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Biochemistry Flashcards

(103 cards)

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1
Q

What are the protein fibers embedded in within the ECM?

A

Ground substance

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2
Q

What are the 3 structural, fibrous proteins of the ECM?

A

Collagen
Elastin
Fibrillin

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3
Q

What are the 2 specialized proteins that link the structural, fibrous proteins to the surface of the cells?

A

Fibronectin and laminin

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4
Q

What are the molecules that comprise long chains of repeating disaccharides, GAGs, are attached to specific core proteins, and are the major component of ground substance?

A

Proteoglycans

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5
Q

What % of proteoglycans is proteins and GAGs?

A

5% protein

95% GAGs

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6
Q

What are the fibers that have a high tensile strength and comprise the most abundant form of protein in animals?

A

Collagen

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7
Q

What is the final assembly molecule of collagen called, where there is cross-linking of triple-helical rods?

A

Tropocollagen

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8
Q

Which cells secrete collagen?

A

Fibroblasts, osteoblasts, and chondroblasts.

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9
Q

What is the most abundant type of collagen?

A

Type I

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10
Q

What is the main collagen in basement membranes?

A

Type IV

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11
Q

In addition to the triple helical rod of tropocollagen, what does it have on the outsides of the triple helix to allow cross linking by both covalent and H-bonds to toughen the structure?

A

R-groups of AA
N-H
C=O

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12
Q

What is the fiber arrangement of collagen in tendon?

A

Parallel bundles

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13
Q

What is the fiber arrangement of collagen in Bone?

A

Angled to the axis of the bone to provide resistance to shear forces

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14
Q

What is the fiber arrangement of collagen in skin?

A

sheets of fibers at many angles

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15
Q

What is the fiber arrangement of collagen in cartilage?

A

No distinct arrangement

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16
Q

What is the fiber arrangement of collagen in the cornea?

A

Planar sheets stacked at right angles to each other to minimize light scatter

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17
Q

What molecule combines with fibrillin to confer elasticity of tissue?

A

Elastin

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18
Q

What cell makes elastin?

A

Fibroblasts

same as collagen

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19
Q

Unlike collagen, what is the secondary structure of elastin?

A

There is a lack of ordered 2o structure.

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20
Q

How many genes encode elastin?

A

1

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21
Q

Although elastin is made from 1 molecule, what process allows it to exist as several variants?

A

Differential mRNA processing

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22
Q

What is elastin synthesized and secreted as, which is converted to the monomer tropoelastin (70kD)?

A

Proelastin

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23
Q

Important: what 2 AA’s is elastin rich in, which collagen isnt rich in?

A

Pro

Lys

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24
Q

What molecule does lysine oxidase use to deaminate Lys to the corresponding aldehyde in elastin?

A

Cu++

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25
What is a commonly occuring linkage in elastin?
3 Al-Lys and 1 Lys --> 4 separate tropelastin chains.
26
The cross-linked derivatives of Lys and stuff (desmosines) gives what characteristic of elastin?
Recoil!
27
What is the function of the single peptide on the preprocollagen in the RER?
Labels them for export
28
Where is the single peptide of the preprocollagen removed, which converts it to procollagen?
RER lumen
29
In addition to a-KG and O2, what molecule is needed to hydroxylate the Pro and Lys residues on procollagen?
Vitamin C
30
Prior to helix formation of procollagne, what 2 things are added to certain HO-LYS residues?
Glucose and Galactose
31
So the golgi secretes what form of collagen otuside of the cell?
Triple helix procollagen
32
What are removed from the triple helix procollagen to make tropocollagen?
Extension peptides
33
Which molecules are secreted by fibroblasts to act as a structural scaffold for the deposition of elastin?
Fibrillin
34
What is the major glycoprotein of the ECM?
Fibronectin
35
What is the major fxn of fibronectin?
Gluing cells together
36
What cells appear to be deficient in surface-boudn fibronectin?
Malignant cells | allows them to spread
37
Though malignant cells lack surface fibronectin, they have fibronectin receptors, which allows them to do what?
Metastasize
38
What is the role of fibronectin in pregnancy?
Attaches the amniotic sac to the lining of the uterus
39
Which test (from the cervical canal) suggest the patient is at risk for preterm labor?
Fetal fibronectin test
40
What is the large cruciform glycoprotein that is an essential component of the basal membrane?
Laminin
41
What is the main fxn of laminin?
Glues membrane to overlying cells
42
What happens if laminin is excessively broken down?
loss of growth control
43
What is the inheritance of OI?
AD
44
What happens to the eyes in OI?
Blue sclera
45
What type of collagen is abnormal or reduced?
Type I collagen
46
What type of OI is the most common and is the mildest?
Type I OI
47
Which type of OI is the most severe, and is frequently lethal at or shortly after birth?
Type II OI
48
Which one is worse: type III or type IV OI?
Type III
49
What happens to type I collagen to cause type I OI?
Reduced production
50
What types of mutations occur to cause type II, III, and IV OI?
Missense mutation | bulky AA's in place of Gly --> destabilize the structure
51
What is the inheritance of Ehlers-Danlos Syndrome (EDS)?
AD
52
What are the main joint/skin Sx of EDS?
Hyperextensibility of skin | Hypermobility of joints
53
Which form of EDS has a mutation in tenascin X and is the most common form?
Hypermobility form (III)
54
Which form of EDS has a mutation in genes encoding type V collagen?
Classic form (I and II)
55
Which form of EDS has a mutation in type III collagen, and is the most severe form?
Vascular form (IV)
56
What is the inheritance of Alport syndrome?
AR or X-linked
57
What is the main type of collagen affected in Alport syndrome?
Type IV collagen | basement membranes
58
What are the main kidney manifestations of Alport syndrome?
Hematuria, proteinuria, kidney failure
59
True or False: Alport syndrome is the 2nd most common cause of inherited kidney failure.
True
60
In addition to kidney failure, Alport syndrome pts develop what other manifestation in early adulthood?
Deafness
61
What is condition where there is a defect in type VII fibers, resulting in breakage and blistering of the skin?
Dystropic Epidermolysis Bullosa (DEB)
62
What is the inheritance of DEB?
AD or AR
63
What is the XR condition that is caused by mutations in copper-binding ATPase?
Menkes syndrome
64
Again, which enzyme required Cu, which is decreased in Menkes syndrome because of lack of intestinal transport?
Lysine oxidase
65
What are the main Sx to Menkes syndrome?
Kinky hair Cerebral degeneration Death in infancy
66
Which disease results in defective hydroxylation of Lys and Pro, leading to bleeding gums, easy bleeding, painful joints, anemia, and the boundless desire to take over other ships?
Scurvy
67
Though Williams syndrome can be AD, what is the most common cause?
Spontaneous mutation
68
What is deleted from chromosome 7 to cause Williams syndrome?
ELN gene | encodes elastin
69
What happens to the large arteries in Williams syndrome?
They narrow (no elastin)
70
What is the main heart condition in Williams syndrome?
Supravalvular aortic stenosis (SVAS)
71
What mythical creature do u look like in Williams syndrome?
Elf
72
What are the neurological problems in Williams syndrome?
Overly-friendly | ADD
73
True or False: SVAS is exclusive to Williams syndrome.
False Smaller deletions of ELN can cause it without the Williams syndrome Sx, also in familial SVAS (AD)
74
What is the inheritance of A1AT deficiency?
AR
75
What is the normal function of A1AT?
Inhibits elastase (degrades elastin)
76
Which cells produce elastase?
Neutrophils
77
Which tissues are broken down in A1AT deficiency?
Alveoli
78
What "act" exasterbates the emphysema seen in A1AT deficiency?
Smoking
79
Various skin diseases (eg Scleroderma) can be caused by the accumulation of what protein?
Elastin
80
What is the inheritance of Marfan syndrome?
AD
81
What is the defect to cause Marfan syndrome?
Fibrillin 1 (FBN1)
82
What 3 systems in the body are affected from the lack of FBN1 in Marfan syndrome?
Ocular Skeletal Cardivascular
83
What is the main ocular problem in Marfan syndrome?
Lens dislocation
84
What are the Skeletal problems in Marfan syndrome?
Ling limbs | Arachnodactyly
85
What is the disorder where there is a defect in laminin 5 or 6, and there is blistering skin and mucous membranes?
Junctional Epidermylysis Bullosa (JEB)
86
What is the disorder where there is a defect in laminin 2 (links muscle and ECM), causing muscle weakness?
Congenital Muscular Dystrophy
87
What are the molecules that are long, unbranches, repeat disarrcharides, often sulphated or acetylated, and often attached to hyaluronate?
GAGs
88
Which GAG is found in granules of mast cell, liver, lung, and skin?
Heparin
89
Which GAG is located on cell surfaces and extracellular, and is involved in cell communicaiton?
Heparin sulfate
90
Which GAG is found in cartilage, bone, tendons, ligaments, and cornea, making the most abundant GAG in the body?
Chondroitin sulfate
91
Which GAG is widely distributed (esp in skin, vessels, and heart valves), and may be involved in the development of atherosclerosis?
Dematan sulfate
92
Where is Keratan sulfate I found?
Cornea
93
Where is Keratan sulfate II found?
Cartilage
94
What is the only non-sulfated GAG, is present in synovial fluid, vitreous humor and loose CT, and allows tumor cells to migrate?
Hyaluronic acid
95
Which molecule si the major proteoglycan in cartilage, interacts strongly with collagen, and contains hyaluronic acid, chondroitin sulfate, and keratan sulfate?
Aggrecan
96
What is the molecule that is a chondroitin sulphate-based proteoglycans that is up-regulated in many human tumors and drives metastasis?
Versican
97
What are the 2 integral trnasmembrane protein that is associated with the actin cytoskeleton inside the cell and interacts with fibronectin outside of the cell?
Syndecan and Thrombomodulin
98
Neurocan, brevican, cerebrocan, and phosphacan are GAGs that are largely restricted to what system?
Nervous system
99
All mucopolysaccharidoses are AR except for what syndromee?
Hunters syndrome (XR)
100
In mucopolysaccharidoses, the defects of degredation of what 2 things can cause skeletal and CT abnormalitis?
Keratan sulphate | Demartan sulphate
101
Only defects in what molecule in mucopolysaccharidoses cuases MR and neurological degeneration?
Heparan sulphate
102
Hurler, Scheie, and Sly can cause what eye abnormality?
Corneal clouding
103
Which 2 GAGs do not accumulate in mucopolysaccharidoses because they have an alternative pathway of degradation?
Chondroitin sulphate | Hyaluronic acid

Dermatology (4 decks)

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