Biology: DNA: Structure and Function

DNA Molecule

(Deoxyrionucleic Acid) The genetic material that provides a blueprint for the organization, development, and function of living things

RNA Molecule

Consists of a single strand of nucleotides

DNA Strand

Consists of two strand that are made up of nucleotides

RNA Strand

A singular strand that is made of nucleotides

Polypeptide

A linear sequence of amino acids; the term denotes structure

Protein

A functional unit composed of one or more polypeptides. Each polypeptide is composed of a linear sequence of amino acids

DNA Replication/DNA Synthesis

The process in which DNA is "unzipped" and the bases of each strand are matched with the appropriate base according to the AT/GC Rule

Gene Expression/Protein Synthesis

Gene function both at the level of traits and at the molecular level

Fredrick Griffith

Discovery: Existence of genetic material

Process: Take type S(Smooth, Lethal) bacteria and type R(Rough, Non-lethal) bacteria and inject into mice. Heat kill type S which was non-lethal. Mix heat-killed type S with living type R which was lethal to the Mouse.

Avery, Macleod, and McCarty

Discovery: DNA is the Genetic Material

Process: Purification of DNA. They added DNA extract from S strain to R strain which transformed R to S. They then added DNase to the DNA extract which broke down the DNA and resulted in no transformation. Rnase and protease were added to the DNA extract and both resulted in transformation of R strain to S strain

Hershey and Chase

Discovery: DNA is the Genetic material of T2 Bacteriophage

Process: Labeled the DNA and Protein of phages and had them infect bacteria cells. The results were that the material that was inserted by the phages was DNA

Watson and Crick

Discovery: Double Helix Structure of DNA

Process: Trial and error with models of DNA. Model-building revealed to them that purine-pyrimidine pairs would form a double helix

Bacteriophage

Virus that infects cells

Nucleotide(Structure)

An organic molecule having three components: one or more phosphate groups, a five-carbon sugar (either deoxyribose or ribose), and a single or double ring of carbon and nitrogen atoms known as a base

Deoxyribose

A five carbon sugar found in DNA

Antiparallel

The arrangement in DNA where one strand runs in the 5' to 3' direction while the other strand is oriented in the 3' to 5' direction

5' End

The connection to the 5th carbon molecule in the deoxyribose sugar

3' End

The connection to the 3rd carbon molecule in the deoxyribose sugar

DNA Helix/Double Helix

Two strands of DNA hydrogen-bonded with each other. In a DNA double helix, two DNA strands are twisted together to form a structure that resembles a spiral staircase

Complementary Base Pairing Rule

Describes the specific base pairing that occurs between strands of nucleic acids; A pairs only with T(DNA) or U(RNA), and G pairs only with C

Semiconservative Replication

The correct model for DNA replication; double-stranded DNA is half conserved following replication, resulting in new double-stranded DNA containing one parental strand and one daughter strand

DNA Polymerase

An enzyme responsible for covalently linking nucleotides together during DNA replication

RNA Primer

Places the site for DNA Polymerase to begin placement of complementary base pairs

DNA Helicase

An enzyme that uses ATP to separate DNA strands during DNA replication

Single-Stranded Binding Proteins

Prevent re-annealing(reformation of H bonds)

Leading Strand

During DNA replication, a DNA strand made in the same direction that the replication fork is moving. The strand is synthesized as one long continous molecule

Lagging Strand

During DNA replication, a DNA strand made as a series of small Okazaki fragments that are eventually connected to each other to form a continuous strand

DNA Ligase

An enzyme that catalyzes the formation of a covalent bond between nucleotides in adjacent DNA fragments to complete the replication process

Okazaki Fragments

Short segments of DNA synthesized in the lagging strand during DNA replication

Topoisomerases

An enzyme that regulates the overwinding or underwinding of DNA.

Telomeres

A region at the ends of Eukaryotic chromosomes where a specialized form of DNA replication occurs

Telomerase

An enzyme that catalyzes the replication of the telomere

Transcription

The use of a gene sequence to make a copy of RNA

Translation

The process of synthesizing a specific polypeptide on a ribosome

Amino Acids

The building blocks of proteins.

mRNA

Carries the genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid

tRNA

Key to deciphering the code words in mRNA

rRNA

Associates with a set of proteins to form ribosomes

Ribose

A five carbon sugar found in RNA

Uracil

Pyrimidine base found in RNA

Codon(Codon Table)

A sequence of three nucleotide bases that specifies a particular amino acid or a stop codon; codons function during translation

Anticodon

A three-nucleotide sequence in tRNA that is complementary to a codon in mRNA

RNA Polymerase

The enzyme that synthesizes strands of RNA during gene transcription

Promoter Region

The site in the DNA that transcription begins

Termination Sequence

One of three-base sequences-UAA, UAG, and UGA- that signals the end of translation

Leader Sequence

The sequence at the 5' end of an mRNA that is not translated into protein

Trailing Sequence

Sequence that follows the termination codon at the 3' end

Protein Encoding Region

Portion of a gene's DNA or RNA, composed of exons, that codes for protein.

Aminoacyl-tRNA Synthetase

An enzyme that attaches the appropriate amino acid onto its tRNA.

Wobble Hypothesis

The third position base-pair rules are more relaxed so that a base can pair with more than one complementary base.

E-Site

The ribosomal site harboring decylated tRNA on transit out form the ribosome

P-Site

The ribosomal site most frequently occupied by peptidyl-tRNA, which carries the growing peptide chain

A-Site

The ribosomal site most frequently occupied by aminoacyl-tRNA

Immature RNA

Incompletely processed mRNA molecule found in the nucleus

Mature RNA

mRNA that has been sliced and processed

3' Poly-A-Tail

String of adenine nucleotides that mature eukaryotic mRNAs have

5' 7-Methylguanosine Cap

cap-binding proteins, which are needed for the proper exit of mRNAs from the nucleus

Splice

The process whereby introns are removed from RNA and the remaining exons are connected to each other

snRNP's

RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome

Post-transcriptional Modifications

Process in cell biology by which, in eukaryotic cells, primary transcript RNA is converted into mature RNA.

Post-translational Modifications

A process of changing the structure of a protein, usually by covalently attaching functional groups; this process greatly increases the diversity of the proteome

Base-Substiutions

A mutation that involves the substitution of a single base in the DNA for another base

Frameshift

A mutation that involves the addition or deletion of a number of nucleotides that are not in multiples of three

Missense

A point mutation in which a single nucleotide change results in a codon that codes for a different amino acid

Nonsense Mutations

A point mutation in a sequence of DNA that results in a premature stop codon

Lac Operon

(Structure and function of all components)

An operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria

Inducible Genes

The presence of a small effector molecule causes transcription to occur

Repressible Genes

A small effector molecule inhibits transcription

Constitutive Genes

An unregulated gene that has constant levels of expression in all conditions over time