Cell biology revision notes PDF

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Cell biology revision notes: Lecture 1: -

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RNA is a long chai like molecule that conveys genetic information and speeds up other chemical reactions DNA took over as heritable genetic material later in life and is believed to have evolved from RNA The Stanley miller experiment shows the abiotic synthesis of amino acids by powering reactions present in earths early atmosphere by an electric spark that stimulated lighting. (the volcanic spark discharge experiment) Amino acids are the building blocks of the world + amines, that forms either instructive or catalyst RNA which lead to the self replicating system Pyrimidine ribonucleotides are derived from prescursor compounds acetylene and formaldehyde which undergo a series of chemical reactions to form them o Nucleic acid precursors were created from hydrogen cyanide (HCN), hydrogen sulphide (H2S) and ultraviolet light, these also created natural amino acids and lipids Formamidopyrimidine (FaPy) reacts to form purines Complementary base pairing allows RNA strands to serve as templates for exact copies o Uracil-adenine, guanine-cytosine o In this way RNA serves as an instruction Base pairing and nonconventional hydrogen bonds allow RNA to fold into unique 3D shapes that are determined by nucleotide sequence o Folding permits RNA to act as a ribozyme for many chemical reactions o Its simple structure limits its catalytic efficiency and scope compared to other enzymes o RNA splicing and translation are fundamental catalytic roles in gene expression RNA predates DNA o Ribose is readily formed from formaldehyde and deoxyribose is produced from ribose in a reaction catalysed by enzymes o Sugar deoxyribose (DNA) Is harder to make RNA compartmentalisation is when the RNA self replicating system is membrane encapsulated by hydrophilic heads and hydrophobic tails of phospholipids DNA arose later and is more suitable as a permanents repository of genetic information o Deoxyribose sugar makes DNA more chemically stable than RNA o Greater lengths of DNA can be synthesized without breakage o Replacement of uracil with thymine makes repair easier thus deamination is easier to detect and repair in DNA The central dogma: DNA  RNA  protein via transcription and translation The origins of life came from mineral rich water being super heated to 400 degrees celcius by magma, followed by raid cooling lead to the abundance of chemical essentials for life creating harsh but teeming with life environments ( worms, crabs, chemosynthetic bacteria) Genetic mutations coupled with natural selection have drove complex speciation of species. The rise in oxygen levels, acquisition of genetic mutations and natural selection pressures led to evolutionary complexity

Lecture 2: -

Prokaryotes: bacteria and archaea, they have a simple structure with no nucleus

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o They are the most diverse and numerous cells on earth o Small (5uM...