Collagen Flashcards

1
Q

What is the most abundant protein in the body?

A

Collagen

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2
Q

What type of tissue contains collagen?

A

Connective tissue

  • loose
  • dense
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3
Q

What are four examples of dense connective tissues that contain collagen?

A

Bone

Cartilage

Ligaments

Tendons

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4
Q

What type of cell produces collagen?

A

Fibroblasts

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5
Q

Which ribosomes produce collagen?

A

Ribosomes on the ER

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6
Q

What form of collagen is produced by the ribosomes?

A

Preprocollagen

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7
Q

What happens to preprocollagen in the ER?

A

Signal peptide is cleaved off to form procollagen

Hydroxylation

Triple helix formation

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8
Q

What exactly in procollagen is hydroxylated in the ER?

A

Proline and lysine residues are hydroxylated

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9
Q

What is the enzyme responsible for hydroxylation of procollagen in the ER?

A

Prolyl hydroxylase

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10
Q

What does prolyl hydroxylase require in order to function?

A

Vit C

Fe2+ ions

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11
Q

What is the importance of hydroxylation of procollagen?

A

Allows for increased hydrogen bonding between collagen chains in triple helix
increased stability of triple helix

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12
Q

What is the disease caused by decreased stability of collagen triple helix?

A

Scurvy

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13
Q

What type of triple helix does procollagen form?

A

Right-handed triple helix

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14
Q

What is each collagen chain in the triple helix called?

A

Alpha chain

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15
Q

How many collagen alpha chains form the triple helix?

A

Three duh

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16
Q

What are the types of alpha chains that make up type 1 collagen triple helix?

A

Alpha-1 x2

Alpha-2

17
Q

What are the features of the triple helix of collagen?

A

Non-compressible

Non-extensible/high tensile strength

18
Q

What is the amino acid sequence of the collagen alpha chains?

A

Glycine-X-Y

X and Y tend to be proline or hydroxyproline

19
Q

Why is glycine repeated in the collagen alpha chains?

A

Only amino acid with small enough side chain to fit in the middle of the triple helix

20
Q

Where are procollagen triple helices transported to from the ER?

21
Q

What happens to procollagen triple helices in the Golgi?

A

Packaged into vesicles

vesicles bud off from Golgi

22
Q

What happens to the vesicles containing procollagen triple helices?

A

Release their contents into the extracellular space by exocytosis

23
Q

What happens to procollagen triple helices in the cytoplasm?

A

N and C terminal peptides cleaved off

to form tropocollagen

24
Q

What happens to tropocollagen in the extracellular space?

A

Tropocollagen comes together to form collagen fibrils
then collagen fibres

cross-links formed between them

25
What is responsible for forming cross-links between tropocollagen molecules?
Lysyl oxidase
26
What does lysyl oxidase require to function?
Vit B6 Cu2+
27
Why is tropocollagen formed extracellularly rather than inside the fibroblast?
Collagen fibres forming inside the fibroblast would damage and kill the fibroblast
28
What type of tertiary structure does collagen have?
Fibrous tertiary structure