Week 1 YR1 Introduction to the Cell 2023 PDF

Building blocks of life Organism Tissues Cells Molecules © Elsevier, Gartner & Hiatt, Color Textbook of Histology 3E. Teaching Organs Why do you need to learn basic science? Himalayan sea salt. Alkaline water “Toxins” “Detox” Homeopathy So you don’t end up sounding like this guy! Why do you need to...

Building blocks of life Organism Tissues Cells Molecules © Elsevier, Gartner & Hiatt, Color Textbook of Histology 3E. Teaching Organs Why do you need to learn basic science? Himalayan sea salt. Alkaline water “Toxins” “Detox” Homeopathy So you don’t end up sounding like this guy! Why do you need to learn basic science? It is the antidote to dogma. – Helicobacter pylori – Until 1982 peptic ulcer disease and gastritis were thought to be caused primarily by stress and lifestyle factors. – Treatment included ant-acids (to neutralize stomach acid) and proton pump inhibitors (PPIs) to reduce acid production. – Two Australian scientists, Barry J. Marshall and Robin Warren, discovered that more than 90% of duodenal ulcers and up to 80% of gastric ulcers were caused by infection with the bacteria helicobacter pylori. – Can be treated with specific antibiotics. – It was 1994 before the NIH recommended testing and treating helicobactor for ulcers. Understanding the basis of disease will make you a better doctor. It will make learning easier. It will make you a competitive doctor. Learning Objectives You should understand the: – basic structure and function of a eukaryotic cell – major cellular organelles and their roles Eukaryotes or Prokaryotes? Animal Plants Algae Protozoa Fungi Bacteria Archaea 6 Viruses 7 Cells Basic structural and functional units 1 million seconds = 11.6 days ~75 trillion cells in our body 1 billion seconds = 31.7 years trillion secondstypes = 31709 years 1 ~206 different of cells Each type of cell performs a different function Retinalganglion ganglioncell cell Retinal Protoplasm is the living substance of a cell Cytoplasm – Cytosol - fluid suspension – Organelles – Cytoskeleton – Inclusions Karyoplasm – Contents of nucleus Typical Features of Cells Primary processes 1. Maintenance of structural integrity. – Cytoskeleton 2. Obtain nutrients from the surrounding aqueous environment. – Cell membrane 3. Make and secrete proteins: – A large percentage of the cell’s machinery is dedicated to making proteins. 4. Convert glucose to ATP. – Mitochondria 5. Replicate. 6. Remove waste products. – Lysosomes 13 Primary processes 1. Maintenance of structural integrity. 2. Obtain nutrients from the surrounding aqueous environment. 3. Make and secrete proteins: – A large percentage of the cell’s machinery is dedicated to making proteins. – Proteins are coded for by DNA, and can be greatly modified from their initial “instructions”, e.g. – – – – 4. Post-transcriptional modifications Post-translational modifications Folding Polymerisation Convert glucose to ATP. – Mitochondria 5. Replicate. 6. Remove waste products. – Lysosomes 14 1. Maintenance of structural integrity Cytoskeletal proteins – Microfilaments – Intermediate filaments – Microtubules 15 1. Maintenance of structural integrity Functions of the cytoskeleton – Provides a structural framework. – Cell motility (crawling, cilia, flagella). – Cell-cell and cell-basement membrane attachment. – Movement of chromosomes during cell division. – Movement of vesicles and organelles. 16 Primary processes 1. Maintenance of structural integrity. 2. Obtain nutrients from the surrounding aqueous environment. 3. Make and secrete proteins: – A large percentage of the cell’s machinery is dedicated to making proteins. – Proteins are coded for by DNA, and can be greatly modified from their initial “instructions”, e.g. – – – – 4. Post-transcriptional modifications Post-translational modifications Folding Polymerisation Convert glucose to ATP. – Mitochondria 5. Replicate. 6. Remove waste products. – Lysosomes 17 2. Obtain nutrients from the surrounding aqueous - cell membrane Primary processes 1. Maintenance of structural integrity. 2. Obtain nutrients from the surrounding aqueous environment. 3. Make and secrete proteins: – A large percentage of the cell’s machinery is dedicated to making proteins. 4. Convert glucose to ATP. – Mitochondria 5. Replicate. 6. Remove waste products. – Lysosomes 19 3. Make proteins 20 The nucleus is the largest organelle The Nucleus Chromatin – Genetic material of cell The nucleolus – Site of ribosomal RNA synthesis Nucleoplasm/karyoplasm – Macromolecules and nuclear particles involved in cell maintenance DNA and Chromatin DNA is the genetic material housed within the nucleus of the cell. – polymer of nucleotides (sugar, phosphate, nitrogen base) in the shape of a double helix. Chromatin Strands of DNA and histone proteins – Heterochromatin – densely packed – Euchromatin – present during transcription. http://medcell.med.yale.edu/ The Nuclear Envelope Parallel membranes separated by 10-30 nm perinuclear cisterna The nuclear pore – gated by glycoproteins – permeable to small molecules and ions – Selective transport – Exportins – carry large molecules to the cytoplasm. – Importins -carry large molecules to the nucleus. 3. Make proteins 25 3. Make proteins DNA Transcribed to mRNA. mRNA travels to ribosomes in the cytoplasm through pores in the nucleus. mRNA is translated to protein. Protein is folded and packaged in the endoplasmic reticulum and Golgi apparatus. Finished protein is trafficked to where it is needed. 26 Transcription - translation 2:41 min https://www.youtube.com/watch?v=gG7uCskUOrA Endoplasmic Reticulum ØLargest membranous system in the cell ØInvolved in synthesis, storage, and transport of macromolecules and detoxification of drugs ØTwo regions: ØRough ER ØSmooth ER Copyright The McGraw-Hill Companies Rough Endoplasmic Reticulum ØRough - ribosomes on cytosolic surface ØRibosomes synthesize proteins which pass through to Cisternae ØIn cisternae original structure is altered ØProteins are then packaged into transport vesicles ØTransport vesicles travel to Golgi Apparatus. Copyright The McGraw-Hill Companies Smooth Endoplasmic Reticulum ØContinuous with RER ØNo Ribosomes ØFunctions in: Ø Synthesis, storage and transport of lipids Ø Calcium storage Copyright The McGraw-Hill Companies Golgi Complex Synthesized proteins in RER – transport vesicles Transport vesicles fuse Proteins are modified as they move from receiving to shipping region Packaged into secretory vesicles Copyright The McGraw-Hill Companies Primary processes 1. Maintenance of structural integrity. 2. Obtain nutrients from the surrounding aqueous environment. 3. Make and secrete proteins: – A large percentage of the cell’s machinery is dedicated to making proteins. – Proteins are coded for by DNA, and can be greatly modified from their initial “instructions”, e.g. – – – – 4. Post-transcriptional modifications Post-translational modifications Folding Polymerisation Convert glucose to ATP. – Mitochondria 5. Replicate. 6. Remove waste products. – Lysosomes 32 4. Convert glucose to ATP. Mitochondria – The“powerhouse” of the cell. – Double membrane organelle. – ATP produced mainly via oxidative phoshorylation – Possess their own DNA – Self Replicate Primary processes 1. Maintenance of structural integrity. 2. Obtain nutrients from the surrounding aqueous environment. 3. Make and secrete proteins: – A large percentage of the cell’s machinery is dedicated to making proteins. – Proteins are coded for by DNA, and can be greatly modified from their initial “instructions”, e.g. – – – – 4. Post-transcriptional modifications Post-translational modifications Folding Polymerisation Convert glucose to ATP. – Mitochondria 5. Replicate. 6. Remove waste products. – Lysosomes 34 5. Replicate 35 5. Replicate Microtubules blue DNA - yellow 36 Primary processes 1. Maintenance of structural integrity. 2. Obtain nutrients from the surrounding aqueous environment. 3. Make and secrete proteins: – A large percentage of the cell’s machinery is dedicated to making proteins. – Proteins are coded for by DNA, and can be greatly modified from their initial “instructions”, e.g. – – – – 4. Post-transcriptional modifications Post-translational modifications Folding Polymerisation Convert glucose to ATP. – Mitochondria 5. Replicate. 6. Remove waste products. – Lysosomes 37 6. Remove waste products. Lysosomes contain an array of enzymes capable of breaking down: proteins, nucleic acids, carbohydrates and lipids. Mutations in these enzymes cause genetic diseases called lysosomal storage diseases. Digest material taken up by the cell in endocytosis. Involved in both autophagy and phagocytosis. – Autophagy: destruction of internal organelles/proteins. – Phagocytosis: destruction of external components. 38 Storage - inclusions are not metabolically active Glycogen – the storage form of glucose Lipids – storage of triglycerides – Efficient form of energy store Pigments – melanin Inclusions are not normally membrane bound Typical Features of Cells Primary processes – in depth 1. 2. Maintenance of structural integrity. – “Cytoskeleton” lecture Obtain nutrients from the surrounding aqueous environment. – “Cell membranes” lecture 3. 4. 5. 6. Make and secrete proteins: – “Exocytosis & endocytosis” lecture – “Genetics II” Dr Elizabeth O’Connor Convert glucose to ATP. – “Glycolysis & the Cori cycle” – “The Krebs cycle & oxidative phosphorylation” Replicate. – “Cell cycle & cell division” lecture Remove waste products. – “Exocytosis & endocytosis” lecture 41