GBIO 106 1st Edition LECTURE 8 Exam 2 Study Guide Cell Structure and Function Robert Hooke Coined the term cells He worked with Sir Isaac Newton Leeuwenhoek Discovered living cells Schleiden and Schwann All living things are composed of cells Cells are the basic unit of life if all living things are made of cells These hypotheses have become known as cell theory Virchow Studied leukemia patients All cells come from pre existing cells General characteristics of cells Plasma membrane Protects absorbs communicates Genetic information DNA blueprint of how to build new cells Also all the instructions on how to perform chemical reactions Chemical reactions Used for energy for cells Cytoplasm All material inside the cell and outside the nucleus Holds water salt and organic molecules Some cells have organelles 70 90 water Two major types of cells Prokaryotic No nucleus Bacteria strep staph e coli anthrax Archaea live in extreme habitats Eukaryotic Have a nucleus In living things Parts of a Cell Membrane bound Organelles Nucleus Control center of the cell Chromatin DNA and protein Later on has to do with chromosomes Nucleolus Where ribosomes are made Ribosomes No membrane They are a place where proteins are built a table to work on Two types some are mobile some are stationary Free ribosomes Proteins made here will function as enzymes within the cytosol Bound ribosomes Attached to rough ER Proteins are made specific like lysosome enzymes membrane proteins or secretory proteins Endoplasmic Reticulum Network of membrane Two types Rough ER Contains ribosomes Involved in protein synthesis membrane production and transporting Smooth ER Does not make proteins Involved in lipid and carb synthesis In the liver it helps detox drugs Golgi complex A bunch of flat sacks of membrane looks like pita bread The cell s warehouse Stores modifies and distributes molecules Vesicles Small sacks of membrane Carry materials around the cell LECTURE 9 Data in DNA orders a secretion to be made RNA lays out instructions and is sent to rough ER into the bound ribosomes Vesicles carry the protein to the Golgi body There it will either be stored or it will be modified Then it can be put back in a vesicle and secreted from the cell The vesicle is used as a new bit of cell membrane DNA RNA Protein Nucleus Rough ER Vesicle Golgi Vesicle Plasma membrane Lysosomes Cell s digestive system Essentially a bigger vesicle with acid that acts as a stomach of sorts Can digest molecules and even complete microorganisms and defective organelles Mitochondria Oval round or tubular organelles made from a double membrane system There is an inner and outer membrane Location of aerobic respiration Cristae Formed from folding of inner membrane Matrix Inner space that contains enzymes and breaks down food molecules Cytoskeleton Network of 3 different protein filaments that are responsible for shape internal organization and movement of the cell Only in eukaryotic cells Microtubules Guide vesicles through the cell to form cilia and flagella Microfilaments Help amoeba and WBCs crawl and cause muscle cells to contract Intermediate filaments Networks of these filaments help determine a cell s shape PLANT CELLS Organelles exclusive to plants Cell Wall causes pressure within the cell by pushing back against stored water Chloroplasts Central Vacuole balloon that holds water and creates pressure LECTURE 10 Chloroplast One of many types of plastids This is where photosynthesis happens Thylakoids contain chlorophyll which traps light energy Stacks of green disks inside the chloroplast Stroma Space not containing chlorophyll where CO2 is turned into glucose Other Plastids Amyloplasts Store starch Chromoplasts store pigments of color like red orange yellow for the flowers Vacuoles In animals vacuoles are usually temporary In plants they are permanent It maintains the cells water balance Turgor pressure pressure of water in the vacuole that pushes the cytoplasm against the cell wall Storage pigments ions proteins and poisons for defense Disposal of metabolic waste toxins The Plasma Membrane All cells have a membrane It isolates the cells contents and regulates what moves in and out of the cell The fluid mosaic model is the most accurate model of the cell membrane The fluid portion is made of phospholipids and the mosaic part is made of proteins Phospholipid bilayer Two layers of phospholipids Membrane proteins move substances across the membrane and communicating with other cells Transport proteins form channels or act as carriers Shapes specifically fit to certain things Receptor proteins when a specific molecule binds to them it triggers a specific cellular response as with secretion and initiation of cell division Recognition proteins serve as cells ID tag or surface attachment sites LECTURE 11 Cholesterol makes the bilayer stronger and less permeable to water soluble substances like ions and sugars Basically a sealant for the cracks in the cell membrane These are LDLs bad cholesterol Necessary for healthy cell membranes Cell membrane has to be flexible to allow it to flex expand and move The plasma membrane does not allow most dissolved substances to pass through It is selectively permeable Water and oxygen move freely through the cell membrane because of how essential they are Smaller molecules move faster because they have less resistance Types of Transport Passive transport Simple diffusion osmosis facilitated diffusion Go with the flow from high to low Does not require ATP energy Simple diffusion Molecules moving from high to low concentration The concentration gradient is the difference in concentration of a substance between two areas Brownian motion has to do with the random motion of molecules It is influenced by temperature and concentration gradient Smaller molecules move faster and diffuse faster Osmosis Movement of water molecules from high to low concentration through a selectively permeable membrane Osmosis is also affected by temperature and the concentration gradient Solutes are dissolved substances where solvents are the liquid in which things are being dissolved Isotonic means that there are equal amounts of solute inside and outside the cell This causes dynamic equilibrium where permeable molecules move in and out of the cell with no net change Hypertonic means that there is a higher concentration of solute outside sugar always have a hypertonic balance On the other hand hypotonic concentration inside the cell than outside the