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Advanced Environmental Biotechnology II Review of Molecular Biology – DNA and RNA structure and protein production.
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Living things are made up of atoms Atoms can be joined together to make molecules
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Organic molecules are made by living things Organic molecules contain carbon An example is methane (CH 4 )
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When two methanes are combined, the resultant molecule is Ethane, which has a chemical formula C 2 H 6. Draw ethane Molecules made up of H and C are known as hydrocarbons.
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When two methanes are combined, the resultant molecule is Ethane, which has a chemical formula C 2 H 6. Draw ethane Molecules made up of H and C are known as hydrocarbons.
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Big molecules are often made by adding smaller subunits together If the subunits are the same then we get a polymer
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These are polymers Many small bits are added Macromolecules are big Macro means big ‘poly’ means ‘many’
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Cells have organic molecules which are needed for life. Many of these are big molecules (what is the name for big molecules?) Can you name any types of big molecules?
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Cells have organic molecules which are needed for life. Many of these are big molecules (macromolecules) Carbohydrates Lipids Proteins Nucleic acids
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Can you guess what types of atoms are in carbohydrates?
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carbon hydrogen oxygen – ate is a way of saying a molecule has lots of oxygen
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Proteins Proteins are polymers of 20 different amino acids.
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Each amino acid has a special side group of atoms The side group of atoms makes the amino acid special
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Amino Acid The amino group on the left and the carboxyl group on the rightaminocarboxyl R is the side group of atoms
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There are 20 Amino Acids. Images from Purves et al., Life: The Science of Biology, 4th Edition,
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Some Amino Acids http://en.wikipedia.org/wiki/List_of_standard_amino_acids
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Amino Acids have different Functional Groups. Images from Purves et al., Life: The Science of Biology, 4th Edition,
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Each protein has a special amino acid sequence
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Amino acids can join to form a peptide bond
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Proteins have Complex Structures. Images from Purves et al., Life: The Science of Biology, 4th Edition,
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The amino acid sequence will make the three-dimensional (3D) structure.
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. Images from Purves et al., Life: The Science of Biology, 4th Edition,
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Functional Groups Biochemical molecules act certain ways because of functional groups of atoms Functional groups are groups of atoms with their own structure and functions
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Example of functional group - Polarity Polar molecules (with +/- charges) like water molecules and are hydrophilic (water lover) Nonpolar molecules don’t like water and do not dissolve in water; are hydrophobic (water fear) Cells are 70-90% water, so how organic molecules act together with water affects their function One of the most common groups is the -OH (hydroxyl) group which lets a molecule be water soluble
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. Images from Purves et al., Life: The Science of Biology, 4th Edition,
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The sequence of amino acids Because of the different functional groups different proteins will do different things Some proteins are used to build cells Other proteins have special work to do These special proteins are enzymes
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Enzymes are the tools which cells use to do things. We use tools If we want to hammer a nail we use a hammer.
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We could use a brick but a hammer would work better.
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To open a bottle we would use a bottle opener.
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If we want to screw in a screw we could use a knife but a screwdriver would work better.
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For special screws we could use special screwdrivers.
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We can use pliers to hold things. To hold different things in different ways we use different pliers.
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All of these are tools. When we have work to do we use a special tool.
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When cells have work to do they use enzymes Cells use enzymes as tools Enzymes do the work in cells
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This enzyme is used to break up proteins
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Different enzymes do different things This enzyme helps cells get energy from sugar
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Some enzymes need metals to help them work Here is an enzyme with a zinc ion This enzyme makes these reactions work CO 2 + H 2 O => HCO 3 - (in tissues - high CO 2 concentration) HCO 3 - => CO 2 + H 2 O (in lungs - low CO 2 concentration, in plant cells)
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There are many different types of enzymes
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Some enzymes can work on many chemical reactions Toluene dioxygenase from Pseudomonas putida can take part in more than one hundred different reactions. Some enzymes can do only a few reactions
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Enzymes can work on the products of other enzymes. There are linked chains of reactions. http://www.genome.ad.jp/kegg/pathway/map/map01110.html
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The living cell needs many different chemical reactions http://www.genome.ad.jp/kegg/pathway/map/map01100.html
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The living cell needs many different chemical reactions http://www.genome.ad.jp/kegg/pathway/map/map01100.html Let’s look at this part
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This part also has many reactions and enzymes http://www.genome.ad.jp/kegg/pathway/map/map01196.html
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This part also has many reactions and enzymes http://www.genome.ad.jp/kegg/pathway/map/map01196.html Let’s look at this small part
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There are many enzymes in this small part Each enzyme has a number like 3.8.1.8 Let’s look at that enzyme http://www.genome.ad.jp/kegg/pathway/map/map00791.html
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Let’s meet atrazine chlorohydrolase atrazine + H 2 O 4-(ethylamino)-2-hydroxy- 6-(isopropylamino)-1,3,5-triazine + HCl
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www.accessexcellence.org/AB/GG/steps_to_Prot.html
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Deoxyribonucleic acid (DNA) DNA contains the genetic instructions which determine protein structure. DNA is a long polymer of nucleotides (a polynucleotide). DNA encodes the sequence of the amino acid residues in proteins using the genetic code, a triplet code of nucleotides. In prokaryotes, including the eubacteria and archaea, DNA is not separated from the cytoplasm by a nuclear envelope. Chloroplasts and mitochondria also carry DNA. During cell division, DNA is replicated.
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Overview DNA consists of a pair of molecules, organized as strands running start-to-end and joined by hydrogen bonds along their lengths.[ Each strand is a chain of chemical "building blocks", called nucleotides, of which there are four types: adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T) These bases of nucleic acids can be arranged in the polymer in any order, giving the molecules a high degree of uniqueness. A strand of DNA contains genes, areas that regulate genes, and areas that either have no function, or a function yet unknown. Genes can be loosely viewed as the organism's "cookbook" or "blueprint". Each base on one strand forms a bond with just one kind of base on another strand, called a "complementary" base: A bonds with T and C bonds with G.
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http://en.wikipedia.org/wiki/DNA
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Molecular structure Each molecule is a strand of DNA: a chemically linked chain of nucleotides, each of which consists of a sugar (deoxyribose), a phosphate and one of five kinds of nucleobases ("bases"). Because DNA strands are composed of these nucleotide subunits, they are polymers.
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http://en.wikipedia.org/wiki/DNA
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Because pairing causes the nucleotide bases to face the helical axis, the sugar and phosphate groups of the nucleotides run along the outside; the two chains they form are sometimes called the "backbones" of the helix. Bonds between the phosphates and the sugars link one nucleotide to the next.
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http://en.wikipedia.org/wiki/DNA
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Nucleotides There are five kinds of nucleotides, which can be named by the names of their bases. These are adenine (A), thymine (T), uracil (U), cytosine (C), and guanine (G). U is rarely found in DNA. RNA usually contains U in place of T, but in certain RNAs such as transfer RNA, T is always found in some positions. The difference between DNA and RNA is the sugar, 2-deoxyribose in DNA and ribose in RNA. A to T pairing forms two hydrogen bonds and C to G forms three hydrogen bonds. The GC content and length of each DNA molecule makes the pairing stronger. The temperature required to break the hydrogen bond, is the DNA’s Melting temperature (also called Tm value).
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Nucleotide sequence The sequence of nucleotides along a DNA strand defines a messenger RNA sequence which then defines a protein. The genetic code consists of three-letter 'words' (termed a codon) formed from a sequence of three nucleotides (e.g. ACT, CAG, TTT). These codons can then be transcribed into messenger RNA. The code is then translated for each amino acid to make a protein. Most amino acid, have more than one possible codon. There are also three 'stop' or 'nonsense' codons.
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Genetic Code http://www.bioss.sari.ac.uk/~dirk/genomeOdyssey/go_1966.html
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Transcription A DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA. Transcription goes in the 5' → 3' direction. Transcription is divided into 3 stages: initiation, elongation and termination.
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RNA polymerase RNA polymerase is an enzyme responsible for making RNA from a DNA template. It does this by constructing RNA chains through a process termed transcription. RNA polymerase is a nucleotidyl transferase that polymerizes ribonucleotides at the 3' end of an RNA transcript. RNA polymerase enzymes are essential and are found in all organisms, cells, and many viruses.
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Look at movie “Transcription” http://www.wehi.edu.au/education/wehi- tv/dna/index.html
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Ribonucleic acid (RNA) RNA is a nucleic acid polymer consisting of nucleotide monomers. RNA nucleotides contain ribose rings and uracil. RNA acts as the template for translation of genes into proteins, (messenger RNA) transferring amino acids to the ribosome to form proteins, (transfer RNA) and translating the transcript into proteins. (ribosomal RNA)
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Ribosomal RNA (rRNA) Ribosomal RNA (rRNA) is the main component of the ribosome. The ribosome makes proteins. The rRNA and about 70 – 80 ribosomal proteins fold up into two complex folded structures. rRNA decodes mRNA into amino acids (at center of small ribosomal subunit) and interacts with the tRNAs during translation by providing petidyltransferase activity (large subunit). rRNA is the most conserved (least variable) gene in all cells. Genes that encode the rRNA (rDNA) can be used to identify an organism's taxonomic group, and calculate related groups. In Bacteria, Archaea, Mitochondria, and Chloroplasts the small ribosomal subunit contains 16S rRNA. S means Svedberg units which is a measure of how quickly the particles sediment. The large ribosomal subunit contains two rRNA species (the 5S and 23S rRNAs).
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rna.ucsc.edu/rnacenter/ribosome_images.html
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http://tigger.uic.edu/classes/phys/phys461/phys450/ANJUM04/ribosome.jpg
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rna.ucsc.edu/rnacenter/ribosome_images.html
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