| A | B |
|---|
| Transformation | A change in genotype and phenotype due to the assimilation of external DNA by a cell |
| Bacteriophage | Viruses that infect bacteria; a.k.a-"bacteria-eaters" |
| DNA Base pairs | The bases of DNA consisting of a nitrogenous base, a pentose sugar known as deoxyribose, and a phosphate group. Bases are adenine (A), thymine (T), guanine (G), and cytosine (C) |
| Double helix | The shape that DNA molecules make, also known as a "twisted ladder" |
| Semiconservative method | Method stating that when the double helix DNA replicates, the two new strands will each consist of one old starnd from the parent molecule and one newly made strand |
| Origins of replication | This is where the replication of DNA begins. It is short stretches of DNA consisting of a specific sequence of nucleotides. |
| Replication fork | The Y-shaped region where the parental strands of DNA are being unwound |
| Helicases | Enzymes that untwist the double helix at the replication forks, separating the two parental strands which makes them available as template strands for new DNA |
| Single-strand binding proteins | Proteins that bind to the unpaired DNA strands and stabilize them |
| Topoisomerase | An enzyme that works ahead of the DNA Helicase to relieve the strain of the tightly twisting DNA by breaking, swiveling, and rejoining the DNA strands |
| RNA Primase | Add an RNA primer onto the parental strand of DNA to prepare the DNA strand for replication |
| DNA Polymerase | Enzymes that catalyzes the synthesis of new DNA by adding nucleotides to the preexisting chain |
| Leading strand | The strand of parent DNA that is replicated continuously by DNA polymerase |
| Lagging strand | The strand of parent DNA that is replicated away from the replication fork in short fragments |
| Okazaki fragments | The name of the short fragments that the lagging strand is replicated in |
| DNA ligase | Enzyme that joins the Okazaki fragments of the lagging strand into one continuous strand of DNA |
| Nuclease | Enzyme that can cut out bits of a damaged strand of DNA at two different points so the DNA strand can be repaired |
| Thymine dimer | A portion of DNA that can cause the DNA to buckle and interfere with DNA replication |
| Histones | Proteins that are responsible for the packing and scaffolding of DNA to form the chromosomes |
| Gene expression | the process by which DNA directs the synthesis of proteins and is done in two stages: transcription and translation |
| Transcription | The synthesis of RNA under the direction of DNA |
| Messenger RNA(mRNA) | Carries a genetic message from the DNA to the protein-synthesizing machinery of the cell |
| Translation | The synthesis of a polypeptide, which occurs under the direction of mRNA |
| Ribosomes | The sites of translation |
| Primary transcript | The initial RNA transcript from any gene, including those coding for RNA that is not translated into protein |
| Codons | Also called triplet code; this is the genetic instructions for a polypeptide chain and is written in the DNA as a series of non-overlapping, three-nucleotide words |
| Template strand | The strand of the DNA that is transcribed |
| Promoter | The DNA sequence where RNA polymerase attaches and initiates transcription |
| Terminator | The sequence of DNA that signals the end of transcription |
| Transcription unit | The stretch of DNA that is transcribed into an RNA molecule |
| Transcription factors | A collection of proteins in eukaryotes that mediate the binding of RNA polymerase and the initiation of transcription |
| Transcription initiation complex | This the entire complex of transcription factors and RNA polymerase II bound to the promoter |
| RNA processing | When enzymes in the eukaryotic nucleus modify the pre-mRNA in specific ways before the genetic messages are dispatched to the cytoplasm. |
| 5' cap | A modified form of a guanine nucleotide added onto the 5' end after transcription of the first 20 to 40 nucleotides |
| poly-A tail | At the 3' prime end, an enzyme adds 50-250 more adenine nucleotides to protect the RNA |
| Introns | These are the non-coding sequences of nucleic acid that lie between coding sections;A.K.A: intervening sequences |
| Exons | These are the coding sequences that are eventually expressed |
| Spliceosome | The combination of several different snRNP's form this which interacts with certain sites along the intron |
| Transfer RNA (tRNA) | Functions to transfer amino acids from the cytoplasmic pool of amino acids to a ribosome |
| Mutations | Changes to the genetic information of a cell |
