FUNBIO 3 2024 Biological Molecules RCSI PDF

Biological molecules: Lipids and Nucleic Acids Class: Foundation Year Course: Fundamentals of Human Biology Code: FUNBIO 3 Lecturer : Dr. Kulwinder Kaur Date: 02-10-2024  Learning Outcomes Outline the classification system for lipid molecules. Describe the basic structure of f...

Biological molecules: Lipids and Nucleic Acids Class: Foundation Year Course: Fundamentals of Human Biology Code: FUNBIO 3 Lecturer : Dr. Kulwinder Kaur Date: 02-10-2024  Learning Outcomes Outline the classification system for lipid molecules. Describe the basic structure of fatty acids and explain their role in the body. Describe the structure of triglycerides and explain their role in cell membranes. Discuss pyrimidines and purines and the formation of nucleosides, nucleotides and ATP. Outline the basic structure of the polynucleotides, RNA and DNA.  Lipids - Background Biomolecules that are water-insoluble but soluble in organic solvents (e.g. chloroform). or ethanol COOH Fatty acids -are carboxylic acids that typically contain between 12 and 20 carbon atoms. Lipid with fatty acids; fats, oils, waxes, phospholipids, Carotenoids Lipids without fatty acids; Steroids Biological Importance; Energy storage, cell membrane, protection (cushion vital organs), Vision, Hormones  Saturated and Unsaturated Fatty Acids  Corn oil contains 86% unsaturated fatty acids and 14% saturated fatty acids. Saturated and Unsaturated Fatty Acids Saturated Fatty Acid Monounsaturated Fatty Acid Polyunsaturated Fatty Acid Polyunsaturated Fatty Acid Triglycerids (Animal fats & vegetable oils) Three fatty acid residues are joined to glycerol by ester bonds. Most abundant lipids in living organisms When metabolized, yield twice as much energy as carbohydrates Carbohydrates and proteins can be transformed into fats by enzymes Triglycerids  Phospholipids Phospholipids are the fat or lipids that are the main constituent of any cell membrane. These phospholipids comprise fatty acid molecules, one phosphate group, and one glycerol molecule. They have a hydrophilic (“water-loving”) and a hydrophobic (“water-fearing”). (amphipathic lipids). The two ends differ physically and chemically. Phospholipids aid in maintaining the functional and structural integrity of cell membranes. Indicate double bond  Phospholipid & phospholipid bilayer One of the constituents of phospholipids is phosphorus which is crucial for maintaining healthy bones, teeth, and DNA. The fundamental structure of the membrane is the phospholipid bilayer, which forms a stable barrier between two aqueous compartments.  Steroids Carbon atoms in four fused/attached rings. They do not resemble the other lipids structurally. They are included in lipid category because they are also hydrophobic and insoluble in water. They are involved in regulating metabolism, growth and reproduction, inflammation and immunosuppression.  Cholesterol is the most common steroid and is mainly synthesized in the liver  Cortisol regulates body's stress response  Carotenoids Lipid molecules synthesized by algae, fungi, plants, and photosynthetic bacteria. Over 700 forms of carotenoids have been identified Responsible for red, orange, and yellow colors in foods and flowers. Consist of isoprene units double-single-double bond etc Vitamin A (Retinol) Converts to vitamin A  Nucleic Acids Large biomolecules that play essential roles in all cells and viruses Storage and expression of genomic information Transmit hereditary information Determine what proteins a cell manufactures Types: Two types of nucleic acid found in cells 1. Deoxyribonucleic acid (DNA) 2. Ribonucleic acid (RNA)  Polymers of nucleotides  Nucleotides The building blocks of nucleic acids (RNA & DNA) Messengers for signal transduction Provide energy for cellular processes Structure: (5 carbons) 1. Pentose sugar: Five carbon sugar 2. Phosphate group 3. Organic base (Nitrogenous base) : Purine (multiring) or Pyrimidine (single ring)  Pentose sugar: Five carbon sugar The pentose sugar can be either ribose(in RNA) or deoxyribose (in DNA). Both are same, except deoxyribose has one less oxygen.  Nucleosides  Nucleosides: pentose sugar + nitrogenous base no phosphate Ribonucleoside Deoxy-ribonucleoside Nucleoside vs nucleotide  Nucleotides as energy deposit : Adenosine triphosphate (ATP)Molecule The chemical bond between phosphates (P-O-P) is the major source of energy in the cell When needed ATP is dephosphorylated, with release of energy Same reactions can occur in opposite direction when energy storage is required ATP Adenosine triphosphate ATP)Molecule Energy Released Energy Absorbed  Deoxyribonucleic acid (DNA) The double-helix model revealed: That the genetic information is hidden in the sequences of the nitrogenous bases The modality through which DNA can self-replicate in daughter cells and thus the way the genetic information could be inherited among generations adenine (A), cytosine (C), guanine (G), and thymine (T): base pairing rules (A with T and C with G) Nitrogenous bases interact with each other complementarily  At actual size, a human cell's DNA totals about 3 meters in length!!  Ribonucleic acid (RNA) Nucleotides are joined by phosphodiester linkages RNA is single stranded i.e. one chain linear chain Carrying the instructions to synthesize proteins to regulating genes. One molecule of phosphoric acid bridges C3 of one nucleotide and C5 of the other. Polynucleotide chain grow always from 5’ to 3’ direction 4** not 5^^^  DNA-RNA-Protein Transcription: The information stored in a gene's DNA is passed to a similar molecule called RNA in the cell nucleus. The type of RNA that contains the information for making a protein is called messenger RNA (mRNA) from the DNA out of the nucleus into the cytoplasm. Translation: The second step takes place in the cytoplasm. The mRNA interacts with a specialized complex called a ribosome, which "reads" the sequence of mRNA nucleotides. Each sequence of three nucleotides, called a codon, usually codes for one particular amino acid. A type of RNA called transfer RNA (tRNA) assembles the protein, one amino acid at a time. Protein assembly continues until the ribosome encounters a “stop” codon (a sequence of three nucleotides that does not code for an amino acid). The flow of information from DNA to RNA to proteins is one of the fundamental principles of molecular biology. Known as central dogma.  Gene Expression Gene is a sequence of nucleotides in chromosomic DNA that encodes the synthesis of a gene product, either RNA or protein. Chromosomes carry DNA in cells. Genes are segments of DNA, which give physical characteristics that make it unique. Process by which the information encoded in a gene is turned into a function When a cell requires a specific protein, it activates the corresponding gene, transcription of RNA molecule followed by translation.  Cyclic adenosine monophosphate (cAMP) Cell signalling Transfers the effects of hormones into cells e.g. glucagon and adrenaline, which cannot pass through the plasma membrane. It is also involved in the activation of protein kinases (ATP-ADP). ATP-cAMP when phosphate is broken down, leftover molecule is called cAMP Overview of Biological Molecules Overview of Biological Molecules Chapter 3 ‘The Chemistry of Life’ Organic Compounds Solomon 11th Ed. Lipids: p56- 59 Nucleic Acids: p68 - 69 Thank you F O R M O R E I N F O R M AT I O N P L E A S E C O N TA N T NAME SURNAME EMAIL: [email protected]