Test 114  (Genetics)
1. The polymerase chain reaction: 
a. produces multiple copies of DNA

b. requires oligonucleotide primers

c. has a high specificity but low sensitivity

d. requires the use of heat 

e. can be used to detect RNA virus

2. With regard to mitochondrial DNA:
a. it is double-stranded

b. it mutates 10 times more frequently than nuclear DNA

c. each mitochondrion contains about 100 DNA 

d. it has no introns

e. Leber's congenital amaurosis is caused by defective 
    mitochondrial DNA

3. The following are true about nuclear DNAs:
a. about 50% of the nuclear DNA codes for proteins

b. they are tightly wrapped around histones to form 
    nucleoprotein complex

c. introns interrupt the coding sequence

d. exons are removed during splicing

e. the base pairings are bound together by hydrogen 

4. The HLA B27 molecule:
a. is class II major histocompatibility antigen

b. is expressed mainly in antigen presenting cells

c. occurs in 8% of the general population

d. occurs in 90% of patients with ankylosing spondylitis 

e. is commoner in patients with Yersinia arthritis

5. The following are true about mRNA:

a. only 1% of the cellular RNA is mRNA

b. human mRNA is monocistronic

c. introns are not transcribed into mRNA

d. mutation of the DNA sequence invariably gives rise to 
    a change in the amino acid sequence of the resulting 

e. RNA polymerase II gives rise to protein encoding 

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