Protein Assembly

Question 1

Fibrous proteins are not _______

Answer 1

water soluble

Question 2

Fibrous proteins are use for body _____

Answer 2

construction

Question 3

Predominant protein in elastic tissue

Answer 3

Elastin

Question 4

Elastin has no ______, but is cross-linked via _______

Answer 4

Elastin has no regular secondary structure, but is cross-linked via lysines

Question 5

Keratin contains ____ that are wound up so tightly in fibrils that it can’t ______

Answer 5

Keratin contains alpha-helices that are wound up so tightly in fibrils that it can’t digested

Question 6

Elastin can be found in the _____

Answer 6

lungs

Question 7

Keratin can be found in ____ and _____

Answer 7

hair and nails

Question 8

Major fibrous protein of the human body

Answer 8

Collagen

Question 9

Collagen has _____ called _____

Answer 9

3 polypeptide chains called alpha chains

Question 10

3 different types of polypeptide chains are produced from ______

Answer 10

1, 2, or 3 different genes

Question 11

Collagen type I is found in ____, _____, and ____

Answer 11

bone, skin, and tendon

Question 12

Collagen Type III is ______. And it supports _____ in soft tissued

Answer 12

Collagen Type III is Reticulin. And it supports mesh in soft tissued

Question 13

5 steps of Procollagen formation in fibroblast

Answer 13

1) Polypeptide chain synthesis
2) hydroxylation
3) glycosylation
4) Disulfide bond formation at C-terminus
5) Triple-helix formation

Question 14

Central repeating region in collagen typically has these amino acids (3)

Answer 14

Glycine, Pr, Hyp (hydroxyproline)

Question 15

During hydroxylation, several _____ and ____ (Amino acid) are hydroxylated in a post translational modification

Answer 15

prolines and lysine

Question 16

Hydroxylation requires the enzymes _____ or _____

Answer 16

prolyl hydroxylase or lysyl hydroxylase with the co-factor ascorbic acid (vitamin C)

Question 17

Improper hydroxylation causes ______ (due to lack of vitamin C)

Answer 17

scurvy

Question 18

In Glycosylation, _____ are attached to _____

Answer 18

sugar molecules are attached to hydroxylysines

Question 19

During disulfide bond formation _____ assemble

Answer 19

3 pro-alpha chains

Question 20

______ is what is secreted from the fibroblast

Answer 20

pro collagen

Question 21

After secretion, pro collagen is turned into ______

Answer 21

After secretion, pro collagen is turned into tropocollagen

Question 22

During procollagen conversion to tropocollagen, _________

Answer 22

The N-terminal and C-terminal propeptidases are cleaved by procollagen peptidases to make collagen alpha-chains

Question 23

The center part of tropocollagen has an unusual structure called _____

Answer 23

collagen helix

Question 24

How do tropocollagen molecules assemble into a fibril?

Answer 24

Spontaneously. (Cleavage of propeptidases generated sticky ends)

Question 25

What happens in Maturation through cross-links?

Answer 25

The enzyme lysyl oxidase catalyzes the formation of allysine residue from some lysine residues.

Fibrils are strengthened by cross-links between lysine and allylsine

Question 26

What causes osteogenesis imperfects?

Answer 26

A glycine to cysteine substitution in the triple-helix region of Collagen type I

Question 27

Mutations that affect collagen synthesis are dominant because

Answer 27

a mutation in one allele affects the function of all other alleles

Question 28

There are two classes of molecular defects:

Answer 28

1. Gene defects in the collagen genes (as described for Osteogenesis Imperfecta). DOMINANT
2. Improper processing of collagen caused by lack of a processing enzyme (usually monomeric; defects occur when homozygous) RECESSIVE

Question 29

4 synthesis Steps after pro collagen exists fibroblast

Answer 29

6. Secretion
7. N-terminal and C-terminal propeptides cleaved by pro collagen peptidases to make collagen alpha-chains. (forming tropocollagen)
8. Tropocollagen molecules spontaneously assemble into a fibril
9. Maturation through crosslinks

Question 30

Examples of the transmissible spongiform encephalopathies caused by misfolded prion protein

Answer 30

• Mad Cow disease

* Creutzfeldt-Jakob disease

Question 31

Two ways of acquiring the “bad” form of the prion protein.

Answer 31

1. Inherit or acquire a missense mutation (classical Creutzfeldt- Jacob disease)
2. Coming into contact with the “bad” form of the protein (new-variant Creutzfeldt-Jacob disease)