Question

1. a) The term ‘amyloid’:

1. Was coined by the German physician, Alois Alzheimer
2. Generally refers to protein aggregates of any form
3. Protein aggregates that stain similarly to the polysaccharide, cellulose when exposed to iodine.
4. None of the above.

1. b) Which of the following is true about Tay Sachs disease? Choose all that apply.

1. It results from an abnormal accumulation of the enzyme, HexA in lysosomes.
2. It results in the abnormal accumulation of GM2 ganglioside inside lysosomes.
3. It is caused by a mutation in a gene on chromosome 15.
4. It can be caused when the HexA enzyme fails to get phosphorylated on one of its sugar residues.
5. It results in the abnormal accumulation of GM2 ganglioside inside the Golgi.
6. It can be caused when the HexA enzyme fails to get glycosylated in the ER.

1. c) Which of the following is not a common symptom or outcome of some forms of Tay Sachs disease?

1. Seizures
2. Low muscle tone
3. Death before age 5
4. Poor vision
5. None of the above

1. d) There are three major types of physiological consequences of protein misolfing.When a mutant protein misfolds and gets degraded in proteasomes, this is called a ____________.

1. gain of toxic function
2. loss of function
3. infectious misfolding
4. dual toxicity

2. a) Mutations in the protein, alpha 1-antitrypsin cause (choose all that apply):

1. it to accumulate in the ER of hepatocytes
2. the release of proteases that damage liver tissue
3. the uninhibited activity of a protease that damages lung tissue
4. prohibit its proper localization to lung tissue

2. b) True or False. Individuals who experience gradual onset of Tay Sachs symptoms are likely to be heterozygous for a HexA mutation.

1. True
2. False

Answer 1

ANSWER A)

Protein aggregates that stain similarly to the polysaccharide, cellulose when exposed to iodine.

Explaination

The name “amyloid” was introduced in 1854 by Virchow, due to the blue-black color change of bound iodine in tissue samples from the brain

ANSWER B)

It results in the abnormal accumulation of GM2 ganglioside inside lysosomes.

It is caused by a mutation in a gene on chromosome 15.

EXPLAINATION

Tay–Sachs disease is caused by a genetic mutation in the HEXA gene on chromosome 15, which codes for a subunit of the hexosaminidase enzyme known as hexosaminidase A. It is inherited from a person's parents in an autosomal recessive manner.The mutation disrupts the activity of the enzyme, which results in the buildup of the molecule GM2 ganglioside within cells, leading to toxicity. Diagnosis may be supported by measuring the blood hexosaminidase A level or genetic testing. Tay–Sachs disease is a type of GM2 gangliosidosis and sphingolipidosis

ANSWER C )

NONE OF THE ABOVE

EXPLAINATION

The most common form of Tay-Sachs disease becomes apparent in infancy. Infants with this disorder typically appear normal until the age of 3 to 6 months, when their development slows and muscles used for movement weaken. Affected infants lose motor skills such as turning over, sitting, and crawling. They also develop an exaggerated startle reaction to loud noises. As the disease progresses, children with Tay-Sachs disease experience seizures, vision and hearing loss, intellectual disability, and paralysis. An eye abnormality called a cherry-red spot, which can be identified with an eye examination, is characteristic of this disorder. Children with this severe infantile form of Tay-Sachs disease usually live only into early childhood.Classic infantile Tay-Sachs disease is a fatal disease and children with this disease usually die by age 5. Juvenile Tay-Sachs is also fatal, with death occurring in adolescence or early adulthood.

ANSWER D)

LOSS OF FUNCTION

EXPLAINATION

Since mutation in the protein and getting degraded in the proteosome does not lead to formation of function of protein anymore thus it is loss of functional

ANSWER A)

it to accumulate in the ER of hepatocytes

the uninhibited activity of a protease that damages lung tissue

EXPLAINATION

Alpha-1 antitrypsin is a protease inhibitor produced primarily in the liver. It inhibits the neutrophil elastase activity in the lung and hence can protect it from proteolytic damage. It is responsible for approximately 90% of the protection against elastolytic activity in the lower airways caused by elastase released from neutrophils. If the neutrophils' elastases are not opposed, panacinar lung tissue is damaged and increases the risk of developing chronic obstructive pulmonary disease (COPD). On the other hand, the retention and accumulation of mutated polymers in the endoplasmic reticulum of hepatocytes renders the individuals with this disease at risk of "a gain of toxic function" leading to liver disease.

ANSWER B)

TRUE

EXPLAINATION

Tay Sach disease is autosomal recessive disorder. an individual who seems normal and later on get the disease would have heterozygous for the gene