Flashcards in Lecture 21 - Prokaryotes 1 (SI) Deck (40):
1
Cell wall
-maintains cell shape
-protects cell
-prevents it from bursting (hypotonic)
2
Chitin
makes up fungal (+heliozoa) cell walls
3
Cellulose
makes up plant cell walls
4
What is archae cell wall composed of?
-polysaccharides
-proteins
5
Peptidoglycan
-cross-linked sugar polymers
-make up bacteria cell walls
-targeted by antibiotics
6
_____ contains a lot of peptidoglycan and ______ contains little peptidoglycan
-gram pos. contains a lot
-gram neg. contains little
7
Which type of bacteria tends to be more toxic/pathogenic?
gram negative
8
Capsule
-polysaccharide or protein layer covering most prokaryotes
9
Nucleoid
chromosomal region in prokaryotes
10
Endospore
-original cell produces copy of its chromosomes
-surrounds that copy with tough multilayered structure
11
Plasmids
-smaller rings of DNA scattered throughout prokaryotic cells
-R carries resistance quality
12
What do fimbriae do?
-allow them to stick to their substrate + other individuals in a colony
13
Pili
-longer than fimbriae
-allow prokaryotes to exchange DNA
14
Flagella
-scattered on surface
-spin for propulsion
15
Convergence
evolved independently in each domain
16
Exaptation
-bacterial model composed of motor + hook + filament
-from ancestral secretory system
17
What is the order of structures of a gram-neg. bacteria from outside to in?
1. capsule
2. membrane composed mostly of lipopolysaccharide
3. peptidoglycan
4. membrane composed mostly of phospholipids
18
What are 3 key features of prokaryote reproduction?
1. prokaryotes are small (.5-5mm)
2. short regeneration time (except endoliths)
3. binary fission
19
3 reasons why prokaryotes have rapid evolution?
1. exchange of genetic material
2. short generation times
3. large populations
20
What are endoliths?
-organisms that live inside rocks + between mineral grains
-chemoautotrophs
-reproduce maybe once per century
21
What is genetic recombination?
-combining DNA from 2 sources
-contributes to diversity
22
Conjugation
-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
23
F factor
-presence of this particular piece of DNA determines ability to form pili
-donate DNA during conjugation
24
R plasmid
-carry genes for antibiotic resistance
-fraction of bacteria with genes from resistance increase in population exposed to antibiotics
25
Transduction
-gene movement between bacteria by bacteriophages
26
Transformation
-change in genotype and phenotype due to assimilation of external DNA by a cell
27
What are the 4 major modes of nutrition
1. photoautotrophy
2. chemoautotrophy
3. photoheterotrophy
4. chemoheterotrophy
28
Photoautotroph
(autotroph)
E source: light
C source: CO2, HCO3 etc
EX: cynatobcteria, plants, algae
29
Chemoautotroph
(autotroph)
E source: inorganic chemicals
C source: CO2, HCO3 etc
EX: sulfolobus
30
Photohetertroph
(heterotroph)
E source: light
C source: organic compounds
EX: aquatic + salt-loving (Rhodobacter)
31
Chemohetertroph
(heterotoph)
E source: organic compounds
C source: Organic Compounds
EX: clostridium, many fungi/animals/plants
32
Nitrogen fixation
-convert N2 to ammonia
-essential for production of amino acids + nucleic acids
EX: anbaena
33
Obligate aerobes
require O2 for cellular respiration
34
Obligate anaerobes
-poisoned by O2
-use fermentation/anaerobic respiration
35
Facultative anaerobes
-survive with or without O2
36
What are heterocysts?
-photosynthetic cells + nitrogen fixing cells in Anabaena
-exchange metabolic products
37
What are taxis?
-ability to move toward or away from stimulus
38
What is an example of an extremophile bacteria?
-endollith
-grow very slowly
39
What are the two domains of prokaryotes?
1. bacteria
2. arcahaea
40