3- Bacterial Gentics

Question 1

carry genetic information In bacteria

Answer 1

Chromosome and plasmid

Question 2

What are the commensals

Give Ex

Answer 2

Harmless microbes that harbour on a living host without causing
any injury to the host eg. Normal bacterial flora

Question 3

✔️or✖️
TORCH infections
Transmissed via the birth canal without causing congenital malformation in
the baby

Answer 3

✖️
Group B Streptococcus, Neisseria gonorrhoeae, Transmissed via the birth canal

Question 4

directly bind to the sugar residues (glycolipids or
glycoproteins) on host cells.

Answer 4

Fimbriae or pili

Question 5

Enhancement of virulence is known as

Answer 5

Exaltation

Question 6

is the natural habitat in which the organism lives and multiplies.

Answer 6

reservoir

Question 7

Infections occurring in hospitals are called

Answer 7

Nosocomial infections

Question 8

Exchange of genetic information through a hollow tube from the donor cell (F+) to the recipient (F-) bacterial cell.

Answer 8

Conjugation
(One of Horizontal gene transfer types)

Question 9

✔️or✖️
Vibrio cholerae carry one chromosomes

Answer 9

✖️
Two

Question 10

virus that replicates inside a bacterial cell

Answer 10

bacteriophage

Question 11

after entering the cell, the phage DNA,
rather than replicating autonomously, can integrate into the chromosome of the host cell (prophage).
and the phage DNA replicates as part of the host’s chromosome.

Answer 11

Temperate phage

Question 12

In contrast to viral infection of vertebrate cells, in which the entire virus is taken up by the cell and its nucleic
acid is released intracellularly

The replicative cycle of prophage :

Answer 12

1-attachment of the phage to receptors
2-injection of the nucleic acid into the bacterial cell

Question 13

What are Saprophytes

Answer 13

Free-living microbes that live on dead or decaying organic
matter. Normally not cause human infection

Question 14

Infective dose of Shigella sps (cause dysentry) - 10 bacilli
✔️or✖️

Answer 14

✔️

Question 15

is the entry of bacteria into host cells, leading to spread within the host tissues.

Answer 15

Invasion
(play role in bacterial pathogenicity)

Question 16

Recount Mode of transmission

Answer 16

§ Contact eg. Sexual contact
§ Inhalation eg. secretions from the nose
§ Ingestion eg. Food borne infections
§ Inoculation eg. Animal bite
§ Blood borne infections eg. Needle prick
§ Vector borne – eg. Mosquitos
§ Ve r t i c a l transmission -(hereditary)

Question 17

What is the reservoir of spores of Anthrax bacilli

Answer 17

Soil (Non living reservoir)

Question 18

Reduction of virulence

Answer 18

Attenuation

Question 19

refers to person, animal, or object from which a microorganism is transmitted to the host.

Answer 19

Source of infection

Question 20

Define the Opportunistic pathogens

Answer 20

Microbes capable of causing disease only in immunocompromised people.

Question 21

are antibiotic like substance secreted by bacterium that inhibits
growth of other baceteria Eg. Colicin secreted by Escerichia coli

Answer 21

Bacteriocins

Question 22

Nonlysogenic bacteria can be made lysogenic by infection with a Virulent phage.
✔️or✖️

Answer 22

✖️
temperate phage.

Question 23

Transformation of DNA from one bacterium to another by a bacteriophage

Answer 23

Transduction (one type of Horizontal gene transfer)

Question 24

Recount The Applications Of Transduction
Give 1 Ex

Answer 24

Transfer drug resistance genes
(Ex.Plasmid coded pencillin resistance in Staphylococci)

Genetic engineering

Question 25

lysogenic conversion is

Answer 25

Acquisition bacteria of prophage properties

Question 26

transfer of bacteriocin producing genes is the application of ….

Answer 26

Conjugation

Question 27

Mutation occur by mutagens such as :

Answer 27

(UV rays, 5 bromouracil, alkylating agents)

Question 28

The Central Dogma of molecular biology is

Answer 28

DNA

Question 29

Plasmids are Intrachromosomal genetic elements . ✔️or✖️

Answer 29

✖️ Extra chromosomal elements

Question 30

What is the difference between Fertility plasmid Resistance plasmid Col plasmid

Answer 30

-F- plasmid codes for sex pili -R- plasmid code for resistance to antibiotics - Col plasmid codes for bacteriocin

Question 31

Give Ex for bacteriocin

Answer 31

Colicin Which is secreted by Escerichia coli

Question 32

Infection of a bacterium results in the death of the cell by lysis

Answer 32

Virulent phage

Question 33

It consists of a piece of nucleic acid encapsulated in a protective protein coat.

Answer 33

bacteriophage (phage)

Question 34

Uptake of DNA from surrounding medium by bacterial cell & incorporated into its chromosome

Answer 34

Transformation

Question 35

What the bacteria called when carry a prophage.

Answer 35

Lysogenic bacteria

Question 36

The association of prophage and bacterial cells is highly unstable ✔️or✖️

Answer 36

✖️ Stable

Question 37

Explain the destabilization steps of prophage and bacterial cells that occurs by various treatments such as exposure to ultraviolet light,

Answer 37

1- repression of prophage gene 2- excision of prophage from the host chromosome 3- production of progeny phage particles

Question 38

Define Parasites

Answer 38

Microbes that live on a host and derive ATP and harm the host

Question 39

Define Infection term

Answer 39

Process in which a pathogenic organism enters, by invades the normal anatomical barrier of the host; resulting in disease

Question 40

Re-infection is

Answer 40

subsequent infection by the same microbe.

Question 41

Iatrogenic infections is

Answer 41

Infections induced during diagnosis or treatment by physician or other health care workers

Question 42

Human reservoirs called

Answer 42

Carrier

Question 43

Bacterial toxins are of two types List their names and characteristics

Answer 43

ENDOTOXINS : - integral **part of cell wall** - produced **by gram +ive** organisms - heat liable - can **produce toxoids** EXOTOXINS : - released **from the cell** - produced **by both gram** organisms - **heat stable** - can’t produce toxoids

Question 44

Invasion produces two types of lesions List them with their Ex

Answer 44

**Generalized lesions** – produced by highly invasive pathogens e.g. **Streptococcus** **Localised lesions** – produced by less invasive pathogens e.g. **Staphylococcus**