Base Sequence of Complementary DNA Strands: One strand of a double-helical DNA has the sequence (5’)(3’). a) Write the base sequence of the complementary strand. b) What special type of sequence is contained in this DNA segment? c) Does the double-stranded DNA have the potential to form any alternative structures?

a) : The complementary strand is

(5ʼ)(3ʼ)

b) This sequence has a palindrome, an inverted repeat with twofold symmetry:

(5ʼ)(3ʼ)

(3ʼ)(5ʼ)

c)Because this sequence is self-complementary, the individual strands have the  potential to form hairpin structures. The two strands together may also form a  cruciform.

Explanation:

One strand of a double-helical DNA has the sequence (5’)(3’)

a) : The complementary strand is

(5ʼ)(3ʼ)  the sequence of a single strand is always written in the 5ʼ→3ʼ direction.

b) This sequence has a palindrome, an inverted repeat with twofold symmetry:

(5ʼ)(3ʼ)

(3ʼ)(5ʼ)

c)Because this sequence is self-complementary, the individual strands have the  potential to form hairpin structures. The two strands together may also form a  cruciform.

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure

answer; polycythemia is the correct answer;