DNA Structure & Properties II: Exam 1

Purine

Purine

This is a two-ringed heterocyclic nitrogenous base (9-atom ring structure).

Pyrimidine

This is a single-ringed nitrogenous base (6-atom ring structure).

O

Deoxyribose is missing an ______ at the H.

Nucleoside

Nitrogenous Base + Deoxyribose Sugar

Nucleotide

Nitrogenous Base + Deoxyribose Sugar + Phosphoric Acid

N-glycosidic Bond

This is the bond between the sugar and nitrogenous base.

purines

Anti-configuration is favored by ______________.

Phosphoric Acid

This attaches nucleosides to each other.

ester

Phosphoric Acid forms two ___________ bonds.

two

Purines have ________ Hydrogen bonds.

three

Pyrimidines have ________ Hydrogen bonds.

pseudo-symmetry

The _____________________________ of base pairs determines if the helices formed by them have grooves with identical/different shapes.

right

DNA has a __________ handed helix.

co-planar

In DNA, bases are not _______________; Hydrogen bonds do not join in a flat plane with each other; they off-set allowing turning & bending.

twisting

Because of base pairing, a shift in the backbone structures results in the _______________ of DNA.

5’ to 3’ with the addition of new nucleotides to the 3’ end.

In terms of polarity, what is the direction of DNA synthesis?

Promotors

What are the DNA regulatory sequences recognized by RNA polymerase called?

redundant

There are 61 different codons that code for amino acids, but only 20 different amino acids. This means that the genetic code is ________________.

grooves

IF deoxyribose sugars were co-planar, there would be similar sized ____________.

B-DNA

This is the hydrated form of DNA; it contains H2O molecules.

B-DNA, A-DNA, Z-DNA

These kinds of DNA contain double-stranded polynucleotide chains.

Z-DNA

This kind of DNA has a left-handed helical formation with a pronounced zig-zag pattern.

B-DNA, A-DNA, Z-DNA

In these kinds of DNA, chains are anti-parallel and complementary.

B-DNA and A-DNA

These kinds of DNA have a right-handed helical formation.

B-DNA and A-DNA

These kinds of DNA have very specific base interactions.

Z-DNA

In this kind of DNA, bases are in both the syn and anti configurations.

B-DNA

In this kind of DNA, bases are stacked and pointed inside the molecule.

A-DNA

In this kind of DNA, bases are tilted (not stacked) but still pointed inside the molecule.

Z-DNA

In this kind of DNA, bases are alternate conformation but still pointed inside the molecule.

Z-DNA

This kind of DNA is more compact (narrower).

A-DNA

This kind of DNA is wider & shorter than B-DNA.

Z-DNA

This kind of DNA has highly specific binding sites for transcription factors.

B-DNA and A-DNA

These kinds of DNA are typically in the anti-configuration.