Cells

Question 1

The structure of a cholera bacterium is different from the structure of an epithelial cell from the small intestine. Describe how the structure of a cholera bacterium is different.

Answer 1

1 Cholera bacterium is prokaryote;
2 Does not have a nucleus/nuclear envelope/ has DNA free in cytoplasm/has loop of DNA;
3 and 4 Any two from
No membrane-bound organelles/no mitochondria / no golgi/ no endoplasmic reticulum/etc;
5 Small ribosomes only;
6 and 7 Any two from
Capsule/flagellum/plasmid / cell wall/etc;

Question 2

Give 2 ways in which pathogens can cause disease when they enter the body of their host.

Answer 2

Damage/destruction of cells/tissues Production of toxins;

Question 3

Describe the difference between an endotoxin and an exotoxin.

Answer 3

Endotoxins produced from the breakdown of bacteria (cell walls);
(allow burst / lyse – do not allow decompose)
exotoxins secreted / released (from living cells) (not produced);
endotoxins are lipopolysaccharides;
exotoxins are protein;

Question 4

Parts of the prokaryotic cell

Answer 4

Cell (surface) membrane: regulates entry/exit/selectively permeable;
Mesosome: respiration/cell division;
Cell wall: (mechanical) protection/prevents (osmotic) lysis;
Slime layer/capsule: protection (against e.g. antibiotics);
Flagellum, movement of cell;
DNA molecule/bacterial chromosome, genetic information;