Micro Ch. 8 & 9

Genotype
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Terms in this set (20)
Genotype
-the sum of all the structural and regulatory genes
-includes the chromosomes and any plasmids
-includes genes that are turned off
-Not always completely expressed
---the envir. affects the expression of genes
---the expressed characteristics of the cell are its phenotype
DNA mutations
-changes in the nucleotide sequence
---the ribose phosphate back bone is stable
---are changes in the nitrogenous base sequence.
---can vary from silent to lethal depending on the resulting protein
Base substitutions
*type of mutation
-usually occur during DNA replication
-the hydrogen bonds get mixed up and the wrong base is inserted
-may result in a wrong amino acid
Base deletions or additions
*type of mutation
-Removal or addition of nucleotides
-can cause a shift in the ribosome reading frame
-Frame shifts change the resulting amino acid sequence and make nonfunctional proteins
Rate of mutations
-Spontaneously: usually during DNA replication
-increase the rate of spontaneous mutation by damaging the DNA
-cause genetic defects but can also be used for cancer chemotherapy
-rapidly replicating cells have more mutation
Chemical mutagens
-a type of mutagen
-damage nucleotide bases: HNO2 & alkylating agents
Base analogs
-a type of mutagen
-DNA polymerase thinks it is a nucleotide but it isn't it changes the codon
Intercalating agents
-A type of mutagen
-chemicals insert into the DNA btwn the bases, cause base additions
Ultraviolet radiation
-A type of mutagen
-causes thymine dimers
Light energy, proofreading, SOS system
*repair of mutations
1)uses it to repair thymine dimers
2)find damaged DNA, cut it out, and repair it
3)allows a cell to skip a damaged section without stopping replication and transcription
consequences of mutations-show genetic diversity -may improve adaption to the envir. & cause evolution -are haploid=mutations r immediately expressedDNA transfer-small circles of DNA can exist outside the chromosome or insert themselves into the chromosome; plasmids -can be transferred from one bacterial cell to another -Recombination: insertion of new, functional DNA into a cell's chromosomeTransformation*means of DNA transfer -naked DNA in the medium can be sucked up by bacteria and integrated into the genomeTransduction*means of DNA transfer -bacterial viruses can pick up bacterial DNA and transfer it to newly infected bacterial cellsConjugation*means of DNA transfer -related bacterial cells can transfer DNA through a pilus if they are touchingplasmids-small circles of extrachromosomal DNA -replicate independently -can recombine w/the chromosomes and pop back out -vary in size from a few to many genes -can be transferred btwn bacteria through conjugation -often contain optional genes like antibiotic resistance genesImportance of DNA transfer-creates new genetic info in the recipient ---functional, gives an advantage in survival, transfer is fast -often moves related genes together as a set ---may acquire several new survival factors or enzymes at onceGenetic engineering-involves manipulating genes to produce the product you wantBiotechnology-involves using microbiology and biochemistry techniques to solve problems & produce products -make scarce human proteins (insulin, growth hormones, antibodies) -Make safer vaccines -Bioremediation (use microorganisms to degrade unwanted chemical pollution)polymerase chain reaction-denature the DNA using temperature -add regulatory primers and DNA polymerase -keeps making new copies every time you cycle the temperature -make large #s of any DNA sequence ---Amplification