Microbial Evolution

Question 1

What does evolution by natural selection lead to?

Answer 1

decent with modification

Question 2

What is the tree of life?

Answer 2

Logical extension of the idea of decent with modification

Question 3

What are all organisms ultimately related to?

Answer 3

Each other

Question 4

What can trees help our understanding of?

Answer 4

Processes like extinction, speciation and relationship between species

Question 5

How were prokaryotes classified on before 1962?

Answer 5

• Biochemistry
• Morphology
• Metabolism

Question 6

Is it bacteria or eukaryotes that have circular chromosomes?

Answer 6

Bacteria

Question 7

Is it bacteria or eukaryotes that have linear chromosomes wrapped around in histones?

Answer 7

Eukaryotes

Question 8

What type of cell wall do bacteria have?

Answer 8

Petidoglycan cell wall

Question 9

What cell walls can eukaryotes have?

Answer 9

-Chitin
and/or
-Cellulose

Question 10

Is it bacteria or eukaryotes which has DNA free within the cell?

Answer 10

Bacteria

Question 11

Where is DNA within in eukaryotes?

Answer 11

Nucleus, mitochondria and sometimes plasmids

Question 12

Is it bacteria or eukaryotes that have sub cellular compartments?

Answer 12

Eukaryotes

Question 13

Is it bacteria or eukaryotes that have larger ribosomes?

Answer 13

Eukaryotes

Question 14

Is it bacteria or eukaryotes that have no cytoskeleton?

Answer 14

Bacteria

Question 15

How do we calculate a universal tree of life?

Answer 15

• DNA sequence information (quantitative data)
• Universal gene present in all life
• Mixture of evolutionary rates to determine relationships between closest and distantly related forms

Question 16

How is the universal tree measures?

Answer 16

Quantitative measure of relatedness

Question 17

What are present in all species?

Answer 17

Ribosomes and ribosomal RNA

Question 18

What rRNA is used to measure relatedness between species for the tree of life?

Answer 18

16s rRNA

Question 19

This is 16s rRNA used for comparison of species relatedness?

Answer 19

Large enough and sufficiently diverse to get good quantitative data

Question 20

How do we carry out 16s rRNA fingerprinting?

Answer 20

• Incubate bacteria with radioactive phosphate (P32)
• Extract rRNA
• Cut with enzyme (T1 ribonuclease) into fragments
• Separate the fragments

Question 21

Why does the resulting garments size differ between species in 16s rRNA fingerprinting?

Answer 21

-rRNA sequences differs as abundance of recognition sites of the enzyme might change

Question 22

What are the three domains of the tree of life?

Answer 22

• Bacteria
• Archaea
• Eucarya

Question 23

Is archaea bacteria?

Answer 23

No

Question 24

Do archaea share common ancestors with bacteria or eucarya?

Answer 24

Eucarya

Question 25

Does archaea have circular or linear chromosomes?

Answer 25

Circular

Question 26

Is archaea chromosomes associated with histones?

Answer 26

Yes

Question 27

Does archaea have peptidoglycan?

Answer 27

No

Question 28

Does archaea have chitin?

Answer 28

No

Question 29

Does archaea have cellulose cell wall?

Answer 29

No

Question 30

Does archaea have DNA in closed or free in the cell?

Answer 30

Free

Question 31

Does archaea have sub cellular compartments?

Answer 31

No

Question 32

How are bacteria and eukaryotes membrane phospholipids linked?

Answer 32

Ester

Question 33

Which domain has ether linked membrane phospholipids?

Answer 33

Archaea

Question 34

Is it always useful to use rRNA to characterise bacterial species?

Answer 34

No, as the sequence diversity can be much larger than other organisms

Question 35

What occurs at horizontal gene transfer?

Answer 35

Gene loss

Question 36

What is core genome?

Answer 36

Share by all members

Question 37

What is pan genome?

Answer 37

Sum of all genes presents

Question 38

What does horizontal gene transfer expand on core or pan genome?

Answer 38

Core genome

Question 39

What is genome is nice-specific?

Answer 39

Pan genomes

Question 40

What is the ring of life hypothesis?

Answer 40

whole genome comparison reveals arrangement of the tree can change depending on how we analyse the data

Question 41

What is happening to the evens across the tree according to the ring of life hypothesis?

Answer 41

- Horizontal gene transfer | - Genome fusion

Question 42

How proposed the ring of life hypothesis and when?

Answer 42

Rivera and Lake 2004

Question 43

What is the endosymbiont hypothesis?

Answer 43

1. a cell engulfs another cell so the host cell and internalise cell form an interaction 2. Drive evolution of organelles 3. Underlies the evolution of complex life

Question 44

Wha is do independent endosymbiotic events lead a formation of?

Answer 44

1. Mitochodria | 2. Plastids

Question 45

What is an example fo endosymbiosis?

Answer 45

After split from archaea, eukaryotes contained mitochondria

Question 46

What is the hydrogen hypothesis - sun biogenesis?

Answer 46

Endosymbiosis of H2 producing bacteria and H2 consuming, methanogenic archaea

Question 47

What are the evidence that mitochondria and chloroplasts are derived from bacteria?

Answer 47

1. Reduced genomes 2. Small, bacteria-like ribosomes and 16S rRNA 3. Double membrane suggesting Gram-negative origin of mitochondria (rRNA similarity to alphaproteobacteria) 4. rRNA similarity of chloroplasts (similarity to cyanobacteria 5. Circular chromosomes

Question 48

What is secondary endosymbiosis?

Answer 48

Evolving multiple times independently

Question 49

What are lokiarcheota?

Answer 49

30% completely unknown proteins 26% bacterial 29% archaea 3% eukaryotic proteins

Question 50

What are eukaryotic signature proteins?

Answer 50

- Eukaryotic-like actin - Many small GTPase - Endosomal sorting complex required for transport - Membrane deformation and phagocytosis-associated ESPs - Ubiquitin

Question 51

What does Loki and Asgard archaea do to the tree of life?

Answer 51

Reshuffle it

Question 52

Does endosymbiosis increase or decrease species diversity?

Answer 52

Increase species diversity