DNA 2D Structure

2-deoxyribose

5 carbon sugar in DNA

5’ and 3’ ends

two ends of a DNA or RNA strand with the 5’ end attached to a phosphate group and the 3’ end having a hydroxyl group

A, C, T, G

4 nitrogenous bases in DNA

A

Adenine

T

Thymine

G

Guanine

C

cytosine

B form

standard, the most common shape of DNA under normal cellular conditions

Central dogma

core principle that genetic information flows from DNA, transcribed to mRNA, then translated into protein

codon

a sequence of three consecutive nucleotides in mRNA that specifies a particular amino acid or stop signal

denaturation

separation of a double-stranded DNA into single strands by breaking the hydrogen bonds between base pairs

DNA polymerase

enzyme that builds new DNA strands

double helix

the twisted ladder structure of DNA, with two strands around each other

electrophoresis

a lab technique that separates DNA (or RNA or protein) fragments by using an electric field

enol/keto isomers

rare alternative chemical forms of the nitrogenous bases caused by a proton shifting position

genetic code

the set of rules that translates mRNA codons into amino acids

genome

complete set of an organism’s DNA, including all its genes and non-coding regions

hybridization

the process where two complementary single strands of nucleic acid bind to form a double-stranded molecule

intercalating agent

a flat, often aromatic molecule that slides between adjacent base pairs in DNA, distorting the helix

major groove

the wider of the two grooves that run along the DNA double helix

Next generation sequencing (NGS)

high-throughput DNA sequencing technologies that can sequence millions of DNA fragments in parallel, making it fast and affordable to sequence whole genomes

nucleotide

basic building block of nucleic acids

phosphodiester bond

covalent chemical bond that links one nucleotide to the next in a nucleic acid strand

purine

class of nitrogenous base with a double ring structure; A and G

pyrimidine

class of nitrogenous bases with a single ring structure; C and T

Sugar-phosphate backbone

repeating structural framework of each DNA or RNA strand, made of alternating sugar and phosphate molecules linked by phosphodiester bonds

x-ray crystallography

technique for determining the 3D structure of molecules by shooting x-rays at a crystal and analyzing the diffraction pattern

What did Chargoff discover in the 1940s

in DNA, the number of G = the number of C and the number of A = the number of T

What did Pauling discover in 1951

amino acid chains form alpha helices and beta sheets

What did Pauling discover in 1952 (wrongly)

DNA is a triple helix

What did Hershey and Chase discover in 1952?

DNA holds the genetic information

What did Franklin and Wilkins do in 1953?

x-ray diffraction image of DNA (photograph 51)

What did Watson and Crick discover in 1953?

DNA is a double helix

What did crick discover in 1957

central dogma

What did Niremberg and Matthae discover in 1961?

translation of the first synthetic codon

What did Khorana discover in 1966?

decryption of most of the genetic code

What did Sanger discover in 1977?

technique to sequence DNA

What is the enzyme that transcribes DNA to RNA

RNA polymerase

What is the enzyme that translates RNA to protein

ribosomes

What is the enzyme that replicates RNA

RNA-dependent RNA polymerase

What enzyme is involved in reverse transcription of RNA to DNA

reverse transcriptase

What enzyme is involved in DNA replication?

DNA polymerase

G-C base pairs have __ hydrogen bonds

3

A-T base pairs have __ hydrogen bonds

2

G-C rich DNA is generally more ___ due to more H bonds

stable

Two strands of DNA are held together by

non-covalent bonds and hydrogen bonds

DNA is strongly ___ charged

negatively

The negative charge makes DNA

highly polar and soluble in water

Two grooves that DNA displays

minor and major

the minor groove of DNA is

narrow and deep

the major groove of DNA is

wide and shallow

Most DNA-binding proteins recognize sequences through interactions in the __ groove

major