Collagen (L5) Flashcards
The most abundant protein in the body is
Collagen
Name the main amino acids in the collagen
Proline
Hydroxyproline
Hydroxylysine
Glycine
Which cells secrete collagen in CT proper?
Fibroblasts
Which cells secrete collagen in Bone?
Osteoblast
Which cells secrete collagen in Cartilage?
Chondroblast
Which type of collagen is the most abundant in human body?
Type 1
Collagen types are divided into 3 groups. Name them.
- Fibrillar Collagen
- Network / Sheet-forming Collagen
- Linking and Anchoring Collagen
Which types of collagen are classed as Fibrillar collagen?
Types I, II, III
Which groups of collagens aggregate to form fibrils?
Fibrillar Collagen
Synthesis of collagen occurs:
A/ Intracellular
B/ Extracellular
C/ Both
Both
What happens to the polypeptide after it detaches from ribosome during collagen synthesis?
It enters rER cisternae
What is the substance required for hydroxylation of proline and lysine?
Ascorbic acid (Vitamin C) as cofactor
Vitamin C acts as a ___________ In collagen synthesis
Cofactor
What is the location of hydroxylation of lysine and proline during collagen synthesis?
rER
State the structure of procollagen
3 alpha chains forming a triple helix
After the 3 alpha chains form procollagen, what will happen?
Procollagen is transported to Golgi body, packaged into vesicles then secreted by exocytosis
What is the function of procollagen peptidase?
Enzymatic cleavage of procollagen producing tropocollagen
How are collagen fibrils formed?
By aggregating tropocollagen
State the structure of tropocollagen.
3 alpha chains in a triple helix about 300nm long and 1.5nm in diameter
What are collagen fibres formed of?
Cross-striated collagen fibrils every 67nm
Every third amino acid in collagen is __________
Glycine
Each alpha chain is made of approximately __________ amino acids
1000
Ehler-Danlos Syndrome is caused by?
Faulty collagen
State the locations of Collagen Type I
Bones Ligaments Tendons Fibrocartilage Skin dermis
Which type of cartilage is present in tendons and ligaments?
Type I
Which type of cartilage is present in skin dermis?
Type I
What is the structure type I collagen?
Large banded collagen fibres
Which of the following is a short banded, non-branched collagen fibre?
A/ Type I
B/ Type II
C/ Type III
D/ Type V
Type II
An example of Network (Sheet-forming) collagen is
Type IV
Collagen secreted by epithelial cells is type?
Type IV
State the location of Type IV collagen
External laminae and all epithelial basal lamina
Linking (Anchoring) Collagen is formed by which type of collagen?
Type VII
What is the function of linking collagen?
Short collagens that connect Fibrillar Collagen to each other
Hyaline cartilage, Elastic Cartilage and vertebral discs contain which type of collagen?
Type II
Vitreous of the eye contains Type ________ collagen
Type II
Type V collagen is found in?
Basement membranes of placenta
What is the main cause of scurvy?
Vitamin C deficiency
Vitamin C / Ascorbic Acid is a cofactor for which of the following enzymes?
A/ Glycine hydroxylase
B/ Prolyl Hydoxylase
C/ Glutamate Hydroxylase
Prolyl Hydroxylase
Mutation that leads to change of 1 amino acid on collagen type I causes which disease?
Osteogenesis Impefecta
A patient comes to the emergency department with ruptured eyeball. On physical examination he is found to have hyperelastic skin. Name the disease he is suffering from.
Ehlers-Danlos syndrome type VI
A patient comes to the emergency department with ruptured eyeball. On physical examination he is found to have hyperelastic skin. State the possible cause of his symptoms
Faulty hydroxylation of lysine
A patient suffers from frequent subluxation of the eyelid and appears to have increased joint mobility. Name this condition and state its cause
Ehlers-Danlos syndrome type VII caused by decrease in procollagen peptidase activity
A patient suffers from gum ulcers. Blood tests reveal that he has vitamin C deficiency. Name the disease he is suffering from.
Scurvy
A patient comes to the ER complaining of spontaneous fractures and bone deformities. On performing a general physical exam, it was found that he also suffers from cardiac insufficiency. Which disease is he suspected to have?
Osteogenesis imperfecta
A patient is brought to the ER by ambulance after suffering intestinal rupture. Name a genetic disease that could cause this condition.
Ehlers-Danlos syndrome type IV
A patient is brought to the ER by ambulance after suffering aortic rupture. Upon examining him the doctor suspects that he suffers from Ehlers-Danlos syndrome Type IV. What is the cause of this disease?
Faulty translation or transcription of collagen type III
An African-American woman attends the dermatology clinic complaining of overgrowth of tissue following an injury. She wishes to have this disfigurement removed. Biopsy reveals that it is made of collagen type III. What is this overgrowth called?
Keloid scar
An African-American woman attends the dermatology clinic complaining of overgrowth of tissue following an injury. She wishes to have this disfigurement removed but the doctor advises against this. Why?
This is a keloid scar. It will likely reform.
Overgrowth of tissue containing type I collagen following injury is called?
Keloid scar
Which types of collagen are found in a Keloid scar?
Collagen types I and III
What is Scleroderma / Systemic Sclerosis?
Autoimmune dysfunction leads to fibrosis (overproduction of fibres)
Symptoms: 1/ Thick, tight skin 2/ Thickening of blood vessels that disturbs their function —> causes hypertension 3/ Tissue damage 4/ Collagen scars on lungs and kidneys
A young child is brought to ENT clinic due to hearing loss. The doctor prescribes hearing aids for her.
A year later, the child begins complaining of pain on the posterior abdominal with blood in her urine.
Which genetic disease can explain her unrelated symptoms?
Alport Syndrome
A young child is brought to ENT clinic due to hearing loss. The doctor prescribes hearing aids for her.
A year later, the child begins complaining of pain on the posterior abdominal with blood in her urine.
The doctor suspects she has Alport Syndrome and orders DNA genotyping to confirm this.
What is the cause of Alport Syndrome?
Inherited defect in Type IV collagen
What is the cause of Osteoarthritis?
Degradation of collagen fibres in joints
Is collagen an inelastic or elastic protein?
Inelastic
A homeless women arrives at the ER after breaking her leg. Examination reveals that she has lost many teeth due to gum ulcers. She also has very brittle bones.
Which vitamin deficiency explains her condition?
Vitamin C deficiency
