Prokaryotes inside and out

Question 1

What is 5 things are required for a pathogenic bacteria to cause disease?

Answer 1

1. Encounter and gain access to host
2. Evade defence mechanism
3. Colonise and maintain colony (replicate)
4. Result in host toxicity or damage (e.g TB)
5. Potential for spread of infection (not always the case)

Question 2

What are the key features of a prokaryote cell?

Answer 2

• Structurally simpler and smaller than eukaryotic cells
• No membrane bound organelles e.g mitochondria, endoplasmic reticulum, golgi, no nucleus
• Singular circular DNA genome (some exceptions)
• Plasmid DNA free in cytoplasm
• Enzymes and ribosomes free in cytoplasm
• Rigid, complex cell wall with appendages
• Extreme adaptation to environment (pH, enzymes, viscosity)

Question 3

What is the flagella used for?

Answer 3

Used for motility and as a sensory organelle

Question 4

What are fimbriae and pili used for?

Answer 4

Cell adhesion

Question 5

What is the importance of sex pili?

Answer 5

For movement of DNA between cells by conjugation

Question 6

Capsule surrounds certain gram+ve and gram-ve bacteria. TRUE OR FALSE?

Answer 6

TRUE

Question 7

What is the capsule consisted of ?

Answer 7

Polysaccharides

Question 8

Does the capsule aid in cell adherence?

Answer 8

YES

Question 9

Capsule is not currently targeted by treatment. TRUE OR FALSE?

Answer 9

TRUE

Question 10

The capsule provides protection from neutrophils. TRUE OR FALSE?

Answer 10

TRUE

Question 11

What is the peptidoglycan made up of?

Answer 11

Disaccharides and amino acids

Question 12

The cell wall of a bacteria does not contain a peptidoglycan layer. TRUE OR FALSE/

Answer 12

FALSE

Question 13

Cell wall is a common target for antibacterial therapy. TRUE OR FALSE?

Answer 13

TRUE

Question 14

What is the periplasm?

Answer 14

Aqueous gel like region between to membranes of gram negative bacteria

Question 15

Periplasm contains enzymes associated with nutrient acquisition and transport and contains defence enzymes used to resist antibiotics. TRUE OR FALSE?

Answer 15

TRUE

Question 16

What structures does the cell wall in a gram positive bacteria contain in its outer membrane?

Answer 16

Lipopolysaccharides and Braun’s lipoprotein which anchors the outer membrane

Question 17

What is the function of the outer membrane of a gram negative bacteria?

Answer 17

Porins allow passive diffusion of molecules into the periplasmic space

Question 18

LPS is a lipid A embedded in membrane, is a core polysaccharide and contains KDO. TRUE OR FALSE?

Answer 18

TRUE

Question 19

LPS is antigenic and varies between cells. TRUE OR FALSE?

Answer 19

TRUE

Question 20

There is a net negative charge over cell surface of gram negative bacteria. TRUE FALSE?

Answer 20

TRUE

Question 21

Gram negative bacteria can be decolourized to accept counter stain (Safranin or Fuchsine); stain red. TRUE OR FALSE?

Answer 21

TRUE

Question 22

Gram positive bacteria retain crystal violet dye and stain dark violet or purple. TRUE OR FALSE?

Answer 22

TRUE

Question 23

What are the three types of active transport in bacteria?

Answer 23

1. PMF driven transport
2. ABC transport (ATP binding cassette)
3. Group translocation

Question 24

What does the cytoplasmic membrane contain?

Answer 24

Cytoplasm which regulates transport

Question 25

The cytoplasmic membrane is the site of assembly of cell wall components. TRUE OR FALSE?

Answer 25

TRUE

Question 26

The nucleoid is associated with histone proteins. TRUE OR FALSE?

Answer 26

FALSE

Question 27

The Nucleoid is circular, supercoiled and double stranded. TRUE OR FALSE?

Answer 27

TRUE

Question 28

Where is the prokaryote DNA found?

Answer 28

In the plasmids

Question 29

What are plasmid and what do they contain?

Answer 29

They are small loops of extrachromosomal DNA and may contain genes that are expressed in response to certain situations.

Question 30

Plasmids can be used to transfer genes between cells, such as resistance to antibiotics. TRUE OR FALSE?

Answer 30

TRUE

Question 31

The plamids cannot be incorporated into the chromosomes. TRUE OR FALSE?

Answer 31

FALSE

Question 32

Single DNA strand is transeferd between cells by conjugation using the rolling circle replication. TRUE OR FALSE?

Answer 32

TRUE

Question 33

Where are the ribosomes located in a prokaryote cell?

Answer 33

They are found free in the cytoplasm

Question 34

What type of ribosomes binds to mRNA, small 30S subunit or large 50S subunit?

Answer 34

30S subunit

Question 35

Large 50S subunit competes with the 70s ribosome. TRUE OR FALSE?

Answer 35

TRUE

Question 36

What type of bacteria is Streptococcus pneumonia and what does it cause?

Answer 36

Gram positive and causes respiratory infections

Question 37

What type of bacteria is E.coli and what areas of the body can it be found or cause disease?

Answer 37

Gram negative and it can be found in urinary and nosocomal infections

Question 38

E.coli does not contain a flagella and fimbriae. TRUE OR FALSE?

Answer 38

FALSE

Question 39

E.Coli 0157:H7 is a gram negative bacteria that has no flagella or fimbriae, works anaerobically/conditions and causes haemorragic disease dut ot its toxic secretion. TRUE OR FALSE?

Answer 39

TRUE

Question 40

What type of bacteria is Clostridium difficile, what conditions does it work in and where is it found?

Answer 40

Gram positive, works in anaerobic conditions and froms part of normal gut microflora

Question 41

What disease does Clostridium difficile bacteria cause?

Answer 41

Causes inflammation colitis and abdominal disease

Question 42

What type of bacteria is Helicobacter pylori and what type of disease is it associated with?

Answer 42

Gram negative spirals, moves using flagella and is associated with chronic superficial gastritis

Question 43

What type of bacterium is mycobacterium tuberculosis and where foes it reside?

Answer 43

Gram positive, moves using flagella and is able to reside inside tissues due to hydrophobic cell wall

Question 44

What type of bacterium is staphylococcus aureus and what dieases does it cause?

Answer 44

Gram positive cocci, it causes a variety of infcetions and disease

Question 45

Which bacteria is associated with causing MRSA?

Answer 45

staphylococcus aureus