Chapter 3 - Genetics Flashcards Preview

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151

termination

(translation)

1. stop codon arrives in A site

2. signal ribsoome to terminate translation

3. DO NOT CODE FOR AMINO ACIDS

4. frequently, polyribosome formed

152

polyribosome formation

(translation - termination)

many ribosomes simultaneously translate a single mRNA molecule forming a polyribosome

occurs during termination 

153

protein primary formation following termination

upon release from ribosome, protein immediately assumes conformation

conformation determined by primary sequence of amino acids

154

Cytoplasmic Inheritance

(molecular genetics)

heredity systems exist outside nucleus

DNA found in chloroplasts, mitochondria etc

cytoplasmic genes interact with nuclear genes ---> determine characteristics of organelles

155

plasmids

(cytoplasmic inheritance)

cytoplasmic DNA

contain 1+ genes

regulate drug resistance in micro-organisms

156

Bacterial genome

structure and location

(Bacterial genetics)

single circular chromosome located in nucleoid

may also contain plasmids

157

plasmids

(bacteria)

small circular rings of DNA 

contain accessory genes

158

episomes

plasmids

capable of intergraiton into bacterial genome

159

replication

(bacterial genetics)

begins at unique origin

proceeds in both directions simultaneously

160

Genetic Variance

3 mechanisms

(bacterial genetics)

 

transformation

conjugation

transduction

161

method of bacterial replication

binary fission

 

162

binary fission

method of bacteria cells replication

asexual process

163

transformation

(genetic variance - bacterial genetics)

foreign chromosome fragment (plasmid) incorporated into bacterial chromosome 

via recombination

164

conjugation

genetic variance - bacterial genetics

"sexual mating" in bacteria

transfer of genetic material between two bacteria that are temporarily joined

 

165

conjugation

mechanism

genetic variance

bacterial genetics

cytoplasmic conjugation bridge formed between two cells

genetic material transferred from donor male (+) to recipient female (-)

bacteria must contain plasmids - sex factors

166

Sex Factor

F factor

Conjugation

Genetic Variation

Bacterial Genetics

present in E. coli

bacteria possessing it - F+

bacteria void - F-

during conjugation bw F+/F-

F+ replicates F factor, donates copy to recipient --> converts to F+

167

Sex Factor and transfer

Conjugation

Genetic Variance

Bacterial Genetics

genes that code for various characteristics

e.g. antibody resistance

may be found on plasmids and transferred to recipient cells along with sex factors (i.e. F+)

168

Consequences of Conjugation + Sex factors

sex factor may become integrated into bacterial genome

during - entire bacterial chromosome replicates and begins to move from donor cell to recipient cell

conjugation bridge breaks before entire chromosome transferred

bacterial genes may recombine with bacteria genes already present to form novel genetic combinations

 

 

169

170

Hfr cells

 bacterium with a conjugative plasmid (often the F-factor) integrated into its genomic DNA

171

Transduction

(genetic variation - bacterial genetics)

fragments of bacterial chromosome accidentally become packaged into viral progeny produced during viral infection

virions may infect other bacteria 

introduce new genetic arrangements through recombination with the new host cell's DNA

the closer two genes are to one another on a chromosome the mroe likely they will be to transduce together

172

Recombination

genetic variation - bacterial genetics

occurs when linked genes are separated

via breakage and rearrangements of adjacent regions of DNA

when organisms carrying different genes or alleles for the same traits are crossed

173

regulation of gene expression allows prokaryotes to control their

metabolism

174

regulation of transcription is based on accessiblity of 

RNA polymerase

175

RNA polymerase

enzyme

3' --->

necessary for constructing RNA chains using DNA genes as templates (transcription)

176

gene regulation enables...

(bacterial genetics)

prokaryotes to control metabolism

 

177

another word for gene expression

(bacterial genetics)

transcription

178

regulation of transcription based on..

(bacterial genetics)

accessbility of RNA polymerase to the genes being transcribed

179

regulation of transcription directed by..

(bacterial genetics)

operon

180

operon

(bacterial genetics)

consists of

structural genes

operator gene

promoter gene