Bio- 2A

11:26 AM

Conditions needed for life to exist:

• Source of energy

• Availability of liquid water

• Life can be found even in hostile environments

Characteristics of a living thing:

• Movement: self-generated, not just because of other forces

• Respiration: extracting energy from organic molecules

• Sensitivity

• Growth

• Reproduction

• Equilibrium: homeostasis

• Excretion: removing waste

• Nutrition: obtaining nutrients

Cell theory:

• Cells are the basic structural and functional units of all life

• All living things are made of one or more cells and the products of cells

• All cells come from pre-existing cells

Prokaryotes DNA:

• Naked

• DNA is circular

• Usually no introns

Eukaryotes DNA:

• DNA bound to protein

• DNA is linear

• Usually has introns

Prokaryotes Organelles:

• no nucleus

• no membrane-bound

• 70S ribosomes

Eukaryotes Organelles:

• has a nucleus

• membrane-bound

• 80S ribosomes

Prokaryotes Reproduction:

• binary fission

• single chromosome (haploid)

Eukaryotes Reproduction:

• mitosis and meiosis

• chromosomes paired (diploid or more)

Prokaryotes average size:

• smaller (~1-5 µm)

Eukaryotes average size:

• larger (~10-100 µm)

Further classification:

Prokaryotes:

• Archaebacteria: unicellular

• Eubacteria: unicellular

Eukaryotes:

• Protista: unicellular or multicellular

• Fungi: unicellular or multicellular

• Plantae: multicellular

• Animalia: multicellular