Lecture 11 and 12

Question 1

What bacteria causes respiratory disease and meningitis in infants and was the first complete genome to have its DNA sequenced?

Answer 1

Haemophilus influenzae

Question 2

How many genes were identified in Haemophilus influenzae?

Answer 2

1743 genes

Question 3

What software can be used to search for similar sequences to see what a gene does?

Answer 3

BLAST (basic local alignment search tool)

Question 4

How can the function of a gene be determined?

Answer 4

• Mutants with defective genes
  Identify effects of mutations (e.g. what metabolites are missing etc.)
  Purify proteins and test in vitro functions

Question 5

How many bacteria have had their whole genome sequenced?

Answer 5

More than 3000

Question 6

What is the size range of a bacterial chromosome?

Answer 6

112kb to 14,800kb

Question 7

What species has two circular chromosomes?

Answer 7

Vibrio species (cholera)

Question 8

Name two bacteria with linear chromosomes

Answer 8

Borrelia burgdoferi (lyme disease)
Steptomyces (antibiotic producers)

Question 9

How many genes are there per kb?

Answer 9

1 gene per 1kb

Question 10

What is a sequence of DNA coding for a sequence of amino acids long enough to be a protein?

Answer 10

Open reading frame

Question 11

What bacteria has the smallest genome?

Answer 11

Nasuia deltocephalinicola

Question 12

How big is N.deltocephalinicola ‘s genome?

Answer 12

112kb (141 genes)

Question 13

Where is N.deltocephalinicola?

Answer 13

Obligate symbiont of a leafhopper

Question 14

What is the confirmed species with the smallest genome?

Answer 14

Mycoplasma genitalium

Question 15

What species have the largest genome?

Answer 15

Sorangium cellulosum (soil organims)
Spretomyces species

Question 16

What does Haemophilus influenzae cause?

Answer 16

Respiratory tract infections

Question 17

What does staphylococcus aureus do?

Answer 17

Cause skin infections

Question 18

Typical range of bacterial genomes

Answer 18

1800-6600kb (Up to 14,800kb)

Question 19

Typical plasmid size

Answer 19

1-1000kb

Question 20

Plasmid shape?

Answer 20

Covalently closed circle, supercoiled

Question 21

How can rare mutations be identified using negative selection?

Answer 21

Replica plating

Question 22

What type of bacteria is used in the ames test?

Answer 22

his- strain of salmonella typhimurium

Question 23

What are the three mechanisms for horizontal gene transfer in prokaryotes?

Answer 23

Transformation, conjugation, transduction

Question 24

Who first observed DNA transformation?

Answer 24

F Griffith

Question 25

Who demonstarted the transforming principle is DNA?

Answer 25

Avery and McCarty

Question 26

How does transformation occur?

Answer 26

DNA binds to DNA binding protein on membrane, one strand passes in, aligns with region of homology, homologous recombination occurs

Question 27

What is conjugation?

Answer 27

Transfer of genetic material between bacteria through direct cell-to-cell contact

Question 28

What is the fertility (F) plasmid?

Answer 28

Found in -ve bacteria Circular DNA molecule Contain DNA replication regulation gene Contains tra genes that encode transfer functions (incl. sex pili synthesis)

Question 29

What name is given to the binding of proteins in outer membrane during conjugation?

Answer 29

Mating bridge

Question 30

Cells containing the integrated F plasmid are called?

Answer 30

Hfr (high frequency of recombination)

Question 31

What is transduction?

Answer 31

Bacteriophage transfers DNA from one cell to another

Question 32

What are the two methods of transduction?

Answer 32

Generalized transduction | Specialized transduction

Question 33

What is generalised transduction?

Answer 33

DNA from bacterial chromosome packed into virion instead of viral genome

Question 34

What is the resulting virion during generalised transduction called?

Answer 34

Transducing particle

Question 35

What is specialised transduction?

Answer 35

Involves intergration of phage genome into host DNA (lysogeny), adjacent chromosomal gene hitchhikes with phage DNA into virion