chapter2- basic component of living systems Flashcards
how are mitochondria similar to prokaryotic cells and how does this provide evidence for endosymbiosis?
they have a double membrane, they have DNA genome inside them, are a similar size to prokaryotes, have 70s ribosomes
what is endosymbiosis
when one bacterium engulfs another
what does “pro” mean
without
chloroplasts where once..
prokaryotes
what does “eu” mean
true
what is the difference between ribosomes in pro/eukayryotes?
pro- 70S (10-20nm diameter)
eu- 80S (22nm diameter)
how is the genetic material organised in a prokaryote
genetic material is naked dna as it is not associated with protein, lipids, or any molecule to help protect it. there is no true nucleus and the DNA consists of chromosomal and the plasmid loop
what are pili and what cells are they on?
prokaryotes and they are hair-like extensions that enable adherence to surfaces or mediate bacterial conjugation
is a ribosome a membrane bound organelle
no
are the rer and ser membrane bound organelles
yes
what is the slime capsule?
polysaccharide layer used for protection against dessication (drying out) and phagocytosis
what is the cell wall made put of in a prokaryote and what is its function
peptidoglycan, it is rigid and maintains shape and prevents lysis
what do flagella do?
projection containing motor protein to enable movement
where were the earliest signs of life found?
hydrothermal vents at the bottom of the ocean
hydrothermal vents also have raw materials for life……
hydrogen gas, carbon dioxide and minerals
hydrothermal vents are (ph)…….
alkaline and the sea water is mildly acidic which provides a source of protons
in eukaryotes how is the dna organised
wrapped around histones to form chromosomes
what is the key difference between pro and eu cells
eukaryotic cells have membrane bound organelles and their dna is contained in a membrane bound nucleus whereas prokaryotic cells dont have membrane organelles and have no true nucleus
do prokaryotes have a nuclear envelope
no
do eukaryotes have a nuclear envelope
yes