Prokaryotes

Question 1

What is present in prokaryote cell walls but not in eukaryotes?

Answer 1

Peptidoglycan

Question 2

What are the 3 types of shape in bacteria?

Answer 2

Rods, spherical/cocci and spirillum

Question 3

how to tell if bacteria is gram positive or negative?

Answer 3

Practical add to bacteria on a slide, heat, add crystal violet to penetrate cells, add iodine to stain cells purple and fix, alcohol to stain, if purple then cell membrane has taken it up = gram positive
- Counter stain with pink saffronin, only see it in ones not stained before = gram negative

Question 4

what are gram positive bacteria?

Answer 4

• Thick cell wall outside cell membrane ONE CELL MEMBRANE AND WALL (peptidoglycan) - good target for antibiotics

Question 5

what are gram negative bacteria?

Answer 5

• Thinner cell wall which is sandwiched in between two membrane which is why crystal violet cant be absorbed into cell wall bc cant get into it.
• Either side of cell wall is called periplasm.
• Outer membrane (lipopolysaccharide)
• Inner membrane = cytoplasmic membrane

Question 6

what is peptidoglycan?

Answer 6

• Made of N-acetylglucosamine (NAG) and n-acetylmuramic acid (NAM) alternating, and some AA’s - peptide crosslink, lots of cross bridges
• B - 1,4 linkage - link NAG and NAM together
• Glycosidic bonds connecting sugars
• Structure of NAG-NAM chain gives it tensile strength