All organisms are made up of cells The cell is the simplest collection of matter that can live Cell structure is correlated with cell function All cells are related by descent from earlier cells Cells are usually too small to be seen by the unaided eye Cells are very complex Cells The fundamental units of life Microscopy Magni cation Resolution the measure of clarity of an image Scientists use microscopes to view cells that are unable to be viewed with the named eye The quality of an image depends on the minimum distance between two distinguishable points Resolution is inversely proportional to the wavelength used to visualize Contrast visible di erences in part of the sample Light microscopes Visible light passes through a specimen and then through lenses which magnify the image Can magnify about 1000x the size of the actual specimen various techniques are used to increase contrast Doug Prasher discovered you could link jelly sh and human genes together so they could glow but the peace prize was awarded to other scientists Scanning electron microscopes Electron Microscopy Focus a beam of electrons onto the surface of a specimen providing an image in 3 dimensions Surface must be covered with a lm usually of gold really looking at the energy given o by the gold Transmission electron microscopy focus a beam of electrons through a specimen Samples are stained with a heavy metal usually urinyl acetate used to study internal structure FSU has a titan krios which is a very big microscope thing Takes apart cells and separates the major organelles from one another Centrifuges and ultracentrifuges fractionate cells into their component parts Cell Fractionation Two Types of Cells All cells Plasma membranes selective barrier that allows passage of oxygen nutrients and waste for every cell generally a phospholipid bilayer Cytosol semi uid interior of a cell Chromosomes carry genes Ribosomes makes proteins Prokaryotic and Eukaryotic Prokaryotic cells do not have a nucleus DNA is in the nuckloid No membrane bound organelles cytoplasm is bound by the plasma membrane Smaller cells Eukaryotic cells Have a nucleus with DNA Have membrane bound organelles cytoplasm between nucleus and plasma membrane larger cells Organelles Endomembrane system membranes eiher directly connected or connected by vesicles Made up of nucleus Information central Double phosopholipid bilayer Endoplasmic reticulum factory Gogli Apparatus Shipping and receiving Lisosomes digestive compartments disassembly and recycling Plasma membrane Energy conversion Mitochondria generate ATP Chloroplasts generate small organic sugars peroxiosomes break down Eukaryotic Cell protein laments chromatin RNA synthesis Endoplasmic reticulum Smooth ER The Nucleus Contains most of the cells genes and is usually the most conspicuous organelle The nuclear envelope separates the nucleus from cytoplasm is a double membrane Pores regulate entry and exit of molecules in nucleus The shape of the nucleus is maintained by nuclear lamina In the nucleus DNA and proteins form the genetic material Chromatin condenses to form chromosomes The nucleolus is located within the nucleus and is the cite of ribosomal Accounts for more than half of the membrane in many eukaryotic cell Contiguous with the nuclear envelope Two distinct regions Synthesizes lipids for the cell metabolizes carbohydrates detoxi es poisons stores calcium Rough ER Has bound ribosomes responsible for some protein synthesis secretes glycoproteins proteins with covalent bonds to carbohydrates Distributes transport vesicles surrounded by membranes membrane factory for the cell Golgi Apparatus Consists of attened membranous sacks called cisterae Functions include Modi cation of products of the ER Manufactures some macromolecules Sorts and packages materials into transport vesicles Orientation of Golgi apparatus is describes by cis and trans sides cis closest to ER trans furthest away Lysosome Membranous sack of hydrolytic enzymes that digest all four classes of biological macromolecule Carbohydrates lipids proteins nucleic acids Some cells can engulf other cells or molecules by a process called phagocytosis the lysosome fuses with that ad digests the contents A plant or a fungal cell may have one or more large storage vaculoes food vaculoes are formed by phagocytosis Contractile vaculoe pumps excess water out of cells Central vaculoes found in many plant cells hold organic compounds Vaculoes and water Organelles that change energy from one form to another Mitochondria sites of cellular respiration generate ATP Chloroplasts found in plans sites of photosynthesis Mitochondria and Chloroplasts not part of the endomembrane system have a double membrane have proteins made by free ribosomes oating in the mitochondria contain their own DNA Peroxisomes oxidative organelles Are in nearly all eukatyotic cells They have a smooth outter membrane and a highly folded inner membrane folds called cristae Inner membrane has two compartments Intermembrane space mitocondrial matrix Mitocondria Some steps of cellular respiration occur in the mitocondrial matrix Cristae present a large surface area for production of ATP Chloroplasts Membrane of a family of plant organelles called plasds Contain the green pigment Chlorophyll Contain enzymes necessary for photosynthesis Found in the leaves and all green organs of plants Structure Double membrane organelle membranes sacs called thylaroids for stacks called grana Internal uid called stroma Peroxisomes Specialized metabolic compartments bounded by a single membrane Use oxygen to break down di erent types of molecules process transfer of hydrogens to oxygens producing hydrogen peroxide H2O2 Convert H2O2 to water The Cytoskeleton Network of bers extending throughout the cytoplasm Organizes the cell structures and activities Also anchors many organelles Composed of three types of molecular structures Extra cellular components and their connections Cell wall of plants cell wall of plants extracellular matrix of animal cells intercellular distinguishes plant cells fungal cells and some protists from animal cells protects the cell Maintains shape prevents excessive water uptake have multiple layers primary cell wall thin and exible middle lamella thin layer between primary cell wall of adjacent cells secondary cell wall in between the primary cell wall and plasma membrane in some cells Plasma desmota channels between plant cells Extracellular matrix of animal cells animal cells
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