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Dna & rna

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Dna & rna

  1. 1. DNA,GENES AND HEREDITY Block 4,Case 2 Pbl G5 2017
  2. 2. OBJECTIVES 1. Define DNA,its function and locations 2. Explain the structure and function of nucleotides 3. Describe Nucleic acids and explain the relationship with nucleotides 4. Explain the chemical structure of nucleic acids 5. Explain the DNA double helix structure 6. Describe genes, its function and types and define the terms translation and transcription 7. Describe DNA sequence in chromosomes 8. Describe DNA assembly 9. Describe heredity
  3. 3. DNA ( deoxyribonucleic acid) DNA (deoxyribonucleic acid) is a type of macromolecule known as a nucleic acid. It is shaped like a twisted double helix and is composed of long strands of alternating sugars and phosphate groups, along with nitrogenous bases (adenine, thymine, guanine and cytosine).
  4. 4. DNA LOCATION DNA is organized into structures called chromosomes and housed within the nucleus of our cells..
  5. 5. Function of deoxyribonucleic acid (DNA) 1- give genetic instruction to organic beings. 2- DNA stores information to tell cells how to function, passing it on to the next generation of life through cells. It also helps in development.
  6. 6. NUCLEOTIDE
  7. 7. Nucleotide Function: 1- Nucleotides have a variety of roles in cellular metabolism. 2- They are the energy currency in metabolic transactions, 3- The essential chemical links in the response of cells to hormones and other extracellular stimuli 4- The structural components of an array of enzyme cofactors and metabolic intermediates. 5- They are the constituents of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
  8. 8. NUCLEIC ACID ● The nucleic acids are the building blocks of living organisms. ● They are molecules that allow organisms to transfer genetic information from one generation to the next. ● They are the polynucleotides having high molecular weight. The monomeric unit of which is nucleotide. ● All the types of NA’s work together to help cells replicate and build proteins.
  9. 9. Types and function of Nucleic Acids: 1) Deoxyribonucleic acid (DNA) ● Occurs in nucleus as well as cell organelles like chloroplast and mitochondria. ● It stores genetic information and control protein synthesis in cell by RNA. 2) Ribonucleic Acid (RNA) ● May be found in nucleus but mainly occurs in cytoplasm ● Directly synthesize specific proteins.
  10. 10. The relation between Nucleic acids and Nucleotides ● Nucleic acids contain genetic information and enable synthesis of proteins. Nucleotides are used to make Nucleic Acids. ● Nucleotides are the subunit that is polymerized (connected into a long chain) to make nucleic acids (DNA and RNA). ● Nucleotides consist of three smaller components: a ribose sugar, a nitrogenous base, and phosphate group(s). ● Nucleotides are the monomers that make up a nucleic acid, such as DNA or RNA.
  11. 11. NUCLEIC ACIDS Nucleic acids are molecules that allow organisms to transfer genetic information from one generation to the next. There are two types of nucleic acids: deoxyribonucleic acid (better known as DNA) and ribonucleic acid (better known as RNA).
  12. 12. What Are Nucleic Acids Made Of? The building blocks (monomers) of nucleic acid chains are nucleotides. Nucleotides themselves, however, are composed of three simpler units: a base, a monosaccharide, and a phosphate. 1- Base : Thus both DNA and RNA contain four bases: two pyrimidines and two purines. For DNA, the bases are A, G, C, and T; for RNA, the bases are A, G, C, and U.
  13. 13. What Are Nucleic Acids Made Of? 2. Sugars The sugar component of RNA is D-ribose .In DNA, it is 2-deoxy-D-ribose 3. Phosphate When this group forms a phosphate ester bond with a nucleoside, the result is a compound known as a nucleotide.
  14. 14. What Are Nucleic Acids Made Of? Summary: A nucleoside = Base + Sugar A nucleotide = Base + Sugar + Phosphate A nucleic acid = A chain of nucleotides .
  15. 15. Genes Definition :The study of the relationships between genes and enzymes, specifically the role of genes in controlling the steps in biochemical pathways. Function : Gene which are made up of DNA, act as instructions to make molecules called proteins.
  16. 16. Dominant Gene A dominant gene is a segment of DNA information that is used to make chromosomes. Dominant genes are a result of dominant alleles in chromosomes. When an allele is dominant it is expressed in the phenotype over a recessive allele. The phenotype is what chromosome is present in the organism. So a person with a dominant allele for brown hair and a recessive allele for red hair (this combination is identified in genetic notation as "Br") will have brown hair.
  17. 17. Recessive Gene A Recessive Gene is a gene that carries information in the DNA, i.e., hair, skin or eye color, blood types, straight or curly hair, etc. but is hidden (not visibly present). A child inherits only half of their DNA information from each parent and in this combination generally display the dominant genes they received. If they inherited only recessive genes for some trait, that is the trait that is displayed. This is why siblings can look very different from one another and why a person with two brown-eyed parents can be born with blue eyes (brown eye gene is dominant, blue eye gene is recessive) if they inherited a recessive blue eye gene from each parent.
  18. 18. Transcription & Translation. The process by which DNA is copied to RNA is called transcription, and that by which RNA is used to produce proteins is called translation. 1 - DNA (transcription) RNA 2 - when RNA leaving the cytoplasm it’s called (mRNA). 3 - (mRNA) will go to the ribosome , where it become a protein.
  19. 19. Compaction Levels of DNA Chains ● If a human DNA molecule were fully stretched out, its length would be perhaps 1 m. ● The DNA molecules in the nuclei are not stretched out, but rather coiled as nucleoprotein ● A high degree of compaction is necessary in order to store the long DNA molecules within cells ● The 1 meter long DNA has to be packed into a nucleus of 10 μm diameter ● Since DNA cannot be directly packed into the final dense structure of chromatin, hence proteins contribute to organization, most abundant are histone proteins. ● Histones are small basic proteins which are involved in the first packaging level of DNA.
  20. 20. Compaction Levels of DNA Chains ● Histones are rich in the positively charged amino acids lysine and arginine, binding tightly to the negatively charged DNA by electrostatic (ionic) forces, forming units called nucleosomes. ● The nucleosomes are linked by a short stretch of ‘linker’ DNA
  21. 21. ● A continuous string of nucleosomes forms a 10 nm filament. ● At the center of this nucleosome core particle, there is an octameric complex of histone proteins, resembling a small cylinder ● 240 bp of DNA are organized per nucleosome ● Next,the 10 nm fiber of nucleosomes forms a left-handed hollow helix of 6 nucleosomes per turn, the 30 nm chromatin filaments
  22. 22. ● They have the shape of a solenoid ● The solenoids are compacted further to form looped DNA domains. Each loop is 300 nm long and contains about 50 solenoid turns ● Loop domains are thought to be the basic unit of higher order DNA structure in all eukaryotic cells. ● During mitosis the loop domains are further packaged to form a 250 nm fiber, which coils to form the arms of a metaphase chromosome
  23. 23. DNA assembly The process of putting fragments of DNA that have been sequenced into their correct chromosomal positions. The pieces of DNA are assembled to reconstitute the sequence of the chromosome from which they came. DNA sequence assembly is a process through which short DNA sequence fragments (called reads or samples) are merged into a longer DNA sequence in the attempt to reconstruct the original DNA sequence. The longer sequence resulted from sequence assembly is called a 'contig' sequence. During sequence assembly the short DNA fragments may also be aligned to a reference sequence in order to see the differences between the contig sequence obtained and the reference sequence.
  24. 24. HEREDITY Heredity refers to the genetic transmission of traits from parents to offspring. Heredity helps explain why children tend to resemble their parents, as well as how a genetic disease runs in a family. Some genetic conditions are caused by mutations in a single gene. These conditions are usually inherited in one of several straightforward patterns, including autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, codominant, and mitochondrial inheritance patterns. Complex disorders and multifactorial disorders are caused by a combination of genetic and environmental factors. These disorders may cluster in families, but do not have a clear-cut pattern of inheritance.
  25. 25. Types of Inheritance 1. Dominant A dominant character or trait is when only one of the two recipes is expressed, be it the mother’s or the father’s, with one dominating over the other 2. Recessive-When both recipes are identical and are present twice 3. Co-dominant-When both recipes are expressed at the same time with the same intensity 4. Intermediate when both recipes are expressed at the same time but the resulting character or trait is an intermediate expression of both, because neither dominates over the other
  26. 26. REFRENCES Books ● Lehninger_principles_of_biochemistry_4th.ed ● Introduction to organic and biochemistry,7th-edition, page 396-399 ● · biochemical pathways An atlas of biochemistry and molecular biology, gerhard michal 2nd edition ● Introduction-to-organic-and-biochemistry-7th-edition .
  27. 27. REFRENCES Websites ● http://www.compoundchem.com/2015/03/24/dna/ ● http://www.chemguide.co.uk/organicprops/aminoacids/dna1.html ● http://lagenetica.info/en/life/types-of-inheritance/ ● http://web.chem.ucla.edu/~harding/notes/notes_14C_nucacids.pdf ● http://www.vanderbilt.edu/AnS/Chemistry/Rizzo/Chem220b/Ch28.pdf ● http://myhome.sunyocc.edu/~weiskirl/nucleotides_nucleicacid.htm ● https://ghr.nlm.nih.gov/primer/basics/gene ● https://www.alleydog.com/glossary/definition.php?term=Dominant%20Gene ● http://www.medicinenet.com/script/main/art.asp?articlekey=16834 ● http://www.medicinenet.com/script/main/art.asp?articlekey=16834 ● https://www.reference.com/science/function-dna-human-body-78e670164570498 ● https://www.thoughtco.com/dna-373454 ● http://www.agriinfo.in/default.aspx?page=topic&superid=4&topicid=1573 ● http://www.chem4kids.com/files/bio_nucleicacids.html

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