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Molecular Genetics - AP Biology Flashcards

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8895114610chromosomesDNA is organized into these, which consist of DNA wrapped around proteins called histones. Found in the nucleus, they direct and control all the processes necessary for life, including passing themselves and their information on to future generations.0
8895114611double helixWhat is the shape of DNA?1
8895114612Watson and Crickthe two scientists that discovered the structure of DNA in 19562
8895114613nucleotidesubunit of DNA that consists of a five-carbon sugar, a phosphate, and a nitrogenous base3
8895114614deoxyribosethe pentagon-shaped sugar in DNA which is linked to a phosphate and a nitrogenous base in a nucleotide4
8895114615purinedouble-ringed nitrogenous base5
8895114616pyrimidinesingle-ringed nitrogenous base6
8895114617adeninea purine (double-ringed nitrogenous base) with a double bond to thymine7
8895114618guaninea purine (double-ringed nitrogenous base) with a triple bond to cytosine8
8895114619cytosinea pyrimidine (single-ringed nitrogenous base) with a triple bond to guanine9
8895114620thyminea pyrimidine (single-ringed nitrogenous base) with a double bond to adenine10
8895114625phosphodiester bondsbonds that link nucleotides together bonds between phosphate group and pentose sugar in nucleic acids11
8895114626complementaryThe two strands of DNA are ______. This means that if you know the sequence of bases in one strand, you'll know the sequence of bases in the other strand. For example, if the base sequence in one DNA strand is ATC, the base sequence in the ______ strand will be TAG.12
8895114627carbonEach DNA strand has a 5' end and a 3' end, so-called for the ____ that ends the strand. The fifth ____ in the sugar ring is at the 5' end, while the third ____ is at the 3' end.13
8895114629antiparallelBecause the DNA strands run in opposite directions, this means that the 5' end has a phosphate group and the 3' end has a hydroxyl group. The 5' end of one strand is always opposite to the 3' end of the other strand. The strands are therefore said to be what?14
8895114630hydrogen (bonds)The DNA strands are linked by what kind of bonds?15
88951146312How many hydrogen bonds hold adenine and thymine together?16
88951146323How many hydrogen bonds hold cytosine and guanine together?17
8895114633protein(s)DNA's main role is to direct the manufacture of what? DNA → RNA → _____18
8895114634RNADNA passes its information to what intermediate molecule? DNA → _____ → proteins19
8895114635DNA replicationthe copying of DNA *Step 1:* unwind double helix by breaking H bonds *Step 2:* DNA topoisomerase cuts and rejoins helix to prevent tangling *Step 3:* DNA polymerase adds nucleotides *Step 4:* Okazaki fragments added *Step 5:* DNA ligase creates continuous strand *Step 6:* hydrogen bonds form between the new base pairs20
8895114636helicasethis enzyme unwinds the double helix by breaking the hydrogen bonds21
8895114637replication forkafter helicase breaks the hydrogen bonds and unwinds the DNA, the exposed DNA strands now form this22
8895114639topoisomerase(s)Because the DNA helix twists and rotates during DNA replication, another class of enzymes called DNA ______ cuts and rejoins the helix to prevent tangling.23
8895114640DNA polymeraseWhich enzyme performs the actual addition of nucleotides alongside the naked strand? Oddly enough, it can only add nucleotides to the 3' end of an existing strand.24
8895114641RNA primaseBecause DNA polymerase can only add nucleotides to the 3' end of an existing strand. This enzyme is necessary to create a short strand of RNA nucleotides called a primer. The primer is later degraded by enzymes, and the space is filled with DNA.25
8895114642leading (strand)What is the DNA strand called that is made continuously during replication, meaning the nucleotides are steadily added one after the other by DNA polymerase?26
8895114643lagging (strand)What is the DNA strand called that is made discontinuously during replication, meaning it is made in small pieces of nucleotides so that DNA polymerase can work in the 5' to 3' direction?27
88951146445 to 3 directionDirection in which DNA and RNA is synthesized.28
88951498563 to 5 directionDirection in which the template DNA is read during DNA replication.29
8895114645Okazaki fragmentsWhat are the small pieces of nucleotides added in the lagging strand so that DNA polymerase can be added in the 5' to 3' direction called?30
8895114646DNA ligaseWhich enzyme links together the Okazaki fragments to produce a continuous strand?31
8895114647semiconservativeWhen DNA is replicated, we don't end up with two entirely new molecules. Each new molecule has half of the original molecule. Because DNA replicates in this way, by conserving half of the original molecule in each of the two new ones, it is said to be what?32
8895114648helicasethe enzyme that unwinds our double helix into two strands33
8895114650DNA ligasethe enzyme that brings together the Ozakai fragments and is used during genetic engineering, to insert the DNA fragment containing the gene of interest into the plasmid.34
8895114653transcription factorsthese proteins control the transfer of genetic information from DNA to RNA by binding to specific DNA regulatory sequences which in turn will help RNA polymerase bind to the promoter.35
8895114654nucleusThe organelle in eukaryotes where transcription occurs?36
8895114655cytoplasmWhere does translation occur?37
8895114656single (stranded)Is RNA single or double stranded?38
8895114657riboseWhat is the five carbon sugar in RNA instead of deoxyribose in DNA?39
8895114658uracilWhat is the nitrogenous base in RNA that replaces thymine?40
8895114659mRNA (messenger)this type of RNA copies the information stored in the strand of DNA and carries it to the ribosome41
8895114660rRNA (ribosomal)this type of RNA is produced in the nucleolus and makes up part of the ribosomes42
8895114661tRNA (transfer)this type of RNA shuttles amino acids to the ribosomes and is responsible for bringing the appropriate amino acids into place at the appropriate time (it does this by reading the message carried by the mRNA)43
8895114662protein synthesisthe process of making proteins that involves three steps: -transcription -RNA processing -translation44
8895114663transcriptionThis step in protein synthesis involves copying the genetic code directly from DNA. The initial steps are similar to the initial steps in DNA replication. The obvious difference is that, whereas in replication we end up with a complete copy of the cell's DNA, we end up with only a partial copy in the form of mRNA.45
8895114666promoterstranscription begins these special regulatory sequences of the DNA strand; this is the area where RNA polymerase attaches.46
8895114669RNA polymerasean enzyme that brings free-floating RNA nucleotides to the DNA antisense strand during transcription47
8895114670RNA processingThis step of protein synthesis occurs only in Eukaryotes. During this step, the newly made mRNA molecule's noncoding regions are removed by a spliceosome and it is capped. This process produces a final mRNA that is shorter than the transcribed mRNA.48
8895114671exonsthe regions on the mRNA that express the code for the polypeptide to be made49
8895114672intronsthe regions on the mRNA that do not express a code for a polypeptide to be made50
8895114674spliceosomethis complex removes introns from the mRNA during RNA processing51
8895114675poly(A) tail and 5' GTP capAdded to the mRNA during RNA processing to help the mRNA: leave the nucleus, land on the ribosome and protect it from the cytosol.52
8895114677translationIn this step of protein synthesis, the mRNA attaches to a ribosome and "waits" for the appropriate amino acids to come to the ribosome. Once the methionine tRNA is attached to the P site of a ribosome, the A site can be filled by the appropriate tRNA that corresponds to the next codon. As each amino acid is brought to the mRNA, it is linked to its neighboring amino acid by a peptide bond. Termination occurs when the ribosome runs into one of the stop codons.53
8895114678codona group of three nitrogenous bases that corresponds to one of the 20 amino acids The mRNA molecule carries the message from DNA in the form of these. The genetic code is redundant, meaning that certain amino acids are specified by more than one codon.54
8895114679ribosomeWhere does translation occur?55
8895114681anticodonThis group on the end of a tRNA molecule has three nitrogenous bases that can base pair with the codon in the mRNA during translation.56
8895114686start codon AUGinitiation of translation occurs when the ribosome runs into one of these57
8895114690stop codon(s)termination of translation occurs when the ribosome runs into one of three of these58
8895114691primary structureone of the four structures of proteins: the linear sequence of the amino acids bonded together with peptide/covalent bonds.59
8895114692secondary structureone of the four structures of proteins: the twisting of the polypeptide that forms either a coil (alpha helix) or a zigzagging pattern (beta-pleated sheets) that occurs with hydrogen bonding in the backbone of the amino acid chain.60
8895114693tertiary structureone of the four structures of proteins: the polypeptide folds in a three-dimensional pattern that is stabilized by many types of bonds between the R groups of neighboring amino acids.61
8895114694quaternary structureone of the four structures of proteins: two or more polypeptides get together; not all proteins have this level of structure.62
8895114696nonsense (mutation)type of mutation in which protein synthesis is terminated early because a stop codon is created.63
8895114697missense (mutation)type of mutation in which a codon is altered and produces a different amino acid64
8895114698silent (mutation)type of mutation in which a nucleotide is selected which creates a codon that codes for the same amino acid and therefore does not change the corresponding protein sequence65
8895114699insertionthe addition of bases into DNA **can cause a frameshift66
8895114700deletionthe removal of bases from DNA **can cause a frameshift67
8895114701duplicationThis can result in an extra copy of genes and are usually caused by unequal crossing over during meiosis or chromosome rearrangements. This may result in new traits because one copy can maintain the gene's original function and one copy may evolve a new function.68
8895114702inversionThis can result when changes occur in the orientation of chromosomal regions. This may cause harmful effects if the inversion involves a gene or an important sequence involved in the regulation of gene expression.69
8895114703translocationThis can occur when a portion of two different chromosomes (or a single chromosome in two different places) breaks and rejoins in a way that the DNA sequence or gene is lost, repeated, or interrupted.70
8895114704recombinant DNAThis type of DNA is generated by combining DNA from multiple sources to create a unique DNA that is not found in nature. A common application of this technology is the introduction of a eukaryotic gene of interest (such as insulin) into a bacterium for production.71
8895114705genetic engineeringthe branch of technology that produces new organisms or products by transferring genes between cells72
8895114706restriction enzymesDuring genetic engineering, unique sequences, which flank the gene of interest in eukaryotic DNA, are recognized and cut by special enzymes called these. Using these, a cut is made in a plasmid to create a site for insertion of the eukaryotic DNA. enzymes, naturally occurring in bacteria, that cut DNA at specific recognition sites73
8895114707plasmida circular, non-essential bacterial DNA This can be cut by a restriction enzyme to create a site for insertion of the eukaryotic DNA. Once this has been cut, the eukaryotic DNA fragment containing the gene of interest is inserted into it by the enzyme DNA ligase.74
8895114709transformationduring genetic engineering, the plasmid DNA is combined with bacteria and placed under conditions that favor uptake of the DNA75
8895262208DNA cloning by Recombinant DNA transformationA process that grows bacteria in order to make copies of a gene or protein of interest.76
8895114710gel electrophoresisDNA fragments can be separated according to their molecular weight or size using this process. Because DNA and RNA are negatively charged, they migrate through the gel toward the positive pole of the electrical field. The smaller the fragments, the faster they move through the gel.77
8895114712DNA fingerprinting or profilingIn this process, DNA left at a crime scene are compared to the DNA of suspects.78
8895114714sticky endsthe uneven ends of a double-stranded DNA molecule that has been cut with a restriction enzyme an end of a DNA double helix at which a few unpaired nucleotides of one strand extend beyond the other When placed together, the gene is inserted into the plasmid creating recombinant DNA.79
8895114715virusa nonliving agent capable of infecting a cell They are considered nonliving because they require a host cell's machinery in order to replicate. It consists of two main components: a protein capsid and genetic material made of either DNA or RNA.80
8895114716lytic cyclea virus cycle in which the virus immediately starts using the host cell's machinery to replicate the genetic material and create more viral genome and protein capsids These spontaneously assemble into mature viruses and cause the cell to lyse, or break open, releasing new viruses into the environment.81
8895114717lysogenic cyclea virus cycle in which the virus incorporates itself into the host genome and remains dormant until it is triggered to switch into the lytic cycle82
8895114718retrovirusa virus that uses reverse transcriptase to convert their RNA genomes into DNA so that they can be inserted into a host genome RNA viruses have extremely high rates of mutation because they lack error-proofing mechanisms when they replicate their genomes of mutation.83
8895114719reverse transcriptasean enzyme that converts a retrovirus's RNA genomes into DNA so that they can be inserted into a host genome84
8895114720genomeall of the genetic information in an organism; all of an organism's chromosomes85
8895341010prophage or provirusviral DNA that incorporates itself into the host DNA86
8895388051frameshift mutationAn insertion or deletion of nucletodies can cause a shift in the reading frame of the mRNA87
8895397713operonA piece of DNA in prokaryotes that consists of a promoter, operator, genes in the same metabolic pathway and a terminator. It is used in gene regulation.88
8895405531repressible operonA type of operon that is typically on and a metabolite, corepressor, can turn off when enough product is present.89
8895413624inducible operonA type of operon that will control catabolic pathways and the substrate will turn on the operon.90
8895420084inducerA metabolite that interacts with the repressor to inactivate it.91
8895423446corepressorA metabolite that interacts with the repressor to activate it.92
8895433355genome and capsidSome viruses can have an envelope but all viruses must have these two components.93
8895444354cell differentiationA cell taking on a specific role because of the activation and silencing of certain genes.94
8895453701antibioticA solution that is used to identify which bacteria took in the recombinant plasmid.95

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