Brainscape's Knowledge GenomeTM

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


See full index

Microbiology > 9.5 Genetic material > Flashcards

9.5 Genetic material Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is polymorphism in mo

A

Polymorphism is ability of some microorganisms to alter their morphology, biological functions, or reproductive modes in response to environmental conditions. Pleomorphism is particularly prevalent in certain groups of bacteria, yeasts, rickettsias, and mycoplasmas, which can exhibit irregular and variant forms within the same species or strain

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

How long is bacterial chromosome

A

More then length of bacterium. DNA is supercoiled and packed with help of Nucleoid-associated proteins (NAPs)

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

What are NAPs influencing

A

They shape DNA structure and function. Aside from influencing their topology( by wrapping it) they constrain supercoiling and contribute to nucleoid formation. They regulate gene expression, participate in short-range interactions, impact processes like transcription, translation and transfer

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

Compare Archaeal chromosome and proteins with bacterial

A

Archaeal chromosome is circular and some species are polyploid( more than one copy of the chromosome per cell)
Associated proteins are different from the bacterial ones, though some have similar function. Some archaea have eukaryotic-like histones

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

What are characteristics of bacterial DNA replication

A

*semi-conservative
*bidirectional replication
*two replication forks

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

What does it semi-conservative replication mean

A

During replication, each DNA strand contains one original( parental) strand and one newly synthesized( daughter) strand. Parental strands serve as templates for the synthesis of complementary daughter strands

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

What do replication forks do

A

Unwind double-stranded DNA

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

Where does initiation of replication starts

A

At oriC( origin of replication)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Who starts replication

A

Initiator proteins. Origin recognition complex( ORC) binds to the origin marking it as a starting point

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

What do initiator proteins do

A

Break hydrogen bonds between the strands, forming replication bubble

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

Who binds to the template DNA in replication bubble

A

SSB: single stranded binding proteins

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

What happens in replication after SSB connect to the strands

A

Helicase and primase connect to replication forks and form primase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does helicase do at replication fork

A

Unwinds DNA strands

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

What does primase do

A

Attaches RNA primers which allows DNA polymerase III to synthesize DNA on the leading strand in 5’ to 3’ direction

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

What does DNA Polymerase III do on the lagging strand?

A

As RNA primase leaves primers, DNA polymerase III makes Okazaki fragments and DNA polymerase I removes DNA primers on the lagging strand and replaces it with DNA

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

Who joins Okazaki fragments together

A

DNA ligase

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

What happens at the end of replication

A

Each strand of DNA will consist of 1 parental strand and 1 daughter strand

18
Q

What is replisome

A

The replisome is a complex molecular machine responsible for DNA replication.

19
Q

What holds 2 DNA polymerase assembles and helicase together

A

Tau subunits

20
Q

What does gyrase do

A

It’s ahead of replication fork and relieves the torsional stress that builds up. It does this by introducing negative supercoils in DNA, allowing helicase to function better

21
Q

In what direction is synthesis done

A

In opposite directions

22
Q

What is ter

A

Terminus of replication. When replication fork hit it and collide, it releases 2 chromosome copies. One set of Ter sites arrest DNA forks progressing in clockwise direction, a second set arrests forks in the counterclockwise directions

23
Q

What binds to the Ter sites

A

Tus protein-a monomer. It inhibits replication fork progression by directly contacting DNA-B helicase, thus inhibiting DNA unwinding

24
Q

What are plasmids

A

Extra-chromosomal elements with self-replicating ability. They are usually dsDNA with variable length. Pool of extrachromosomal DNA for horizontal gene transfer

25
Q

Are plasmids essential

A

No, they also have simple genetic growth

26
Q

What kind of plasmids do we have

A
  1. Metabolic: confer some metabolic functions like degradation of toxins, use of compounds as a source of energy
    2.Resistance(R):antibiotics, toxic metals
    3.Virulence:production of bacteriocins, invasion of animal cell and tissues, toxins and capsule
    4.Conjugation(plasmid F)
27
Q

How can we differentiate plasmids based of their copy number

A

-Low copy number- usually 1-3 copies; they often contain genes that are toxic for the cell at higher concentrations
-High copy number-30-50

28
Q

What does the ability to transfer plasmids to daughter cell depend on

A

Copy number:
Low copy number->high risk to lose the plasmid
Because of this there was evolution of segregation syste,s

29
Q

What are ParC, ParR and ParM

A

ParC- specific sequence of the plasmid
ParR- protein that bids ParC and ParM
ParM- polymerising protein that produces filaments that allow equal partitioning

30
Q

How can plasmids coexist in the same cell

A

They have to be compatible
If two of them are incompatible one of them will be lost during cell division

31
Q

When are two plasmids incompatible

A

When they have same origin of replication. The smallest one replicates faster and will survive
They are also incompatible when they compete for the same replication factors( similar origins)

32
Q

What usually happens to plasmids

A

They diffuse into the cytoplasm of bacterial cell

33
Q

What’s transposition

A

Process by which a DNA sequence can repeatedly move from one location to another within the chromosome by insertion

34
Q

What’s transposition similar to

A

Site-specific recombination

35
Q

What are insertion sequences

A

Insertion sequences(IS)_sequencess of 700-2000 bp(base pairs) with inverted and repeated sequences at both ends(16-25bp).IS contains at least the transposase gene, which encodes the protein responsible for the site-specific recombination

36
Q

What can IS transposition induce

A

Insertional mutagenesis

37
Q

What are trasposons

A

Mobile genetic elements more complex that insertion sequences
They include other genes aside from transposase

38
Q

What do tasposons carry

A

Resistance genes to antibiotic and toxins

39
Q

What is difference between eukaryotes and prokaryotes when it comes to replication, transcription and translation

A

-Euk: Transcription and translation happen as separate moments while in prok they happen simultaneously
-In euk: transcription happens in nucleus, forming complementary mRNA from DNA . The way pre-mRNA matures before exiting nucleus is by addition of 5’cap and 3’poly-A tail.
-In euk there is splicing of introns( noncoding parts od DNA) and they are removed and only exons are left

40
Q
A

Microbiology (20 decks)

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