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Micro Biology > Chapter 8 > Flashcards

Chapter 8 Flashcards

1
Q

A) What is natural selection?

A

a

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2
Q

B) What is genotype and phenotype?

A

phenotype: observable characteristics
genotype: sequence on nucleotides

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3
Q

C) What are the two mechanisms that cause genetic change in bacteria? [Figure 8.1]

A

mutation : change in sequence of dna

horizontal gene transfer- aquisition of genes from other cells

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4
Q

1) What is the difference between an auxotroph and a phototroph?

A

depends on and requires a growth factor ( that is when mutated cells can grow)
Phototroph: do not need growth factors

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5
Q

A) What are spontaneous mutations and how do they occur?

A

mutations due to normal cell processes.

typically happen at cell division

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6
Q

B) What are base substitutions? [Figure 8.2]

A

when and incorrect nucleotide is incorperated

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7
Q

C) What are frameshift mutations and what is their possible outcome? [Figure 8.4]

A

adding or subtracting of nucleotides which can shift the reading frame resulting in non functional protiens

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8
Q

D) What are transposons and what can happen when they “jump”? [Figure 8.5 and 8.6]

A

they are jumping segments of dna. they go from one location to another cells genome.

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9
Q

A) What are induced mutations?

A

due to exposure/ environment outside of cell

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10
Q

B) What are mutagens? Give some examples. [Table 8.1]

A

things that cause mutation. radiation, chems

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11
Q

1) What can be the effect of mutagens? Give examples. [Figure 8.7]

A

nitrosoguanidine causes guanine to pair with tyrosine

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12
Q

C) What are base analogs and why can they be problematic? [Figure 8.8]

A

structurally resemble nucleobases, but have different bondign properties. problem arises is that somethimes they are used in place of nucleobases when nucleotides are made and then incorp. into dna

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13
Q

D) What do intercalating agents do and how do they do it?

A

slide in between and it causes a shift in the reading frame can cause extra base pair to be added and sometimes some nucleotides to be deleted

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14
Q

E) What are the two kinds of radiation that can cause mutations? What do they each do to DNA?

A

UV radiation: causes covalent bonds between two thymines

x ray: can cause strand breaks or changes nucleobases

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15
Q

E) What are the two kinds of radiation that can cause mutations? What do they each do to DNA?

A

a

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16
Q

B) How does proofreading work?

A

dna polymerases verify that they are accurate. They can back up and remove nucleotides not correctly bonded

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17
Q

C) How does mismatched repair work and what type of mutations does it work on? [Figure 8.10]

A

fixes errors missed by polymerase. this binds to mismatch nucleobases and directs and enzyme to degrade portion of the sugar phosphate background. This also causes another to get rid of the nucleotide and then the gap is filled.

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18
Q

D) How can oxidized guanine be repaired? [Figure 8.11]

A

glycosylase can cut out the oxidized nucleobase

19
Q

E) What are the two methods by which a thymine dimer can be repaired? [Figure 8.12]

A

phptp reactivation: takes e of light an breaks the covalent bonds between thyamine.
Excision repair: enzyme cuts out the damaged work

20
Q

F) What is SOS repair and how does it work?

A

has no proofreading ability. only activated when dna is severly damaged

21
Q

A) How and why do you use direct selection? [Figure 8.13]

A

when bacteria introduced to agar that parent cells cannot live in, but the mutant can

22
Q

B) How and why do you use indirect selection?

A

used to get auxotroph from prototrophic parent strain. use replica plating.

23
Q

1) How do you use replica plating? [Figure 8.14]

A

they take a master agar and press it to a velvet one. then take the velvet and transfer to nurient agar and gluclose salts agar. the parents can grow in both, but not the auxotrophs

24
Q

2) Why is a penicillin enrichment used? [Figure 8.15]

A

increase proportions of auxotrophs( this kills the replicating prototrophs and the non replicatin auxotrophs thrive.

25
Q

C) What are carcinogens? Give some examples.

A

cancer causing. hair dyes, cosmetics, food additives

26
Q

D) What is the Ames test used for and how does it work? [Figure 8.16]

A

when you take histadine requiring autotrophs and follow the reversion rate of them. and compare those with chemical added to others with no chem added. if chem is mutagenic the rate will be faster!

27
Q

1) How can you experimentally show horizontal gene transfer? [Figure 8.17]

A

pg 201

28
Q

E) What are the three ways for genes to be transferred? [Table 8.3]

A

Dna transformation:naked dna is taken up by the cell

conjagation: cell to cell contact and dna is transfered
transduction. virus injects dna into a cell

29
Q

F) What has to happen after gene transfer so the DNA can be passed on? [Figure 8.18]

A

must replicate the dna

30
Q

1) What is the process of homologous recombination?

8. 6 DNA-Mediated Transformation [pg. 202]

A

if the cells have simulair nuclotide sequence in a region the donated piece of dna will go to the simulair sequence of the hosts dna and take it’s place

31
Q

A) What does it mean for a cell to be competent? Why is that important?

A

in order for it to accept dna it must have a physiological state to allow it to take it up

32
Q

B) How does DNA-mediated transformation occur? [Figure 8.19]

A

double standed dna molecules line up to the

33
Q

A) What can use transduction to transfer genes from a donor to a recipient?

A

bacteriophages

34
Q

1) What are the two types of transduction and how do they differ? [Figure 8.20]

A

specialized: transfers only a few specific genes
generalyized: results from a rare error in the construction of a phage. where a phage dna enters and cuts up bacteria dna. then a piece of that dna gets intothe protien coat of the phage and it taken to another cell

35
Q

B) What are conjugative plasmids?

A

direct their own transfer from donor to recipeint cells

36
Q

1) What is the F plasmid and what does it code for? [Figure 8.21]

A

codes those required for transfer of dna

37
Q

C) What are the steps of plasmid transfer? [Figure 8.22]

A

contact: f pilus of donor binds to receptor of other cell walls
initiate transfer:fpilus retracts bringing cells together and plasmid is cut
transfering dnastrand of f plasmid enters the cell. once inside the strand serves as a template for dna synthesis.
transfer complete: now both cells are f + and can donate the plasmid

38
Q

D) How is chromosomal DNA transfer done? [Figure 8.24]

A

with hfr cells: are f plasmids which join the chrososome because a similar match. now hfr cells create an f pilus and then transfer the f plasmid along with some chromosome, but not all the f is transfered and therefore the cell injected is still f -

39
Q

A) What is the core genome and mobile gene pool of a species? [Table 8.4]

A

core: ones that make up a species.
mobile: are the varying different strains

40
Q

B) What are plasmids and what are their properties? [Table 8.5]

A

are not essential for cell survivial, but are like chromosomes they are double stranded dna.
they have varying properties, but can help them adjust to their environment.

41
Q

1) What do R plasmids do? [Figure 8.25]

A

encode resistance to antimicrobials.

42
Q

C) What are the different types of transposons and what are their characteristics? [Figure 8.26]

A

mechanism for transfering genes.
IS: encodes enzymes responsible for transposition
composite: consist of 1 or more genes flanked by IS’s they are mobile and can integrate into the new home via non holologous recombination( meaning it inserts inot dna, but doesn’t replace anything.

43
Q

E) What are genomic and pathogenetic islands?

A

a segments of dna that originated in another speices

pathogenic are latter genome islands

44
Q

E) What are genomic and pathogenetic islands?

A

a

Micro Biology (25 decks)

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