01:694:301 Lecture Notes - Lecture 1: Stromatolite, Eukaryote, Extremophile
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14 Nov 2018
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Intro to Biochemistry and Molecular Biology
(001:694:301) - Section H1
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Study Guide
Chapter 1 – ‘Biochemistry: An Evolving Science’
• The most power lesson of Biochemistry is the great similarity between all life forms on Earth.
o Only logical explanation ! common ancestry; all life forms are related (far back in time)
• Analogy: one ‘operating system’ + one kind of ‘software’ (genetic code) used by every organism on
the plant
• There are three domains of life: Eukarya, Bacteria (prokaryotes), and
Archaea (also prokaryotic)
o Figure 1.3
" All multicellular organisms are Eukarya and their cells have
nuclei and other structures inside
" Bacteria have no nucleus and no real subcellular compart-
ments
" Archaea are single celled organism with no nucleus which
tend to be found in extreme environments (hot, acidic, salty) !
‘extremophiles’
o Figure 1.2 – Note the following timeline: *2.25 bya O2 came into at-
mosphere
" Earth was more than 2 billion years old, ferrous chloride ubiquitous; in presence of O2 fer-
rous chloride ! ferrous oxide;
" ~2.25 bya O2 caused depletion of iron salts in ocean; deposits of iron ! banded iron for-
mations (BIFs) (red beds);
" Banded iron is made of iron which could only be dissolved in water under anaerobic condi-
tions; provides evidence that the Earth used to be anaerobic with no free O2
" Stromatolites are photosynthesized colonies (cyanobacteria) which puts oxygen into the air
• How did O2 affected BIFs and stromatolites?
• KNOW the structure of DNA as described on pg. 4 – 5
o DNA illustrates how form and function interplay
o DNA is constructed of 4 building blocks (monomers)
" Each monomer of DNA consists of sugar phosphate unit + one the following 4 bases:
• Thymine (T), Adenine (A), Cytosine (C), Guanine (G)
• **Uracil (U) is only found in RNA, not DNA (if found in DNA it is a mistake); when C is
oxidized (deamination) ! U
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