Ch.27 Prokaryotes
AP Bio Review
Check out Ch.27.1 Activity on the Campbell Website
Bacterial adaptations:

capsule: shields prokaryotes fro host’s immune system like the
pneumococcus bacterium in Griffith’s experiment with mice.

plasmids: confer “contingency” functions such as antibiotic
resistance like in our transformation lab.

endospores: enable cells to survive harsh conditions and to revive
when the environment becomes favorable. Autoclaves sterilize
surgical instruments under pressure to kill endospores.
Quick response to changing environments:

rapid reproduction: enables a favorable mutation to spread
quickly through a prokaryotic population by natural selection.
E. coli reproduces every 20 min. under ideal conditions.

transcription and translation can occur simultaneously due to the
lack of a nuclear envelope.

mRNA degrades sooner in the cytoplasm
Bacteria can increase genetic variation even though they
reproduce by binary fission which creates clones:

transformation: lab

transduction

conjugation
Compare Prokaryotic and Eukaryotic reproduction and mechanisms of
creating genetic variation.
PROKARYOTIC
EUKARYOTIC
SINGLE-CELLED
Reproduction
by binary fission
MULTICELLED
CLONES?
Yes
GENETIC
DIVERSITY
ACHIEVED
HOW?
Mutation
Transformation:
(foreign plasmids)
Transduction:
(foreign DNA by viruses)
Conjugation:
(sharing through pili)
Reproduction
by mitosis
Meiosis: Egg and sperm (2nn)
Mitosis: Growth, Maintenance,
Repair, Asexual Reprod. (2n2n, nn)
Mitosis: yes
Meiosis: no
Mitosis: by mutation
Meiosis: Mutation
Two sources of DNA (parents)
Independent Assortment of homologues
Segregation of alleles
random fertilization
Explain how daughter prokaryotic chromosomes are separated from
each other during binary fission.

As the chromosome is duplicating, one copy moves toward the
opposite end of the cell.

Meanwhile, the cell elongates.

Plasma membrane pinches double-sized cell into two.
Compare the structure of prokaryotic and eukaryotic chromosomes.
Prokaryotes:

Nucleoid Region

Main chromosome: large, circular

Plasmids: very small, circular, satellite DNA

DNA + proteins
Eukaryotes:

located in:
o nucleus
o mitochondria (bacteria-like)
o chloroplasts (bacteria-like)

linear

DNA + proteins, many more than prok., more complex

Two forms:
o chromatin: diffuse mass of long, thin fibers
o distinct chromosomes: before cell division
Comparing Prokaryotes and Eukaryotes
Prokaryotic
similarities
differences
Eukaryotic
Plasma membrane
Ribosomes
Cytoplasm
Enzymes
DNA
Smaller max,
No
membranebound
organelles,
circular
chromosomes
antibiotics
Classification of Bacteria:
Larger max,
Organelles,
Compartmentalized,
Linear
chromosomes
cytoskeleton