3A Prokaryotic Cells

Question 1

cell wall (5)

Answer 1

• layer of peptidoglycan (many parallel polysaccharide chains with short peptide crosslinkages)
• big molecule with net-like structure
• prevents cell from swelling and bursting
• maintains shape of bacterium
• gives support and protection to the contents of cell

Question 2

capsule~ (3)

Answer 2

• slime layer around cell wall
• protects bacterium from phagocytosis
• covers cell markers, so can make it easier for bacterium to be pathogenic

Question 3

Pili~ (3)

Answer 3

• thread-like protein projections found on surface of some bacteria
• function: attachment to a host cell for sexual reproduction
• make bacteria more vulnerable to virus infections

Question 4

Flagellum~ (2)

Answer 4

• made of many-stranded helix of the protein flagellin

- moves the bacteria by rapid rotation

Question 5

Cell Surface membrane (3)

Answer 5

• similar to those in eukaryotic cells
• can contain mesosomes (infoldings of the membrane)
• bacteria have no mitochondria so the cell memrane is also the site for some of the respiratory enzymes

Question 6

nucleoid (2)

Answer 6

• genetic material that consists of single, circular strand of DNA
• DNA is folded and coiled to fit into bacterium

Question 7

Plasmids~ (3)

Answer 7

• much smaller circle of DNA
• codes for a particular aspect of bacterial phenotype
• for example can code for resistence to antibiotic

Question 8

70S ribosomes (3)

Answer 8

• smaller than 80S
• has two subunits
• involved in synthesis of proteins

Question 9

draw and label prokaryotic cell (11)

Answer 9

see book