BIOLOGY 111 1st Edition Lecture Outline of Last Lecture I. PolypeptidesII. Proteins structureA. Primary B. SecondaryC. TertiaryD. QuaternaryIII. Nucleic AcidsA. NucleotidesB. PolynucleotidesC. Chargaff’s ruleOutline of Current Lecture I. Cell sizeII. Prokaryotic CellIII. Plasma membraneIV. Eukaryotic cellA. Animal B. PlantV. Endosymbiont TheoryCurrent LectureCells Size- sizes range from .1nm to 10m- most plant and animal cells are between 10-100um in diameter and are only visible under microscope Why are cells this small? Why don’t cells grow in proportion with us? - In order to be most efficient, cells remain small in size to maintain their surface area to volume ratio. If cells were to grow in proportion with organisms, their surface area increases. As surface area increase, the volume also increases BUT proportionally more than the surface area does. Therefore, there needs to be large enough surface area to 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.cover the volume. Larger organisms do not have larger cells than smaller organisms, they just have more cells. - why cells stop growing o internal region of cell served by part of cell surfaceo cells grow bigger, volume enlarges and the cell membrane expandso at some point, not enough surface is available to service all the interioro must stop growing and divideo *the surface are to volume ratio gets smaller as the cell gets larger, which is not ideal - smaller cells have higher surface area to volume ratio Plasma membrane occurs as a double layer (bilayer)- The hydrophobic parts (tails) are found inside the membrane- The hydrophilic parts (heads) are found on the outside of the membrane. This is so that they are in contact with aqueous solution (and not the hydrophobic part)*the major difference between Prokaryotic and Eukaryotic cells is the location of their DNAProkaryotic cell - “before the seed” (no nucleus) - nucleoid - DNA floats freely in non-enclosed membrane- ribosomes - make protein- cell wall – rigid structure outside the plasma membrane- capsule – jellylike outer coating - plasma membrane – membrane enclosing the cytoplasm- fimbriae – attachment structure on the surface- flagella - locomotion organelles on outside of cell wall*at first it was Eukarya and Bacteria, but then some organisms were found in extreme environments which gave Archaea (differ from bacteria because of RNA sequence)Animal Eukaryotic cell - “true nucleus” (has a nucleus)o nuclear envelope – double membrane enclosing the nucleuso nucleolus – nonmembranous structure involved in ribosome production and located atthe center of nucleus o chromatin – material consisting of DNA and proteins- plasma membrane – membrane enclosing the cello microvilli - increase surface area and traps unwanted things- Endoplasmic Reticulum (ER) – active in membrane synthesis and other synthetic and metabolic processes, and has rough and smooth regions o Rough ER - have ribosomeso Smooth ER - smooth b/c doesn't have ribosomes (detoxifies and stores calcium)- Golgi Apparatus – active in synthesis, modification, sorting, transporting of cell products- Mitochondria – cellular respiration occurs and most ATP is generated- peroxisomes – various specialized metabolic functions, converts hydrogen into hydrogen peroxide as by-product, then converts it to water- Lysosomes - digestive enzymes where macromolecules are hydrolyzed- Cytoskeleton -gives shape to cell and is made up of proteins that differ based on diameter o Microfilaments – actin filaments *thinnest of the threeo microtubules - (13 columns) hollow tubes, made up of protein call tubulin (alpha and beta)*thickest of the three types maintain cell shape cell motility- motor protein (ATP powered)- receptor for motor protein chromosome movements in cell division organelle movementso intermediate filament – fibers *medium of the three- Centrosomes (occur in triplets) where cells microtubules are initiated, contains…o Centrioles – nine sets of triplet microtubules arranged in a ring, before a cell divides, centrioles replicate, they help to organize microtubule assembly in microtubules - Flagellum – locomotion (only on some cells, not all)- Cilia (occur in doublets) o motile (move) & nonmotile (fixed)o “9+2” pattern – nine doublets of microtubules are arranged in a ring, at the center are two single microtubules. o Dynein – large motor proteins, composed of several polypeptides, responsible forbending movement of organelle o basal body – structurally similar to a centriole, with microtubule triplets in a “9+0” pattern, anchors flagellum of cilium to the cellIn animal cells BUT not in plant cells- Lysosomes - Centrosomes and centrioles- Flagella (although present in plant sperm)In plant cells BUT not in animal cells - cell wall – outer layer that maintains cell shape and protects from mechanical damage, made of cellulose, other polysaccharides, and protein- central vacuole – prominent in older plants, function in storage, breakdown of waste products, hydrolysis of macromolecules, enlargement of vacuole (plant growth)- chloroplast – photosynthetic organelle that converts energy of sunlight into chemical energy stored in sugar molecules - plasmodesmata – cytoplasmic channels through cell walls that connect the cytoplasms of adjacent cellsEndosymbiosis theory – mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell thenevolved into a single organism - endosymbiont - a cell living within another