Cell (Learning Objectives) 1. Understand & describe the basic components necessary for a functional cell. 2. Review the order of appearance of cells on earth and explain the endosymbiotic theory. 3. Compare and contrast prokaryotic and eukaryotic cells 4. Review the emergent functional properties of a eukaryotic cells. 5. Review the structure of membranes and explain the importance of different proteins for creating intracellular membranous compartments where different cellular functions can take place. 6. Identify the components of the cytoskeleton and their role in cellular structural support, movement, and communication. 7. Describe the flow of genetic information within a living cell from DNA into proteins and the processes involved. 8. Explain the structure and role of membranes in compartmentalization of eukaryotic cell functions. 9. Identify the cellular organelles of the endomembrane system and the role of each in the manufacture and breakdown of important cellular molecules and intracellular trafficking of biomolecules. 10.Identify the cellular organelles that are involved in energy transformation and recycling of matter and the forms of energy and matter they transform. 11.Identify peroxisomes and their cellular function. 12.Explain the source and importance of the extracellular matrix and intercellular junctions.
Cell (Outline) - Components of a functional cell - Major Events in the History of Earth: abiotic and biotic phases; anaerobic and aerobic atmosphere - Prokaryotic cells impact on the biosphere - Origin of Eukaryotic cells - Emergent properties of eukaryotic cells: animal and plant cells - Role of cellular membranes: external and internal - Cytoskeleton: structure and functions - Flow of genetic information: DNA to protein - The endo-membrane system - Other organelles: Fatty acid metabolism and Energy Processing - Cell surface and extracellular matrix
Components of a functional cell Boundary-membrane Cytoplasm: Cytosol (soluble components) & particulates DNA-information Ribosomes-protein synthesis
Major Events in the History of Earth Cenozoic Humans Land plants Animals Origin of solar system and Earth Multicellular eukaryotes 1 Proterozoic eon 2 Archaean eon 3 4 Anaerobic Single-celled eukaryotes Atmospheric oxygen Prokaryotes Aerobic
Prokaryotic Cell Structure Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Eukaryotic Cell Structure
Cenozoic Humans Land plants Animals Multicellular eukaryotes Single-celled eukaryotes 1 Proterozoic eon 2 Archaean eon 3 Origin of solar system and Earth 4 Atmospheric oxygen Prokaryotes Evolution of larger Eukaryotic cells increase in surface area/volume ratio The Endo-symbiotic Theory
Size Limitations For single-celled organisms- - physical force of diffusion of material in and out of the cells. - Increase in size is limited by surface area : volume ratio For multi-cellular organisms - Number of cells increases size. - Individual cells vary in size
The Endosymbiotic Theory: Origin of Eukaryotes
Ancestral eukaryotic cells two or more prokaryotic cells in a state of endo-symbiosis: animal cell- 2 different prokaryotes plant cell- 3 different prokaryotes Mitochondrion Engulfing of aerobic prokaryote Host cell Some cells Engulfing of photosynthetic prokaryote Chloroplast Mitochondrion Host cell
Comparing Prokaryotic and Eukaryotic Differ in - size - complexity Cells - internal membrane, creating organelles (Sub-cellular compartments where different cell functions of eukaryotic cells are carried out)
Emergent Properties of Eukaryotic cells Functions Structural support, movement, and communication Manufacturing of molecules Breakdown of molecules Energy processing Eukaryotic cells structures and organelles specialize for functions
Cell Animation
Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Role of Cell membranes in Compartmentalization of cellular functions
A. Plasma membrane - Boundary of the cell - Surrounds the cytoplasm - Selective barrier - Allows passage of oxygen, nutrients, and wastes.
B. Internal membranes of eukaryotes Partitioning the cell into compartments - Sites of metabolic reactions, enzymes - Local environments that facilitate specific metabolic functions
Cytoskeleton The cytoskeleton is a network of protein fibers that functions in cell structural support and motility Nucleus Nucleus Actin subunit Fibrous subunits Tubulin subunit 7 nm 10 nm 25 nm Microfilament Intermediate filament Microtubule
Cytoskeleton fibers Microtubules: cell shape, movement of organelles, chromosome separation during cell division, and cilia and flagella (hollow/tubulin) Microfilaments three-dimensional network just inside the plasma membrane (actin) Actin and myosin/cell motility and cytoplasmic flow http://staffa.wi.mit.edu/microscopy/macrophage.shtml http://www.nytimes.com/2009/06/09/science/09cell.html?_r=1 Intermediate filaments They reinforce cell shape and fix organelle location (keratin)
Components of the cytoskeleton pull past each other Vesicles or organelles carried to various destinations along monorails of microtubules.
The Flow of Genetic Information: The Central Dogma of Molecular Biology The sequence of bases in DNA determines the sequence of amino acids in proteins - DNA codes for the production of messenger RNA. - Messenger RNA codes for the production of protein. - Proteins do not code for the production of protein, RNA or DNA
Cell organelles and structures involved with the flow of genetic information Nucleus Ribosomes
Nucleus Home of most genetic material (DNA) Double membrane with pores, nuclear envelope Shape maintained by nuclear lamina, a network of protein filaments
The Nucleus: Site of transcription of messenger RNA (mrna) The nucleolus Site of ribosomal RNA (rrna)synthesis and ribosome assembly
Ribosomes Made of rrna and protein. two subunits that combine to carry out protein synthesis Number of ribosomes vary between cells Free and bound ribosomes (to endoplasmic reticulum)
The Endomembrane System Sub-cellular components Nuclear envelope Endoplasmic reticulum Golgi apparatus Vesicles Lysosomes Vacuoles Plasma membrane Function - Sites of certain metabolic functions in the cell (Synthesis, modification, & breakdown of macromolecules) - Regulation of protein traffic within the cell
Two connected regions of ER that differ in structure and function. Smooth ER (No ribosomes) Rough ER (bound ribosomes) are attached to the outside
Smooth ER Contains enzymes for synthesis of lipids, phospholipid, steroids Metabolism of carbohydrates Detoxification of poison Storage of Ca +2 for in muscle cells (necessary for contraction)
Rough ER (membrane factory) - Produces proteins and membranes for transport by vesicles, destined for secretion - Membrane-embedded and secretory proteins - Site of protein glycosylation (glycoproteins)
Transport vesicle buds off 4 Ribosome Secretory protein inside transport vesicle 1 3 Sugar chain Polypeptide 2 Glycoprotein Rough ER
The Golgi Apparatus Finishing, sorting, and shipping cell products Transport vesicles from the ER travel to the Golgi apparatus for modification of their contents Extensive in cells specialized for secretion. http://vcell.ndsu.edu/animations/proteintrafficking/movieflash.htm
Lysosomes Digestive compartment within the cells. Membranebounded sacs of hydrolytic enzymes that digests large particles made of macromolecules: proteins, fats, polysaccharides, and nucleic acids. http://highered.mcgrawhill.com/sites/0072437316/student_view0/chapter5/animations.html#
The lysosomal enzymes and membrane are synthesized by rough ER and then transferred to the Golgi.
Vacuoles Larger versions of vesicles Many functions in cell maintenance Food vacuoles Contractile vacuoles, found in freshwater protists, pump excess water out of the cell. Central vacuoles- mature plant cells storage of some pigments.
Other Membranous Organelles not part of the endomembrane system Peroxisomes generate and degrade H 2 O 2 in performing various metabolic functions Fatty Acid metabolism Mitochondria and chloroplasts- sites of energy transformation from one form to another and of recycling of matter - Mitochondria (respiration) are present in animal & plant cells - Chloroplasts (photosynthesis) only in plant cells
Peroxisomes A single membrane Abundant in liver and kidney - breakdown of fatty acids for transport to mitochondria for fuel - detoxify alcohol and other harmful compounds. - Conversion of fatty acids in seeds to sugars.
Mitochondria and Chloroplasts Contain their own ribosomes and cytosol Contain small quantities of DNA that direct the synthesis of the polypeptides produced by these internal ribosomes. Grow and reproduce as semi-autonomous organelles Not part of the endomembrane system
Mitochondria Video (4) Matrix-contains DNA and ribosomes Cristae-contains enzymes for ATP generation during cellular respiration
Chloroplasts Present in plants and eukaryotic algae are the Sites of photosynthesis-production of sugar from CO 2 and water (high levels of the green pigment chlorophyll)
Mitochondria and chloroplasts - dynamic structures. - mobile and move around the cell along tracks in the cytoskeleton. - have double membranes. Cytoplasmic Streaming Video Campbell
Review of Functional Compartments of Eukaryotic cells Structural support, movement, and communication: cytoskeleton, plasma membrane, and cell wall Manufacturing: nucleus, ribosomes, endoplasmic reticulum, and Golgi apparatus Breakdown of molecules: lysosomes, vacuoles, and peroxisomes Energy processing: chloroplasts & mitochondria
Cell wall in some organisms proteins and polysaccharides, in plant cells The extracellular matrix (ECM) proteins and polysaccharides, in animal cells Extracellular components and connections between cells help coordinate cellular activities Cell Surfaces
Glycoprotein complex with long polysaccharide Collagen fiber EXTRACELLULAR FLUID Connecting glycoprotein Integrin Plasma membrane Microfilaments Functions of the ECM include Support Adhesion Movement Regulation CYTOPLASM A proteoglycan complex Polysaccharide molecule Carbohydrates Core protein Proteoglycan molecule
Intercellular junctions Plants- Plasmodesmata Animals- Tight junctions Desmosomes Gap junctions Activity: Cell Junctions