Exam 3 Chapter 16 A discrete unit of hereditary information consisting of a specific nucleotide Genetic information is stored in Genes and it is expressed in transcription and translation Single DNA strands are held together by covalent bonds and double stranded DNA is held by hydrogen bonds Covalent bonds are stronger DNA replicates semi conservatively Exponential scales are very important for biology and all of science Some examples are Exponential growth PH Length scales on volumes Centrifuges work by spinning and separating materials molecules by density Primers are nucleic acids used to start a DNA synthesis Repairs Nucleotide excision repair fixes damaged DNA Mismatch repair fixed mistakes in newly synthesized DNA this mechanism is able to distinguish the new DNA from the old DNA because of methyl location Chromosomes can be more or less condensed example More condensed are mitotic chromosome Less condensed are chromatin chromatins are also highly organized in the nucleus A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA or RNA in some viruses a chromasome b chromatin c genome d gene e none of the above If one strand of a DNA molecule has the sequence of bases 5 GATTACA 3 the other complementary strand would have the sequence a 5 CTAATGT 3 b 5 CUAAUGA 3 c 5 ACATTAG 3 d 5 TGTAATC 3 e 3 CTAAGTG 5 b 24 hours one day c 48 hours two days d 72 hours three days e 96 hours four days A group of cells in a laboratory experiment is known to go through one complete cell cycle every 24 hours one day If a scientist has 1000 cells how long would he or she expect to wait to have 4000 cells a 12 hours half a day An enzyme that catalyzes the elongation of new DNA for example at a replication fork by the addition of nucleotides to the 3 end of an existing chain h a DNA synthase b DNA nuclease c DNA ligase d DNA polymerase e none of the above Which of the following is true of DNA during interphase a It is in the form of highly condensed chromosomes it is called heterochromatin b It is in the form of highly condensed chromosomes and is unavailable for gene expression c It exists as chromatin it is completely uncoiled and loose d It exists as chromatin and is unavailable for gene expression e It exists as chromatin and is less condensed than mitotic chromosomes The two strands in a double stranded DNA molecule are held together by a hydrogen bonds b covalent bonds c peptide bonds d ionic bonds e Van der Waals interactions 1 DNA replication The process by which a DNA molecule is copied also called DNA synthesis Replication The leading strand is synthesized forwards the replication fork The lagging strand is synthesized away from the replication fork 2 Transformation 1 The conversion of a normal animal cell to a cancerous cell 2 A change in genotype and phenotype due to the assimilation of external DNA by a cell When the external DNA is from a member of a different species transformation results in horizontal gene transfer 3 Bacteriophage A virus that infects bacteria 4 Virus An infectious particle incapable of replicating outside of a cell consisting of an RNA or DNA genome surrounded by a protein coat capsid and for some viruses a membranous envelope 5 Double helix The form of native DNA referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape 6 Antiparallel Referring to the arrangement of the sugar phosphate backbones in a DNA double helix they run in opposite 5 3 directions 7 Semiconservative model Type of DNA replication in which the replicated double helix consists of one old strand derived from the parental molecule and one newly made strand 8 Origin of replication Site where the replication of a DNA molecule begins consisting of a specific sequence of nucleotides 9 Replication fork A Y shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized 10 Primer A short stretch of RNA with a free 3 end bound by complementary base pairing to the template strand and elongated with DNA nucleotides during DNA replication 11 DNA polymerase An enzyme that catalyzes the elongation of new DNA for example at a replication fork by the addition of nucleotides to the 3 end of an existing chain 12 Okazaki fragments A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication Many such segments are joined together to make up the lagging strand of newly synthesized DNA 13 DNA ligase A linking enzyme essential for DNA replication catalyzes the covalent bonding of the 3 end of one DNA fragment such as an Okazaki fragment to the 5 end of another DNA fragment such as a growing DNA chain DNA ligase connects two DNA strands covalently 14 Mismatch repair The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides 15 Nuclease An enzyme that cuts DNA or RNA either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides 16 Telomere The tandemly repetitive DNA at the end of a eukaryotic chromosome s DNA molecule Telemers are DNA sequence at the end of chromosomes that get shorter each time the chromosome is replicated 17 Nucleoid A non membrane bounded region in a prokaryotic cell where the DNA is concentrated 18 Chromatin The complex of DNA and proteins that makes up eukaryotic chromosomes When the cell is not dividing chromatin exists in its dispersed form as a mass of very long thin fibers that are not visible with a light microscope 19 Heterochromatin Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed 20 Euchromatin The less condensed form of eukaryotic chromatin that is available for transcription Chapter 17 All of life more or less uses the same genetiv code Because of that we can transfer genes beteween orrganisms by genetic engineering RNA is first synthesized as primary transcript which can be processed to form mRNA Exons are the parts of a transcript that are processed Gene expression is a process by which the DNA sequence of a gene is used as a template for the synthesis of a protein sequence Transfer RNA determines the genetic code Translation Ribosomes carry out translation tRNA determines the genetic code there is 3 sites on the ribosome E siste exit P site peptide and A site amino acid more than one ribosome can process a single mRNA molecule at a time
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