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BIBC120 > Final Review Part 1 > Flashcards

Final Review Part 1 Flashcards

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1
Q

Name the functions of Vitamin A (Retinal). (Hint: We discussed 5)

A

● normal vision
● acts as hormone—affects gene transcription
● proper immune functioning
● structural integrity of epithelial tissue (e.g. skin)
● antioxidant
● other things not covered

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2
Q

Name the enzymes that act on the following: 1) Retinol, 2) Retinal. What products do each of these enzymes make?

A

1) Retinol dehydrogenase, product is retinal;

2) Retinal dehydrogenase, product is retinoic acid

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3
Q

B-carotene makes 2 of what molecule?

A

Retinal

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4
Q

Is the starting retinal molecule cis- or trans- before introducing light?

A

Cis-retinal

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5
Q

Describe how Vitamin A acts as a hormone.

A

● binds to nuclear receptors
● 9-cis RA binds to retinoid X receptors (RXR)
● 9-cis RA & all-trans RA bind to retinoic acid
receptors (RAR)

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6
Q

Describe Vitamin A’s role in immune responses (there are 2).

A

● needed for proper immunity in the GI tract
● deficiency can cause impaired gut immunity
and lead to diarrhea

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7
Q

Describe how the structural integrity of epithelial tissue (skin) is affected by lack of Vitamin A.

A

● deficiency leads to hyperkeratosis
(keratinization of epithelial tissue)
● cornea of eye composed of an outer layer of
epithelial tissue
○ deficiency: cornea gets keratinized → dry and
opaque → blindness

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8
Q

Vitamin A deficiency is the leading cause of blindness in children worldwide. What are some other symptoms of Vitamin A deficiency (there are 2)?

A

● night blindness
● xerophthalmia (due to insufficient tear
production)

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9
Q

What is the UL for Vitamin A?

A

3000micrograms/day from animal sources

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10
Q

What are the acute symptoms of Vitamin A toxicity from animal sources (there are 3)?

A

acute: nausea, headache, dizziness

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11
Q

What are the chronic symptoms of Vitamin A toxicity from animal sources (there are 2)?

A

chronic: liver damage, hair/bone loss

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12
Q

What are the teratogenic effects of Vitamin A toxicity from animal sources (there are 2)?

A

birth defects, spontaneous

abortion

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13
Q

True or False: Unlike Vitamin A from animal sources, carotenoids (provitamin A) do not cause
toxicity and have no UL

A

True.

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14
Q

Where is vitamin A stored?

A

Fat tissue (beneath skin)

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15
Q

What are the major functions of Vitamin D (there are 4)?

A

● calcium homeostasis: increases Ca2+
absorption in SI
○ if [Ca2+]blood is low, Ca2+ gets released from bones
● secosteroid hormone
○ cell differentiation in skin, bone, and SI
● supports resistance to infection
● reduces risk of certain cancers (breast,
prostate, colon)

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16
Q

What is the name of the medical condition caused by Vitamin D deficiency?

A

● Rickets (bones get soft and deformed)

○ also from deficiency of calcium and/or phosphorous

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17
Q

What are the symptoms of Vitamin D toxicity (there are 3)?

A

● Ca2+ depleted from bones → malformations
● Ca2+ deposited in soft tissues (calcification)
● kidney stones

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18
Q

What are the 2 major functions associated with Vitamin E?

A

● antioxidant (only vitamin with this sole
function)
● prevents oxidative damage to cell
membranes (resides within lipid membranes)
○ quenches free radicals (ROS)

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19
Q

The active form of Vitamin E is regenerated by which other vitamin?

A

Vitamin C

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20
Q

Describe the two main risks of Vitamin E deficiency.

A

● hemolysis, RBC sensitivity due to oxidative
damage → hemolytic anemia
● high risk for smokers, premature infants
exposed to high O2

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21
Q

Name the major symptom of Vitamin E toxicity.

A

● hemorrhaging

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22
Q

In general, B vitamins are co-factors/co-substrates in energy metabolism. What other general details did they ask us to memorize?

A
  • Fast turnover and small storage pool(except B12)

- Low toxicity

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23
Q

What is the active form of Vitamin B1 (Thiamin)?

A

Thiamin Pyrophosphate (TPP)

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24
Q

What is the name of the reactive group in Vitamin B1?

A

Thiazole ring

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25
What kind of reaction would Vitamin B1 typically participate in?
Decarboxylation
26
The medical condition Beriberi results from Vitamin B1 deficiency. Describe this condition.
weak, poor coordination, thin, apathetic, short term | memory loss
27
How does alcohol consumption affect Vitamin B1 levels?
alcohol inhibits B1 absorption and stimulates | secretion -> thiamin deficiency -> staggering gait, eye trouble, derangement
28
Describe the structure of Vitamin B2 (riboflavin).
Ribose, FAD?
29
What is the active molecule of Vitamin B2 (riboflavin)?
FAD
30
Deficiency symptoms for Vitamin B2 (riboflavin) appear after 2 months. Describe these symptoms.
inflammation of throat, mouth, tongue(glossitis), anemia, fatigue
31
What is the active molecule in Vitamin B3 (Niacin)? What type of reactions does it play a role in?
Nicotinamide/NAD+/NADH; Redox reactions
32
Describe the symptoms of Vitamin B3 (Niacin) deficiency (There are 7).
Pellagra (broken skin), damage to body, | dementia, delirium, diarrhea, dermatitis, death
33
Vitamin B3 (Niacin) is used as a treatment for what disease? How does it work?
Atherosclerosis; Decreases LDL, increases HDL
34
Describe the symptoms of Vitamin B3 (Niacin) toxicity.
flushing, swollen tongue, GI, liver damage
35
In insane asylums, individuals were fed corn, but were also deficient in niacin. Describe an easy solution to this deficiency.
Treat the corn with alkali from lime juice to promote release of niacin from protein binding.
36
What is the active form of Vitamin B6 (Pyridoxal)?
Pyridoxal phosphate (PLP)
37
The intermediate form of Vitamin B6 is a Schiff's base. What is the reactive group in Vitamin B6 (Pyridoxal)?
CHO (Aldehyde)
38
Describe the symptoms of a Vitamin B6 (pyridoxal) deficiency.
convulsions, and anemia, dermatitis and neural issues | in adults
39
What kind of enzyme does Vitamin B6 play a role in?
Transaminase
40
What are the three parts of Vitamin B9 (Folate)?
pteridine + para-aminobenzoic acid + glutamate
41
What is the active molecule in Vitamin B9 (Folate)?
Tetrahydrofolic acid (THFA)
42
Describe the symptoms for Vitamin B9 (Folate) deficiency (there are 3).
megaloblastic anemia, spina bifida, | increased homocysteine levels
43
What is the health issue associated with increased homocysteine levels?
endothelial damage, cholesterol oxidation, platelet aggregation, CVD
44
Vitamin B12 (Cobalamin) deficiency symptoms include (there are 4):
megaloblastic anemia, nerve degeneration, fatigue, high homocysteine levels (CVD)
45
Vitamin B12 can be found in animal liver. This is because Vitamin B12 is stored in the liver. How long does this supply typically last after stopping Vitamin B12 intake?
2-3 years.
46
Vitamin B12 functions in metabolism. Deficiency in Vitamin B12 leads to the medical condition known as:
Pernicious anemia
47
Describe pernicious anemia.
autoimmune disease destroys gastric parietal | cells, secrete intrinsic factor needed for B12 absorption, leads to low RBC, hemoglobin, nerve degeneration
48
Ascorbic Acid (Vitamin C) is involved in what type of reactions?
Redox
49
What is the major function of Vitamin C?
- Antioxidant (Reducing agent) - collagen synthesis (Pro -> Hydroxyproline) - free radical trap (esp for eye, leukocytes, immune system) - regenerate Vit E - iron absorption - hormone and neurotransmitter synthesis (pituitary & adrenal, brain)
50
Deficiency symptoms start appearing 20-40 days after intake of Vitamin C stops. Describe these symptoms.
Fatigue, pinpoint hair follicle hemorrhages, scurvy | bleeding gums and joints, slow wound healing
51
Describe the relative RDA levels for Smokers, Females and Males.
Smokers (need most) > Males > Females (need least)
52
Describe the pros of taking multivitamins.
•Most people do not meet recommendations •Esp people with increased micronutrient needs: Older adults, African American, obese people •Low cost •No long term health risk
53
What are the cons of multivitamins?
* Whole food safer, more complete * Toxicity: Vit A (carotenoids), folate (colon cancer), iron (oxidant) * ...Unless: deficiency
54
In a steady state, input=output. Describe the typical inputs and outputs of water for the body.
○ input: fluids, food, metabolism | ○ output: urine, stool, sweat/breath
55
Too much water leads to:
● overwhelmed kidneys, and can cause | hyponatremia
56
Too little water leads to:
● dehydration (flushed skin, nausea, headache) ○ during vigorous exercise, can lose up to 1L of water/hr ○ during air travel, can lose up to 1.5L in 3 hrs
57
There are two classes of minerals differed by RDA: Major and Minor. What is the RDA for Major minerals?
RDA is >100mg/day OR >0.01% of body | weight
58
Describe bioavailability and what affects it.
● amount (%) absorbed by the body ● controlled in part by antinutrients, which inhibit absorption, and by pronutrients, which promote absorption
59
Name the three types of antinutrients discussed in class.
Phytic acid, oxalic acid, tannins
60
Describe the source and role of phytic acid.
``` Phytic acid ● whole grains, beans, nuts, seeds ● yeast breaks down phytic acid so leavened bread is less of a problem than unleavened bread ● inhibits absorption of zinc and iron ```
61
Describe the source and role of oxalic acid.
● high in spinach | ● inhibits iron and calcium absorption
62
Describe the source and role of tannins.
● high in tea and coffee | ● inhibits iron absorption
63
Calcium is the most abundant mineral in the human body. It is present in bones and teeth in what form?
Hydroxyappetite, a complex of Calcium, Phosphorus, and hydroxide ions
64
The percentage absorption of calcium is ~25%. What other vitamin does it require to be absorbed?
Vitamin D.
65
What are the major functions of calcium?
● neurotransmission (signaling) ● muscle contraction (signaling) ● Major components of bones and teeth
66
The structures of bones and teeth are dynamic. What mediates their dynamic structures?
osteoblasts (build bone) and osteoclasts (bone resorption)
67
Normal blood calcium range is 8.5-10.8mg/dl. What hormone INCREASES in response to LOW blood calcium?
parathyroid hormone (PTH)
68
Increased levels of parathyroid hormone lead to:
``` increased ○ Vit. D levels, ○ Ca mobilization from bones, ○ Ca retention by kidneys, ○ Ca uptake by intestines ```
69
Normal blood calcium range is 8.5-10.8mg/dl. What hormone INCREASES in response to HIGH blood calcium?
calcitonin
70
Increased levels of calcitonin lead to:
``` ● decreased ○ PTH, Vit. D, ○ Ca release from bones, ○ Ca retention by kidneys, ○ Ca uptake by intestines ```
71
What is the bottom line of taking calcium supplements (3 things)?
●
72
Osteoporosis is defined as having a bone mineral density 2.5 std. dev. below peak bone mass (20 yr old sex matched healthy person average). Name some risk factors for Osteoporosis.
● long term deficiency in calcium intake ● estrogen loss from menopause or amenorrhea ● inactivity ● genetics: Asians
73
What are some ways to prevent osteoporosis?
adequate exercise and adequate calcium and Vit. D in diet
74
Phosphorus and Magnesium both are involved in bone growth and maintenance, nucleic acid and energy metabolism, have good absorption (enhanced by Vit. D), and are regulated by the kidneys. Which of the two is consumed in insufficient levels in most of the population?
Magnesium (UI...avg intake
75
A deficiency in phosphorus leads to (3 things):
bone loss, poor growth and tooth development, rickets in | children (related to deficiencies in Vitamin D)
76
Phosphorus in excess leads to (2 things):
impaired kidney function and vascular damage
77
A deficiency in magnesium leads to (2 things):
neuronal and cardiac problems
78
Magnesium in excess leads to (2 things):
diarrhea and kidney failure
79
Name the three major electrolytes discussed in class.
Na+, K+, Cl-
80
Which electrolyte(s) are high concentration outside of the cell?
Na+, Cl-
81
Which electrolyte(s) are low concentration inside of the cell?
K+
82
Which electrolytes are involved in nerve impulses?
Na+, K+
83
Which electrolyte(s) are in severe deficit in most of the population? What are the symptoms of this deficiency?
K+; first a loss of appetite, muscle cramps, confusion → heart stops
84
Na+ is overconsumed. What medical conditions does it promote (3 of them)?
diabetics, hypertension, chronic kidney disease
85
What primarily maintains the electrolyte concentration across the plasma membrane? Describe how it works and its importance.
the Na+/K+ ATPase; ● 3Na+ out, 2K+ in ● accounts for ⅓ of energy use in most cells ● accounts for ⅔ of energy use in neurons
86
Hypertension is a major risk factor for what diseases (3 of them)?
CHD, stroke, kidney disease
87
In class, a video explained the test to validate the effect of flax on HBP. Explain how it was conducted and briefly what the results were.
● double blind ● hypertension patients were given ¼ cup of ground flax-containing foods, or a placebo ● decreased hypertension with efficacy that is comparable to drugs
88
Name three trace minerals discussed in class.
Iron, Zinc, Iodide
89
Heme iron is found in meat, while Fe3+ ferric and Fe2+ ferrous forms are found in plants. How do they differ in terms of percent absorption?
The Heme iron is more readily absorbed (~30%) while the plant forms are only 2-10% absorbed.
90
Name some ways that can promote iron absorption (there are 3).
○ gastric acid helps solubilize ○ Vit. C: Fe3+ ---> Fe2+ via ferric reductase, which uses e- from Vit. C. it also chelates and stimulates absorption of iron ○ meat protein increases absorption 2-3X
91
Name some inhibitors of iron absorption (4~5 total).
phytic acid, oxalic acid, tannins, low gastric acid, some antacids
92
What are the three major functions of iron?
● As a component of hemoglobin and myoglobin, iron is involved in oxygen and CO2 transport ● energy metabolism (cytochromes) ● detoxification (cytochrome p450)
93
What are three main causes of iron deficiency?
● low intake of iron from diet ● poor absorption of iron ● excessive blood loss
94
True or False: In the first stage of iron deficiency, blood Hb levels remain normal, as iron storage pools are depleted first.
True.
95
True or False: In the advanced stage of iron deficiency, blood Hb levels are low.
True.
96
Name the high risk groups for iron deficiency (there are 3).
● women of childbearing age, esp, pregnant women and teenage girls ● infants and toddlers ● vegans
97
Name the low risk groups for iron deficiency (there are 2).
1) adult men and 2) post-menopausal women
98
What is the UL for iron intake? What are the symptoms of iron toxicity?
``` UL= 45 mg/day; ○ GI distress (vomiting, diarrhea) ○ ROS production via Fenton reaction ---hydroxyl radical-->inflammation, CVD, diabetes, stroke, glaucoma ```
99
What is the leading cause of iron toxicity in children?
chewable iron-containing supplements
100
Name the major proteins involved in iron transport (there are 6).
1) ferritin (duodenal absorptive cell) 2) ferroportin (duodenal absorptive cell) 3) transferrin (blood to liver/other organs) 4) transferrin receptor (at receiving cells) 5) hemoglobin (bound to iron in blood stream) 6) myoglobin (bound to iron in muscles)
101
How is high iron regulated by ferritin?
increase ferritin in absorptive cells, and these cells with trapped iron get excreted
102
How is high iron regulated by hepcidin from the liver?
hepcidin causes internalization and degradation of ferroportin
103
Why is hepcidin released during infection?
To reduce blood iron levels so that pathogens have less iron for growth. Thus, chronic infection or inflammation can lead to anemia
104
How is low iron regulated by ferritin?
reduce ferritin levels to prevent iron trapping in absorptive cells and allowing iron to get through to blood
105
What are the major functions of zinc (there are 3)?
● required for many enzymes including ADH, carbonic anhydrase, superoxide dismutase ● promote growth and sexual maturation ● taste sensitivity
106
The percent absorption for zinc is ~40%. What two factors can inhibit zinc absorption?
high Ca++ or phytic acid
107
What is the consequence of zinc deficiency (there are 3)?
slow growth, slow sexual maturation in young males and poor taste sensitivity
108
The UL of Zinc is 40 mg/day. If exceeded, zinc may interfere with absorption of what other mineral?
copper
109
What is the difference between the thyroid hormones thyroxine (T4) and thyronine (T3)?
T4 has 4 iodide ions, T3 has 3.
110
Which thyroid hormone is responsible for regulating energy metabolism?
T3 is the active form that regulates energy metabolism
111
A deficiency in iodide can lead to a disease called:
Goiter- enlargement of the thyroid gland to try to absorb more iodide from blood
112
How much higher is the risk of obesity for obese children than normal weight children?
7.5X
113
The two groups most at risk for obesity are:
○ Pima Indians in Arizona | ○ African-American women > 40 yrs
114
Obesity Increases Risk of...(name some diseases or medical conditions; there are many).
``` ● Diabetes (T2D) ● Cancer ○ Hypercholesterolemia → 27HC (hydroxycholesterol) → binds estrogen receptor → breast cancer ○ Altered microbiota → convert bile to DCA → liver cancer ● Hypertension ● CVD ● Atherosclerosis ● Neurodegenerative diseases ```
115
What genes are important to understand obesity?
● Ob gene controls satiety ○ Mutated gene → morbidly obese mice ● MRAP2 controls energy homeostasis in brain
116
Name a couple environmental factors that promote obesity.
● Eating more, exercising less | ● Close, mutual friend who becomes obese

BIBC120 (21 decks)

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