Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
86 Cards in this Set
- Front
- Back
steps of cell duplication
|
prokaryotic chromosome - duplication of chromosome - continued growth of cell - division into 2 cells
|
|
during division of cells genetic info has to be____________
|
duplicated
|
|
DNA replication
|
DNA goes through transcription to form RNA wich goes through translation to make proteins (DNA encoded into proteins)
|
|
DNA replication: Mutations
|
when your gene is altered, if beneficial it will be passed to next generation, if not beneficial it will probably die.
|
|
DNA
|
deoxyribonucleic acid
blueprint for all components of the cell (fingerprint of life) |
|
characteristics of DNA
|
blueprint can be passed from one generation to the next
the structure of DNA allows replication and transcription to be a simple process |
|
DNA structure
|
double stranded helix
composed of nucleotides |
|
nucleotides in DNA contain is made up of______________
|
a phosphate
sugar (deoxyribose) nucleotide(nitrogenous) base |
|
2 types of DNA bases
|
purines - large double ring structure
pyrimidine - smaller single ring structure |
|
purines
|
adenine and guanine
|
|
pyrimidines
|
thymine and cytosine
|
|
DNA has a helix structure due to the paring of purine with pyrimidine
|
adenine pairs with thymine
cytosine pairs with guanine |
|
How DNA structure is formed
|
nucleotides join to form a chain (3' hydroxyl of one joins 5" hydroxyl of other)
|
|
DNA strands are (parallel/anti-parallel)?
|
anti-parallel
|
|
mismatched pairs of DNA is_______________
|
chemically unstable
|
|
genetic information of DNA is found in the sequence or order of the four bases________________
|
A,T,C,G
|
|
Anti-parallel DNA strand
|
1 strand= 3' end and 5' end and 2 strands switched = 5' end then 3' end
|
|
DNA replication (copying)
|
controlled and regulated, involves specific components and mechanisms, accurate, fast
|
|
supercoiling is a characteristic of_____________structures
|
helical
|
|
strands must be____________________ before replication
|
uncoiled, unwound ans separated
|
|
the unwinding of DNA is accomplished by two enzymes
|
topoisomerase (unwinds the supercoils)
helicase (separates and unwinds the strands) |
|
2 requirements for replication
|
a lot of supply of the nucleotides (A, T, C, G)
a primer - template junction |
|
each single strand of DNA is a______________
|
template
|
|
a portion of the DNA is paired with a short piece of RNA called a_____________
|
primer
|
|
RNA
|
ribose nucleic acid
|
|
difference between DNA and RNA
|
RNA - sugar ribose, DNA - deoxyribose
RNA - uracil (pairs up with adenine) , DNA - thymine RNA - single stranded, DNA - double stranded RNA - not stable, DNA - stable |
|
DNA replication is performed by an enzymes called__________
|
DNA polymerase - form new strands of DNA using the primer: template junction as a guide
|
|
DNA replication is very accurate
|
there could be some mistakes like mutations
errors occur approximately once in 10^10 pairings |
|
in DNA replication improperly paired bases are removed by an_______________
|
exonuclease
|
|
replication fork of DNA structure
|
double helix is unwound and and strands separate.
were replication occurs |
|
the separated strands at the replication fork are anti-parallel and are identified as________________
|
leading strand
lagging strand |
|
leading strand follows the way of the_____________and the lagging strand goes the opposite way
|
polymerase
|
|
Transcription
|
the process by which RNA is made from DNA template
|
|
transcription characteristics
|
does not require a primer: template junction
RNA does not remain base-paired to DNA not as accurate as DNA synthesis |
|
RNA polymerase has no _____________capability
|
proofreading
|
|
Translation (process by which proteins are made)
|
sequence of nucleotides in mRNA is translated in to a sequence of amino acids by ribosomes
|
|
translation is directly affected by any errors in either______________
|
DNA or RNA
|
|
translation is a highly conserved function seen in_______cells
|
all
|
|
ribosome in translation is composed of______________
|
3 molecules of rRNA and over 50 proteins
|
|
ribosome in translation adds___________amino acids per second
|
2-20
|
|
polyribosome or polysome
|
more than one ribosome that moves along the same mRNA during translation
|
|
transcription and translation are______________
|
linked
|
|
in regulation of gene expression, protein synthesis is ______________expensive and highly_____________
|
energetically
regulated |
|
constitutive genes
|
genes that are always turned on (ribosome genes)
|
|
repressible genes
|
genes are on and can be turned off
|
|
inducible genes
|
genes are off and can be turned on (stimulation of glucose transporter proteins by insulin)
|
|
Operons
|
set of genes that is regulated (bacteria)
there are many operons in chromosomes - primarily in prokaryotes |
|
induction
|
induction turns ON genes that are OFF (repressed)
|
|
a good example of induction is _______________ which is the metabolism of lactose
|
lac operon
|
|
repression
|
turns OFF genes that are ON - very important for the conservation of energy
|
|
repression has similar mechanisms to_________________
|
feedback inhibition
|
|
a good example of repression mechanism is________________which is an essential amino acid
|
tryptophan operon
|
|
mutions are important for non-pathogenic bacteria because
|
it makes factors more virulent
become resistant to antibiotics changes host range |
|
the transfer of genetic information is important for non-pathogenic bacteria because
|
virulence factors are acquired
genes for anti-biotic resistance is acquired changes in host range is acquired |
|
mutations and transfer of genetic information is important for bacteria because
|
it causes disease!
|
|
mutations
|
changes in DNA sequence
|
|
changes in DNA sequence can cause changes in___________
|
proteins (mutations must be kept to a minimum)
|
|
mutations can occur due to
|
errors in DNA replication
chemical damage to DNA insertions generated by tansposons |
|
mutations that occur due to replication errors
|
point mutation
frameshift mutations |
|
point mutation
|
simplest type of mutation - one base is switched for another
|
|
frameshift mutation
|
more drastic mutations - caused by insertion or deletion of bases
|
|
DNA can be damaged (mutation) by
|
hydrolysis
deamination chemical mutagens (tobacco smoke) alkylation oxidation base analogs radiation |
|
deamination (mutation due to damage)
|
loss of amino group - changes normal base into atypical base
|
|
alkylation (mutation due to damage)
|
G-C base pair changed to A-T pair
|
|
oxidation (mutation due to damage)
|
oxidation of guanine to derivative that binds to both cytosine and adenine
|
|
base analogs (mutation due to damage)
|
molecules similar to DNA bases are inserted into DNA strands during replication
|
|
Radiation (mutation due to damage)
|
cause double strand breaks in DNA
|
|
chemical mutagens: DNA adduct
|
bond between DNA and cancer causing agent, start of carcinogenesis
covalent adduct between benzopyrene (mutagen in tobacco) and DNA |
|
3 principal mechanisms of DNA repair
|
base excision and nucleotide excision (removal and repair of altered bases) and photoreactivation (removal of damaging thymine dimers upon exposure to UV radiation)
|
|
base excision repair
|
repair enzymes look for damaged bases, the damaged base is removed (excised) from the double helix and a DNA polymerase fills the gap and a DNA ligase repairs the break in the strand
|
|
Nucleotide excision repair
|
repair enzymes look for distortions in the helix, a short secretion of DNA surrounding the distortion is removed, DNA polymerase fills in removed sections and DNA ligase repairs the break in the strand
|
|
genetic recombination
|
genetic material is broken and joined to other genetic material (genetic variation and adaptation)
|
|
bacteria have______chromosome, but the can obtain extra ______ in order for recombination to occur
|
one
DNA |
|
4 ways in which genetic recombination in bacteria can occur
|
transposition (within same cell)
transformation (between cells) conjugation (between cells) transduction (between cells) |
|
transposition
|
caused by genetic elements called transponsons, that move from one place of the chromosome to another.
|
|
tansponsons
|
can move into or out of the chromosome and cleavage and rejoining mechanisms (cutting and pasting) - can be beneficial or detrimental
|
|
transformation
|
transfer of genetic material between cells, by naked DNA
|
|
naked DNA
|
used in transformation, is taken up by a bacterial cell and recombines with the genes of that cell ex. streptococcus pneumoniae
|
|
transduction
|
transfer of genetic material between cells, common in Gram (+) and Gram (-) bacteria
|
|
transduction uses a _____________ for transfer
|
bacterial virus (phage)
|
|
2 forms of transduction
|
generalized - random
specialized - specific |
|
conjugation
|
transfer of material between cells, through direct contact between donor and recipient cells
|
|
In conjugation, Gram (+) cells________to each other and Gram (-) cells use ________as a conduit for DNA transfer
|
stick
pili |
|
in conjugation, DNA moves from the ________to the_________cell
|
donor
recipient |
|
Conjugation involves________DNA
|
plasmid
|
|
plasmid DNA
|
genetic material that is separate from the chromosome and replicates independently of chromosome
|