Introduction to Molecular and Cell Biology BIO 150 PDF

INTRODUCTION TO MOLECULAR AND CELL BIOLOGY BIO 150 University of the Philippines - Baguio | Pablo Serrano A.Y. TERM 22 23 - L1A: HISTORICAL LANDMARKS IN DETERMINING CELL STRUCTURE ● OUTLINE I. HISTORY OF CELLULAR AND MOLECULAR BIOLOGY A. WHAT IS MOLECULAR BIOLOGY B. MOLECULAR BIOLOGY TIMELINE...

INTRODUCTION TO MOLECULAR AND CELL BIOLOGY BIO 150 University of the Philippines - Baguio | Pablo Serrano A.Y. TERM 22 23 - L1A: HISTORICAL LANDMARKS IN DETERMINING CELL STRUCTURE ● OUTLINE I. HISTORY OF CELLULAR AND MOLECULAR BIOLOGY A. WHAT IS MOLECULAR BIOLOGY B. MOLECULAR BIOLOGY TIMELINE HISTORY OF CELLULAR AND MOLECULAR BIOLOGY ● ● ● ● ● ● ● ● ● 1665: Robert Hooke ○ Used a primitive microscope to describe small pores in sections of cork that he called “cells” ○ Hooke’s most important publication was Micrographia, a 1665 volume documenting experiments he had made with a microscope. 1674: Anton van Leeuwenhoek ○ Using a microscope, he looked at water droplet that came from a pond water ○ Reported his discovery of protozoa which he called “animalcules” ○ He sees bacteria for the first time 9 years later ○ Father of Microbiology 1833: Robert Brown ○ Published his microscopic observation of orchids clearly describing the cell nucleus 1838: Matthias Schleiden and Theodore Schwann ○ Proposed the cell theory, stating that the nucleated cell is the universal building block of plant and animal tissues ○ Cell Theory: ■ All Living things are made up of cells. ■ Cells are the basic units of structure and function of living things. ■ New cells are only from existing cells 1857: Albert von Kolliker ○ Looked at muscle cells and observed the mitochondria 1879: Walther Flemming ○ Described with great clarity chromosome behavior during mitosis in animal cells 1881: Santiago Ramon y Cajal ○ Developed staining methods that revealed the structure of nerve cells and the organization of neural tissues ○ Founder of modern neurobiology 1898: Camillo Golgi ○ Applied a staining method using silver nitrate ○ Described the Golgi Apparatus ○ Golgi’s method was used to visualize nervous tissues in the brain 1902: Theodor Boveri ○ Linked chromosome and heredity by observing chromosome behavior during sexual reproduction ○ Boveri was the first to see evidence of meiosis in horse nematode ● ● ● ● ● ● ● 1952: Palade, Porter and Sjostrand ○ Developed methods of Electron Microscopy that enabled many intracellular structures to be seen for the first time ○ The “big three” in the 1950’s for their pioneering use of the electron microscope to describe details of cellular structure that anchored the current field of cell biology. A. George Palade ○ First to show the structure of the mitochondrion (Palade, 1952) ○ Was even able to visualize a structure that was later identified as ATPase ○ Described small granular components called the ribosomes (Palade, 1955) ○ Described the Endoplasmic Reticulum B. Fritiof S. Sjostrand ○ contributed the first high-resolution pictures of mitochondria and dramatically improved techniques for ultrathin sectioning with minimal distortion. ○ Much of his effort went into distinguishing real observations from distortion artifacts. 1930-1950’s: 3 disciplines merged to give rise to Cell Biology ○ Cytology: Invention of the electron Microscope ○ Biochemistry: Kreb elucidated the TCA cycle ○ Genetics: Avery, Mcleod & McCarthy; showed that DNA is the agent of genetic transformation 1952: Hugh Huxely ○ Showed the muscles contains arrays of protein filaments –the first evidence of the cytoskeleton ○ Along with J. Hanson, they proposed the sliding theory of muscle contraction 1957: James David Robertson ○ Described the bilayer structure of the cell membrane, seen for the first time in EM 1960: John Kendrew ○ Described the first detailed protein structure (sperm whale myoglobin) to a resolution of 0.2 nm using Xray Crystallography ○ Shared the 1962 Nobel Prize in Chemistry with Max Perutz 1968: Mojmir Petran & Collaborators ○ Developed the Tandem Scanning Microscope, the first confocal microscope 1974: Elias Lazarides and Klaus Weber ○ Developed the use of fluorescent antibodies to stain the cytoskeleton ○ Microfilaments: globular protein actin = G actin ○ Microtubules: globular proteins tubulins ○ Intermediate filaments: various fibrous proteins 1994: Martin Chalfie et al. ○ Introduced the green fluorescent protein (GFP) as a marker in microscopy ○ GFP expression can be used in monitoring gene expression studies and localization of proteins in living organisms LAGRASON, LIECA ANGELINE L. | BS BIOLOGY 1 WHAT IS MOLECULAR BIOLOGY ● ● The attempt to understand biological phenomena in molecular terms. The study of gene structure and function at the molecular level (Weaver, R., 2008) ● ● MOLECULAR BIOLOGY TIMELINE ● 1995: Craig Venter and Hamilton Smith ○ Determined the base sequence of two bacteria: Haemophilus influenzae and Mycoplasma genitalium (first free-living organisms to be sequenced) ○ Sanger Sequencing Method in 6 steps: ● ● ● ● ● ● 1996: Many investigators ○ Determined the base sequence of the genome of brewer’s yeast (Saccharomyces cerevisiae) first eukaryotic organisms to be sequenced 1997: Ian Wilmut et al. ○ Cloned a sheep (Dolly) from an adult sheep udder cell 1998: Andrew Fire and Craig Mello ○ Discovered that RNAi works by degrading mRNAs containing the same sequence as an invading dsRNA ○ RNAi - is a biological process in which RNA molecules inhibit gene expression by causing the destruction of specific mRNA ○ How RNAi Work: ■ DICER processes dsRNA creating siRNA ■ siRNA associates with RISC ■ Guided by the siRNA, the siRNA-RISC will bind to mRNA and cleave – inhibiting translation 2003: Many Investigators ○ Reported and finished sequence of the human genome 2007: Craig Venter and colleagues ○ Used traditional sequencing to obtain the first sequence of an individual human (Craig Venter) ○ Initiated a race in sequencing the entire human genome 2008: Jian Wang and colleagues ○ Used “next generation” sequencing to obtain the first sequence on an Asian (Han Chinese) human 2012: Jennifer Doudna & Emmanuelle Charpentier ○ A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity ○ Search-and-replace genome editing without double-strand breaks of donor DNA F.H. Westheimer, Prof Emeritus of Chemistry, Harvard University ○ “The greatest intellectual revolution of the last 40 years may have taken place in biology. Can anyone be considered educated today who does not understand a little about molecular biology?” Table No. 1 Year and Scientist Summary YEAR PERSON 1665 Robert Hooke 1674 Anton Van Leeuwenhoek 1833 Robert Brown 1838 Matthias Schleiden and Theodore Schwann 1857 Alvert von Killiker 1879 Walther Flemming 1881 Santiago Ramon y Cajal 1898 Camillo Golgi 1902 Theodor Boveri 1952 George Palade Fritiof S. Sjostrand Porter 1952 Hugh Huxely 1957 James David Robertson 1960 John Kendrew 1968 Mojmir Petran & Collaborators 1974 Elias Lazarides and Klaus Weber 1994 Martin Chalfie et al. 1995 Craig Venter and Hamilton Smith 1996 Many investigators 1997 Ian Wilmut et al. 1998 Andrew Fire and Craig Mello 2003 Many Investigators 2007 Craig Venter and colleagues 2008 Jian Wang and colleagues 2012 Jennifer Doudna & Emmanuelle Charpentier LAGRASON, LIECA ANGELINE L. | BS BIOLOGY 2 L1B: EVOLUTION OF PROKARYOTES, EUKARYOTES, AND VIRUSES OUTLINE I. II. III. IV. A. Prokaryotes vs Eukaryotes Evolution of Prokaryotes A. Miller’s Experiment B. Genetic Material and Lipids Evolution of Eukaryotes A. Endosymbiosis B. Multicellularity Evolution of Viruses ○ HISTORY OF CELLULAR AND MOLECULAR BIOLOGY Table No. Prokaryotes VS Eukaryotes PROKARYOTES EUKARYOTES Without nucleus Contain nucleus (and organelles) Circular DNA Linear or segmented DNA Domains: Kingdoms: ● Archaea ● Animalia ● Bacteria ● Plantae ● Fungi ● Protista ● EVOLUTION OF PROKARYOTES Self-replication of RNA ■ Complementary pairing between nucleotides (adenine [A] with urinal [U] and guanine [G] with cytosine [C] allows one strand of RNA to serve as a template for the synthesis of a new strand with the complementary sequence. Lipid membrane ○ ○ First cell structure to develop Lipid membrane are composed of phospholipid bilayer ■ Amphipathic How it formed: ■ When water and lipid are vigorously mixed micelles (1 layer) and liposomes (2 layers) spontaneously form. ■ By chance, RNA becomes enclosed in these lipid membranes, which allowed them to be maintained as one unit. ○ THE EVOLUTION OF METABOLISM ● ● Miller’s Experiment ○ Spontaneous formation of organic molecules ○ Atmospheric Gases on Earth: CO2, N; H2, H2S and CO ○ Miller’s Experiment ■ Produced H2, CH4, NH3, and some amino acids ■ Demonstrated that monomers can polymerize spontaneously under plausible prebiotic conditions ○ Characteristics of the first polymer formed: 1. Capable to self-replicate 2. Be a catalyst themselves ○ What macromolecule can perform these 2 characteristics? RNA, the first macromolecule RNA ● ● Adenosine Triphosphate (ATP) = energy Metabolism - the chemical processes involved in the production of ATP ● Metabolic Pathways (in order): A. Glycolysis - ubiquitous process ○ Because only primordial gases are present ○ Can occur in the absence of oxygen (aerobic conditions) B. Photosynthesis ○ May have developed during the oxygenation of the Earth ○ Production of Oxygen resulted in the formation of the ozone layer C. Oxidative Metabolism ○ Cellular respiration LAGRASON, LIECA ANGELINE L. | BS BIOLOGY 3 ○ Used and requires oxygen ○ EVOLUTION OF EUKARYOTES ○ Algae have both multicellular and unicellular species An amoeba Dictyostelium discoideum can transition from unicellular to multicellular ■ Depending on the environment EVOLUTION OF VIRUSES ● ● ● Virus ○ ○ Not considered as living organisms Obligate intracellular parasites ■ Requires a host ○ Found in DNA ○ Lacks the cellular machineries necessary to replicate Virus has existed for a long period of time ○ Retoriviral cDNA is found in 5-8% of ○ Proof: visual representation of polio in artifacts Believe to arose from the branch of Archaea ○ From the endosymbiotic relationship of bacteria and archaea ○ Proof: first cell has similar metabolism with the archaea ENDOSYMBIOSIS ● ● ● Mitochondria and Chloroplasts are theorized as previous aerobic bacteria and photosynthetic bacteria, respectively ○ Archaea - same metabolism ○ Bacteria - has own cell membrane Mitochondria ○ Has own DNA ○ Has 2 cell membrane ○ Same size as bacteria Why? MULTICELLULARITY ● Nucleus and other organelles ○ Invagination Hypothesis ● Unicellular to multicellular ○ Occurred Multiple Time in Nature ● May have existed before life ● Simple structure: ○ Genetic Material (DNA or RNA) ○ Proteins (capsid) ○ Envelope (Lipid Membrane) ■ May or may not be present Reductive evolution ○ Giant viruses ■ Its size can be phagocytosed ■ Encodes for translating genes ■ Contains protein information (genetic code) from prokaryotes that it doesn’t use ■ Said to come from prokaryotes but it discarded unnecessary parts and devolved into a virus instead. ● LAGRASON, LIECA ANGELINE L. | BS BIOLOGY 4