BIOL111_2024 AG_lecture_1 version 1.pptx

BIOL/BCHM 111 2024 Lectures 13-24 Ashley Garrill [email protected] SBS Room 420 Metabolism, energetics and membrane transport https://www.youtube.com/watch?v=HT _Zs5FKDZE  A bit of background about me BSc L...

BIOL/BCHM 111 2024 Lectures 13-24 Ashley Garrill [email protected] SBS Room 420 Metabolism, energetics and membrane transport https://www.youtube.com/watch?v=HT _Zs5FKDZE  A bit of background about me BSc Leeds UK: Genetics and Plant Biology (1986) PhD Liverpool UK: Genetics and Microbiology (1990) Research positions in Canada (Toronto) and Australia (Adelaide) prior to UC  A bit of background about me My research group looks at the cell biology and biophysics of pathogenic microorganisms How they grow and cause disease Fungi and oomycetes – myrtle rust and kauri dieback  A bit of background about me In the movie we’re using a device called Lab-on-a-Chip to measure forces exerted by oomycete hyphae Very small – a few mN But because exerted over a small surface area – a huge pressure Equivalent to an elephant standing on your big toe!!! So they can force their way into plant tissue  Lectures Please ask questions at any stage and remember – THERE IS NO SUCH THING AS A SILLY QUESTION I will usually recap the previous lectures material at the start of each lecture There is a question box if you don’t want to ask in the lecture Also put in any music requests (for the start of the lecture) and also favourite animals/plants/microbes I’ll try to incorporate as many of these into the lectures as I can – to try to put the concepts we cover into real life examples (e.g.today I’ll use meerkats and birds of paradise) Reading for next 2 weeks Biology 2e – WEB https://openstax.org Chapters 6 (Metabolism) and 7 (Cellular Respiration) Biology: A Global Approach. (Global Edition) 11th Edition. Campbell et al. – Chapter 6 (Energy and Life) and Chapter 10 (Respiration)  What you need to know by the end of the lecture today  Cells need to do work to live  Movement, transport, chemical synthesis  Metabolism is the collection of chemical reactions that transform matter in a cell and enable work  Metabolic pathways can be catabolic or anabolic and these may be coupled  Metabolic pathways are controlled to meet the needs of the cell   From Grant’s lectures…. % by weigh t Living organisms are composed of lifeless molecules – Albert Lehninger Figure 2-29 Molecular Biology of the Cell (© Garland Science 2008) Are our cells just bags of chemicals? No – a bag of chemicals is just a bag of chemicals - a cell is living Living cells/organisms can do all sorts of cool stuff – and that’s how we try to define life!! To carry out all these properties/processes of life - cells have to  3 Types of Work Movement Membrane Transport Chemical synthesis Cells need to move organelles (a specialised subunit in a cell that performs a function) around. Here is a movie of vesicles (small organelle) moving around in a nerve cell Why do they do this?  3 Types of Work Movement Membrane Transport Chemical synthesis Certain organelles are used to move things (e.g. proteins, membrane). Sometimes these are moved from the nucleus to the outside of the cell. Sometimes from the outside of the cell to the nucleus. Vesicular trafficking.  3 Types of Work Movement Membrane Transport Chemical synthesis Sometimes big cells need to mix things around (organelles, nutrients, biomolecules). This cell is Elodea (Canadian pond weed) Cytoplasmic streaming  3 Types of Work Movement Membrane Transport Chemical synthesis kinesin These intracellular movements are powered by motor proteins Kinesin, dynein, myosin Move along tracks inside the cell – microtubules and microfilaments (cytoskeleton)  3 Types of Work Movement Membrane Transport Chemical synthesis Entire cells also need to move – cell motility This is a neutrophil (part of your immune system) chasing a bacteria  3 Types of Work Movement Membrane Transport Chemical synthesis Cell motility is also a normal part of development Cells move to their correct location in an embryo These cells are moving and forming the lateral li ne in a Zebrafish - they will enable the fish to det ect water movements  3 Types of Work Movement Membrane Transport Chemical synthesis How do cells move? Their cytoskeleton “pushes” the front end of the cell forward and also “pulls” the back of the cell forward. Actin enabling cell motility (3:33)  3 Types of Work Movement Membrane Transport Chemical synthesis Other cells use cilia or flagella to swim Tetrahymena - a ciliated protist If you do 300 level cell biology, we use Tetrahymena in two lab classes.  3 Types of Work Movement Membrane Transport Chemical synthesis And in multicellular animals we move due to muscle contraction Meerkats   3 Types of Work Movement Membrane Transport Chemical synthesis Movement of molecules or ions across membranes Important to maintain osmotic balance with solution outside the cell If not - cells can burst or shrivel up  3 Types of Work Movement Membrane Transport Chemical synthesis ~50% of energy used by your brain simply used to move Na+ and K+ across cell membranes Important in nerve cells and nerve impulses Na pump  3 Types of Work Movement Membrane Transport Chemical synthesis In your muscle cells a Ca2+ pump is very important It keeps Ca2+ levels in the cells very low (moves Ca2+ out) Then they can respond to a sudden increase  3 Types of Work Movement Membrane Transport Chemical synthesis In Grant’s lectures he will have covered the importance of making macromolecules from monomer subunits Polysaccharides from sugars, proteins from amino acids and nucleic acids from nucleotides  3 Types of Work Growth and development Energy processing Regulation Order Think about how Evolutionary adaptation movement, Response to the membrane environment Reproduction transport and chemical synthesis enable some of the characteristics of life in the bird of paradise dance video https://www.youtube.com/watch?v=nWfyw51DQfU&list= RDCMUCwmZiChSryoWQCZMIQezgTg&start_radio=1&t=0  Work… Cells can do work because they can transform molecules and energy  Transformation of molecules Molecules are transformed (i.e. slightly modified) via chemical reactions that occur within a cell  Transformation of molecules Reactions are controlled Typically by proteins called enzymes – typically specific Catalyse reactions – decrease time taken to come to equilibrium (speed up reactions)  Transformation of molecules First reaction in glycolysis Glucose converted to glucose-6-phosphate Catalysed by the enzyme hexokinase  Transformation of molecules If glucose, hexokinase and ATP were isolated in a test tube Reaction would come to equilibrium  Transformation of molecules In a cell the reaction doesn’t come to equilibrium – metabolic disequilibrium Glucose-6-phosphate is the substrate for the second reaction in glycolysis Metabolic pathway  Metabolism All of the metabolic pathways in a cell constitute its metabolism Fig. 6.1 The inset shows the first two steps in the catabolic pathway that breaks down glucose.  Metabolism and Energy Metabolic pathways can be catabolic Break complex molecules into simpler ones Are spontaneous Yield energy  Metabolism and Energy Or Anabolic Build complex molecules from simple ones Are non-spontaneous Cost energy  Metabolism and Energy Energy coupling Energy derived from catabolic pathways can be used to drive anabolic pathways Energy carriers: ATP, NADH, NADPH ATP NADH  Metabolic Regulation Pathways are regulated - depending on the energy needs of the cell/organism Regulated via enzymes Allosterically Covalently Genetically Metabolic Regulation  Metabolic Regulation If you’ve had no breakfast and then eat a crème egg…. Energy levels low thus the sugar in the egg will be broken down via catabolic pathways Fig. 6.1 The inset shows the first two steps in the catabolic pathway that for energy breaks down glucose.  Metabolic Regulation Enzymes which catalyse the reactions that break down sugar are sensitive to the energy status Fig. 6.1 The inset shows the first two steps in the and are switched catabolic pathway that breaks down glucose. on  Metabolic Regulation If you have just eaten breakfast Energy levels high Don’t need the energy from the egg immediately so….  Metabolic Regulation Glucose in the egg will be converted to glycogen (storage carbohydrate). Anabolic Fig. 6.1 The inset shows the first two steps in the catabolic pathway that pathway. breaks down glucose. Enzymes that do  Metabolic Regulation Glucose in the egg will be converted to glycogen (storage carbohydrate). Anabolic pathway. Fig. 6.1 The inset shows the first two steps in the catabolic pathway that breaks down glucose. Enzymes that catalyse sugar breakdown are  Metabolic Regulation Cells are able to control their metabolism by regulating enzymes. This ensures that they have the Fig. 6.1 The inset shows the first two steps in the catabolic pathway that materials and breaks down glucose. energy to do work and hence be alive.