lesson 2 - prokaryotic cells and virus structure

Question 1

what are in prokaryotes?

Answer 1

slime capsule - protects cell from antibiotics and viruses
ribosomes
dna - no histones so no chromosomes made
plasmid - usually contain useful genes such as antibiotic resistance
cell wall
flagellum
pilli - allow attachment to other surfaces
no membrane-bound membranes

Question 2

describe the binary fission of prokaryotes

Answer 2

1) dna and plasmids replicate
2) cell elongates (grows) and dna moves to opposite poles of cell
3) cytoplasm begins to divide and new cell walls begin to form (cytokenesis)
4) cytoplasm divides to form new daughter cells - each contain an identical DNA loop, but different no. of plasmid copies

Question 3

why are viruses not considered microorganisms?

Answer 3

they’re not alive and cannot reproduce by themselves

Question 4

microorganisms

Answer 4

• prokaryotae
• protoctista
  fungi

Question 5

how many times smaller are viruses than bacteria?

Answer 5

1000x smaller

Question 6

structure of a virus:

Answer 6

consists of genetic material: DNA or RNA, protected by a protein coat called a capsid - has attachment proteins/antigens to help them recognise a host

Question 7

describe virus replication

Answer 7

• virus detects host cell by recognising a protein marker on its membrane - virus attaches to the cell using attachment proteins
• virus injects genetic material into the cell
• cell reproduces the genetic material and reads it creating new viral proteins
• virus leaves cell using some of the cell’s own membrane to form itself

Question 8

what’s a bacteria cell wall made of?

Answer 8

peptidoglycon

Question 9

size of ribosomes in:
1. animal cell
2. plant cell
3. fungal cell
4. bacteria cell
5. virus

Answer 9

1. 80s / 10 mm
2. 80s / 10 mm
3. 80s / 4 mm
4. 70s / 1 mm
5. absent / 0.02 mm