Biochemistry MT 6310 Lecture Notes PDF

BIOCHEMISTRY MT 6310 | LECTURE | 1ST TERM, AY 2021-2022 UNIT 1: BIOCHEMISTRY IN THE CELL CELL: FUNCTIONAL & STRUCTURAL UNIT OF LIFE OUTLINE...

BIOCHEMISTRY MT 6310 | LECTURE | 1ST TERM, AY 2021-2022 UNIT 1: BIOCHEMISTRY IN THE CELL CELL: FUNCTIONAL & STRUCTURAL UNIT OF LIFE OUTLINE Types of Cells I Biochemistry o prokaryote: “before the nucleus” II Biochemical Features of Living Organisms III Cell: Functional & Structural Unit of Life § single-celled organisms A Prokaryotic Cell § include bacteria and cyanobacteria i Structure and Function o eukaryote: “true nucleus” B Eukaryotic Cell § contain a well-defined nucleus surrounded by a i Structure and Function nuclear membrane IV Structure and Function of Eukaryotic Cells § can be single-celled, such as yeasts and A Cell Membrane Paramecium, or multicellular, such as animals and B Nucleus plants C Mitochondrion D Chloroplast E Endoplasmic Reticulum F Golgi Complex G Lysosome H Peroxisome I Cytoskeleton J Centrosome and Vacuole BIOCHEMISTRY multidisciplinary science that explores the chemistry of living organisms and the molecular basis for the changes occurring in living cells o ex. genetic code: all living organisms encodes information through synthesis of amino acids following same genetic code Basic principles of biochemistry are common to all living organisms. The knowledge of biochemistry can be applied to solve problems in medicine, agriculture, environmental sciences, etc. BIOCHEMICAL FEATURES OF LIVING ORGANISMS cells o basic structural and functional units of all living organisms o highly organized o constant energy source is required to maintain a cell’s function and ordered state Living processes consist of thousands of chemical reactions; precise regulation and integration of these reactions are required to maintain life. PROKARYOTIC CELL o Certain biochemical reaction pathways, ex. glycolysis considered as the ancestor of the eukaryotic cell and Krebs cycle, are found in almost all organisms. unicellular All organisms use the same types of biomolecules: two major divisions of prokaryotes: Archaebacteria proteins, nucleic acids, carbohydrates, lipids. (ancient class) and Eubacteria (true bacteria) The instructions for growth, development, and reproduction Escherichia coli – most studied prokaryote are encoded in each organism’s nucleic acid. STRUCTURE AND FUNCTION 2 definite membranes in a bacterial cell: cell wall and plasma membrane interior of the cell consists of the cytoplasm and nucleoid region o ribosomes, various RNAs, proteins (including enzymes) and small molecules (ex. water) fill the cytoplasm o bacterial chromosome – single circular molecule of naked DNA hair-like projections (flagella and/or pili) are also present [AUTHOR NAME] 1  Unit 1: Biochemistry in the Cell EUKARYOTIC CELL structurally more complex presence of nucleus phospholipid bilayer o possess a number of separate chromosomes filled with diverse structures o membrane-bound organelles o cytoplasmic membranes o other structures that lack surrounding membranes NUCLEUS principal feature that distinguished eukaryotic from prokaryotic cells serves both as repository of genetic information and as the cell’s control center processes involved: DNA replication, transcription, and RNA processing STRUCTURE AND FUNCTION cell membrane cytoplasm o organelles o cytoskeletal elements o cytosol STRUCTURE & FUNCTION OF EUKARYOTIC CELLS CELL MEMBRANE thin film of lipid and protein molecules held together by noncovalent interactions functions: o define and compartmentalize the cell MITOCHONDRION o serve as scaffold for biochemical activities plays a critical role in the generation of useful energy o provide selectively permeable barrier derived from the breakdown of lipids and carbohydrates o provide means of transporting solutes contains their own DNA encoding for tRNA, rRNA and some o play a role in cell-to-cell communications and detection mitochondrial proteins of external signals most mitochondrial proteins are synthesized on free ribosomes [AUTHOR NAME] 2  Unit 1: Biochemistry in the Cell GOLGI COMPLEX consists of a series of flattened membranous sacs (cisternae) involved in modifying, sorting, and packaging of macromolecules for secretion or for export to other organelles o posttranslational modification: occurs after protein synthesis o cotranslational modification: occurs during protein synthesis form by fusion of vesicles that bud off the ER CHLOROPLAST can harness solar energy to convert CO2 and H2O into carbohydrates; photosynthetic generation of ATP synthesize their own amino acids, fatty acids, and lipid components of their own membranes reduction of NO2- to NH3 also occurs in chloroplasts LYSOSOME membrane-enclosed organelle that functions to degrade materials taken into the cell and to digest worn out or unnecessary cell components o when a protein is synthesized, it undergoes folding to become a native protein o folding sometimes doesn’t happen which produces unnecessary cell component that will be hydrolyzed/digested instead contains about 50 different hydrolytic enzymes that can breakdown macromolecules – for hydrolysis ENDOPLASMIC RETICULUM network of membrane-enclosed tubules and sacs that extend from the nuclear membrane throughout the cytoplasm largest organelle in the cell two types: rough ER and smooth ER rough ER o flattened sheets that is continuous to the other nuclear membrane o characterized by the presence of ribosomes on the cytosolic side of the membrane smooth ER o tubular in shape PEROXISOME o involved in lipid and metabolism and several cellular small membrane-enclosed organelle that contain enzymes processes: drug detoxification, carbohydrate in a variety of metabolic reactions metabolism and synthesis of neutral fats, production and decomposition of H2O2 phospholipids, and steroids oxidative reactions of uric acid, amino acids, and fatty acids synthesis of cholesterol, dolichol, and bile acids in specialized cells in plants, glyoxylate cycle and photorespiration occurs [AUTHOR NAME] 3  Unit 1: Biochemistry in the Cell CYTOSKELETON complex networks of protein filaments extending throughout the cytoplasm determines cell shape and internal organization, responsible for the movement cell three principal types of cytoskeletons: o microfilaments o intermediate filaments o microtubules CENTROSOME AND VACUOLE centrosome o aka microtubule organizing center o function: to aid cellular division vacuole o functions as storage depots for nutrients, wastes, and specialized materials such as pigments [AUTHOR NAME] 4