Week 2 - The Tree of Life and Early Earth Environments

Question 1

Protein synthesis

Answer 1

DNA –(transcription)–>

-> mRNA (information)

+ tRNA (amino acids) —>

• > RIBOSOME (rRNA + proteins) —-(synthesis/translation)—->
• > PROTEINS

Question 2

Early Earth - events leading to life

Answer 2

cooling + differentiation + MF

• early heavy bombardment -
• > early life in sulphur-rich environment

Question 3

16S rRNA

Answer 3

prokaryote ribosome, used bc of slow evolution rates

Woese and Fox - used in phylogenetics

Question 4

Carl Woese

Answer 4

defined Archaea as a new kingdom using 16S rRNA phylogenetic taxonomy -> find molecular sequences in mRNA and organisms, compare for evolutionary history data

(prior to that - life was prokaryotes -> eukaryotes, molecular biology not very concerned with evolution)

Question 5

oligonucleotide cataloguing

Answer 5

A process used to determine phylogenetic groupings and evo relationships based on the chemical composition of nucleic acids.

Question 6

Phylogeny

Answer 6

st. relationships btween groups of organisms from genetic makeup

Question 7

Proteins

Answer 7

chains of amino acids held together by peptide bonds

• one or multiple polypeptide chains

Question 8

Essential for all known life

Answer 8

DNA + RNA + protein

Question 9

tRNA and mRNA bases

Answer 9

3 for each; 3 bases - codon

Question 10

First microscope

Answer 10

1674

Antonie van Leeuwenhoek

Question 11

Antonie van Leeuwenhoek

Answer 11

1674

First microscope

Question 12

Carl Linneaus

Answer 12

Morphology-based taxonomy
2 kingdoms - plantae and animalia
1735

Question 13

Ernest Haeckel

Answer 13

Taxonomy based on a wider range of observation types (morphology, microscopic)

intr. protista and monera

Question 14

Monera

Answer 14

A previous classification introduced by Haeckel

Incl. Bacteria and Archaea

Question 15

Robert Whittaker

Answer 15

1969
Linear tree of life:

PROKARYOTES (Monera) –> EUKARYOTES (Protista) –> PLANTAE, FUNGI and ANIMALIA

Question 16

HGT - methods of transfer

Answer 16

TRANSFORMATION: prokaryotes taking free DNA fragments from the environment

CONJUGATION: temporary union between 2 cells (eg. cilliated protozoans)

TRANSDUCTION: DNA transmitted between cells via a bacteriophage

Question 17

GC evolution to -more or less- current universal form

Answer 17

3.8 - 3.5 mya; before LUCA

Question 18

Darwin on distinguishing between trivial and nontrivial characteristics

Answer 18

look @ embryonic characteristics as opposed to later adaptations - but that’s impossible with microbes

Question 19

why is the GC evolution hard to analyse?

Answer 19

GC is highly conserved -> low viariation -> fewer means of analysing

Question 20

ablation (ice)

Answer 20

removal of glacial ice via erosion, evaporation etc directly into gas phase

Question 21

ALH84001 - timeline

Answer 21

~ 4 bya: formation and solidification 
~ 3.6 bya: fracturing
* water flow -> mineral precipitation of calcium carbonate
* meteor hit
~ 13 kya: Earth entry

Question 22

ALH84001 - composition

Answer 22

orthopyroxene:

• igneous (on Earth - in igneous and metamorphic rocks)
• orthorhombic
• commonly found in mafic rocks
• v dark

water precipitation -> calcite

Question 23

calcium carbonate

Answer 23

CALCITE - most stable polymorph of CaCO3

mineral precipitated from water solutions and secreted by animals to form a skeleton or shell

yellowstone hot springs