Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CFoM > 07b: CT and ECM Formation > Flashcards

07b: CT and ECM Formation Flashcards

1
Q

Primary structure of collagen molecule contains which key AA?

A
  1. Glycine
  2. Proline/hydroxyproline (imino acids)
  3. Lysine/hydroxylysine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which AA is not found in collagen?

A

Cysteine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Collagen MW is (X). The triple helix has about (Y) number of AA residues.

A 
X = 300 kDa
Y = 3000 residues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Gelatin is essentially (X), which can occur in which environment?

A

X = denatured collagen

37oC (Tm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Collagen, as a triple helix, has which special property that the three separate alpha chains don’t have?

A

Resistant to proteases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

1/3 of collagen alpha chain is (X) AA.

A

X = glycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

1/4 of collagen alpha chain is (X) AA.

A

X = proline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The collagen triple helix is (RH/LH).

A

RH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The transcribed collagen alpha chains are (shorter/longer/same length as) final polypeptides. Explain.

A

Longer; presence of N-terminal leader sequence, N-terminal and C-terminal extensions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

(Free/bound) ribosomes translated collagen alpha chains.

A

Bound; (translocated into ER)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

First post-translational modification of collagen alpha chains:

A

Hydroxylation of proline and lysine residues in rER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which enzyme hydroxylates (X) residues of collagen alpha helix?

A
  1. Prolyl hydroxylase (for proline residues)

2. Lysyl hydroxylase (for lysine residues)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe how scurvy occurs.

A

Deficiency of ascorbate (required via diet), which is cofactor for prolyl and lysyl hydroxylases; hydroxylation required for stabilization of collagen fibrils (cross-linking)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Symptoms of scurvy.

A

Skin lesions, fragile blood vessels, poor wound healing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which post-translational modifications of collagen alpha helix take place in Golgi?

A

Glycosylation of select hydroxylysine residues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Genetic dysfunction of lysyl hydroxylase results in which disease?

A

Ehlers-Danlos syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Clinical hallmarks of Ehlers-Danlos syndrome:

A
  1. Soft, hyper extensible skin
  2. Hypermobile joints
  3. Tissue fragility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Importance of hyroxylysines in collagen.

A
  1. Attachment sites for glycosyl residues

2. Critical in determining cross-linking pattern, stability, and tensile strength of collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cure for Ehlers-Danlos.

A

Replace dysfunctional Lysyl hydroxylase enzyme (not impossible if done early)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

T/F: Dysfunction of prolyl hydroxylase will also result in Ehlers-Danlos syndrome.

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Lack of hydroxylated prolines in collagen has which effect?

A

Prevents secretion of pro-collagen from the cell

22
Q

Collagen triple helix is stabilized at (X) end by (intra/inter)-molecular (Y) bonds.

A

X = C-terminal
Both intra- and inter-molecular
Y = disulfide

23
Q

Once (X) is exocytosed from the cell, (Y) cleave the frayed ends, yielding (Z).

A 
X = pro-collagen
Y = pro-collagen peptidases
Z = tropocollagen
24
Q

Collagen fibril formation/alignment is driven by:

A

Ionic forces

25
Q

A soluble collagen molecule is formed after:

A

Cleavage of pro-collagen N and C ends

26
Q

What type of bonds are found in collagen fiber cross-links?

A

Covalent

27
Q

Collagen fiber stabilization involves (X) enzyme, which specifically catalyzes which reaction?

A

X = lysyl oxidase

Oxidizes amino group in lysine/hydroxylysine into aldeghyde

28
Q

Which side groups are crucial for forming the cross-links in collagen fiber?

A

Aldehyde groups (very reactive)

29
Q

BAPN, aka (X), inhibits which enzyme/reaction in fiber synthesis?

A

X = beta-aminopropionitrile

Lysyl oxidase (cross-link formation in collagen fiber synthesis)

30
Q

Cross-links formed in collagen fiber synthesis are (inter/intra)-molecular.

A

Both! Form between collagen chains and between separate collagen molecules

31
Q

Mammalian collagenases cleave at which site(s)?

A

Make single split across the 3 alpha chains, 75% from N-terminal

32
Q

What does cleavage by mammalian collagenases do to the fiber?

A

Decreases Tm to 30o (helices will denature at body T)

33
Q

Half-life of collagen is:

A

tissue-specific

34
Q

Waste products of collagen synthesis (such as N/C terminal extensions) end up in (X). Degradation products end up in (Y).

A

X = Y = urine/serum

35
Q

Osteogenesis imperfecta is characterized by (X) symptom. What’s the cause?

A

X = brittle bones

Point mutations (replace glycine) in genes for alpha1 and alpha2 Type I collagen chains

36
Q

In (X), why would mutations in alpha1 be (better/worse) than mutations in alpha2?

A

X = osteogenesis imperfecta
Worse;
Twice as many alpha1 per molecule

37
Q

T/F: Osteogenesis imperfecta results in under-hydroxylation and glycosylation.

A

False - over-hydroxylation and glycosylation

38
Q

Elastin is formed form (X) number of polypeptides.

A

X = 1

39
Q

Which elastin residue(s) is/are glycosylated?

A

None!

40
Q

Which AA is quite abundant in elastin, giving it (X) characteristic.

A

X = hydrophobic (90% of elastin is hydrophobic)

Valine

41
Q

33% of elastin molecule is (X) AA. 20% of elastin molecule is (Y)% AA.

A 
X = glycine
Y = proline
42
Q

Which elastin residue(s) is/are hydroxylated?

A

None!

43
Q

MW of elastin.

A

69 kDa

44
Q

Names of cross-links in elastin.

A

Desmosine and Isodesmosine

45
Q

Emphysema is a result of:

A

Destruction of elastic fibers of lung

46
Q

Turnover of elastin is (fast/slow)

A

Very slow

47
Q

When is elastin soluble?

A

Soluble elastin molecule (tropoelastin) synthesized in cell, but upon secretion to extracellular fluid, cross-links form and make it highly insoluble

48
Q

Cross-linking of elastin carried out by which enzyme?

A

Lysyl oxidase

49
Q

Factors that cause imbalance and, thus, emphysema.

A
  1. Anti protease inhibitor deficiency

2. Smoking

50
Q

Absence of MFAP-4 has which effect on (X) process?

A

X = elastic fiber formation

Without MFAP-4, fibrillin-1 can’t form microfibrils, which cross-link with tropo-elastins to allow proper formation of elastic fibers

51
Q

GAGs are (mono/di/poly)-saccharides with which (non-repeating/repeating) unit(s)?

A

Polysaccharides; repeating disaccharide units:

  1. Uronic acid
  2. Amino sugar
52
Q

Proteoglycans are primarily synthesized in (X) and degraded in (Y).

A 
X = ER
Y = lysosomes

CFoM (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions