Question

Give the sequence of the complementary strand of the following DNA of one DNA strand of a DNA double helix is the (6 pts) nd of the following DNA strands. The nucleotide sequence a. 5'-GGATTTTTGTCCACAATCA-3' b. 3'-TTCGAGTCCAAGTCGTACTA-S or magnesium chloride (MgCl) is dissolved in 2.40 L of water. (Molar mass of MgCl2 -.11g/mole) (15 pts) a. What is the molarity of solution? b. How many moles of MgCl, are contained in 1.76L of solvent? C. How many liters of solvent would contain 0.0150 moles of MgCl2?

Answer 1

Complementary sequence would be

a) 3’-CCTAAAAACAGGTGTTAGT-5’

b) 5’-AAGCTCAGGTTCAGCATGAT-3’

I am assuming that 6.7 gm MgCl2 is dissolved in 2.4 L water and we know that molecular mass of this chemical is 95.211 gm/mol

a) The formula for molarity is (M)= number of moles/number of liters (M=# moles/# L)

6.7 gm MgCl2 1000mL (1 mol. MgCl2)

2400mL H20 1L (95.211gm MgCl2)

= 6.7x 1000

   2400x95.211

=0.02932 M (So if we dissolve 6.7 MgCl2 in 2.4 L then it will give 0.029 M solution)

b) Molarity can be calculated using following formula

C1V1=C2V2

C1=0.029 M

V1=2.4

C2=?

V21.7

So, 0.029x2.4=C2x1.7

C2= 0.029x2.4/1.7

=0.0409 M, so answer is 0.0409 M

C) again use C1V1=C2V2

C1=0.029

V1=2.4

C2=0.0150

V2=?

V2= C1V1/C2

= 0.029x2.4/0.0150

=4.54 liters

So, correct answer would be 4.54 liters

[Note: Using these simple steps you can calculate any molarity or concentration].