Hmb Exam 2 Microbial Genetics

Front 1

steps of cell duplication

Back 1

prokaryotic chromosome - duplication of chromosome - continued growth of cell - division into 2 cells

Front 2

during division of cells genetic info has to be____________

Back 2

duplicated

Front 3

DNA replication

Back 3

DNA goes through transcription to form RNA wich goes through translation to make proteins (DNA encoded into proteins)

Front 4

DNA replication: Mutations

Back 4

when your gene is altered, if beneficial it will be passed to next generation, if not beneficial it will probably die.

Front 5

DNA

Back 5

deoxyribonucleic acid
blueprint for all components of the cell (fingerprint of life)

Front 6

characteristics of DNA

Back 6

blueprint can be passed from one generation to the next
the structure of DNA allows replication and transcription to be a simple process

Front 7

DNA structure

Back 7

double stranded helix
composed of nucleotides

Front 8

nucleotides in DNA contain is made up of______________

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a phosphate
sugar (deoxyribose)
nucleotide(nitrogenous) base

Front 9

2 types of DNA bases

Back 9

purines - large double ring structure
pyrimidine - smaller single ring structure

Front 10

purines

Back 10

adenine and guanine

Front 11

pyrimidines

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thymine and cytosine

Front 12

DNA has a helix structure due to the paring of purine with pyrimidine

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adenine pairs with thymine
cytosine pairs with guanine

Front 13

How DNA structure is formed

Back 13

nucleotides join to form a chain (3' hydroxyl of one joins 5" hydroxyl of other)

Front 14

DNA strands are (parallel/anti-parallel)?

Back 14

anti-parallel

Front 15

mismatched pairs of DNA is_______________

Back 15

chemically unstable

Front 16

genetic information of DNA is found in the sequence or order of the four bases________________

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A,T,C,G

Front 17

Anti-parallel DNA strand

Back 17

1 strand= 3' end and 5' end and 2 strands switched = 5' end then 3' end

Front 18

DNA replication (copying)

Back 18

controlled and regulated, involves specific components and mechanisms, accurate, fast

Front 19

supercoiling is a characteristic of_____________structures

Back 19

helical

Front 20

strands must be____________________ before replication

Back 20

uncoiled, unwound ans separated

Front 21

the unwinding of DNA is accomplished by two enzymes

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topoisomerase (unwinds the supercoils)
helicase (separates and unwinds the strands)

Front 22

2 requirements for replication

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a lot of supply of the nucleotides (A, T, C, G)
a primer - template junction

Front 23

each single strand of DNA is a______________

Back 23

template

Front 24

a portion of the DNA is paired with a short piece of RNA called a_____________

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primer

Front 25

RNA

Back 25

ribose nucleic acid

Front 26

difference between DNA and RNA

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RNA - sugar ribose, DNA - deoxyribose
RNA - uracil (pairs up with adenine) , DNA - thymine
RNA - single stranded, DNA - double stranded
RNA - not stable, DNA - stable

Front 27

DNA replication is performed by an enzymes called__________

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DNA polymerase - form new strands of DNA using the primer: template junction as a guide

Front 28

DNA replication is very accurate

Back 28

there could be some mistakes like mutations
errors occur approximately once in 10^10 pairings

Front 29

in DNA replication improperly paired bases are removed by an_______________

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exonuclease

Front 30

replication fork of DNA structure

Back 30

double helix is unwound and and strands separate.
were replication occurs

Front 31

the separated strands at the replication fork are anti-parallel and are identified as________________

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leading strand
lagging strand

Front 32

leading strand follows the way of the_____________and the lagging strand goes the opposite way

Back 32

polymerase

Front 33

Transcription

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the process by which RNA is made from DNA template

Front 34

transcription characteristics

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does not require a primer: template junction
RNA does not remain base-paired to DNA
not as accurate as DNA synthesis

Front 35

RNA polymerase has no _____________capability

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proofreading

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Translation (process by which proteins are made)

Back 36

sequence of nucleotides in mRNA is translated in to a sequence of amino acids by ribosomes

Front 37

translation is directly affected by any errors in either______________

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DNA or RNA

Front 38

translation is a highly conserved function seen in_______cells

Back 38

all

Front 39

ribosome in translation is composed of______________

Back 39

3 molecules of rRNA and over 50 proteins

Front 40

ribosome in translation adds___________amino acids per second

Back 40

2-20

Front 41

polyribosome or polysome

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more than one ribosome that moves along the same mRNA during translation

Front 42

transcription and translation are______________

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linked

Front 43

in regulation of gene expression, protein synthesis is ______________expensive and highly_____________

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energetically
regulated

Front 44

constitutive genes

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genes that are always turned on (ribosome genes)

Front 45

repressible genes

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genes are on and can be turned off

Front 46

inducible genes

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genes are off and can be turned on (stimulation of glucose transporter proteins by insulin)

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Operons

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set of genes that is regulated (bacteria)
there are many operons in chromosomes - primarily in prokaryotes

Front 48

induction

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induction turns ON genes that are OFF (repressed)

Front 49

a good example of induction is _______________ which is the metabolism of lactose

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lac operon

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repression

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turns OFF genes that are ON - very important for the conservation of energy

Front 51

repression has similar mechanisms to_________________

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feedback inhibition

Front 52

a good example of repression mechanism is________________which is an essential amino acid

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tryptophan operon

Front 53

mutions are important for non-pathogenic bacteria because

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it makes factors more virulent
become resistant to antibiotics
changes host range

Front 54

the transfer of genetic information is important for non-pathogenic bacteria because

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virulence factors are acquired
genes for anti-biotic resistance is acquired
changes in host range is acquired

Front 55

mutations and transfer of genetic information is important for bacteria because

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it causes disease!

Front 56

mutations

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changes in DNA sequence

Front 57

changes in DNA sequence can cause changes in___________

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proteins (mutations must be kept to a minimum)

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mutations can occur due to

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errors in DNA replication
chemical damage to DNA
insertions generated by tansposons

Front 59

mutations that occur due to replication errors

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point mutation
frameshift mutations

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point mutation

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simplest type of mutation - one base is switched for another

Front 61

frameshift mutation

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more drastic mutations - caused by insertion or deletion of bases

Front 62

DNA can be damaged (mutation) by

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hydrolysis
deamination
chemical mutagens (tobacco smoke)
alkylation
oxidation
base analogs
radiation

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deamination (mutation due to damage)

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loss of amino group - changes normal base into atypical base

Front 64

alkylation (mutation due to damage)

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G-C base pair changed to A-T pair

Front 65

oxidation (mutation due to damage)

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oxidation of guanine to derivative that binds to both cytosine and adenine

Front 66

base analogs (mutation due to damage)

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molecules similar to DNA bases are inserted into DNA strands during replication

Front 67

Radiation (mutation due to damage)

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cause double strand breaks in DNA

Front 68

chemical mutagens: DNA adduct

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bond between DNA and cancer causing agent, start of carcinogenesis

covalent adduct between benzopyrene (mutagen in tobacco) and DNA

Front 69

3 principal mechanisms of DNA repair

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base excision and nucleotide excision (removal and repair of altered bases) and photoreactivation (removal of damaging thymine dimers upon exposure to UV radiation)

Front 70

base excision repair

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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

Front 71

Nucleotide excision repair

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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

Front 72

genetic recombination

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genetic material is broken and joined to other genetic material (genetic variation and adaptation)

Front 73

bacteria have______chromosome, but the can obtain extra ______ in order for recombination to occur

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one
DNA

Front 74

4 ways in which genetic recombination in bacteria can occur

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transposition (within same cell)
transformation (between cells)
conjugation (between cells)
transduction (between cells)

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transposition

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caused by genetic elements called transponsons, that move from one place of the chromosome to another.

Front 76

tansponsons

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can move into or out of the chromosome and cleavage and rejoining mechanisms (cutting and pasting) - can be beneficial or detrimental

Front 77

transformation

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transfer of genetic material between cells, by naked DNA

Front 78

naked DNA

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used in transformation, is taken up by a bacterial cell and recombines with the genes of that cell ex. streptococcus pneumoniae

Front 79

transduction

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transfer of genetic material between cells, common in Gram (+) and Gram (-) bacteria

Front 80

transduction uses a _____________ for transfer

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bacterial virus (phage)

Front 81

2 forms of transduction

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generalized - random
specialized - specific

Front 82

conjugation

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transfer of material between cells, through direct contact between donor and recipient cells

Front 83

In conjugation, Gram (+) cells________to each other and Gram (-) cells use ________as a conduit for DNA transfer

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stick
pili

Front 84

in conjugation, DNA moves from the ________to the_________cell

Back 84

donor
recipient

Front 85

Conjugation involves________DNA

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plasmid

Front 86

plasmid DNA

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genetic material that is separate from the chromosome and replicates independently of chromosome