Prokayotic cells

Question 1

Name they key parts of a prokayotic cell

Answer 1

Nuclioid region- contains a circular chromosome
Cytosol with ribosomes
Plasma membrane
Peptodiglycan cell wall
Flagella motility
Pili and fimbra (attachcemnt and gene transfer)
Free genetic material = plasmids

Question 2

How is shape of prokayotes determined

Answer 2

The orietation of the peptidoglycan layer
can form circular rod or spiral shape`

Question 3

What is the function of peptidoglycan

Answer 3

Provides strength
Protection of osmotic lysis
confers shape - dependant on orientation

Question 4

What is the Structure of peptidoglycan

Answer 4

Carbohydrate chains of NAM and NAG cross linked with polypeptide chain, has tetrapeptide side chain to link virical sheets
Layed down by transpeptidase enzyme

Question 5

What are the steps of a gram stain and its relivance

Answer 5

1) Stain with crystal violet
2) Use a mordant such as iodine to confer violet
3) Quick alcohol wash to remove from -ve cells,
4) Counter stain with Safranin
Safranin stains -ve and crystal violet stains +ve

Question 6

what is the difference between Gram positve and negative bacteria

Answer 6

Gram +ve have a thick layer of peptidoglycan acting as a cell wall, stains purple as it is hard to wash the pruple out of the cell

Gram -ve have a thin layer of peptioglycan and an outer membrane with liposacharides pitruding making up the cell wall
(also has an inner cell membrane)
easy to wash out the purple so they get restained by safranin

Question 7

How do cells move through a liquid medium

Answer 7

Via Flagella
Not present in all bacteria, Used to move the cell around in intervals, chemoreceptors are used to determined when it is travling to nutrianct rich or detrimental enviroment. no higher thinking just chemical reception.

Question 8

What is the process of cell movement towards or away from conc grandients call and what can occur

Answer 8

Chemotaxis:
Cells with motility respond to concentration grandients

If high in glucose cell will move towards the region
If high in a negative solution cells with move away from solution

Question 9

What part of prokaryotes are the adheresion factors and each function

Answer 9

Fimbriae Adherence pili / Adhesins:
function-> adhere to surfaces, different fimbriae can attach to different mediums

Pili, Sex pili-> Used to transfer genetic material in a process called
Conjunction = horisontal gene transfer

Question 10

What is thee outermost layer of some bacteria called and the function and structure

Answer 10

Glycocalyx: A layer of Polysacharies around the outside of the bacteria

can be slime of capsual structure, slime = disorganised, capsual = organised

Functions:
prevent the cell from desiccation
Virulance factors: prevetning bacteria from being phagocytosed

Question 11

What is the process of endospores

Answer 11

Endospores: When nutriance is low or negative conditon
some Gram postive cells shift from the vegitative state to the endospore state,
can return back to vegitative state when good conditions arrise,