Chapter 16- Prokaryotes and Intro to Eukaryotes

Prokaryotes

organisms with cells that lack membrane-bound organelles and a membrane-bound nucleus (includes domains bacteria and archaea)

eukaryotes

organisms with cells that have membrane-bound organelles and a membrane-bound nucleus (includes protists, plants, fungi, and animals)

Prokaryote genomes

generally smaller than eukaryote genomes

has circular chromosomes

prokaryote chromosomes

plasmids

prokaryote-specific, small, independently replicating, circular DNA molecules, carry alleles for antibiotic resistance

binary fission

how prokaryotes reproduce, the splitting of one cell into two after replication of genetic information

Archaea

single celled prokaryotes

extremophiles

lovers of extreme conditions, archaea

extreme thermophiles

thrive in extreme heat

extreme halophiles

live in very salty environments

qualities of mitochondria and chloroplasts

1. their own lipid bilayers

2. circular DNA molecules that can replicate independently

3. their own ribosomes that are smaller than the ribosomes of the cell in which they live

4. reproduce by a splitting process similar to fission

endosymbiont theory

mitochondria and chloroplasts derived from ancestral prokaryotes that were engulfed by another cell and the relationship became symbiotic

protists

a group of mostly unicellular eukaryotic organisms that are not fungi, plats, or animals

are protists a valid evolutionary group?

no, not monophyletic

Unicellular

most eukaryotes are protists and most protists are unicellular

green algae

a photosynthetic protist, the closest relative of land plants

Green algae are not a valid evolutionary group, but a

paraphyletic group

charophytes

green algae

characteristics of green algae

1. embryos not protected by parent organism following fertilization

2. flagellated games swim to each other through water

3. no internal structural support, supported by water

4. no vascular tissue, lack a transport system

challenges for movement onto land

1. must be able to avoid desiccation

   1. must develop supportive tissue to remain upright

need to have gametes that don’t require water to swim in to meet each other and achieve fertilization