Reference reading chapter 1 pages 1 11 23 24 im only

This preview shows page 23 - 36 out of 98 pages.

Reference reading : Chapter 1, pages 1-11 23
24 I’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 more It can also allow YOU to make more informed decisions:
25 Amyotrophic lateral sclerosis - ALS Superoxide 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 ALS Banci L. 2008. PLoS ONE 3(2): e1677. doi:10.1371/journal.pone.0001677 2O 2 - + 2H + O 2 + H 2 O 2 . ALS is a disease that results from the gradual death of motoneurons (due to buildup of toxic molecules) motoneuron SOD1
Life depends on chemical information that is stored, replicated and interconverted 26 Chemical information: a lot of it is “stored” as DNA
Chemical information 27
Figure 1-2 Molecular Biology of the Cell , Fifth Edition (© Garland Science 2008) DNA stores the code of life 28
Figure 1-3 Molecular Biology of the Cell , Fifth Edition (© Garland Science 2008) DNA Replication makes faithful copies of the living code 29
Figure 1-5 Molecular Biology of the Cell , Fifth Edition (© Garland Science 2008) TRANSCRIPTION: Converting the DNA code (gene) into RNA 30 RNA are intermediates of information transfer. Transcription permits a choice: express or repress a gene!
Main types of RNA 1. 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 ribosome 2. tRNA: transfer RNA An intermediate that matches the mRNA codon to the corresponding amino acid 3. rRNA: ribosomal RNA Structural RNA molecules that build the ribosome along with ribosomal proteins 31
Figure 1-10a Molecular Biology of the Cell , Fifth Edition (© Garland Science 2008) TRANSLATION: ribosomes read mRNA into protein 32
33 Life is driven by energetic processes The 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?
34 Laws 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 universe increased entropy ( +S ) = increased disorder = spontaneous decreased entropy ( -S ) = decreased disorder = non- spontaneous but… +S - S
35 Laws of Thermodynamics Enthalpy , H : energy content (heat) derived from volume, pressure and different types and number of bonds.

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture