This set of Cell Biology Assessment Questions and Answers focuses on “Extracellular Matrix and Cell Interactions – Adherens Junctions and Desmosomes”.
1. Who discovered desmosomes?
a) Giulio Bizzozero
c) J Rhodin
d) Van Beneden
Explanation: Desmosomes were discovered by Giulio Bizzozero from the epidermal layer, stratum spinosum. He was named as “a life senator” by King Humbert I, for all his scientific achievements. He named them “nodes of Bizzozero”.
2. What is the size range of adheren junctions?
a) 20-100 nm
b) 30-100 nm
c) 40-100 nm
Explanation: The adherens junction is made up of several number of proteins. These adherens junctions have a size range from 30-100nm. They occur in epithelial and endothelial tissues.
3. Who coined the term desmosomes?
a) Edward Jenner
b) Robert Koch
c) Josef Schaffer
d) Giulio Bizzozero
Explanation: Josef Schaffer in the year 1920, coined the term “Desmosomes”. He got the word desmos from Latin, meaning binding and somes which means body.
4. Which tissues in our body contains abundant desmosomes?
a) Liver tissues
c) Cardiac tissues
d) Nervous tissues
Explanation: The desmosomes are found abundant in the cardiac, gastrointestinal and epithelial tissues. These desmosomes are found in the cells with more mechanical stress and has a stronger cell to cell adhesion.
5. Which of the following filaments bind to the cadherin and catenin complex?
Explanation: The basic mechanism of adherens junction is that its cytoplasmic side should join with the actin filaments. The cadherins and catenin protein complex attaches itself to the actin filaments.
6. How many amino acids does the plakoglobin has?
Explanation: The plakoglobin otherwise known as gamma catenin is a protein component of both adherens junction and desmosomes. These are about 81.7 KDa and has around 745 amino acids.
7. EPLIN acts as an enhancer for the binding process of actin cytoplasm and catenims.
Explanation: EPLIN is epithelial protein lost in neoplasm. It acts as an enhancer that helps in binding of actin cytoskeleton with the catenin complex and also in suppression of actin depolymerization.
8. What is macula adhaerens?
a) Adheren junction
Explanation: Desmosomes are otherwise known as macula adhaerens. This word is derived from the Latin language meaning adhering spot.
9. Which of the following disease is caused by the mutation of desmosomes?
a) Parkinson’s disease
b) Down’s syndrome
d) Bubble Boy Syndrome
Explanation: The arrhythmogenic right ventricular cardiomyopathy is caused by the mutations in the desmosomes. This disease commonly affects most of the young male atheletes.
10. Which of the following disease is associated with desmoplakin disorder?
b) Carvajal syndrome
c) Myocardial infarction
d) Zellweger syndrome
Explanation: Carvajal syndrome is a genetic disorder caused by both autosomal recessive and dominant gene. The disease makes the palms and soles’ skin thickened.
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