Unformatted text preview: Lab Safety Biology 111 Lab 5 - Cells Goggles and closed-toed shoes are required! Gloves must be worn when handling chemicals. Refer to the lab manual for Bunsen burner use. Immediately turn off the gas to the burner when you finish. Do not open the antibiotic plates on demonstration. Place used cotton swabs in the biohazard bag. Put used cheek cell slides and cover slips in the 25% bleach solution on the side counter. After they have soaked for at least 15 minutes, your T.A. will transfer them to the glass discard container. Place all slides used for Gram staining in the 25% bleach solution on the side counter. Dispose of all Gram stain solutions (Gram's Crystal Violet, Safranin, Gram's Alcohol, and Gram's Iodine) in the solvent waste container on the side counter. Keep waste containers closed except when disposing of waste. Do NOT fill past the indicated line. Tell your TA if a waste container fills. Do not eat or drink in lab. Follow general safety precautions and use common sense in addition to these guidelines. Ask your TA if there is doubt about any procedure. Cells Objectives eukaryotic vs prokaryotic cells Differentiate animal and plant cells Identify cellular components of eukaryotic cells Distinguish the three morphological types of bacteria Use the Gram's stain technique to investigate a bacterial infection Prokaryotic Eukaryotic Eukaryotic eu- cells vs. Prokaryotic cells "true" pro- "before" Prokaryotic cells DO NOT have a nucleus.
The genetic material is in the nucleoid region. There is no membrane separating it from the rest of the cell. Eukaryotic cells have a true, membrane bound nucleus containing their genetic material. cells generally bigger and more complex than prokaryotic cells Eukaryotic Endosymbiotic Theory Eukaryotic Includes cells protists, fungus, plants, animals We will concentrate on plant & animal cells In addition to a nucleus, eukaryotic cells have a variety of sub-cellular organelles and membrane systems Structures Cell
Controls common to both plant & animal
passage of materials in and out of cell membrane surrounding cell organelles Membrane-bound
Nucleus- contains the chromosomes Mitochondria- site of cellular respiration Structures common to both plant & animal Internal membrane system Endoplasmic reticulumRough ER- surface is covered with ribosomes Site of protein synthesis and sorting Smooth ER- surface has NO ribosomes System of membranes containing enzymes for lipid synthesis, metabolisms and detoxification Golgi apparatus- modify, store, and route products of endoplasmic reticulum Structures common to both plant & animal Non-membrane bound organelles Ribosomes- make proteins, can be free floating or bound to rough ER or nuclear envelope Structures unique to a plant cell Plastids site of photosynthesis chloroplast storage starch leucoplast storage of pigments - chromoplast Structures Large unique to a plant cell central vacuole- storage of water, pigments and waste Cell wall- composed of cellulose, provides structure Plasmodesmata- channels through cell walls that connect the cytoplasm of adjacent cells Structures found only in animal cells
digests macromolecules Lysosomes- Centrioles- assists in cell division Prokaryotic Cells They dominate our biosphere outnumbering eukaryotes are extremely small. include Archaea and Bacteria Characteristics Most are unicellular Most have a cell wall to maintain shape About half are capable of movement
Flagella are the most common means of motion Reproduce asexually through binary fission Basic components Nucleoid: region where DNA is located
Has a large circular chromosome Plasmids- small rings of DNA Contains genes for resistance to antibiotics Ribosomes: organelles that synthesize proteins Plasma membrane Cell wall: outside the plasma membrane Capsule: jellylike outer coating on many
for protection allows organisms to adhere Pili: another way some prokaryotes adhere Identification is partially based on Morphology (shape) Coccus (Cocci) Bacillus (Bacilli) Spirillum (Spirilla) Structure of cell wall another method of identificantion Cell wall composed of peptidoglycan Peptidogylcan - modified sugars cross-linked with short polypeptides Gram + cells have a thick wall with a lot of peptidoglycan. This makes them more absorbent and easier to stain. Gram cells have a thin wall with a little peptidoglycan and a second lipid layer. This makes them less absorbent and harder to stain. Gram bacteria are generally more threatening than Gram + species Gram bacteria are commonly more resistant to antibiotics than Gram + species Many antibiotics inhibit the formation of peptidoglycan thus preventing the formation of a functional cell wall. The drugs don't harm humans because we don't make peptidoglycan. Roles of prokaryotic cells Decomposers for recycling of chemical elements Pathogens Help initiate the breakdown of oil in areas of oil spills Used in sewage treatment Used to convert milk to yogurt Used to produce acetone and other products ...
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