Nucleotides and DNA Structure

Question 1

When 2 phosphates, aka 2 orthophosphates, are bound together, they form ___1____, the bond of which that connects these 2 phosphates is called a __2___ linkage.

Answer 1

1) pyrophosphate

2) anhydride linkage

Question 2

Give 3 reasons that the phosphate anhydride bonds store so much energy

Answer 2

1) when phosphates are linked together, their negative charges repel each other strongly
2) orthophosphate has more resonance forms and thus a lower free energy than linked phosphates
3) orthophosphate has a more favorable interaction with the biological solvent (water) than linked phosphates

Question 3

What are the building blocks of nucleic acids RNA and DNA?

Answer 3

nucleotides

Question 4

Each nucleotide contains a _____ or ____ sugar group; a ____ or ____ base; and 1,2,or3 _____ units

Answer 4

ribose or deoxyribose sugar group
purine or pyrimidine base
phosphate units

Question 5

Which carbon is the purine/pyrimidine base and which carbon is/are the phosphate groups bound to on the ribose ring?

Answer 5

purine or pyrimidine are joined to C#1

phosphate units are joined to C#5

Question 6

ATP is a ____nucleotide

Answer 6

ribonucleotide

Question 7

ATP is a ribonucleotide, where ___ is the sugar

Answer 7

ribose (as opposed to deoxyribose)

Question 8

The building block of DNA id dNTP, which stands for _________.

Answer 8

deoxyribonucleoside triphosphate (connected to the 5’ C)

Question 9

A deoxynucleoside is a __1__ sugar whereas a nucleoside is a __2___ sugar

Answer 9

1) deoxyribose

2) ribose

Question 10

Which nitrogenous bases are pyrimidines and which are purines?

Answer 10

pyrimidines = Cytosine, Thymine, and Uracil
purines = Adenine, Guanine

Question 11

Which nitrogenous bases have a double ring structure (6 membered ring connected to a 5 membered ring) and which have a single 6 membered ring structure?

Answer 11

Purines = double ring structure
pyrimidines = single ring structure

Question 12

What happens when turning a ribose into a 2’ deoxyribose?

Answer 12

The hydroxy group is taken off of the 2’ C of the ribose, hence the name deoxyribose

Question 13

Differentiate between a nucleoside and a nucleotide

Answer 13

nucleoside: the pentose sugar and the nitrogenous base only
nucleotide: the pentose sugar, the nitrogenous base, and the phosphate groups

Question 14

What is the building block of DNA?

Answer 14

2’ deoxyribonucleoside triphosphate (aka 2’ dNTP)

Question 15

Nucleic acid polymerization: the ____ carbon of one dNTP is linked with the phosphate group of another dNTP

Answer 15

3’

Question 16

What is the directionality of Nucleic Acid polymerization?

Answer 16

5’ to 3’ direction

Question 17

which groups form the backbone of DNA?

Answer 17

the phosphate and sugar groups

Question 18

DNA is antiparallel and complementary. What does this mean.

Answer 18

Antiparallel: If one strand is traveling in the 5’ to 3’ direction, the other strand is traveling in the 3’ to 5’ direction
complementary: the nitrogenous bases on one strand are specifically paired up with other nitrogenous bases on the other strand

Question 19

2 nucleotides are joined together via a _____ bond

Answer 19

phosphodiester bond

Question 20

base pairing of nitrogenous bases are held together by ____ bonds

Answer 20

hydrogen

Question 21

How many H bonds connect A and T, and how many H bonds connect C and G?

Answer 21

2 H bonds between A and T

3 H bonds between C and G

Question 22

What is the name of all the DNA that an organism possesses called?

Answer 22

genome