DNA replication, transcription, and translation, gene regulation, and viruses.
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| 655322145 | Frederick Griffith | This person made an experiment that involved injecting mice with pneumonia: smooth S cells, rough R cells, heat-killed S cells, and heat-killed S cells with living R cells. | |
| 655322146 | Avery, McCarty, and MacLeod | First to show that DNA was the genetic material, but not believed. Repeated Griffith's experiment, but subjected the strains to different enzymes, isolating RNA, DNA, lipids, carbohydrates, and proteins. Only the DNA killed the mice; the others had the mice survive. | |
| 655322147 | Hershey and Chase | Used T4 bacteriophages in radioactive phosphorus to track DNA and radioactive sulfur to track proteins to determine what is the transformational material in genes. Radioactive phosphorus found in host bacteria, but no sulfur, proving once and for all DNA was the genetic material. | |
| 655322148 | Erwin Chagraff | Analyzed the base composition of DNA and saw that it varied from species to species (shows the diversity of species). He also found that the amount of A nucleotides equaled the number of T nucleotides, and the number of C nucleotides equaled the number of G nucleotides. | |
| 655322149 | Wilkins and Franklin | Used a technique called x-ray crystallography to produce a picture of the DNA molecule | |
| 655322150 | Watson and Crick | Figured out structure of DNA was a double helix, and used Chagraff's observations to determine that purines pair with pyrimidines to maintain equidistance in the helix. (A with T and C with G) | |
| 655322151 | Conservative Model | The parental double helix is copied as a full double helix; proved false | |
| 655322152 | Semi-Conservative Model | The parental double helix is unzipped, and copied as individual template strands; Watson and Crick assumed this was correct, and it is | |
| 655322153 | Dispersive Model | The parental double helix is copied in fragments; proved false | |
| 655322154 | Meselson and Stahl | Proved that DNA replicates in a semiconservative fashion, confirming Watson and Crick's hypothesis. Cultured bacteria in a medium containing heavy nitrogen (15N) and then a medium containing light nitrogen (14N); after extracting the DNA, they demonstrated that the replicated DNA consisted of one heavy strand and one light strand | |
| 655322155 | Origin of Replication | Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides. | |
| 655322156 | Replication Bubble | A region of DNA, in front of the replication fork, where helicase has unwound the double helix | |
| 655322157 | Replication Fork | A Y-shaped point that results when the two strands of a DNA double helix separate so that the DNA molecule can be replicated | |
| 655322158 | DNA Helicase | An enzyme that unwinds the DNA double helix during DNA replication | |
| 655322159 | Single-Strand Binding Proteins | Small proteins that bind to either of the template strands in replication to prevent them from coming together again | |
| 655322160 | Topoisomerase | A protein that functions in DNA replication, helping to relieve strain in the double helix ahead of the replication fork. | |
| 655322161 | RNA Primer | A small RNA sequence that is complementary to a DNA sequence, and allows a new DNA strand to begin being formed | |
| 655322162 | Primase | An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template. | |
| 655322163 | DNA Polymerase | Enzyme involved in DNA replication that brings individual nucleotides to produce a new DNA molecule | |
| 655322164 | Antiparallel | How new DNA strands must be built. If the parental strand was from 3- to 5-, the new strand must be built 5- to 3-, and vice versa | |
| 655322165 | Leading Strand | The parental 3- to 5- strand which builds from 5- to 3-, the mandatory direction, allowing for continuous growth | |
| 655322166 | Lagging Strand | The parental 5- to 3- strand, which builds from 3- to 5-, which is impossible, so it must be built in Okazaki Fragments | |
| 655322167 | DNA Ligase | An enzyme that joins together the Okazaki Fragments of the Lagging Strand | |
| 655322168 | Mismatch Repair | The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides. | |
| 655322169 | Nulcease | An enzyme that cuts out a damaged portion of DNA, which is then cleaved together using DNA polymerase and DNA ligase | |
| 655322170 | Nucleotide Excision Repair | The process of removing and then correctly replacing a damaged segment of DNA using the undamaged strand as a template | |
| 655322171 | Telomeres | Repeated DNA sequences at the ends of eukaryotic chromosomes. | |
| 655322172 | Telomerase | an enzyme in eukaryotic gamete cells that can add telomeres to the ends of chromosomes after they go through meiosis | |
| 655322173 | Histone | Protein which DNA is tightly coiled around in heterochromatin. There are five types of them, one I, and two of each II, III, IV, and V | |
| 655322174 | Nucleosome | Bead-like structure in eukaryotic chromatin, composed of a short length of DNA wrapped around a core of histone proteins | |
| 655322175 | Beads on a String | 1st level of DNA packing; when DNA coils around the histone complexes to make nucleosomes | |
| 655322176 | 30-nm Fiber | Nucleosome interactions cause extended fiber to coil into an denser coil | |
| 655322177 | Looped Domains | 30-nm fiber forms loops that attach to a protein chromosome scaffold. | |
| 655322178 | Heterochromatin | Densely packed chromatin; typically in chromosome form during mitosis/meiosis. Too tight for transcription to occur, and visible under a light microscope | |
| 655322179 | Euchromatin | The more open, unraveled form of eukaryotic chromatin that is available for transcription. | |
| 655322180 | Primary Transcript | An initial RNA transcript; also called pre-mRNA. | |
| 655322181 | Codon | A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid | |
| 655322182 | Anticodon | Group of three bases on a tRNA molecule that are complementary to an mRNA codon | |
| 655322183 | RNA Polymerase | The only enzyme used in DNA transcription; pulls apart the DNA double helix and creates a strand of RNA off of the leading strand, and rezips the double helix | |
| 655322184 | Promoter | Region of DNA that indicates to RNA Polymerase where to bind to begin transcripting DNA | |
| 655322185 | Terminator | Sequence of non-coding DNA that signals for the RNA Polymerase to stop making RNA, and break off | |
| 655322186 | Transcription Factor | A regulatory protein that binds to DNA and stimulates transcription to begin by causing RNA polymerase to bind to the promoter and begin transcripting | |
| 655322187 | Control Elements | Includes the TATA box and the CAAT box, they are repeating, non-coding sequences in the DNA that are located near the promoter (either proximal or distal) and allow a transcription factor to bind to them to stimulate the beginning of transcription | |
| 655322188 | Transcription Initiation Complex | The completed assembly of transcription factors, control elements, and RNA polymerase bound to the promoter. | |
| 655322189 | Modified Guanine Cap | An addition of a modified guanine nucleotide to the 5- end of pre-RNA after transcription | |
| 655322190 | Poly-A Tail | An addition of a long sequence of adenine to the 3- end of pre-RNA after transcription | |
| 655322191 | RNA Splicing | Process by which the introns are removed from RNA transcripts and the remaining exons are joined together | |
| 655322192 | Intron | Sequence of DNA that is not involved in coding for a protein | |
| 655322193 | Exon | Sequence of a gene's DNA that transcribes into protein structures | |
| 655322194 | Spliceosome | A large RNA and protein complex (made up of snRNP's) that binds to the RNA transcript (pre-mRNA) and cuts out the intron, and cleaves together then remaining exons | |
| 655322195 | Alternative RNA Splicing | Explains how one gene can account for multiple proteins. When the pre-RNA is processed, different areas can code for introns and be spliced out, and the various introns spliced out creates different mRNA, which codes for different proteins. Allows for a small number of genes but a large number of proteins | |
| 655322196 | Aminoacyl-tRNA Synthetase | An enzyme that joins each amino acid to the correct tRNA. | |
| 655322197 | Wobble Hypothesis | The hypothesis that some tRNA molecules can pair with more than one mRNA codon, tolerating some variations in the third base, as long as the first and second bases are correctly matched | |
| 655322198 | Polyribosome | String of ribosomes simultaneously translating regions of the same mRNA strand during protein synthesis | |
| 655322199 | Signal Peptide | A stretch of amino acids on a polypeptide that targets the ribosome to bind to the Endoplasmic Reticulum | |
| 655322200 | Signal-Recognition Particle | A protein-RNA complex that recognizes a signal peptide as it emerges from a ribosome and helps direct the ribosome to the endoplasmic reticulum (ER) by binding to a receptor protein on the ER | |
| 655322201 | Point Mutations | Gene mutations involving a change in one nucleotide | |
| 655322202 | Nucleotide-Pair Substitution | Replacement of one nucleotide and its partner with another pair of nucleotides. It can have no affect on the coded protein, due to the redundancy of the genetic code, but depending on its location, also can affect the protein | |
| 655322203 | Silent Mutation | A mutation that changes a single nucleotide, but does not change the amino acid created. | |
| 655322204 | Missense Mutation | A mutation in which a nucleotide in a sequence that specifies an amino acid is mutated into a nucleotide that changes the sequence and specifies a different amino acid instead. Depending on where this amino acid is located in the protein, it may or may not affect the protein structure | |
| 655322205 | Nonsense Mutation | A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein. | |
| 655322206 | Insertion | Addition of extra nucleotides into a gene | |
| 655322207 | Deletion | Removal of nucleotides from a gene | |
| 655322208 | Frameshift Mutation | Mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide; if the number of nucleotides inserted is not a multiple of three, it can change every amino acid past the site of the mutation, causing severe protein misformation, and usually results in a non-functional protein | |
| 655322209 | Mutagen | Any agent (physical or environmental) that can induce a genetic mutation or can increase the rate of mutation | |
| 655322210 | Operon | A form of gene regulation found only in prokaryotes, it was the first to be discovered | |
| 655322211 | Operator | A segment of DNA in an operon that acts as an "on-off switch" for a gene | |
| 655322212 | Repressor | A molecule that binds to the operator in an operon to inactivate a gene | |
| 655322213 | Corepressor | A molecule that binds to the repressor in an operon to help the repressor inactivate a gene | |
| 655322214 | Inducer | A specific small molecule that inactivates the repressor in an operon by pulling it off of the operator | |
| 655322215 | Activator | A protein that binds to DNA and stimulates transcription of a gene, such as cAMP | |
| 655322216 | Differential Gene Expression | The expression of different sets of genes by cells with the same genome; allows for cellular specialization in multicellular organisms |
