MICROBES Lecture 6-9

Question 1

Carl Woese

Answer 1

Three domains tree 1987
Bacteria, Archaea, Eukarya
new domain discovered -> archaebacteria

Question 2

Universal homologies

Answer 2

found in all organisms. All life is related and connected by a pattern of ancestry and descent

Question 3

LUCA

Answer 3

Last Universal Common Ancestor of all organisms

evidence - Use of DNA as genetic material

Question 4

Carl Woese and the three domains of life, why use rRNA

Answer 4

because

1) evolved slow enough that gene sequence can be used and analyzed among distantly related species
2) is evolutionarily ancient and was found in the common ancestor of life
3) no free-living organism lacks rRNA, can be compared through the tree of life

Question 5

Carl Woese and the three domains of life, why use rRNA

Answer 5

because

1) evolved slow enough that gene sequence can be used and analyzed among distantly related species
2) is evolutionarily ancient and was found in the common ancestor of life
3) no free-living organism lacks rRNA, can be compared through the tree of life

Question 6

Eocyte tree

Answer 6

two archaea groups one of which is the sister taxon to eukaryotes
Archaea is paraphyletic (not including eukaryotes)

Question 7

Prokaryotes

Answer 7

bacteria and prokaryotic archaea
circular chromosomal DNA
unicellular
many have only one chromosome

No nucleus
membrane-enclosed organelles
cytoskeleton

Question 8

Eukaryotes

Answer 8

unicellular and multicellular
nucleus
membrane-enclosed organelles (mitochontria, golgi apparatus, etc.)
DNA in nucleus

Question 9

Binary Fission

Answer 9

vertical transmission
asexual reproduction
two identical daughter cells (cells)

Question 10

genetic variation in binary fission

Answer 10

1)mutations and selection
prokaryotes are haploid, selection happens quickly
2) plasmids- small circular DNA molecules
non-essential genetic material
autonomously replicate in the host cell via origin of replication

Question 11

What is Lateral (horizontal) gene transfer

Answer 11

nonsexual transmission of genetic material
ONE WAY TRANSFER
across domains and species or same species

Question 12

types od Lateral gene transfer

Answer 12

1) Conjugation - sex pilus/ conjugation tube
2) Transformation- bacterial chromosomes escape from cell and a part of the chromosomes transfer into another bacterial cell
3) Transduction- Phage or Bacteriophage = “bacteria eater”

Question 13

conjugation

Answer 13

sex pilus/ conjugation tube

Question 14

transformation

Answer 14

bacterial chromosomes escape from cell and a part of the chromosomes transfer into another bacterial cell

Question 15

Tansduction

Answer 15

Phage or Bacteriophage = “bacteria eater”

Question 16

biofilms

Answer 16

a community of bacteria that attach to a surface by excreting a substance that encompases the bacteria in a matrix

Question 17

Quorum Sensing

Answer 17

bacteria “talk” to each other
bacteria are “multi-cellular”
bacteria can distinguish self from other

bacterial protein detects signal
bacterial receptor protein detects signal from same species “counting”