Textbook Notes (362,842)
Canada (158,078)
Biology (305)
BIOL 102 (99)
Chapter 5

Chapter 5bio.docx

8 Pages
Unlock Document

Queen's University
BIOL 102
Wayne Snedden

Chapter 5 Chapter 5: Systems biology  Researchers study living organisms in terms of their underlying network structure rather than their individual molecular components  The goal is to understand how the organization of the cell arises by complex interactions between its various components and parts. Four system works together 1. Interior of the nucleus 2. Cytosol 3. Endomembrane system 4. Semiautonomous organelles ex. Mitochondria, chloroplasts • protein-protein interactions critical • Continual synthesis new molecules and breakdown unwanted components From genome to transcriptome to proteome... Genomes, proteomes and cell structure/function and organization  Proteome is responsible for the structure and function of cells  Gene and protein regulation causes the proteome to be dynamic  Proteins have sorting signals (must be in the right place).  Cells require pre-existing organization Structure determines function.  Jobs are derived from complements of proteins; might be some overlap.  Own proteome: different jobs, different machines (While genome is static even when genes are being turned on and off, but proteome is changing from minute to minute). b) Isolate proteomes, they would be different, but genomes would be the same. - Proteome, controlled by genome. - Protein-protein interactions critical - Continual synthesis new molecules and breakdown unwanted components. They will be tightly bound together (but not covalent bonding) other bonding that hold proteins together. Molecular machines (multi-unit machine). A machine is an object that has moving parts and does useful work : • provide structure and organization to cells • ATP synthase is a molecular machine – Molecular recognition allows for complex assembly • Subunits recognize each other and bind in a specific way Illustrates molecular machines: ATS synthase found in bacteria, mitochondria and chloroplasts. ATP synthase subunits self-assemble based on shape but the site structure most also be correctly oriented relative to the cell membrane to function. (protons are moved = gradient): turns kinetic energy into potential energy – when we get protons through ATP synthesis, kinetic energy can be used to make chemical energy to make covalent bonds. Other molecular machines a) Ribosomes in the act of making polypeptides - Compartmentation, allow you to separate different environments. - - Proteins are what controls gene activity. Flagellum, microtubulars attached to motor proteins held in place so when it undergoes cycle of change; pulls on microtubular. Protein protein interaction + protein-RNA and RNA-RNA interaction where ribosomes will recognize and recreate rRNA and tRNA … Introduct concept: elegant molecular machine : subunit to mRNA. b) The flagella of sperm contain a molecular machine for locomotion Cytoskeleton: cytoskeleton contributes to structure and cell movement. Serve as meshwork within a cell. Important role in getting things where they have to be in the cell. Intermediate filaments less dynamic… than… a) Bioconcave disk shape of red blood cells b) Cytoskeletal connections to the red blood cell membrane Role of cytoskeleton in moving things around (neyron: microtubule drawing). Alpha and Beta – non covalent, polymerizing, and depolimerizing… provide a road way to move cargo. Ability to bind will change when they come in contact with tubuline, they ones motor proteins will face. High enough affinity – tightness in bonding, but not high enough to not be able to pull them apart. Modulated by different events in the cell. Semiautonomous organelles: - Mitochondria - Chloroplasts Must have their own genome and increase in number via binary fission = binary fission = division of cells. (ex. peroxixomes have the ability to do binary fission – but not part of semiautonomous organelles, because they don’t their own genome). Circular DNA, own proteins created, own genome, double membrane (derived from an engulfing event), go through binary fission. Dual Origin Proteomes: some included by nuclear genome, and some by their own. Vast majority are encoded by nuclear genome and some from their own. Endomembrane system -> include: outer membrane of nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, vacuoles, secretary vesicles, and plasma membrane (Nuclear envelope attached, but Golgi is not – rather receives vesicles) Role: Transport of membrane vesicles among its various components: gets proteins to destination. Major site of metabolic reactions : most of cell’s lipids and proteins are made in ER membrane. -> synthesis of proteins and lipids + sorting. - Storage and recycling or organic molecules ex. Vacuoles (proteins, carbs, fats) - Breaking down of molecules ex. Lysosomes Notes on previous image: Nuclear envelope creates space for nucleus (nucleus not part of endomembrane system). Synthesis of membrane phospholipids in ER Cytosol and endomembrane system: work together to synthesize most lipids. (occurs in cytosolic leaflet). Steps: 1) fatty acids activated by attachment of CoA molecules 2) fatty acids bond glycerol-phosphate + inserted into cytosolic leaflet of ER membrane 3) phosphate removed by a phosphatase enzyme 4) Appreciate role of ER : lipid biosynthesis 5) flippases transfers some of the phospholipids to other leaflet. *definition of enzymes Lipid transfer throughout a eukaryotic cell * Compartmentation needed for lipid synthesis. Function associated to position in membrane. Put energy into flipping, must go through interior of membrane to go through hydrophilic to hydrophobic environment – needs energy. Feature investigation Palade demonstrated that secreted proteins move sequentially through organelles of the
More Less

Related notes for BIOL 102

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.