Classification of Life Flashcards
Homeostasis
“same state”, maintenance of internal balance
Taxonomy
branch of biology that names and classifies living organisms
Linnaean classification system
/Genus species/
Classification system that groups species into increasingly inclusive categories based on similarities
Organism
one or more cells that possess the characteristics of life (individual single or multicellular living things)
Cell
the simplest collection of matter that can live
organelle
membrane-bound structure within the cell that carries out highly specialized functions
molecule
combinations of atoms in defined proportions
atom
the smallest unit of matter that still retains properties of its element
genome
the complete set of genetic material within an organism
universal structures of cells
- plasma membrane
- ribosomes
- genetic info
- cytosol
characteristics of life
- order
- energy processing
- regulation
- response to the environment
- reproduction
- growth and development
- evolution
incremental genetic change
- genes gain sequence changes over generations
- more genetic differences=less related
- divergence earlier in history=more time for genetic differences to occur
how does the genetic composition of an organism change?
- fusion of organisms
- engulfing of organisms
- transfer of plasmid DNA
- DNA transfer by viruses
key features of eukaryotic cells
- DNA located in nucleus (w double membrane boundary)
- linear chromosomes
- organelles
- may or may not have cell wall
key features of prokaryotic cells
- only single celled organisms
- circular chromosome concentrated in nucleoid region
- NO organelles
- typically have a cell wall
evolution of cell walls
Bacteria-enzyme to make peptidoglycan Archaea-enzyme to make pseudopeptidoglycan Eukarya: yeast-enzyme to make chitin plants-enzyme to make cellulose
ribosomes across the domains of life
- related in all species
- most sequence similarity btw archaea and eukarya
- some antibiotics specifically bind to bacterial ribosomes
habitat resilience across the domains of life
- ocean vent archaea can survive up to ~120C (unique to archaea)
- some bacteria survive up to 110C
are viruses cells?
they don’t possess ribosomes or have cytosol, may not have a plasma membrane and cannot replicate without a host, so no
which two domains of life share the most genetic similarity (and are therefore more closely related)?
eukarya and archaea
what evolutionary change gave rise to the divergence of eukarya and archaea?
the eukarya developed a nuclear envelope
histones
proteins found in eukaryotic and some archaic cells used to package DNA
eukaryotes
cells with a nucleus. animal, plant, fungal or protist.
prokaryotes
cells with no nucleus. encompasses archaea and bacteria.
