Biology 1002B Lecture Notes - Lecture 3: Photosynthesis, Arginine, Domain Model
27 Jun 2018
School
Department
Course
Professor
Luca%lived%3.8-3.5%%billion%years%ago%this%is%a%fact%even%though%theres%no%evidence,%
because%it’s%the%most%parsimonious/simple%way%that%all%forms%of%life%share%all%
common%ancestral%traits%of:
Cells%made%of%lipids
1)
Genetic%system%based%on%DNA
2)
DNA%to%RNA%to%protein%central%dogma%transfer%of%DNA
3)
Common%system%of%protein%assembly%(ribosomes)
4)
ATP
5)
Glucose%&%Glycolysis-everything%can%metabolize%glucose%and%has%glycolysis%
which%is%system%that%gets%energy%out%of%glucose%
6)
I%WANT%TO%KNOW%WHAT%GENES%I%COULD%USE%TO%BUILD%THE%TREE%OF%LIFE,%THEY%
MUST%BE%INCLUDED%IN%ONE%OF%THE%6%PROCESSES!
*LUCA%also%had%all%of%these%traits
The%chance%that%you%would%evolve%everything%you%need%for%glycolysis/all%forms%
of%life%develop%DNA%is%rare%so%you%must%have%got%it%passed%down,%that’s%the%
easiest%reason
-
Prokaryotes%don’t%exist
Bacteria%are%distinctly%different%then%archaea
-
Prokaryotes%mean%before%nucleus
But%we%have%NO%evidence%that%bacteria%that%has%no%nucleus%evolved%
before%nucleus%
○
No%evidence%
○
-
Arrow%of%complexity-evolution%by%natural%selection/adaptation%has%this%
direction,%more%simple%to%more%complex%(have%more%things)%but%natural%
selection%doesn’t%drive%increase%in%complexity.%There's%a%lot%of%things%that%
become%less%complex%overtime.
-
Hypothesis%that: LUCA%%might%of%mean%a%proto-eukaryote%%and%that%bacteria%
and%archaea%underwent%reductive)evolution/streamlining.%The%advantage%for%
them%to%under%go%this%could%be%less%energy%%to%maintain%cell%because%don’t%
need%as%much%STUFF.%%Reductive)evolution)allows)you)to)adapt)faster)to)
changing)environments.
-
The%people%that%worked%on%this%5%kingdoms%thought%they%were%right%and%then%
carl%wose%came%along%and%said%that%the%actual%tree%looks%like%you%have%to%have%
traits%that%
-
occur%in%all%organismsA)
Reflect%the%cellular% line%of%descent%-cant%use%genes%that%move%around%between%
bacteria%and%archea%ie.%not%something%that%came%in%%-something%that%was%in%
lineage%from%the%start.%
B)
Highly%conserved-looking%for%a%gene%sequence%that%hasn’t%changed%much,%may%
be%some%differences%but%if%you%were%given%the%sequence%you%knew%what%it%was.%
C)
You%cant%compare%genes%that%are%too%different%and%have%changed.%
Sufficiently%large%to%contain%lots%of%information%
A%gene%4%nucleotides%long%is%not%good%enough%to%compare%,%longer%a%
gene%is=%the%more%information%you%have%
○
D)
WHAT%ARE%THE%GENES%THAT%ARE%SHARED%"WHAT%MOLEUCLES%CAN%BE%USED%TO%
MAKE%TREE%OF%LIFE"?
Gene%used%to%create%a%ribosomal%RNA%,%there%so%similar%that%you%know%there%
was%once%one%kind%and%now%we%have%2%types%of%ribosomes.%
Large%and%small%subunit
○
The%genes%that%we%used%was%the%gene%that%encodes%the%RNA%that%makes%
up%the%subunit%.%
○
Genes%encode%these%RNAs%and%about%1800%base%pairs%long%and%are%
evolutionary%related%
○
Small%subunit%of%archaea%is%more%similar%to%small%subunit%of%eukaryotes%
○
1)
Photosynthesis%occurs%in%all%3%bacteria,%archaea,%eukaryotes%but%cant%use%this%
to%compare
-
Rna%is%so%primitive%(not%derived%from%anything%else)%,%the%reason%why%bacteria%
sequence%has%diverged%is%that%this%had%diverged%earlier%then%the%branch%that%
led%to%eukaryotes%and%archaea
-
Build%tree%based%on%the%small%subunit%is%different%,%we%use%more%then%one%gene%
to%build%the%trees%,%what%other%gene%could%you%use%to%build%this%tree?
-
LUCA%wasn’t%the%only%or%first%form%of%life%
-
Relationship)b/w)Eukaryotes)and)Archaean's
Based%on%molecular%phylogeny%,%morphology%is%biased%
-
There's%80%proteins%required%to%make%ribosome%and%30%of%them%are%very%
similar%b/w%archea%and%eukaryotes%then%b/w%aracha%and%bacteria%,%the%
biochemistry%is%also%the%same.%%The%pathway%that%makes%the%pyrimidine%used%
to%make%DNA%and%RNA%are%similar%that%makes%a.a%arginine.%All%organisms%have%
these%pathways.%
-
We%don’t%know%the%timing%of%arachea%and%eukaroytes.%O
-
We%don’t%know%which%is%right.%On%left%3%domain%model%all%come%at%once,%on%right%you%
only%start%with%2%and%then%eukaryotes%are%derived%from%arachean%
We%can%date%LUCA%using%molecular%phylogeny%to%about%3.5%-3.8%BYA
-
4%billion%BYA%is%the%biotic/abiotic%
-
There%could%have%been%other%form%of%life%before%LUCA%and%maybe%form%of%life%
after%LUCA%
-
There%is%many%origins%of%life%but%there%is%ONE%origin%of%life%that%lead%to%LUCA%
-
Life%evolved%pretty%quick%after%formation%of%earth%-view%is%that%life%sprung%up%
many%times%and%the%other%origins%of%life%just%died%off%(prob%had%only%some%of%
the%characteristics%of%life)%
-
It’s%the%only%one%lineage%and%evolution%that%occurred%there%where%all%
fundamental%factors%of%life%are%formed%in%a%single%life%form%which%is%LUCA%
-
L3
Saturday,%January%13,%2018
9:54%PM
Document Summary
Luca lived 3. 8-3. 5 billion years ago this is a fact even though theres no evidence, because it"s the most parsimonious/simple way that all forms of life share all common ancestral traits of: Dna to rna to protein central dogma transfer of dna. Glucose & glycolysis- everything can metabolize glucose and has glycolysis which is system that gets energy out of glucose. I want to know what genes i could use to build the tree of life, they. Must be included in one of the 6 processes! The chance that you would evolve everything you need for glycolysis/all forms of life develop dna is rare so you must have got it passed down, that"s the easiest reason. But we have no evidence that bacteria that has no nucleus evolved before nucleus. Arrow of complexity- evolution by natural selection/adaptation has this direction, more simple to more complex (have more things) but natural selection doesn"t drive increase in complexity.
