Flashcards in Lecture 21 - Prokaryotes 1 (SI) Deck (40)
-maintains cell shape
-prevents it from bursting (hypotonic)
makes up fungal (+heliozoa) cell walls
makes up plant cell walls
What is archae cell wall composed of?
-cross-linked sugar polymers
-make up bacteria cell walls
-targeted by antibiotics
_____ contains a lot of peptidoglycan and ______ contains little peptidoglycan
-gram pos. contains a lot
-gram neg. contains little
Which type of bacteria tends to be more toxic/pathogenic?
-polysaccharide or protein layer covering most prokaryotes
chromosomal region in prokaryotes
-original cell produces copy of its chromosomes
-surrounds that copy with tough multilayered structure
-smaller rings of DNA scattered throughout prokaryotic cells
-R carries resistance quality
What do fimbriae do?
-allow them to stick to their substrate + other individuals in a colony
-longer than fimbriae
-allow prokaryotes to exchange DNA
-scattered on surface
-spin for propulsion
evolved independently in each domain
-bacterial model composed of motor + hook + filament
-from ancestral secretory system
What is the order of structures of a gram-neg. bacteria from outside to in?
2. membrane composed mostly of lipopolysaccharide
4. membrane composed mostly of phospholipids
What are 3 key features of prokaryote reproduction?
1. prokaryotes are small (.5-5mm)
2. short regeneration time (except endoliths)
3. binary fission
3 reasons why prokaryotes have rapid evolution?
1. exchange of genetic material
2. short generation times
3. large populations
What are endoliths?
-organisms that live inside rocks + between mineral grains
-reproduce maybe once per century
What is genetic recombination?
-combining DNA from 2 sources
-contributes to diversity
-DNA is transferred between 2 prokaryotic cells (usually of same species) that are temporarily joined
-bacteria, DNA transfer always one way
-cell donates DNA, other receives it
-presence of this particular piece of DNA determines ability to form pili
-donate DNA during conjugation
-carry genes for antibiotic resistance
-fraction of bacteria with genes from resistance increase in population exposed to antibiotics
-gene movement between bacteria by bacteriophages
-change in genotype and phenotype due to assimilation of external DNA by a cell
What are the 4 major modes of nutrition
E source: light
C source: CO2, HCO3 etc
EX: cynatobcteria, plants, algae
E source: inorganic chemicals
C source: CO2, HCO3 etc