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Reference reading: Chapter 1, pages 1-1123
24I’m only here because I have to take cell biology as part of my degree – why should I care about cell biology?Understanding how cells work allowed development of treatments for :•Cancer(chemotherapy, radiotherapy, surgery)•Diabetes(insulin, TZDs, metformin, more)•Infectious diseases (antibiotics, aseptic techniques)•Cystic Fibrosis (antibiotics, other drugs)•Many, many moreIt can also allow YOU to make more informed decisions:
25Amyotrophic lateral sclerosis - ALSSuperoxide dismutase (SOD1)•SOD1 enzyme catalyzes conversion of superoxide radical to dioxygen and hydrogen peroxide•About ~12 mutations in SOD1 are known to lead to inherited ALSBanci L. 2008. PLoS ONE 3(2): e1677. doi:10.1371/journal.pone.00016772O2-+ 2H+O2+ H2O2.•ALS is a disease that results from the gradual death of motoneurons (due to buildup of toxic molecules)motoneuronSOD1
Life depends on chemical information that is stored, replicated and interconverted26Chemical information: a lot of it is “stored” as DNA
Main types of RNA1.mRNA: messenger RNA:•intermediate encoding the protein sequence•Each specific amino acid is represented by a specific set of three-nucleotide sequences = codons•These codons are translated into protein by the ribosome2.tRNA: transfer RNA•An intermediate that matches the mRNA codon to the corresponding amino acid3. rRNA: ribosomal RNA•Structural RNA molecules that build the ribosome along with ribosomal proteins31
33Life is driven by energetic processesThe laws of thermodynamics tell us that spontaneous reactions are those that either (intuitively):- reduce the enthalpy of the system- increase the entropy (disorder)of the system (or both)Cells are ordered structures that take relatively simple molecules and make them into more complex ones (e.g. DNA), which is both-an increase in enthalpy AND -a reduction in entropy (disorder)how does that happen?
34Laws of Thermodynamics•Law 2: Conversion of potential energy to work is always accompanied by transformation into heat and/or increased entropy•Entropy, S: randomness and disorder of the universeincreased entropy (+S) = increased disorder = spontaneousdecreased entropy (-S) = decreased disorder = non-spontaneous but… +S- S
35Laws of Thermodynamics•Enthalpy, H: energy content (heat) derived from volume, pressure and different types and number of bonds.