Test 7 (genetics)
1.  The following are caused by defect in the the mitochondrial DNA:
a. Leigh disease

b. Kearn-Sayer's syndrome

c. myotonic dystrophy

d. Leber congenital amaurosis

e. Leber hereditary optic neuropathy

2. The following are true about mitochondrial DNA:
a. the sperm does not contain mitochondrial DNA

b. it accounts for 10% of total human DNA

c. it encodes protein needed for oxidate phosphorylation

d. defect results in the formation of red ragged muscle

e. the inheritance of mitochondrial disorder is similar to X-linked 


3. Down's syndrome:
a. has an incidence of 1:700

b. is associated with the age of the mothers

c. mosaicism accounts for 2% of all Down's syndrome

d. is more accurately diagnosed in pregnant woman with amiocentesis 
    than hormonal tests

e. is associated with congenital glaucoma

4. The following are true about the offsprings of a female carrier of an X-linked 
    recessive disorder  and a normal male:

a. half of their children will symptomatic

b. half of their daughters will be symptomatic

c. half of their sons will be asymptomatic carriers

d. half of their daughters will be carriers

e. half of their sons will be symptomatic


5. With regard to p53 tumour suppressor gene:
a. it is located on chromosome 17

b. it encodes 53 kDa protein

c. it holds the cell cycle in the G1 phase

d. it is stimulated by ionizing radiation

e. abnormal gene is associated with childhood tumours

6. The following are true about restriction fragment length polymorphisms (RFLPs):

a. they show individual variation

b. they can be used to determine the position of specific genes

c. they are produced by enzymes which cleave DNA at specific sites

d. they can be used for prenatal diagnosis

e. they have not known useful function


7. Retinoblastoma:
a. is associated with loss of the short arm of chromosome 13

b. is caused by mutation in the growth suppressor gene

c. is an autosomal dominant condition

d. is sporadic in the majority of unilateral cases

e. is inherited in the majority of bilateral cases


8. In the human cell cycle:
a. cell division occurs in the S phase

b. G1 precedes mitosis

c. DNA synthesis occurs in G0

d. vincristine acts on the M phase

e. methotrexate acts on the S phase


9. True statements include:
a. before RNA can be studied by PCR (polymerase chain reaction), it 
    has to be translated into complementary DNA

b.Western blotting  is used to detect specific protein in a mixture of 

c. Northern blotting is used to detect DNA sequence

d. Southern blotting is primarily used to detect DNA sequence

e. gel electrophoresis is used in both Southern and Northern blottings


10. The following are true:
a. proto-ongenes regulate the normal cell division

b. mutated proto-oncogenes are associated with cancer

c. gene translocation can transform proto-oncogenes

d. viral insertion can disrupt normal proto-oncogenes

e. ras oncogenes are the most commonly observed oncogenes in 
    human tumours.


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