BIOL1020 - 11.1

difference between prokaryotes and eukaryotes

• pro: no nucleus, no membrane-bound organelles, single-celled

• eu: have nucleus and organelles, can be multicellular

3 domains of life

• bacteria

• archaea

• eukarya

key features of bacteria

• single-celled, no nucleus

• diverse and abundant

• can be harmful or beneficial

• some perform photosynthesis

• helped produce oxygen

• essential for ecosystems

bacterial DNA

• one circular chromosome

• located in cytoplasm

• has plasmids

human microbiome

• microorganisms living in and on the body

• found in the gut, mouth, skin, and airways

• helps in digestion, produce vitamins, support immune system

horizontal gene transfer

• transfer of DNA between organisms via plasmids

cyanobacteria

• photosynthetic bacteria that is responsible for oxygen accumulation

key features of archaea

• prokaryotic

• important in carbon and nitrogen cycles

• found in extreme environments and microbiomes

extremophiles

• organisms that live in extreme conditions

key features of eukaryotes

• cells with nucleus and organelles

• larger and can be multicellular

eukaryotic complexity and multicellularity

• cytoskeleton: shape and structure

• membrane system: transport within cell

• linear chromosomes and gene regulation

• cell specialization → different cell types

endosymbiosis theory

• early cell engulfed bacteria that lived inside it

• became organelles over time