What are some examples of foods with trans-fat due to hydrogenation?

A

Processed foods like cookies, chips, crackers, vegetable shortening, microwave popcorn, fried fast food, bakery items, and non-dairy creamer

91
Q

In the typical American diet, what are the four main fatty acids consumed?

A

Palmitic acid
Stearic acid
Oleic acid
linoleic acid

92
Q

What are the two most commonly consumed short/medium chained fatty acids?

A

Butyric acid found in milk fat
Lauric acid found in coconut oil

93
Q

What are the two essential fatty acids?

A

Linoleic acid (omega-6 FA) and alpha-linolenic acid (omega-3 FA)

94
Q

Why are linoleic and linolenic acids essential fatty acids?

A

Humans lack delta-12 and 15 desaturases which are needed to incorporate the double bonds past the 9th carbon on their hydrocarbon tail. They are also precursors for important long-chain fatty acids.

95
Q

What are the reasons and symptoms of essential fatty acid deficiency?

A

The reason is due to an overall low intake of fats, and symptoms include poor growth, dermatitis, kidney lesions, neural delays, and early death

96
Q

What is linoleic acid a precursor for?

A

Arachidonic acid

97
Q

What is alpha-linolenic acid a precursor for?

A

EPA and DHA

98
Q

What is Spirulina?

A

Type of blue-green algae that is high in omega-3 fatty acids, vitamins, and minerals.

99
Q

What are eicosanoids?

A

These are polyunsaturated fatty acids composed of 20 carbons. They are made from linoleic and alpha-linolenic acid. The three classes include prostaglandins, thromboxanes, and leukotrienes.

100
Q

What are some of the functions of prostaglandins?

A

Promote inflammation, support blood clotting, and contribute to vasodilation.

101
Q

What inhibits the action of prostaglandins?

A

NSAIDS block the enzyme COX that converts arachidonic acid to prostaglandins.

102
Q

What are the benefits and side effects of NSAIDs?

A

Benefits include reduced prostaglandin synthesis, so decreased fever and pain. Side effects include increased blood pressure, kidney damage, allergic reactions, and ulcers from long-term use.

103
Q

What are the main two functional groups of a triglyceride?

A

A glycerol backbone with 3 fatty acids attached.

104
Q

What are the 3 basic steps of lipid metabolism?

A
  1. Dietary lipids are absorbed from the intestine
  2. Lipids packaged into chylomicrons for delivery to peripheral tissues
  3. Lipids derived from the liver are packaged into lipoproteins for delivery to tissues
105
Q

What are some basic facts about bile?

A

Bile is made in the liver from cholesterol and stored in the gallbladder. The hormone CCK stimulates contraction of gallbladder which releases bill into the duodenum. The function of bile is to emulsify fats.

106
Q

What is the function of the enzyme lipase?

A

The enzyme lipase is stored and secreted from the pancreas into to duodenum. The function of lipase is the break ester bonds between fatty acid chains and glycerol.

107
Q

How are lipids absorbed from GIT?

A
  1. Ingested lipids are emulsified into micelles.
  2. Lipase in duodenum then breaks apart glycerol and fatty acid bonds where they enter GIT cells.
  3. The fatty acids link again to form triglycerides.
  4. Fatty acids then combine with proteins to form chylomicrons.
  5. Chylomicrons enter lymphatic system and are carried away from intestines.
108
Q

What are the four basic components of lipoproteins?

A

Triglycerides, phospholipids, cholesterol, and protein

109
Q

What are apolipoproteins?

A

The protein component of lipoproteins. Apoproteins confer specificity for lipoprotein complexes allowing them to be recognized by specific receptors on cell surface.

110
Q

What are the main classes of lipoproteins?

A

Chylomicron (dietary lipid), VLDL (hepatic lipid), LDL (hepatic lipid), and HDL

111
Q

What happens to dietary lipids once they are absorbed from GIT and already packaged in chylomicrons?

A
  1. Enzyme lipoprotein lipase breaks down the triglycerides inside into 3 fatty acids and glycerol
  2. Fatty acids are absorbed into the cell
  3. Chylomicron remnants now have less triglyceride content and are transported back to the liver
112
Q

What happens to endogenous lipids (dietary or synthesized) once they are absorbed from the GIT?

A

1.They are packaged in VLDL which has the highest concentration of triglycerides.
2. Lipoprotein lipase breaks down the triglycerides inside
3. VLDL is degraded into IDL and then LDL

113
Q

Why is ApoB-100 so important?

A

ApoB-100 is the main apoprotein found on LDL. The higher a person LDL cholesterol is, the higher their ApoB-100 levels.

114
Q

How is high LDL cholesterol treated?

A

With the use of Statins that inhibit HMG-CoA reductase. Benefits include reduced cholesterol and risk of CVD. Side effects can include nausea, headaches, and muscle aches

115
Q

What are the main characteristics of fatty acid synthesis?

A

Goal is to make triacylglyerols from glucose and fatty acids. Only active in the FED state. Main point is acetyl CoA being converted to Malonyl CoA.

116
Q

What is the key regulatory point of fatty acid synthesis?

A

When Acetyl CoA is converted to Malonyl CoA where it can leave mitochondria and enter cytoplasm. Called the citrate-malate shuttle.

117
Q

What is fatty acid oxidation?

A

This is the breakdown of stored fats by oxidizing carbon molecules to be used for ATP synthesis.

118
Q

What are the main characteristics of fatty acid oxidation?

A

Active in the FASTED state. Happens in seperate area as fatty acid synthesis.

119
Q

What are the steps of fatty acid oxidation?

A
  1. Stored fatty acids are transported to mitochondria by important transporter called carnitine
  2. Once in mitochondrial matrix, the fatty acids undergo beta oxidation.
  3. Degraded into Acetyl CoA where it can enter to citric acid cycle OR be used for ketone body synthesis.
120
Q

What is the key regulator of fatty acid oxidation?

A

Malonyl CoA is an inhibitor of fatty acid oxidation because it turns on fatty acid synthesis. Malonyl CoA will inhibit fatty acids from entering the mitochondria by inhibiting carnitine acyl transferase 1 (CPT-1).

121
Q

What is happening in the liver during fed and fasted states regarding fatty acids?

A

In FED state, the liver synthesizes fatty acids and sents them to be stored in adipose tissue
In FASTED state, fatty acids are converted to ketone bodies in the liver.

122
Q

What are the four components of an amino acid?

A
  1. Acid- carboxylic acid
  2. Amine
  3. Hydrogen
  4. R-group
123
Q

What are the 9 essential amino acids?

A

Phe, Val, Trp, Thr, Ile, Met, His, Leu, and Lys
(PVT TIM HILL)

124
Q

What are conditionally essential amino acids?

A

When certain physiological conditions make nonessential amino acids essential like in pregnancy, growth, trauma, etc.

125
Q

What are the bonds involved in secondary structures of amino acids?

A

Hydrogen bonds

126
Q

What are the bonds involved in the tertiary structures of amino acids?

A

This is when R-groups interact and bonds include hydrogen, disulfide bridges, ionic bonds, and hydrophobic interactions.

127
Q

What happens to proteins in the FED state?

A

Once amino acids are absorbed they are used to build other things and are not stored.

128
Q

What absolutely always needs to happen in order for an amino acid to enter into energy metabolism?

A

The amino group must be removed either through deamination or transamination.

129
Q

What is deamination?

A

This is when the amino group is completely removed. The amine group is then converted to an ammonium ion and goes to liver where it enters urea cycle to be excreted via the urine.

130
Q

What is transanimation?

A

The transfer of amino group from amino acid to keto acid. This process occurs in all organs and synthesizes all nonessential amino acids. Enzymes ALT and AST are involved.

131
Q

What is the enzyme alanine amino-transferase (ALT)?

A

Catalyzes the transfer of the amino group of alanine to an alpha-ketoglutarate.

132
Q

What is the enzyme Aspartate amino-transferase (AST)?

A

This catalyzes the transfer of the amino group aspartate to alpha-ketoglutarate.

133
Q

What is the clinical significance of ALT and AST levels?

A

These are liver enzymes. Elevated levels of liver enzymes indicate inflammation or damage to liver cells.

134
Q

What are causes and symptoms of elevated AST/ALT levels?

A

Caused by inflammation of liver, hepatitis, cirrhosis, alcoholic fatty liver, or decreased blood flow to liver. Symptoms include fatigue, fainting, jaundice, dark-colored urine, and weight loss.

135
Q

What are the normal levels of ALT and AST?

A

ALT= 7-56 U/L
AST= 5-40 U/L

136
Q

What are some medications that increase AST/ALT levels?

A

Tylenol (acetominophen), naproxen, statins, and antibiotics.

137
Q

What are the two ketogenic amino acids?

A

Leucine and Lysine

138
Q

What are ketogenic amino acids?

A

Ketogenic amino acids will end up forming Acetyl CoA to form ketone bodies.

139
Q

What are glucogenic amino acids?

A

Glucogenic amino acids can form pyruvate, oxaloacetate, Alpha-ketoglutarate, succinyl CoA, or fumarate.

140
Q

What amino acids are both ketogenic and glucogenic?

A

Tryptophan, phenylalanine, tyrosine, isoleucine, and threonine.

141
Q

What is the urea cycle?

A

The urea cycle is responsible for converting toxic ammonia into non-toxic urea. The cycle occurs in the liver and requires input of 4 ATP.

142
Q

How is the urea cycle linked to the Krebs cycle?

A

Amino acids enter urea cycle from oxaloacetate being transaminated to aspartate. Additionally, the synthesis of fumarate from urea cycle can enter into the Krebs cycle.

143
Q

What is BUN?

A

Blood urea nitrogen. Screening test used to evaluate renal function. Normal levels are 8-20mg.

144
Q

What is UUN?

A

Urine Urea nitrogen. Indication of nitrogen status and protein intake. Normal levels are 12-20 grams in a 24-hour collection.

145
Q

If you ate a meal containing protein, what is most likely happening?

A

The amino acids are transferred to the liver and other tissues for anabolism. Could be used for energy production but usually only 5% of energy is supplied by protein.

146
Q

If a person is in a starvation state, what is most likely happening to amino acids?

A

The body does not store protein. There could be some protein catabolism occuring with acute starvation but not much.

147
Q

What is Methionine?

A

Methionine is an essential amino acids that contains sulfur. Methionine can be converted into the non-essential amino acid cysteine.

148
Q

What is an intermediate of synthesis of cysteine from methionine?

A

Homocysteine

149
Q

What are the best sources of methionine?

A

Animal foods like meat

150
Q

Is homocysteine toxic?

A

Yes, a build up can have adverse health effects.

151
Q

Would you want to consume excess methionine?

A

No, methioine consumption increases homocysteine levels.

152
Q

Which vitamins are essential for normal homocysteine metabolism?

A

B6, B12, and folate

153
Q

Why is homocysetine important?

A

Increase homocysteine levels are a risk factor for chronic diseases like CVD, Alzheimer’s, and some cancers.

154
Q

What is the quick history of vitamin discovery?

A

Vitamins were first discovered in 1912 by Dr. Funk who discovered thiamin (B1).

155
Q

What are the 5 classifications of vitamins?

A
  1. organic nutrients
  2. essential nutrients
  3. naturally occur in foods
  4. signs/symptoms of deficiency occur when nutrient is lacking in diet
  5. good health restored if deficiency treated early
156
Q

What are the fat-soluble vitamins?

A

K, A, D, and E

157
Q

What are the water-soluble vitamins?

A

All B vitamins (thiamin, riboflavin, niacin, vitamin B6, B12, pantothenic acid, folate, and biotin), and vitamin C.

158
Q

How are water-soluble vitamins absorbed, stored, and excreted?

A

Water-soluble vitamins are absorbed via passive or facilitated diffusion in GIT. They are transporting directly in the blood and are not stored at high amounts. They are excreted in the urine. Need on regular basis due to high clearance rate.

159
Q

How are fat-soluble vitamins absorbed, stored, and excreted?

A

Fat-soluble vitamins need to help of fat and bile to be absorbed in the GIT. They are transported through the lymph system first. They are then stored in adipocytes and the liver. They are not readily excreted and can be toxic in large amounts due to storage capacity.

160
Q

What are the 5 factors that influence the bioavailability of a vitamin?

A
  1. Efficiency of digestion (diarrhea/ bariatric surgery and gallbladder disease/ pancreatitis)
  2. Previous nutrient intake and nutritional status
  3. Other foods eaten at the same time (vitamin C and Fe)
  4. food processing and preparation techniques
  5. Source of the vitamin (natural, synthetic, or fortified)
161
Q

Remember, fat soluble vitamins are absorbed with lipids in the GIT and require _______ and ________ for absorption.

A

fat and bile

162
Q

What compounds are included in the vitamin A family called Retinoids?

A

Retinol, retinal, and retinoic acid

163
Q

What are the two pro-forms of vitamin A?

A

Carotenoids and Beta-carotene

164
Q

What are sources of beta-carotenoids?

A

Plant food sources like leafy greens, sweet potatoes, and carrots.

165
Q

What are sources of retinyl esters?

A

Animal foods like fish, eggs, and meat

166
Q

What are the top 10 sources of vitamin A in the US?

A

Carrots, vegetable soup, mixed green, spinach, garden salad, orange juice, sweet potatoes, beef stew, mixed veggies, and cantaloupe.

167
Q

What is the bioavaliabilty of retinyl esters?

A

80-90% absorbed

168
Q

What is the bioavailability of beta-carotene?

A

40-60%

169
Q

How much vitamin A is stored in the liver? The other percentage is divided between adipose tissue, lungs, and kidney.

A

90%

170
Q

What nutrients interfere with vitamin A absorption?

A

Vitamine D, K, and E. Zinc and Iron as well.

171
Q

What are the key functions of vitamin A?

A

Night vision (vitamin A required to form complex rhodopsin which performs critical function of stimulating rod cell to result in vision), cellular growth, and immune system.

172
Q

What is the recommended intake of vitamin A for males and females?

A

Males: 900 micrograms
Females: 700 micrograms

173
Q

What is vitamin A upper limit?

A

3,000 microgram

174
Q

What are the populations at greatest risk for vitamin A deficiency?

A

Developing parts of the world, GIT malabsorption (celiac disease, IBD, gallbladder removal), and pancreatitis.

175
Q

What are the major signs of a Vitamin A deficiency?

A

Night blindness, xerophthalmia (dry eye), poor growth, frequent infections (due to T cell growth), and cutaneous change

176
Q

What are signs of vitamin A toxicity?

A

Headache, nausea, vomiting, visual distrubances, hair loss, bone pain, bone fractures, and carotenemia.

177
Q

What is Accutane?

A

Vitamin A derivative of isotretinoin.

178
Q

What is toxic levels of vitamin A for adults and children?

A

Adults: >200 mg
Children: > 100mg
Serum vitamin A levels >200 mg

179
Q

How much energy is required to run the Cori Cycle?

A

Takes 6 ATP to convert lactate to glucose

180
Q

The brain uses glucose as its main energy source. What is the next best option for the brain in the FASTED state?

A

Ketone bodies

181
Q

What is the main fuel source of resting muscle?

A

Fatty acids

182
Q

What are the four types of ketogenic diets?

A

Classic Ketogenic diet, Modified Atkins Diet (MAD), Medium Chain Triglyceride based KD (MCT), and Low glycemic index KD (LGI).

183
Q

What is the macronutrient composition of the classic ketogenic diet?

A

90% of kcal from fat
3% kcal from carbs
7% kcal from protein

184
Q

What is the macronutrient composition of the modified Atkins diet (MAD)?

A

70% of kcal from fat
5% of kcal from carbs
25% of kcal from protein

185
Q

What is the macronutrient composition of the medium-chain triglyceride-based KD (MCT)?

A

70% of kcal from fat
20% of kcal from carbs
10% of kcal from protein

186
Q

What is the macronutrient composition of the low glycemic index-based KD (LGI)?

A

45% of kcal from fat
27% of kcal from carbs
28% of kcal from protein

187
Q

What were three different intermittent fasting diets used in the research paper discussed?

A
  1. Continuous energy-restricted diet asked to follow restriction during the whole trial period
  2. WOWO- a week on, week-off group restricted for 1 week and ate habitually the other week.
  3. 5:2 group consumed very low calorie diet 2 days per week and had 5 days of habitual eating.
188
Q

Which lipoprotein has the largest percentage of cholesterol?

A

LDL

189
Q

Which lipoprotein has the largest percentage of triglycerides?

A

Chylomicrons

DHN 510 (3 decks)

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