Molecular, Biochemical and Cellular basis.

Question 1

Terms : 1. Housekeeping Protein

Answer 1

Maintenance of cell structure and function
-Present in every cell
-rarely causes pathological changes
(90% mRNA in cell)

Question 2

2. Specialty Protein

Answer 2

Unique functions contribute to individuality
of cells in which they are expressed.
-produced in one/limited cell.

Question 3

3. Genotype

Answer 3

Genetic constitutions of an individual, either overall/at specific locus.

Question 4

4. Phenotype

Answer 4

Observable trait.

Question 5

5. Allelic Heterogeneity

Answer 5

Existence of many diff disease-causing alleles at a locus.

Question 6

6. Locus Heterogeneity

Answer 6

Determination of the same phenotype by mutations at different loci.

Question 7

7. Modifier genes

Answer 7

Expression of gene can influence a phenotype resulting from a mutation at another locus.

Question 8

Diseases involving enzymes

Answer 8

1. Aminoacidopathies
2. Lysosomal Storage Disease
3. Altered protein func. due to abnormal Post-Translational Modification
4. Loss of protein function due to ;
   - impaired binding
   - metabolism of cofactors
5. Mutation of an enzyme inhibitor
6. Defect in gene regulation

Question 9

1. Aminoacidopathies

Answer 9

PKU

• AR
• PAH gene
• CNS damage
• Newborn screening
• LOW phenylalanine diet

Question 10

2. Lysosomal Storage Disease

Answer 10

1. Tay Sachs Disease
   - AR
   - Hex A gene
   - Death at 2-4 years old
2. Mucopolysaccharidoses
   - Hurler syndrome (Alpha-iduronidase AR)
   - Scheie (Alpha iduronidase gene AR)
   - Hunter Synd. = iduronate sulfatase gene, XR)

• Coarse facial features
• Skeletal abnormalities
• mental retardation

Question 11

3. Altered protein func. due to abnormal Post-Translational Modification

Answer 11

1. Loss of glycosylation : I Cell disease
   - AR
   - Lysosomal enzymes ;
   - reduced level in lysosomes
   - high in body fluids

• Facial features
• Skeletal abnormalities
• Growth and mental retardation
• Death 5-7 yo.

Question 12

4. Loss of protein function due to ;
   - impaired binding
   - metabolism of cofactors

Answer 12

1. Homocysteineuria
   - AR
   - CBS gene
   - Vitamin responsive

• Lens dislocation
• Long limbs
• Vascular abnormalities (MI)

Question 13

5. Mutation of an enzyme inhibitor

Answer 13

Alpha 1 Antitrypsin deficiency

• AR
• A1AT - inhibits elastase
• COPD (emphysema)
• Liver cirrhosis

Question 14

6. Defect in Gene regulation

Answer 14

Acute intermittent Porphyria

• AD
• Deficiency in enzyme in haem biosynthesis pathway
• Intermittent neurological dysfunction
• HMBS gene