Biochemistry for Medlab Sciences Past Paper PDF '24-'25

MT T E R M BIOCHEMISTRY FOR MEDLAB SCIENCES CHEM 20 – [LEC] \ YRAD, FLORA...

MT T E R M BIOCHEMISTRY FOR MEDLAB SCIENCES CHEM 20 – [LEC] \ YRAD, FLORA ‘24 ‘25 01 TOPIC 1: BASIC BIOLOGY PROKARYOTIC AND EUKARYOTIC CELLS OUTLINE 2 major groups are the prokaryotes and I The Bio of Biochemistry eukaryotes II Cells A. Prokaryotic and Eukaryotic Cells Prokaryotes a. Bacteria ○ Lack a nucleus and other organelles b. Archaea ○ Unicellular organisms c. Eukaryotes III Organelles ○ Smaller than eukaryotic cells (sizes range from A Eukaryotic DNA 0.5 - 5 μm) IV The Cytoskeleton A Microtubules ○ Typically have circular chromosomes and may B Microfilaments sometimes contain extra-chromosomal DNA C Intermediate Filaments V Tissues elements known as plasmids A. Connective Tissue ○ DNA is not wrapped around histones B. Nerve Tissue ○ DNA-protein complexes create a structure called C. Muscle Tissue nucleoid Nucleoid is not enclosed by a nuclear THE BIO OF BIOCHEMISTRY envelope The number of eukaryotic species is at about 8.7 Eukaryotes million, while bacteria account for anywhere ○ contain numerous internal membrane-bound between 107 and 109 different species. compartments, including a nucleus The number of archaea is uncertain but is expected Proteins in archaea resemble eukaryotic histones to be very large Proteins in bacteria are different from both All living things are made up of cells. A fact eukaryotic and archaeal DNA packaging proteins discovered by Robert Hooke in 1665 Prokaryotes are divided into 2: The 3 domains of life ○ Bacteria ○ Bacteria ○ Archaea ○ Archaea Thought to be a subgroup of bacteria but now ○ Eukaryotes classified in a domain of their own CELLS BACTERIA All cells have a plasma membrane that serves as a Has a plasma membrane boundary for the cell, separating it from its Exterior cell wall is comprised of an interlocked surroundings. peptidoglycan network. Cells also possess a genome made up of DNA Pili - hair-like appendages that allow them to adhere ○ DNA encodes information for making the proteins to other cells and plays a role in bacterial required by the cell. conjugation ○ DNA is also the repository of information that gets ○ Bacterial conjugation - process of DNA transfer copied and transmitted to the next generation. between bacterial cells ○ DNA allows cells to reproduce Flagella - enables the cell to move through their Ribosomes and tRNAs are the cell’s machinery for surroundings protein synthesis Quorum sensing - bacteria communication process ○ These translate the information in DNA and using chemical signals make the proteins it encodes ○ Allows bacteria to assess conditions around Different sources of energy for different organisms: them ORGANISM SOURCE OF ENERGY ○ Plays a role in bacterial infections and formation Metabolic energy Phototrophs of biofilms from light Oxidation of Biofilms are mats of cells that adhere to Chemotrophs chemical fuels each other and protect the bacteria against Light or chemical environmental hazards Autotrophs sources Lipids used in the plasma membrane are fatty Organic compounds Heterotrophs made by other acids organisms ARCHAEA Auto = self, troph = nourishing Initially found in harsh environments (e.g. salt flats & Cells may be aerobic or anaerobic hot springs) and described as extremophiles ○ Aerobic - uses oxygen Now known to be found in every environment ○ Anaerobic - can live without oxygen Unicellular and superficially resemble bacteria Obligate anaerobes - require an environment Transcriptional machinery, promoter sequences free of oxygen and ribosomes are much more like eukaryotes. Facultative anaerobes - can live with or Unique in their use of ether linkages to join lipids without oxygen used in their plasma membranes to glycerol. ○ Lipids used in the plasma membrane are long isoprene-derived chains CORTES / FERNANDO / VIRTUDAZO | BSMT II 1  TOPIC 1: BASIC BIOLOGY Makes the membrane highly stable and ○ Prevents loss of information when linear advantageous in extreme conditions chromosomes are replicated Cell wall contains either of the following: Nuclear envelope ○ peptidoglycan-like molecules ○ Double membrane structure that encloses the ○ glycoproteins and polysaccharides nucleus ○ Regulates entry of proteins, an important way to EUKARYOTES control gene expression Found in both unicellular and multicellular Nucleus organisms, ○ Contains enzymes required for replication and Surrounded by a plasma membrane transcription of genetic information Difference in cell walls: MItochondria and chloroplasts TYPE OF CELL CELL WALL ○ Have their own DNA separate from nuclear DNA Animal Cell No cell wall DNA is small and circular Contains cellulose, ○ Have their own ribosomes and tRNAs Plant Cell hemicellulose, and pectin ○ Can carry out their own protein synthesis Fungal Cell Contains chitin ○ Likely derived from prokaryotes that once lived as endosymbionts within ancient eukaryotic cells Typically larger (10-100 μm) and eventually became integrated into their host Contains considerably more DNA than prokaryotes cells. Presence of internal membrane-bound structures (organelles) CYTOSKELETON The cytoskeleton is made up of a network of ORGANELLES interlinking protein fibers. Divides the interior of the cell into discrete parts Three major classes: microtubules, having specialized functions microfilaments, and intermediate filaments. ○ All eukaryotic cells have microfilaments and ORGANELLE FUNCTION microtubules, but plant cells may lack Nucleus Houses DNA intermediate filaments. Electron transport ○ It is now known that some cytoskeletal elements Mitochondria system/oxidative phosphorylation are present in bacteria and archaea Ribosome synthesis The cytoskeleton is dynamic. Nucleolus and assembly ○ Microfilaments and microtubules disassemble Lipid metabolism and rearrange on an ongoing basis, as needed. Endoplasmic Reticulum Targeted protein synthesis ○ Intermediate filaments are also broken down and folding and rebuilt, at specific times, during cell division. Golgi Apparatus Protein modification The classes are distinguished by: and secretion ○ the proteins that they are composed of Oxidation of very long fatty Peroxisomes acid chains ○ the way those proteins assemble into the Present only in plant cells structures seen in the cell. Chloroplasts The cytoskeleton helps organize the contents of Photosynthesis the cell. Synthesis and storage of Plastids ○ organelles are anchored by attachment to the compounds in plants Hydrolytic enzymes cytoskeleton. Lysosomes in animals Interactions among cytoskeletal proteins and Contains endocytosed components of the extracellular matrix are crucial Endosomes material in maintaining tissue structure. Maintains water balance in plant cells Cytoskeletal proteins have a role in cell signaling Vacuoles pathways. Storage of waste products ○ Membrane-associated signaling proteins are in animal cells sometimes linked to components of the cytoskeleton, Presence of membrane-bounded compartments: ○ Permits reactions requiring specific conditions to MICROTUBULES be carried out in isolation made up of tubulin E.g.: Formation of disulfide bonds in play vital roles in cell division proteins is possible in the conditions within ○ The spindle fibers that attach to chromosomes the endoplasmic reticulum. during metaphase ○ Allows reactants to be more concentrated ○ Also help separate the two sets of chromosomes because of the smaller volume of the organelle They serve as tracks ○ along which motor proteins, like dynein and EUKARYOTIC DNA kinesin, transport cargo to different parts of the Chromosomes cell. ○ DNA that was divided into several linear bundles MICROFILAMENTS ○ Contain genomic DNA wrapped arounf histones composed of the protein actin ○ Ends have telomeres underlie the plasma membrane of animal cells ○ Surrounded by the nuclear envelope gives characteristic shapes Telomeres ○ By remodeling, it changes the shape of the cell, ○ short (less than 10 bp) sequences repeated and is important for cell movement thousands of times. CORTES / FERNANDO / VIRTUDAZO | BSMT II 2  TOPIC 1: BASIC BIOLOGY actin plays a role in cytokinesis, Nervous System function include: ○ It helps cleave the cell into two after nuclear ○ Receiving input from senses division. ○ Homeostasis ○ Integration of information INTERMEDIATE FILAMENTS ○ Mental activity made up of a variety of proteins with a common structure, and assemble into fibers NERVEL CELLS/NEURONS resembles a cable made up of many individual Transmit and receive signals. strands of wire twisted together. *Specialized cell called GLIA assist in transmitting the ○ provides structural support to various cell nerve signal and also provide nutrients for the neurons. structures. (mechanical strength) All nerve cells contains an AXON Ex. Nuclear lamina - the nuclear envelope’s network ○ Axon - long fiber-like structures responsible for of intermediate filaments in animal cells. sending signals in the form of action potentials to adjacent cells TISSUES Cells in multicellular organisms are organized into MUSCLE TISSUE tissues that play specialized roles in the body. Muscle tissue is formed during embryonic In animals, there are 4 Tissues types: development by a process known as myogenesis ○ Epithelium/Epithelial Tissue Mammals have three types of muscle tissue ○ Connective Tissue ○ Skeletal/striated muscle voluntary ○ Nerve Tissue ○ Smooth, non-striated muscle involuntary ○ Muscle Tissue ○ Cardiac muscle involuntary EPITHELIAL TISSUE Epithelial cells line the cavities and surfaces of blood vessels and organs in the body. REFERENCES Epithelial cells are categorized by their shape: ○ Squamous Notes from the discussion/learningmats by: FLORA YRAD ○ Columnar ○ Cuboidal Silliman University PowerPoint presentation: *Can be simple or stratified depending in the layers of Chapter 1: Basic Biology cells FUNCTIONS: TRANSES ARE EXCLUSIVE TO ICLS STUDENTS ONLY. CONTENTS TRANSCRIBED HERE ARE WITHIN THE INTELLECTUAL ○ Protection PROPERTY OF THE UNIVERSITY. SHARING OF TRANSES OUTSIDE THE INSTITUTION IS CONSIDERED AS A BREACH OF ACADEMIC INTEGRITY AND IS SUBJECT TO LEGAL ACTION. PLEASE BE GUIDED. ○ Secretion ○ Selective Absorption ○ Transport ○ Sensing *Layers of epithelial cells do not contain blood vessels and must receive nutrients through the process of diffusion of materials from underlying connective tissue, through the basement membrane. CONNECTIVE TISSUE Connective tissue fills the gaps between all the other tissues of the body, including the nervous system THREE MAIN COMPONENTS ○ Cells ○ Ground Substances ○ Fibers *BLOOD and LYMPH also contains Cells and Ground Substances, but not fibers. Cell Types found in Connective Tissues ○ Adipocytes ○ Fibroblasts ○ Mast Cells ○ Macrophages ○ Leucocytes NERVE TISSUE The nervous system contains 2 components: ○ Central Nervous System (CNS) Brain and Spinal Cord Tissue types are referred to as White Matter or Grey Matter ○ Peripheral Nervous System (PNS) Tissue types include the nerves and ganglia CORTES / FERNANDO / VIRTUDAZO | BSMT II 3