Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 222 > Ch. 8 Microbial Genetics > Flashcards

Ch. 8 Microbial Genetics Flashcards

1
Q

central dogma of biology

A

DNA (transcribes into) mRNA (translates into) protein (shaped into its) function.

Mutations affect DNA, which alters mRNA, which alters proteins, which alters function.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

gene

A

sequence of bases in DNA that codes for a functional protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

allele

A

a specific version or form of a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

genotype

A

all alleles in an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

phenotype

A

the physical expression of a genotype; characteristics of an organism determined by genetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

vertical gene transmission

A

parent cell –> replication –> fission (daughter cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

horizontal gene transmission

A

recombination; gene transmission between cells of the same generation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

DNA chemical components

A
  • sugar phosphate backbone
  • nitrogenous bases (GC - TA)
  • “twisted ladder” structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

DNA Polymerase

A

sets down matching nitrogenous bases, breaking H-bonds and synthesizing new strands across from the template strands.

in a bacteria, once it goes fully around the circle (circular DNA), there are 2 full identical DNA molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

replication fork

A

where unwinding takes place; bidirectional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

DNA transcription

A

DNA –> mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

differences between DNA and RNA

A
  • different sugar in backbone (ribose instead of deoxyribose)
  • Uracil instead of Thymine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

RNA Polymerase

A

1) connects at the promoter
2) adds complementary base pairings of RNA
3) reaches the terminator and releases; Polymerase dissociates and mRNA is released.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

promoter

A

beginning of a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

terminator

A

end of a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

translation

A

mRNA –> amino acid sequence of a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

codons

A

3 bases coding for a specific amino acid

AUG: start codon (methianine)
UAA, UAG, UGA: stop codon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

steps of translation

A

1) large and small ribosomal units (rRNA) come together on the mRNA start codon
2) start codon enters the P-site
3) tRNA with the anticodon and amino acid bonding sit for that specific codon pairs (in start, methianine)
4) the next tRNA enters the A-site, bringing along its amino acid. peptide bond forms between amino acids by a ribozyme. P-site tRNA and aa separate. (CLEAVE PEPTIDE CHAIN FROM P-SITE, ATTACH TO A–SITE, TRANSLOCATE, REPEAT)
5) ribosome translocates 3 bases down. P-site codon and tRNA moves to E-site; A-site codon and tRNA move to P-site
6) new tRNA arrives with a new amino acid. empty tRNA from the E-site is ejected and may be reused. repeat until stop codon is reached. (CLEAVE PEPTIDE CHAIN FROM P-SITE, ATTACH TO A–SITE, TRANSLOCATE, REPEAT)
7) stop codon - no matching tRNA; subunits, tRNA, and polypeptide all dissociate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

in what type of cell can coupled transcription and translation occur (translation of proteins as an mRNA is being transcribed)

A

prokaryotes. Eukaryotes need to have mRNA removed from the nuclear membrane to the rRNA in the cytoplasm; prokaryotes do not have a nuclear membrane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

operon does what?

A

regulates bacterial gene expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

pre-transcriptional control

A

are you going to make mRNA or nah

22
Q

constitutive genes/enzymes

A

always produced

AKA housekeeping enzumes

23
Q

operon consists of..

A

1) promoter
2) operatory
3) structural genes (code for enzymes that work together and are regulated together)

24
Q

not part of operon, but produces repressor protein:

A

regulatory or I gene (I stands for inhibitory)

25
Q

2 kinds of operons

A

inducible operon

repressible operon

26
Q

inducible operon

A

default is: OFF

inducer turns it: ON

27
Q

repressible operon

A

default is: ON

repressor turns it: OFF

28
Q

Lac operon

A

when lactose is absent, these genes are OFF, thus enzymes to catabolize lactose are not produced.
When lactose is present, allolactose binds to the inducer, thus turning ON these structural genes, thus, catabolizing enzymes are produced.

INDUCIBLE OPERON

29
Q

trp operon

A

when tryptophan is absent, these genes are ON, thus producing tryptophan.
when tryptophan is present, it acts as a corepressor (activating the protein to bind to the O-site), thus turning OFF these structural genes.

REPRESSIBLE OPERON

30
Q

mutations

A

permanent change in DNA sequence

31
Q

mutagens

A
  • radiation

- chemical

32
Q

Bruce Ames

A

created the Ames test for using bacteria to screen for mutagens; if a chemical is mutagenic, it may be carcinogenic and further testing can ensue.

33
Q

Ames test

A

1) his- salmonella culture is grown in minimal culture (only has glucose and some minerals). This salmonella cannot grow since it does not have access to histidine
2) a substance is added to the culture along with rat liver extract; if the substance mutates from his- to his+, it is mutagenic

34
Q

why is liver extract used in the Ames test?

A

most carcinogenic substances only express their carcinogenic nature after being processed in the liver

35
Q

horizontal gene transfer methods

A
  • transformation
  • conjugation
  • transduction
36
Q

plasmids

A

extra circular chromosomal DNA (separate from the main chromosome)

  • do NOT carry housekeeping genes
  • various kinds (a plasmid can be more than one kind)
37
Q

dissimilation plasmid

A

contain genes for breaking down unusual carbon sources

38
Q

increased virulence plasmids

A

it’s in the name, bro

39
Q

R factor

A

increase resistance to different antibiotics (spread of antibiotic resistance)

40
Q

conjugative

A

can be transmitted from donor to receptor (pilus)

41
Q

transformation was discovered by…

A

Frederick Griffith (1928)

42
Q

steps of transformation

A

1) recipient cell (competent) takes up donor DNA
2) donor DNA aligns with complementary DNA
3) recombination occurs between donor DNA and recipient DNA (occurs during DNA repair; new allele or entirely new properties!)

43
Q

conjugation methods

A

A) sex pilus (gram negative)
B) mating bridge (gram positive)

both are hollow tubes

44
Q

donor and recipient in conjugation

A

F+ (donor)

F- (recipient)

45
Q

F-factor

A

fertility factor; makes a cell F+ and codes for a pilus or bridge

46
Q

conjugation steps

A

1) pilus or bridge forms;
2) F+ attaches to F- through signals
3) DNA in F-fact replicated and passed through the pilus/bridge; resulting in 2 F+ cells
4) Brownian motion breaks pilus/bridge

F+ + F- => F+ + F+

47
Q

Hfr cell

A

high frequency of recombination cell; when F-factor becomes integrated into chromosome

48
Q

Hfr cell passes what to its recipient?

A

part of its chromosome! a piece of the F-factor translates, as well as part of its main chromosome. Brownian motion breaks the bridge before it can complete the circle and pass the entire F-factor, and thus the recipient cell remains F- as it does not have the F-factor. However, it has received some new genes!

49
Q

Hfr “equation”

A

Hfr + F- => Hfr + F- (w some new DNA)

50
Q

Can Hfr return to being just F+?

A

Yus

51
Q

generalized transduction

A

1) phage (protein coat, DNA core) infects donor bacteria by injecting its DNA
2) bacteria becomes “phage-producing factory”, creating phage DNA and proetins. the bacterial chromosome is broken into pieces
3) errors – phage capsids may pack bacterial DNA instead of phage DNA
4) donor cell lyses and releases phages, some of which contain bacterial DNA
5) phage with bacterial DNA infects recipient bacteria
6) recombination may occur; leading to a cell with a different genotype (may help it resist the bacteria? who knows)

BIOL 222 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions