Cell Biology Lecture Notes PDF

8/27/2024 2024/08/27 Tuesday Biol 3320 Cell Biology CRN 13746 Introduction & overview (cont.)...

8/27/2024 2024/08/27 Tuesday Biol 3320 Cell Biology CRN 13746 Introduction & overview (cont.) Protein structure & function (I) 1 1 II. Introduction to Cells 1. Cells are the fundamental units of life - What is life? - The seven pillars of life a. Program b. Improvisation c. Compartmentalization d. Energy e. Regeneration f. Adaptability Organismal, behavioral responses that is part of the program Koshland ( 2002) Science 295: 2215 2 2 1  8/27/2024 II. Introduction to Cells 1. Cells are the fundamental units of life - What is life? - The seven pillars of life a. Program b. Improvisation c. Compartmentalization d. Energy e. Regeneration f. Adaptability g. Seclusion Koshland ( 2002) Science 295: 2215 3 3 Seclusion of pathways allows thousands of reactions to occur with high efficiency in the tiny volumes of a living cell, while simultaneously receiving selective signals that ensure an appropriate response to environmental changes Fig. 2 - 62 4 4 2  8/27/2024 II. Introduction to Cells 1. Cells are the fundamental units of life - What is life? - The seven pillars of life a. Program b. Improvisation c. Compartmentalization d. Energy e. Regeneration f. Adaptability g. Seclusion Koshland ( 2002) Science 295: 2215 5 5 II. Introduction to Cells 1. Cells are the fundamental units of life 2. The Prokaryotic cell The prokaryotic cells are simple in structure but are the most diverse and inventive in terms of chemistry Fig. 1- 10 6 6 3  8/27/2024 Escherichia coli A small, rod-shaped eubacterium The most thoroughly studied living organism Contains genomic DNA of ~ 4.6 Mb, which encodes ~4,300 different proteins Fig. 1- 11 7 7 II. Introduction to Cells 1. Cells are the fundamental units of life 2. The Procaryotic cell 2. The Eukaryotic cell - Eukaryotes: organisms whose cells have nucleus (plants, animals, and fungi) 8 8 4  8/27/2024 II. Introduction to Cells 1. Cells are the fundamental units of life 2. The Procaryotic cell 3. The Eucaryotic cell - Eucaryotes: organisms whose cells have nucleus (plants, animals, and fungi) - Organelles a. Nucleus b. Endoplasmic reticulum (ER) c. Golgi apparatus b. Mitochondria e. Chloroplasts (plants and algae only) f. Lysosomes, peroxisomes, and vesicles 9 9 Fig. 1- 21 10 10 5  8/27/2024 Fig. 1- 25 11 11 Fig. 1- 28 12 12 6  8/27/2024 II. Introduction to Cells 1. Cells are the fundamental units of life 2. The Procaryotic cell 3. The Eucaryotic cell -Eucaryotes: organisms whose cells have nucleus (plants, animals, and fungi) -Organelles -Cytoskeleton a. Microtubules b. Microfilaments c. Intermediate filaments 13 13 II. Introduction to Cells 1. Cells are the fundamental units of life 2. The Procaryotic cell 3. The Eucaryotic cell - Eucaryotes: organisms whose cells have nucleus (plants, animals, and fungi) - Organelles - Cytoskeleton - Cytosol Contains a concentrated mixture of large and small molecules that carry out many essential biochemical processes 14 14 7  8/27/2024 Cytoplasm vs. Cytosol 01_24_Organelles.jpg The cytosol is the liquid component of the cytoplasm in a cell, excluding organelles and other suspended particles 15 E2- 1 15 II. Introduction to Cells 1. Cells are the fundamental units of life 2. The Prokaryotic cell 3. The Eukaryotic cell 4. Model Organisms - A small number of organisms chosen as a focus for intensive investigation - Common characteristics a. Easy to study in the laboratory b. Short life cycle c. Easy to manipulate genetically 16 16 8  8/27/2024 Baking yeast Saccharomyces cerevisiae A small, single-celled fungus Reproduces almost as rapidly as bacterium Genome size ~12.1Mb (~ 2.5x of that of E. coli) Important for studying cell-division cycle Yeasts are simple, free-living eukaryotes 17 Fig. 1- 39 17 Arabidopsis thaliana - A model organism for flowering plants - Can be grown indoors in large numbers - Produces thousands of seeds within 8 to 10 weeks - A fully sequenced genome of ~120 Mb Fig. 1- 41 18 18 9  8/27/2024 The nematode worm Caenorhabditis elegans An ideal model for studying development (exactly 959 body cells) A fully sequenced genome of ~97Mb containing ~ 19,000 genes An Important model for studying programmed cell death Fig. 1- 42 19 19 Fruit fly Drosophila melanogaster A model for studying embryonic and larval development A fully sequenced genome of ~185Mb Its ~13,000 genes cover counterparts for most of the genes known to be important in human diseases 20 Fig. 1- 43 20 10  8/27/2024 Vertebrate models: - Frog - Zebrafish 21 Fig. 1- 45 & 46 21 Human and mouse: similar genes & similar development Fig. 1- 48 22 22 11  8/27/2024 Protein structure & function 23 23 The main elements in cells The four elements C, H, N, and O constitute 99% of the total number of atoms present in the human body An additional seven elements Na, K, Ca, Mg, P, S, Cl highlighted in blue, together represent about 0.9% of the total The elements shown in green are required in trace amounts by humans Fig. 2 - 1 24 24 12  8/27/2024 02_04_element abundance.jpg 25 Fig. E2-2 25 The four main families of small organic molecules in cells Fig. 2 - 6 26 26 13  8/27/2024 The approximate composition of a bacterial cell The composition of an animal cell is similar, even though Fig. 2 - 7 its volume is roughly 1,000 times greater. 27 27 Why starts with protein ? Examples? Proteins are the most diverse and complex macromolecules in the cell, providing the cell with much of its structure, function, and information Fig. 2 - 7 28 28 14  8/27/2024 Examples of Protein Functions Fig. E2-3 29 29 Examples of Protein Functions Fig. E2-4 30 30 15  8/27/2024 Examples of Protein Functions Fig. E2-5 31 31 How can proteins possess such a wide variety of functions? 1. A protein’s function is determined by its 3-D structure 2. Proteins can assume almost unlimited numbers of different shapes yielding theoretically an unlimited number of different functions 3. The unlimited number of shapes derives from the large number of ways 20 AAs can be strung together to form different sequences 32 32 16  8/27/2024 Panel 3 - 1 33 33 All amino acids found in proteins are L-stereoisomers 34 Panel 3 - 1 34 17  8/27/2024 Basic side chains: can accept a proton and usually contain an amino group (-NH₂) that can gain a proton to become positively charged (-NH₃⁺) 35 Panel 3 - 1 35 Acidic side chains: can donate a proton (H⁺) and typically contain a carboxyl group (-COOH) that can lose a proton to become negatively charged (-COO⁻) Panel 3 - 1 36 36 18  8/27/2024 Non-polar side chains: do not interact well with water (hydrophobic) 37 Panel 3 - 1 37 Uncharged but polar side chains: can interact with water -- can form hydrogen bonds with water (hydrophilic) 38 Panel 3 - 1 38 19