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BIOC61H3 Chapter Notes -Convergent Evolution, Biological System, Complex System

Biological Sciences
Course Code
Karen Williams

of 2
BIOC15 - Genetics
(Lecture 1+2 reading notes; Chapter 1)
1.2 Proteins: the functional molecules of life processes
Most properties of life came from proteins (chains of amino acids and fold into 3D
o Organisms grow from time to time (could be drastic -> metamorphoses)
o Ability to move (animals walk and run; plants grow towards and away from light)
o Metabolism: ability to use sources and energy and matter to grow (convert other
substances into body masses)
1.3 Complex systems and molecular interactions
Biological system: any complex network of interacting molecules or groups of cells that
function in a coordinated manner through dynamic signalling
o Ie) human pancreas, community of animals
1.4 Molecular similarities of all life-forms
Many scientists believe that RNA was the first information processing molecular to
RNA is similar to DNA
o Bases (G, C, A, U -> T for DNA)
o Has the capacity to store, replicate, mutate and express information
o Not as stable as DNA; functions as a intermediary from DNA to protein
RNA is like protein:
o Able to fold into 3-D structures
All living organisms use the triplet groupings of the bases to encode for amino acids
o Genes in one organism might be able to function fine in another related
Convergent evolution: features in organisms that developed independently
o Ie) the eyes
Due to the similarities, model organisms are used to analyze human genes
1.5 The modular construction of genomes
Genetic complexity (families of genes) arose from duplicates of primordial genes
Protein-coding region of most genes is divided into small portions (exons) and separated
by noncoding regions (introns)
o This aids and promotes rapid rearranging of genes during evolution
1.6 Modern genetic techniques:
With a lot of organisms’ genomes sequenced, researchers only need to inactivate a
certain genes and observe the consequences that follow
o Ie) loss of gene for visual pigment produces fruit flies with white eyes instead of
the usual red colour
DNA chips (hybridization): chips have specific strings of DNA that would bind when
exposed to complementary sequences of the fluorescently labelled DNA sample.
1.7 Human genetics:
Molecular studies of human genome may lead to predictive or preventive medicine
o While some mutations always cause death, others will only predispose to
o Specific single base mutation in the beta-globin gene will almost always lead to
sickle cell anemia (to different degrees)
o BRAC1 (breast cancer 1) increases the risk of a woman of getting breast cancer
by 40-80% if she has one copy of the gene
o Further studies in genetics might be able to lead to insight in ways to
prevent/cure diseases
While genetics may be great for preventative purposes, tight guidelines might be set to
prevent the misuse of such knowledge