Flashcards in chapter 7 Deck (34):
what is genome?
sum total of genetic info of a cell(bacteria)
compare the # of chromosomes of bacteria with the human cell..
bacteria= 1 chromosome HAPLOID n
human= 46 DIPLOID 2 or more cells
what types of nucleic acid make up the genome of bacteria?
what can you find in DNA in bacteria? plant and animals DNA?
plants & animals= nucleus
describe bacterial chromosome: shape, how its packaged inside the cell?
DNA. circular DNA. packaged in loops back and forth.
-chromosome is larger than bacterium
what is a nucleioid
describe bacterial plasmids.. shape, size in relation to bacterial cell
circular DNA molecules, 0.1-10% size of chromosome
also smaller than chromosome.
function of plasmids:
** not all bacteria have a plasmid
can replicate independently of chromosome, carry genes for resistance. ex: antimicrobial resistance
heavy metal resistance
explain R plasmid conjugation
-used for resistance
-bacteria has R plasmid= resistance
-both cells after conjugation become R+
describe structure of DNA in bacteria..
one long circular DNA ring----> replicated in say way with eukaryotic DNA.
how many origin of replication are there in bacterial DNA?
how many replication forks are formed during DNA replication?
only 2 replication forks are used in prokaryotes
what is the semi-conservative method of DNA replication?
conserving one original strand of DNA in each new cell..
what is gene expression?
process by which DNA directs protein synthesis.
DNA--> RNA---> Proteins
what is transcription?
process by which DNA is transferred from one bacterium to another by a virus.
what is translation?
process by which nucleotide sequence of mRNA is converted to amino acid sequence of a polypeptide.
what part of the cell transcription in prokaryotes is taking place? in eukaryotes?
what part of the cell translation in prokaryotes is taking place? in eukaryotes?
what is gene transfer?
mechanisms for uptake of DNA of create variability .
what are two types of gene transfer? describe each.
1. virtical- mother to daughter
2. horizontal- cell to cell (in same generation)
what are the 3 processes of gene transfer in bacteria? describe.
1. transformation- uptake of DNA from enviroment
2. transduction- via bacteriophage (lytic, lysogenic cycles)
3. conjegation- direct cell to cell contact
describe the process of bacterial transformation..
uptake of 'naked' DNA from enviroment.
what is a competent cell?
the ability to uptake extracellular 'naked' DNA from enviroment.
what is transduction?
involves the transfer of DNA from 1 bacterium to another with the use of a bacteriophage.
what are the two primary types of bacteriophages? how do they replicate?
1. lytic bacteriophages- replicate by the lytic cycle
2. temperate bacteriophages- replicate by lysogenic life cycle.
describe the lytic cycle..
2. DNA and bacteriophages enter, capsid stays out
3. viral DNA degrades bacterial DNA (degradation)
4. synthesis- making more parts to make more phages
5. assembly- phages are present
6. exit= killing the cell
describe lysogenic cycle.
3. prophage in chromosome(becomes part of DNA=integration!)
4. replication of chromosomes & cell division
5. inducing agent (antibiotics)
8. release or exit
describe generalized transduction.
1. phage injects its DNA
2. phage enzymes degrade host DNA
3. cell synthesizes new phages that incorporate phage DNA& mistakenly, some host DNA
4. transducing phage injects donor DNA
5. donor DNA is incorporated into recipient chromosome by recombination.
what does a transducing phage carry?
what is bacterial conjugation?
transfer genetic info via direct cell to cell contact, thru sex pilus
describe plasmid transfer of F+ conjugation.
1. donor cells attach to a recipient cell with its pilus, then pilus draws cells together
2. cells contact one another
3. one strand of plasmid DNA transfers to recipient
4. the recipient synthesizes a complementary strand to become and F+ cell; the donor synthesizes a complementary strand restoring its complete plasmid
discuss chromosomal transfer conjugation of Hfr conjugation..
1. F plasmid integrates into chromosome by recombination
2. cells join via conjugation pilus
3. portion of F plasmid partially moves into recipient cell trailing a strand of donor DNA
4. conjugation ends with pieces of F plasmid & donor DNA in recipient cell; cells synthesize complementary DNA strands
5. Donor DNA & recipient DNA recombine making a F- cell.
what are the requirements for 1. transformation 2. transduction and 3. conjugation
1. free DNA in environment and a competent recipient
3. cell to cell and F plasmid