Topic 1.6

Compare and contrast DNA and RNA.

Both are nucleic acids and house information crucial to the cell. However, they are very different. DNA is a doubles stranded helix with deoxyribose for its sugar. It has the base thymine. RNA is single stranded and has uracil in place of thymine. Its sugar is ribose.

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

List the possible nitrogenous bases that can be found in nucleotides.

Adenine, thymine, cytosine and guanine are the four nucleotides found in DNA.

Gene

A segment of DNA on a chromosome that codes for a specific trait

What does it mean that DNA is antiparallel? Use a drawing to support your answer.

A term applied to two molecules that are side by side but run in opposite directions.

Purine

Adenine and Guanine

What is the monomer called if it is lacking a phosphate group?

Nucleosides differ from nucleotides in that they lack phosphate groups.

Antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix.

Draw adenine bonded to thymine. Then draw cytosine bonded to guanine. What do you notice?

You see, cytosine can form three hydrogen bonds with guanine, and adenine can form two hydrogen bonds with thymine. C will only bond with G and A will only bond with T in DNA.

Pyrimidine

a nitrogenous base that has a single-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; thymine, cytosine, or uracil

What functional group defines the 3' end?

hydroxyl

Nucleic acid

macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus

Nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

Where can DNA be found in a cell? What about RNA?

nucleus, in the cytoplasm of the cell

What functional group defines the 5' end?

phosphate group

Identify the three components of a nucleotide.

phosphate group; sugar group; nitrogenous base

RNA

ribonucleic acid