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Chapter 5 the structure and function of large biological molecules

Chapter 5 the structure and function of large biological molecules . Key concepts: Macromolecules are polymers , built from monomers Carbohydrates serve as fuel and building material Lipids are a diverse group of hydrophobic molecules

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Chapter 5 the structure and function of large biological molecules

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  1. Chapter 5the structure and function of large biological molecules Key concepts: • Macromolecules are polymers, built from monomers • Carbohydrates serve as fuel and building material • Lipids are a diverse group of hydrophobic molecules • Proteins have many structures, resulting in a wide range of functions • Nucleic acids store and transmit hereditary information Dr.Dalia Mohsen Ms: Hiba salah

  2. Macromolecules are polymers, built from monomers • The large molecules can be called macromolecules • The four classes of macromolecules are: carbohydrates, lipids, proteins, and nucleic acids. • Three of the four classes of macromolecules form chain like molecules called polymers. • Polymers consist of repeated units linked by covalent bonds. • The repeated units are small molecules called monomers. Dr.Dalia Mohsen Ms: Hiba salah

  3. The Synthesis and Break down of PolymerIn dehydration (removing water) the covalent bond is formed. Dr.Dalia Mohsen Ms: Hiba salah

  4. In hydrolysis (adding water), the covalent bond is broken. Dr.Dalia Mohsen Ms: Hiba salah

  5. Carbohydrates • Carbohydrates serve as fuel and building material. • Carbohydrates include:- • Monosaccharides or simple sugars. • Disaccharides, consist of two monosaccharides. • Polysaccharides are polymers of monosaccharides. Dr.Dalia Mohsen Ms: Hiba salah

  6. Monosaccharides: Monosaccharides have a carbonyl group (CHO) and multiple hydroxyl groups (OH). The most common one is : Glucose(C6H12O6) • It’s the major nutrient for cell. • It Serves for the synthesis of amino acids or fatty acids. Dr.Dalia Mohsen Ms: Hiba salah

  7. Galactose Glucose Fructose Monosaccharides Dr.Dalia Mohsen Ms: Hiba salah

  8. Disaccharides:Two monosaccharides bonded with a glycosidic linkage to form a disaccharide via dehydration.For example, Maltose, is formed from two glucose molecules. Sucrose, is formed from glucose and fructose. Dr.Dalia Mohsen Ms: Hiba salah

  9. Dr.Dalia Mohsen Ms: Hiba salah

  10. Polysaccharides are polymers of hundreds to thousands of monosaccharides bonded by glycosidic linkages. They serve as; • Storage materials • Building materials Dr.Dalia Mohsen Ms: Hiba salah

  11. Storage polysaccharides: • Starch (a storage polysaccharide of plants). • Glycogen(a storage polysaccharide of animals in liver and muscles). • Structural polysaccharides: • Cellulose (plant cell walls). • Chitin important for arthropods. Dr.Dalia Mohsen Ms: Hiba salah

  12. Lipids Lipids are a diverse group of hydrophobicmolecules. They have the same properties:- • do not have polymers. • They all have no affinity for water, they don’t mix with water • They have nonpolar covalent bonds. The most important biological types Fats, phospholipids and steroids. Dr.Dalia Mohsen Ms: Hiba salah

  13. Fats and oils Phospholipids forms cell membrane Cholesterol and sex hormones Dr.Dalia Mohsen Ms: Hiba salah

  14. 1. Fats: • Constructed of two kind of molecules: Glycerol and fatty acid joined together by ester linkage. • Saturated fats: are haven't double bond between carbon atoms in the hydrocarbon chain. • Unsaturated fats: have one or more double bond Dr.Dalia Mohsen Ms: Hiba salah

  15. A diet rich in saturated fats may cause cardiovascular disease. • Unsaturated fats must be supplied in human food , include omega-3. Fish and vegetable oil are rich in omega-3. • The major function of fats is energy storage as a subcutaneous layer (beneath the skin). Dr.Dalia Mohsen Ms: Hiba salah

  16. Triacyglycerol A kink where double bond is Straight line Dr.DaliaMohsen Ms: Hibasalah

  17. Phospholipids: • It is very essential for cell membrane. • Consist of two fatty acids attached to glycerol joined to phosphate group. • Has hydrophilic polar head and hydrophobic non polar tail. Dr.Dalia Mohsen Ms: Hiba salah

  18. Phospholipids molecule Dr.Dalia Mohsen Ms: Hiba salah

  19. Phospholipids are very essential for cell membrane. Dr.Dalia Mohsen Ms: Hiba salah

  20. Steroid: • Are lipids characterized by carbon skeleton consisting of four rings . Dr.Dalia Mohsen Ms: Hiba salah

  21. Examples :- • Sex hormones. • cholesterol is common component in animal cell membrane. High level of cholesterol in blood cause Arteriosclerosis. Dr.Dalia Mohsen Ms: Hiba salah

  22. Proteins • Proteins Account more than 50% of dry mass of cell. • A protein is a polymer of Constructed from the same set of 20 aminoacids (monomer). Dr.Dalia Mohsen Ms: Hiba salah

  23. They serves as: • Catalyst: act as enzymes. • Defense: such as antibodies. • Storage • Transport • Cellular communication • Movement and structural support Dr.Dalia Mohsen Ms: Hiba salah

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  29. Aminiacid monomer Dr.Dalia Mohsen Ms: Hiba salah

  30. The physical and chemical characteristics of the R group determine the unique characteristics of a particular amino acid. Dr.Dalia Mohsen Ms: Hiba salah

  31. If R group is hydrophilic, the amino acid is hydrophilic. Dr.Dalia Mohsen Ms: Hiba salah

  32. If R group is hydrophobic, the amino acid is hydrophobic Dr.Dalia Mohsen Ms: Hiba salah

  33. If R group is an acid, the amino acid is an acid.If R group is a base, the amino acid is a base. Dr.Dalia Mohsen Ms: Hiba salah

  34. Amino acids are joined together via dehydration. • The resulting covalent bond is called a peptide bond. • Repeating the process over and over creates a long polypeptide chain. Dr.Dalia Mohsen Ms: Hiba salah

  35. A change in suitable condition cause protein denaturation (protein will destroy ) As example, change in pH, salt concentration, temperature. Dr.Dalia Mohsen Ms: Hiba salah

  36. Protein structure:- • A cell synthesizes a polypeptide • Then it folds spontaneously to form the functional structure. • The four level of protein structure: • Primary • Secondary • Tertiary • Quaternary Dr.Dalia Mohsen Ms: Hiba salah

  37. The functional structure is unique for every protein Fibrous Globular Dr.Dalia Mohsen Ms: Hiba salah

  38. Chaperonin (chaperon) Is a protein molecule assist proper folding of polypeptide. Dr.Dalia Mohsen Ms: Hiba salah

  39. Nucleic acid Nucleic acids are polymers of monomers called nucleotides. Each nucleotide consists of three parts: a nitrogen base, a pentose sugar, and a phosphate group. Dr.Dalia Mohsen Ms: Hiba salah

  40. The component of nucleic acid Dr.Dalia Mohsen Ms: Hiba salah

  41. There are two families of nitrogenous bases: • Pyrimidines(cytosine, thymine, and uracil)have a single ring. • Purines(adenine and guanine) have two ring. Dr.Dalia Mohsen Ms: Hiba salah

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  43. There are two types of nucleic acid: • DNA, the sugar is deoxyribose (ribose sugar without one oxygen atom). • RNA, the sugar is ribose Dr.Dalia Mohsen Ms: Hiba salah

  44. Polynucleotide strand is synthesized by connecting the sugar of one nucleotide to the phosphate of the adjacent nucleotide with a phosphodiester linkage.Adenine (A) always pairs with thymine (T) and guanine (G) with cytosine (C). in RNA A with U. Dr.DaliaMohsen Ms: Hibasalah

  45. Nucleic acids store and transmit hereditary information DNA / Gene: is the genetic information for an organisms inherited from parents. Chromosome: is long DNA molecule carry hundreds or more gene. DNA provides directions for its own replication And directs synthesis of messenger RNA (mRNA) and, through mRNA, controls protein synthesis Protein synthesis occurs by ribosomes. Dr.Dalia Mohsen Ms: Hiba salah

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  47. One end of phosphate group attached to 5 ̄ carbon and other end attached to 3̄ carbon of sugar. • The sequence of bases along DNA or mRNA is unique for each gene and provides very specific information. For example: The sequence 5̄ -AGGTCTT-3̄ has different meaning from 5̄-CGCTTTAC-3̄. Dr.Dalia Mohsen Ms: Hiba salah

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  49. The differences between DNA and RNA:1- RNA is a single polynucleotide chain but DNA has two polynucleotide strands form a double helix.2- DNA is longer and larger than RNA3- RNA has Uracil instead of Thymine.4- The pentose sugar in DNA is Deoxyribose instead of ribose in RNA. Dr.Dalia Mohsen Ms: Hiba salah

  50. 2- To what does the term "polypeptide" mean? inorganic molecules linked by dehydration amino acids linked by hydrolysis carbohydrates with a hydrogen bond holding them together none of the above 3- If a strand of DNA has the nitrogen base sequence ATTTGC, what will be the sequence of the matching strand? a) GCAAAT  b) ATTTGC  c) TAAACG  d) TUUUCG e) UAAACG 1- The fatty acid tails of a phospholipid are ___ because they __. A) hydrophobic ... dissolve easily in waterb)  hydrophobic ... Do not dissolve in water Dr.Dalia Mohsen Ms: Hiba salah

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