Topic 2.2

Question 1

Name features of a Prokaryotic cell

Answer 1

Nucleoid, Plasmid, Capsule, Pili, Cell Wall, Cytoplasm, Flagellum, Ribosomes

Question 2

What’s the purpose of a Capsule?

Answer 2

Helps the cell cling to other cells and surfaces, and stops the cell from drying out

Question 3

What’s the purpose of the Cells Wall?

Answer 3

Maintains shape and proteins in the interior

Question 4

What’s the purpose of the Cell Membrane?

Answer 4

Controls what goes in and out of the cell

Question 5

What’s the purpose of the cytoplasm?

Answer 5

Houses and maintains optimum environment for organelles in the cell

Question 6

What’s the purpose of the flagellum?

Answer 6

Used for movement of the cell

Question 7

What’s the purpose of Pili?

Answer 7

Used for attachment to surfaces

Question 8

What’s the purpose of ribosomes?

Answer 8

To synthesise proteins

Question 9

What’s the purpose of plasmids?

Answer 9

To carry bacterial DNA into non-bacterial cells

Question 10

What’s the purpose of a Nucleoid?

Answer 10

Regulates growth, reproduction and controls the function of the cell

Question 11

What are the main 3 physicalities of bacteria?

Answer 11

Spherical (coccus), Rod (bacillus), Spiral (spirillum)

Question 12

What are the two types of bacteria?

Answer 12

*Gram-Negetive
*Gram-Posotive

Question 13

What’s the difference between Gram- to Gram+?

Answer 13

*Lipid bilayer forming BOTH cytoplastic and outer membrane
*Lipoproteins and Lipopolysaccharides
*Thin peptidoglycen layer between outer and cytoplastic membrane

Question 14

Whats the difference between Gram+ to Gram-

Answer 14

*Lipid bilayer forming ONLY cytoplastic membrane
*Thick outer layer of peptidoglycen

Question 15

What Gram are penicillins and polymyxins used on?

Answer 15

Penicillins- Gram+
Polymixibs- Gram-

Question 16

What does penicillin do to Gram+?

Answer 16

Inhibits the cross linking of the peptidoglycen, did functioning the cell wall- killing the cell

Question 17

What does Polymyxins do on Gram-?

Answer 17

Interact with phospholipids, destroying outer membrane structure

Question 18

What are antibiotics?

Answer 18

Medicine to treat bacteria infections

Question 19

How do antibiotics work?

Answer 19

They target the cell wall+ membrane, genetic material, cellular enzymes or 70S ribosomes

Question 20

What technique is used to identify bacteria?

Answer 20

Gram staining

Question 21

What are Obligate aerobes?

Answer 21

Organisms that need oxygen for respiration

Question 22

What are Obligate anaerobes?

Answer 22

Organisms that respire in the absence of oxygen and killed by oxygen

Question 23

What are Facultative anaerobes?

Answer 23

Organisms that use oxygen for respiration but can respire and survive if it’s not available

Question 24

Why must fresh cultures be used for Gram staining?

Answer 24

Older cells dont absorb the stain as much so won’t be as visible

Question 25

How are cells fixed?

Answer 25

By putting the microscope slide under a Bunsen burner

Question 26

How does Gram staining go in steps?

Answer 26

1. Use Crystal violet to stain a fixed culture(binds to peptidoglycen membrane)
2. Rinse the slide after a minute then add iodine solution
3. Add ethanol (breaks down Gram- membrane- decolourised) then counterstain with red safarnin

Question 27

What colours will the bacteria be after Gram staining?

Answer 27

Purple-Gram+
Red- Gram-

Question 28

What are Viruses?

Answer 28

obligate intercellular parasites(cannot grow outside cells)

Question 29

What are the steps of a bacteria-phage invasion?

Answer 29

1. Phage attaches to host
2. Phage inserts DNA
   3a. Viral DNA incorporated into host- viral DNA is divided every time bacterium divides
   3b.(lysogenic) Phage DNA inactivates host DNA taking over cell chemistry
   4.(lytic pathway) New phage particles assembled-enzyme lysozyme released
3. Cell bursts due to action of lysozyme, releasing phages to other cells

Question 30

How do DNA viruses take over a cell?

Answer 30

Use the hosts DNA as a template for new viruses

Question 31

How does RNA virus take over a cell?

Answer 31

In most cases uses mRNA to directly replicate. In a negative sense would need to be transcribed and translated

Question 32

How do RNA retrovirus take over a cell?

Answer 32

They manufacture enzymes(transcriptase) which turns RNA into DNA which incorporates into the hosts genome

Question 33

What’s an example of a DNA virus?

Answer 33

Common cold

Question 34

What’s an example of a RNA virus?

Answer 34

Ebola

Question 35

What’s an example of RNA retrovirus?

Answer 35

HIV

Question 36

What’s the Lytic Cycle?

Answer 36

When the cell reproduces so much of the phage that it bursts the cell