The Z-DNA helix,The shine-Dalgrano sequence is responsible for

Q.Free fatty acids are transported in the blood

(1) Combined with albumin

(2) Combined with fatty acid binding protein

(3) Combined with-lipoprotein

(4) In unbound free state

Ans.(1) Free fatty acids pass from the adipocyte into the blood, where they bind to the blood protein serum albumin and are carried to the tissues such as skeletal muscle, heart and renal cortex.

Q.The Z-DNA helix

(1) Has fewer base pairs per turn than the B-DNA

(2) Is favored by an alternating GC sequence

(3) Tends to be found at the 3’-end of genes

(4) Is inhibited by methylation of the bases

Ans.(2)The Z-DNA helix is favoured by an alternating GC sequence. Z-DNA can form in regions of alternating purine - pyrimidine sequence; (GC)n sequences form Z-DNA most easily. (AT)n sequences generally does not form Z-DNA since it easily forms cruciform’s.

Q.The shine-Dalgrano sequence is responsible for

(1) Binding of RNA polymerase to gene during transcription

(2) Binding of DNA polymerase to origin of replication during DNA replication

(3) Binding of riosomes to mRNA during initiation of translation

(4) Binding of snURPs during splicing

Ans.(3)Shine - Dalgarno sequence is responsible for binding of ribosome to mRNA during initiation of translation. It is a short polypurine sequence centered about 10bp upstream of the initiation codon.The shine-dalgarno sequence is complementary to a region at the 3’ end of the 16S rRNA, and it is thought that base-paring between the two is involved in the attachment of the small subunit of the mRNA