Nucleic Acids and DNA Structure

Flashcards covering key vocabulary terms related to nucleic acids, DNA, RNA, and genomics.

Gene

A unit of inheritance that programs the amino acid sequence of a polypeptide.

Genes

Made of DNA, a nucleic acid comprised of nucleotide monomers.

Nucleotides

Comprise a base, a sugar, and phosphate and have additional biological functions like energy storage (ATP) and molecular transport

DNA

Deoxyribonucleic acid; one of the two types of nucleic acids.

RNA

Ribonucleic acid; one of the two types of nucleic acids.

DNA

Directs the synthesis of messenger RNA (mRNA) and, through mRNA, controls protein synthesis, a process called gene expression.

Nucleic acids

Polymers made of monomers called nucleotides.

Nucleotide

Each consists of a nitrogenous base, a pentose sugar, and one or more phosphate groups.

Nucleoside

The portion of a nucleotide without the phosphate group.

Deoxyribose

The sugar found in DNA nucleotides.

Ribose

The sugar found in RNA nucleotides, which contains an additional oxygen atom.

Pyrimidines

Nitrogenous bases with a single ring, including cytosine (C), thymine (T), and uracil (U).

Purines

Nitrogenous bases with a double ring, including adenine (A) and guanine (G).

Base

Joined to a sugar by a glycosidic bond between the C1′ of the sugar and the N1 of a pyrimidine or N9 of a purine.

DNA and RNA polymers

Formed when nucleotides are joined by a phosphodiester bond via a dehydration reaction, linking the 3′ hydroxyl of one sugar to the phosphate attached to the 5′ hydroxyl of the next sugar.

NA Strands

NA sequences are written in the 5′ to 3′ direction

Sugar-phosphate backbone

Formed by the sugars and phosphates; it is always the same, but the attached bases vary.

DNA

Molecule with two polynucleotides spiraling around an imaginary axis, forming a double helix.

Antiparallel

A arrangement where the two backbones run in opposite directions from each other.

Most energetically favorable formation of double-stranded DNA

The two strands wind around one another in a right-handed double helix.

Van der Waals

Interaction between the bases that stabilize the double helix formation

Watson-Crick base pairs

Bases pair precisely with their complementary base: A pairs with T (2 H-bonds) and C pairs with G (3 H-bonds).

B-DNA

Configuration is the predominant configuration of DNA, repeating every 10.5 base pairs with base pairs 3.4 Å apart.

B-DNA

Helix the forms a major groove (~13 Å) and a minor groove (~9 Å).

A-DNA

A right-handed helix with 11 base pairs per turn, induced by DNA binding proteins.

Z-DNA

A left-handed helix that can result from methylation of cytosine, tortional stress, and high salt concentrations.

Dickerson & Colleagues

Determined the first B-DNA structure

RNA

Uses uracil instead of thymine and has a hydroxyl at the C2 instead of H.

Post-transcriptional modification

Chemical modification after synthesis, usually permanent and not regulatory.

2’OH of ribose

Facilitates a reaction that can break phosphodiester bonds

Secondary structures

Used to describe short double-helical regions of RNA

Tertiary Structure

The arrangement of the double-helices and single stranded regions in the final configuration of the RNA.

RNA

Double helix is typically short, usually 6-8 base pairs, in A-helix formation

Tertiary RNA

Structure is formed when short double stranded helices interact with each other and with single-stranded regions

Genomics

The approach used to analyze large sets of genes or compare the genomes of different species.

Proteomics

The similar analysis of proteins