Do Now 1/6/2014Probity: virtue, integrity

Task: Copy the drawing below. Identify the organism. Label the areas identified by arrows.

05/04/23 1

Hint: used for moving

Hint: outer cover

Hint: inner lining

Hint: small “hairs”

Most difficult: loop of DNA

Bacterial Reproduction

05/04/23 3

IntroductionBacteria can reproduce in one of two ways:

1. Asexually2.Sexually

05/04/23 4

Asexual ReproductionBinary Fission: one parent involved offspring are identical to parent & each other

Advantages:1. simple: only 1 parent2. offspring are fully formed (no maturation needed)3. very fast (20 min. in ideal conditions) after 24 hrs:

1 bacterium 2x106 kg of cells (enough to cover the earth)

Asexual Reproduction

Disadvantages:• no genetic variety• one unfavourable environmental condition can wipe out

whole population

05/04/23 5

05/04/23 6

Asexual ReproductionBinary Fission:

05/04/23 7

Asexual Reproduction

Binary Fission:

05/04/23 8

Sexual Reproduction two parents involved offspring are genetically different

to parents & to each otherAdvantages:

genetic variety i.e. some are able to adapt to unfavourable conditions (ex: antibiotic resistance)

Disadvantages:1.more complex: slower because must find a

compatible partner

2.no new individuals produced (i.e. no increase in population)

Bacterial Conjugation

05/04/23 9

• plasmid copies itself• passes through pili (cytoplasmic bridge) into recipient cell

•cells separate with both cells containing the plasmid

plasmid

donor recipient cell (+) cell ( - )

pili

05/04/23 10

Homework In text book: read pages 148-149 Quiz Wednesday Test Friday