LT: Connective Tissue

Question 1

A high molecular weight extracellular like a protein in the basal lamina

Answer 1

Laminin

Question 2

Hetrotrimeric

Answer 2

Laminin

Question 3

What does Hetrotrimeric in laminin look like

Answer 3

3 different chains (a, bets, gama) intersected to form hetrotrimers of cross like structure

Question 4

Hetrotrimers arranges in sideways in laminin gives

Answer 4

Hetrotrimic dimers

Question 5

Hetrotrimers arranges in head to tail in laminin gives

Answer 5

Elastin polymers —> arranged in antiparallel way —> 1)microfibril sheets in basal lamina 2) organize tissue and cells to the membrane

Question 6

Imp for glomerulus basement membrane

Answer 6

Laminin

Question 7

When does assembly of laminin happen

Answer 7

Post- transcription

Question 8

Mutation is laminin causes

Answer 8

Junctional epidermolysis bullosa
—> a lethal skin blistering disease

Question 9

Null mutation in laminin B2 gene (LAMB2) gives rise to which disease

Answer 9

Pierson syndrome
—> a severe congenital nephrotic syndrome with ocular and neurological defects

Question 10

Provides mechanical strength, glowing skin and found in skin bone Cartilage and heart

Answer 10

Collagen

Question 11

has 3 a-helix chains , 2 are identical, 1 is different

Answer 11

Collagen

Question 12

Arranged in a helical matter

Answer 12

Collagen

Question 13

Is a right handed triple helix

Answer 13

Collagen

Question 14

In this fiber, 1/3 of all amino acids are glycine( RICH)

Answer 14

Collagen

Question 15

Protein and hydroxyproline make up 17 to 18% of this fiber

Answer 15

Collagen

Question 16

Explain how collagen fibers are formed

Answer 16

1)Glycine proline and hydroxyproline Form procollagen
2) The N & C terminus are cleaved by peptidase = tropocollagen
3) Triple collagen is arranged longitudinally by overlapping 3/4 of the length = fibrils
4) fibrils fibrils fibrils fibrils fibrils= collagen fibers


Question 17

These two amino acids are important for forming the helical structure in the collagen +explain

Answer 17

Glycine and proline
- Glycine is very small so it fits the small spaces and the triple helix
-proline Ben’s chain by forming beta turns


Question 18

What stabilizes the Triple helix structure in collagen

Answer 18

Hydroxyproline

Question 19

How is procollagen modified

Answer 19

hydroxylation

Question 20

Why is hydroxylation or procollagen important

Answer 20

For proper assembly of collagen chains

Question 21

By what, and where is the procollagen hydroxlized 

Answer 21

1)
N: lysyl hydroxylase
C: propyl hydrozylase
Are cleaved from the protein and lysine residues

2)
Both enzymes require vitamin C as equal factor, hence low vitamin C = weak collagen fibers = nutrition scurvy+ gum bleeding

Question 22

Fibril formation reinforcement is by which type of bonds? Where in the structure and how?

Answer 22

Covalent bonds
Between lysine residues
catalyzed by lysyl oxidase (cu dependents)

Question 23

Hydroxylation of procollagen occurs in which organelle

Answer 23

RER

Question 24

Explain the pathogenesis behind OI

Answer 24

Glycine is replaced by bulky aromatic amino acid residues, which are less flexible and Brittle 

Question 25

Allows the skin to resume its shape after stretch

Answer 25

Elastin

Question 26

Tropoelastin Is characterized by high percentage of

Answer 26

Random coil confirmation

Question 27

Has alternating hydrophobic and hydrophilic motifs 

Answer 27

Elastin

Question 28

Hydrophobic motif elastin is responsible for

Answer 28

Aggregating topo elastic an extra cellular matrix by a reversible and thermodynamically process calledcoacervasion 

Question 29

Hydrophilic motifs in elastic is responsible for

Answer 29

Lysyl residues cross-links tropoelastin monomers= formation of desmosine which consist of 4 lysyl residues

Question 30

Cross-linking lysyl residues is catalyzed by ___that requires___

Answer 30

Lysyl oxidase Cu

Question 31

Elastin can be damaged by inducing

Answer 31

Elastase enzyme

Question 32

Elastase enzyme secreted by

Answer 32

Neutrophils in the lungs

Question 33

How is elastase enzyme induced

Answer 33

Mutation AAT Infection inflammation such as asthma

Question 34

Explain the mutation that induces elastase enzyme

Answer 34

Serpin, AAT is an inhibitor of elastase and it is secreted by hepatocytes. It’s a natural defense against elastase. I mutation will not allow this inhibitor to function well therefore it will 1)hydrolyze elastin 2) damage the elasticity of the lungs

Question 35

Can cause COPD or emphysema

Answer 35

Mutation in AAT or asthma

Question 36

A group of small proteins

Answer 36

Lamins

Question 37

Components of nuclear lamina

Answer 37

Lamins

Question 38

LMNA, LMNB, LMB2 encodes for (4) ____isoforms And it is ___ (elastin , collagen, lamins, laminin)

Answer 38

A,B1,B2,C Lamins

Question 39

Side-side monomers of lamins result in __ Where? Function? How?

Answer 39

Fibrous sheets called nuclear lamina Underneath the nuclear envelope Support and protect nucleus and cytoplasmic structures By connecting and stabilizing the chromatin —> plays an imp role in gene expression

Question 40

Play an important role in gene expression

Answer 40

Lamins

Question 41

Mutation in lamin gene causes ___

Answer 41

Laminopathy HPGS, silent mutation GGC—> GGT; gly 608 gly Creates alternative splicing site = altered lamins

Question 42

Head-tail lamin dimers result in

Answer 42

Polymers

Question 43

Produced by alternative splicing in the LMNA gene

Answer 43

A, C isoforms of lamins