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Biochem BLOCK 4 > Deevska Review > Flashcards

Deevska Review Flashcards

1
Q

Why is vitamin C (ascorbic acid) important for collagen

A

Required as a cofactors for the enzymes involved in hydroxylation of proline and lysine residues in collagen

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2
Q

What does a deficiency in vit C do?

A

Lack of proline and lysine hydroxylation lead to impairment of the interchain H bond formation which prevents the formation of a stable triple helix and affects proper cross-linking

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3
Q

What is the effect of vitamin C deficiency on collagen directly

A

Greatly decrease the tensile strength of the assembled fiber

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4
Q

What disease is caused by vitamin c deficient and what are the symptoms

A

Scurvy

  • easy bruising
  • loose teeth an bleeding gums
  • poor wound healing
  • poor bone development
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5
Q

What is the main difference between the structure of elastin and collagen?

A

Collagen contains hydroxyproline and hydroxylysine whereas elastin contains scant amounts of this

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6
Q

Extensively interconnected, rubbery network that can stretch and bend in any direction when stressed, giving connective tissue elasticity

A

Elastin

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7
Q

What is the makeup of elastin

A
  • insoluble protein polymer synthesized from a precursor tropoelastin
  • rich in proline and lysine but contains scant amounts od hydroxyproline and hydroxylysine
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8
Q

_________ modifies lysyl side chains in tropoelastin forming a desmosine corsslinking which produces ______

A

Elastin

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9
Q

What AA are both elastin and collagen abundant in

A

Proline and glycine

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10
Q

Fibrous proline composed of alpha chains forming triple stranded helix

A

Collagen

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11
Q

What does collagen have that elastin does not have much of

A

Contains hydroxyproline and hydroxylysine formed by post translational hydroxylation of proline and lysin residues

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12
Q

Collage requires what as a reducing agent

A

O2, Fe2+, and vit C

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13
Q

What is the most abundant protein in the human body

A

Collagen

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14
Q

What types of collagen in cornea

A

I and VIII

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15
Q

What types of collagen in vitreous

A

II

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16
Q

Large complexes of heteropolysaccharide chains associated with a small amount of protein
95% carbohydrates
5% protein

A

Proteoglycans

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17
Q

Protein with a variable but typically small amount of carbohydrate

A

Glycoproteins

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18
Q

Produce a gel like matrix, form basis of the body’s ground substance, function to form ECM, serves as flexible support for ECM, sieve influencing the movement of materials through the ECM, contributes to the viscous lubricating properties of mucous secretions

A

Proteoglycans

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19
Q

What are proteoglycan aggregates composed of?

A

1 proteoglycan monomers

  • GAGs
  • a core protein
    2. Hyaluronic acids
    3. Link protein
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20
Q

What is the anchor point for the proteoglycan

A

Hyaluronic acid

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21
Q

Small protein that stabilizes the association between the core protein and hyaluronic acid in a proteoglycan

A

Link protein

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22
Q

Part of the proteoglycan monomer that us linked to a serine residue with 100s of monosaccharide chain extending out from it

A

Core protein

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23
Q

Long unbranched, heteropolysaccharide chains, six different types, always found external to the cytosol in the proteoglycan

A

GAGs

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24
Q

Characteristics of GAGs

A
  • unbranched
  • repeating disaccharide units

Large complexes of NEGATIVELY charged heteropolysaccharide chains

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25
What gives the GAGs their unique function
Negative charge
26
What kind of charge does a GAG have and why
Negative because carboxyl groups and sulfate groups
27
What does the negative charge on the GAGs contribute to
- hydraulic absorption and resilience of synovial fluid and vitreous humor of the eye - lubricating effects of mucous and synovial fluid
28
Functions of membrane bound glycoproteins
- cell surface recognition by other cells, hormones, viruses - cell surface antigenicity - formation of ECM and mucins
29
non membrane bound glycoproteins
- almost all globular proteins secreted in the plasma are glycoproteins - many of the lysosomal proteins are glycoproteins
30
Structure of the carbohydrate chain of a glycoprotein
- short - no serial repeats - often branched - may/may not be negatively charged - highly variable in amount and comp of carbohydrate
31
Structure of the linkage between carbohydrate and protein in a glycoproteins
- N-glycosidic link: sugar chain attached to abide group of asparagine - O-glycosidic link: sugar chain is attached to the hydroxyl group of either serine or threonine Glycoprotein can contain one of these or both of these
32
What are the 6 major classes of GAGs
- chondroitin sulfate - keratin sulfate I and II - hyaluronic acid - dermatan sulfate - heparin - heparin sulfate
33
What is the most abundant GAG in the body?
Chondroitin sulfate
34
Where is chondroitin sulfate (GAGs) found
Cartilage, tendones, ligaments, and aorta
35
Where is keratin sulfate I and II found
KSI: in coreans KSII: loose connective tissue proteoglycan aggregates with chondroitin sulfate
36
What is the only GAG not attached to a core protein?
Hyaluronic acid
37
What is the only GAG not sulfated?
Hyaluronic acid
38
Where is hyaluronic acid found
- animal and bacteria | - synovial fluid in joints, vitreous, umbilical cord, loose connective tissue, cartilage
39
Where is dermatan sulfate found
Skin blood vessels, and heart valves
40
What is the only GAG that is intercellular
Heparin
41
Where is heparin found and what does it do
Intracellular component of mast cells that line arteries, especially in liver, lungs, and skin Serves as an anticoagulant
42
Where is heparin sulfate found
Basement membrane
43
What is the difference between heparan and heparin sulfate?
Heparin sulfate-some glucosamine are acetylated and there are fewer sulfate groups
44
What is the most heterogenous GAG
Keratin sulfate
45
A defect in the sulfation of the growing glysoaminoglycan chains results in one of several disorders that affect the proper development and maintainence of the skeletal system
Chondrodystrophy
46
What kind of inherited disorder is chondrodystrophy
Autosomal recessive
47
Characteristics of chondrodystrophy
- dwarfism - over 100 specific skeletal dysplasias - rare
48
Progressive disorders characterized by glycosaminoglycans accumulating in the lysosomes of various tissues results in oligosaccharides in the urine
Mucopolysaccharides
49
What kind of inheritance is mucopolysaccharidoses
Autosomal recessive
50
Diagnosis of mucopolysaccharidoses
- the specific MPS is determined by identifying the structure present at the non-reducing end of the oligosaccharide - diagnosis is confirmed by measuring the patients cellular level of lysosomal hydolases
51
Symptoms of mucopolysaccharidoses
- apparently normal at birth, gradually deteriorate, could cause childhood mortality - skeletal and extracellular matric deformities and mental retardation
52
What are all the MPS diseases
- hurler - hunter - sanfilippo - sly
53
Ocular symptoms of hurler syndrome (MPS)
Corneal clouding
54
Ocular symptoms of hunter syndrome (MPS)
None
55
Ocular symptoms of sanfillipo syndrome
None
56
Ocular symptoms of sly syndrome (MPS)
Corneal clouding
57
Which 2 MPS cause corneal clouding
Hurler and Sly
58
Deficiency in the ability to phosphorylate mannose.
I-cell disease
59
What kind of disease is I-cell
Lysosomal storage disease. Accumulation of large lysosomal inclusion bodies composed of the missing hydrolase substrate
60
Symptoms of I cell
- skeletal abnormalities, restricted joint movement, coats dysmorphic facial features, severe psychomotor impairment - death likely prior to 8 years old
61
What is the genetic predisposition for DM type I
Moderate
62
What is the genetic predisposition for DM type II
Very strong
63
What biochemical and physiological changes is often seen in type I but not type II
Ketosis
64
Which type of DM has no insulin
Type I
65
What type of diabetes has insulin, but has a resistance
Type II
66
Metabolic changes in type I DM
Hyperglycemia Ketosis and ketoacidosis Hyperlipidemia
67
Symptoms of type I DM
- Polyuria, polydipsia, and polyphagia - ketoacidosis - fatigue - weight loss
68
How does the body react in type I DM
As if it is in starvation state
69
What is type II Dm a result of
- insulin resistance | - dysfunctional beta cells
70
The decreased ability of target tissues, such as liver, adipose, and muscle, to respond properly to normal (or elevated) circulating concentrations of insulin
Insulin resistance
71
Why does insulin resistance alone not type II DM?
Type II DM develops in insulin resistance individuals who also show impaired B cell function that cannot longer secrete sufficient insulin to compensate for elevated blood glucose levels
72
What is the leading cause of adult blindness?
Retinopathy - an abnormal metabolic change from diabetes - in tissues in which glucos uptake is not dependent on insulin, hyperglycemia causes an increase in uptake
73
What is BMI
Body mass index - provides indirect measure of body fat - moderately correlated with more direct measures of body fat obtained from other more direct methods - NOT a diagnostic of the body fatness or the health of an individual
74
What is normal BMI
18.5-<25
75
Waist to hip ratio
- Reflects central abdominal fat amount | - excess central fat correlates with higher risk for morbidity and mortality
76
What is a better measurement for obesity, BMI or waist to hip ratio?
Waist to hip ratio
77
Why is hip to waist ratio a better tool for assessing obesit?
Visceral fat ( around the middle) is linked with metabolic syndrome
78
What was the first identified adipocytes peptide hormone
Lepton
79
What kind of signal does lepton give
Anorexigenic signal (loss of appetite)
80
Where does lepton get secreted
From white adipose tissue
81
What recognized leptin
Leptin receptors in the hypothalamus Highest levels in evening hours Secreted in proportion to the size of fat stores
82
"Not all fats are the same"
Data not show that the type of fat is a more important risk factor for disease than the total amount of fat consumed
83
Which fats are the best?
Monounsaturated fats
84
What are bad fats
Trans fats Some saturated fats PUFA to some degree
85
A wasting disorder characterized by loss of appetite and muscle atrophy
Cachexia
86
Protein deprivation is relatively greater than the reduction in total calories
Kwashiorkor Fatty liver and edema
87
Calorie deprivation is relatively greater than the reduction in proline
Marasmus No edema
88
Protein energy malnutrition
- decreases appetite - alter how nutrients are digested or absorbed - inadequate intake of protein and/or energy is the primary cause - depressed immune system - death from secondary infection is common
89
What are the fat soluble vitamins
DEAK
90
Usually precursors of coenzymes for different enzymes
Water soluble vitamins
91
What is the only fat soluble vitamin that functions as coenzyme
Vitamin K
92
Where is vitamin A stored?
Liver and adipose tissue
93
What is another name for vitamin A
Retinoids
94
Deficiencies of vitamin A
- night blindness | - severe: xerophthalmia
95
What is a component of rhodopsin
Vit A
96
Hypervitaminosis of vitamin A
- dry skin - cirrhotic liver - mimic brain tumor
97
Where is vitamin D stored
Plasma
98
What is the active form of vitamin D
Calcitrol
99
Precursors of active form of vit D
D2 and D3
100
Functions of vit D
Maintain adequate plasma levels of calcium
101
Deficicneis in vit D
-demineralization of bone resulting in rickets in children and osteomalacia in adults
102
Hyperviatminosis of vit D
-hypercalcemia-lead to deposition of calcium in many organs, particularly the arteries and kidneys
103
What are the different forms of vit K
K1 in plants | K2 produced by intestinal bacteria
104
Functions of vit K
Posttranslational modification of a number of proteins involved with blood clotting
105
Deficiencies of vit K
- unusual because intestinal bacteria usually produce sufficient amounts - in condition associated with loss of bacteria functions - newborns receive single dose
106
Hypervitaminosis of vit K
Hemolytic anemia and jaundice in the infants in prolonged use

Biochem BLOCK 4 (11 decks)

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