Bacterial genome Flashcards

1
Q

What is a gene?

A

Region of DNA (RNA in some viruses) encoding a discrete hereditary characteristic

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2
Q

What do genes include?

A

Coding sequence
Non-coding (regulatory) sequence
Introns (eukaryotes)

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3
Q

What does the bacterial genome determine?

A

Phenotype (how bacterium looks and functions)

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4
Q

How are genes organized?

A

Organized into chromosomes and extra-chromosomal genetic elements (plasmids)

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5
Q

True or false: Bacteria is diploid

A

Bacteria is haploid

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6
Q

How are bacterial chromosomes kept in nucleoid?

A

Highly compacted
Kept in nucleoid thanks to nucleoid associated proteins (HU protein)

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7
Q

What is the size of chromosomes in bacteria?

A

0.6 Mb (base pairs) to 10 Mb

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8
Q

What is the size of plasmids in bacteria?

A

1 kb > 1 Mb

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9
Q

True or false: Bacterial chromosomes and plasmids are solely circular

A

False: Can be circular and linear

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10
Q

What is negative supercoiling?

A

DNA double helix is underwound - strands separate more easily

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11
Q

What is positive supercoilingg?

A

DNA double helix is overwound - strands harder to separate

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12
Q

How is supercoiling regulated?

A

Regulated in cell by topoisomerase enzymes like DNA gyrase

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13
Q

Why is relaxing positive supercoiling important?

A

Important for replication and transcription

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14
Q

How is the replicating prokaryotic genome process?

A

DNA replication proceeds in both directions until replication complexes meet

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15
Q

What is the difference between chromosomes and plasmids?

A

Chromosomes -> carry essential genes
Plasmids -> carry non-essential genes

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16
Q

What are transposons?

A

Knock out genes and stop them from working
Capable of moving from one site to another

17
Q

What is the copy and paste transposition?

A

Copy of itself (replicative)

18
Q

What are HGTs?

A

Transposition from chromosome to plasmid

19
Q

What is the cut and paste transposition?

A

Cuts out and moves elsewhere (non-replicative)

20
Q

What are bacteriophages?

A

Virus that infects only bacteria
Protein capsid surrounding nucleic acid genome

21
Q

What are the two types of bacteriophages?

A

Lytic or lysogenic

22
Q

What is a lytic phage?

A

Replicates then lyses (destroys) their host

23
Q

What is lysogenic phage?

A

Insert into genome and passively replicated with chromosomes

24
Q

What are prophages?

A

Lysogenic phage inserted into genome that carry important genes

25
Q

Are prophages important for HGTs?

A

Yes, are important vehicles for HGT