BIOL 1411 1st Edition Lecture 5 Outline of Current Lecture 1. Cell theory2. How we study cells3. Common features of cells4. Prokaryotic cells features5. Eukaryotic cells featuresCurrent Lecture- Cell theory and it’s implicationso Cells=fundamental to life (smallest entity that can be alive and function independently)o All organisms consist of one or more of cellso They are microscopic (1-100 micrometers in diameter)o All cells come from preexisting cells (smallest unit of production)o How do we study cells? Bright-field microscopy Phase contrast microscopy Differential interference-contrast microscopy Stained bright-field microscopy Fluorescent microscopy- Use florescent labels to distinguish structures or specific molecules within a cell- Absorbs light of low wavelength, emits at higher wavelengths - Fluorescent molecule attaches to antibody which allows us to specify where certain proteins are inside a cell Confocal microscopy Electron microscopy- - shower of electrons provides high resolution cells- not a good method for living cells, howeverThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Why are cells so small? So they can exchange materials within the environment. Step by step process goes like this:- Nutrients in- Distribution- Cell metabolism- Metabolic wastes out Exchange with environment and cell occur at surface and are limited by surface area Distribution and metabolic reactions are limited by the inside volume of cell As cell size increases, cell volume increases more than surface area.- SA/VOL ratio decreases with increases cell dimensions, but increases with decreased cell dimensions o Common features of cells Plasma membrane- - makes up outer cell Cytoplasm- - inner cell, water based cytosol Genome of DNA Ribosomes- - Molecule machines for making cell proteinso Prokaryotic cells Bacteria and archea- Smallest structurally simplest of cells- Genomes consisting of one or two molecules of DNA concentratedin a nucleoid- Great metabolic diversityo Found everywhere on eartho Can use a wide array of energy sourceso Can exist as free-living single cells, though also live in aggregates (chains, clusters, or biofilms) Variable structural features- Exterioro Many have a rigid cell wallo Some have outer membrane additionallyo Some have slimy capsule of polysaccharides o Some have flagella and/or pili (hair-like projections)- Interioro Extensions (in-folding) of plasma membranes for energy transformation processes or cell divisiono Cytoskeleton (in a few only)o Eukaryotic cells Protists, fungi, plants, animals Generally larger/more complex than prokaryotic cells Larger genomes, organized chromosomes Organelles- Membrane enclosed compartments within cell- Each organelle has specific role in cell function, different chemical reactions happen within each individual cell Separations of celluar activities has allowed diversification of functions and specialization of eukaryotic cells Organization of cell- Must have plasma membrane, cytoplasm, and a nucleus for a eukaryotic cell to function- Cytoplasm must have cytosol (water based)+organelles+cytoskeleton to function properly Major organelles- Nucleuso Large, dense, visible with light microscope o Houses nucleolus as well as DNA Nucleolus is where DNA is made- Nuclear envelope o Two membrane layer with poreso Pores important so enzymes can pass in and out to transferDNA- Endomembrane system o Interconnected system of membranes that includes the nuclear envelope, endoplasmic reticulum, golgi, lysosomes, and plasma membraneo Tiny membrane surrounded vesicles shuttle substances between the various
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