bacteria

Question 1

what to include in drawing a baterium

Answer 1

capsule, cell wall, cytoplasm, cell membrane, circular DNA (distinctive feature), plasmid, fimbriae, sex pilli, flagellum

Question 2

what are the points of comparison between bacterial and eukaryotic chromosome (7)

Answer 2

size, appearance, association with proteins, location, presence of extrachromosomal DNA, presence of intron, presence of operon

Question 3

what is the role of plasmid

Answer 3

• used EXTENSIVELY in genetic engineering as vectors for carrying and expressing foreign DNA in bacterial cells

Question 4

describe plasmids

Answer 4

they are a SMALL, CIRCULAR autonomously replicating DNA molecule

Question 5

explain the function of cell wall in bacteria

Answer 5

1. protects the cell from osmotic lysis
2. confers rigidity and shape to cell

Question 6

describe the cell wall structure

Answer 6

consists of a polymer called peptidoglycan: long chains of sugars cross-linked by short peptide chains

Question 7

describe capsule

Answer 7

some bacteria have a layer of polysaccharides known as glycocalyx to the exterior of the cell wall

the glycocalyx can be a distinct layer: that exists as a diffused mass known as the slime layer

Question 8

function of capsules

Answer 8

1. protects the bacteria from being taken in via phagocytosis by the phagocytes which are unable to recognise the bacteria due to the capsule
2. enables bacteria to adhere to one another/surfaces
3. prevent desiccation of bacteria, as it contains water to prevent the bacteria from drying out