BIOL 1543 Custom Edition Lecture 2 Outline of Last Lecture I Introduction to organic compounds II Organic molecules III Carbon chains vary in many ways IV Functional groups V Cells build large molecules from smaller ones VI Dehydration reactions VII Hydrolysis VIII Carbohydrates IX Monosaccharides X Cells link two single sugars to form disaccharides XI Polysaccharides are long chains of sugar units XII Lipids XIII Fats also known as triglycerides XIV Other lipids XV PROTEINS XVI NUCLEIC ACIDS Outline of Current Lecture I The Art of Looking at Cells II Life began on a young Earth III How did life form These 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 IV Other critical steps V Additional critical steps VI PROKARYOTES VII The two kinds of cells prokaryotic and eukaryotic VIII Size of a cell IX PROTISTS the early Eukaryotes X A model of the origin of eukaryotes XI An animal cell contains various membranous organelles XII Plant cells XIII The Endomembrane System XIV The Smooth Endoplasmic reticulum XV The Rough ER XVI The Golgi apparatus finishes sorts ships cell products XVII Lysosomes are digestive compartments within a cell XVIII Vacuoles XIX The endomembrane system XX ENERGY CONVERTING ORGANELLES XXI Cell surfaces protect support and join cells Current Lecture I The Art of Looking at Cells a Early scientists who observed cells made detailed sketches of what they saw i These early sketches revealed an important relationship between art and biology the most visual of the sciences ii first microscopes in 1590 II Life began on a young Earth a Planet Earth formed some 4 6 billion years ago b Fossilized prokaryotes called stromatolites oldest macroscopic evidence of life on earth date back 3 5 billion years a fossil is a remnant of an organism of a past age imbedded and preserved in the earths crust c The early atmosphere probably contained H2O CO CO2 N2 and some CH4 d Volcanic activity lightning and UV radiation were intense III How did life form a Simulations of Earth s early conditions have produced amino acids sugars lipids and the nitrogenous bases found in DNA and RNA IV Other critical steps a Organic polymers such as proteins and nucleic acids may have formed on hot rocks or clay b The first genetic material and enzymes may both have been RNA V Additional critical steps a Membranes may have separated various aggregates of self replicating molecules areas in the cell that can reproduce themselves RNA and polypeptides which could then be acted on by natural selection A Membrane is a thin pliable layer of tissue covering surfaces or separating areas within a cell VI PROKARYOTES a Prokaryotes unicellular organisms not having a true nucleus appeared on Earth billions of years ago b They are the oldest life forms and remain the most numerous and widespread organisms c The prokaryote domains Archaea and Bacteria are distinguished mainly by genetic differences i Archaea old ones AKA extremophiles love extreme conditions never been shown to cause disease ii Bacteria cause disease VII The two kinds of cells prokaryotic and eukaryotic a Prokaryotic cells are small relatively simple cells that do not have a membrane bound nucleus b eukaryotic cells possess a true nucleus i a nucleus is the membrane bound structure that contains the cells hereditary info and controls production ii Organelles are a differentiated structure in the cell that preform a specific function VIII Size of a cell a A small cell has a greater ratio of surface area to volume than a large cell of the same shape i multi cellular is much more effective because it has a large cell membrane and is more functional at getting things in and out of the cell 10 m 30 m 30 Surface area of one large cube 5 400 m2 10 m Total surface area of 27 small cubes 16 200 m2 IX PROTISTS the early Eukaryotes a Protists are eukaryotes that are not animal plant or fungi like an ameba b The eukaryotic cell probably originated as a community of prokaryotes i Eukaryotic cells evolved from prokaryotic cells more than 2 billion years ago ii The nucleus and endomembrane system this is the technical term for all organelles probably evolved from infoldings of the plasma membrane 1 Endomembrane system is the system of internal membranes within eukaryotic cells that divide the cell into functional and structural components iii Mitochondria and chloroplasts probably evolved from aerobic and photosynthetic endosymbionts any organism that lives within the cells of another organism respectively X A model of the origin of eukaryotes a Eukaryotic cells are partitioned into functional compartments i All other forms of life are composed of more complex eukaryotic cells distinguished by the presence of a true nucleus the defining structure ii Membranes form the boundaries of many eukaryotic cells compartmentalizing the interior of the cell and facilitating a variety of metabolic activities b Heterotrophic is not cell sustainable can t sustain itself c Chloroplast are photosynthetic d Endosymbiosis is any organism that lives within the cell of another XI An animal cell contains various membranous organelles a Do not contain chloroplasts b Do have mitochondria also in plant cells to produce ATP c nucleus i controls chemical reactions ii stores information for cellular division XII Plant cells a Plant cells have structures that an animal cell lacks such as chloroplasts and a rigid cell wall XIII The Endomembrane System a The endomembrane system is a collection of membranous organelles that manufactures and distributes cell products b The largest organelle is usually the nucleus headquarters which is separated from the cytoplasm by the nuclear envelope c The nucleus is the cellular control center containing the cell s DNA which directs cellular activities XIV The Smooth Endoplasmic reticulum a Smooth endoplasmic reticulum has a variety of functions know the functions i Smooth endoplasmic reticulum or smooth ER 1 Synthesizes lipids 2 Processes toxins and drugs in liver cells 3 Stores and releases calcium ions in muscle cells XV The Rough ER a Rough endoplasmic reticulum makes membrane and proteins i The rough ER manufactures membranes ii Ribosomes on the surface of the rough ER produce proteins polypeptides that are secreted inserted into membranes or transported in vesicles to other organelles b The ribosomes on its surface make it rough XVI The Golgi apparatus