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micro unit test 1
dtcc micro unit test 1
| Question | Answer |
|---|---|
| what is a microbe? | a small living thing that can only be seen with a microscope |
| What are some of the ways in which microbes interact with the environment? | photosynthesis structure and content of soil, water, and atmosphere heat flow of energy and food in ecosysytem |
| What are some of the ways, harmful and otherwise, in which microbes interact with humans? | bread, alcohol, cheese, treatment, cleaning up contamination |
| What is a pathogen? | microbes that cause disease |
| How prevalent are pathogens among microbes? | all over the world most common cause of death |
| What is the primary difference between prokaryotes and eukaryotes | eukayrotic have nucleus and membrane organelles |
| what is a virus | an obligate intercellular parasites |
| what are some important characteristics of viruses | infect every type of cell needed for evolution |
| How would you recognize a properly written scientific or binomial name | Escherichia coli. (italicized and underlined) |
| What do the two parts of that name indicate? | combination of genus and species name |
| What are the major groups of microbes? Which are prokaryotes and which are eukaryotes? | P- bacteria, e- protoza, e-fungi, e-algae, neither-viruses, p-archea |
| What are some characteristics of the major groups of microbes | domain, most distinct from each other (taxonimic) |
| What were the first types of organisms to appear on Earth | ancestor of bacteria, archea, eukaroytes |
| About how long did it take for more complex, multicellular organisms such as animals to evolve? | billions of years |
| What are the three domains of life? | bacteria, archaea, eukarya |
| List the ranks of the taxonomic hierarchy, from domain to species. Which level contains organisms that are most similar to one another | domain (most different) kingdom plylum of divison class order family genus species (most similar) |
| Which contains organisms that are most different from one another? | domain |
| How is rRNA relevant in classification of organisms | rrna is different but nearly identical in species |
| Why is rrna used instead of DNA? | not really affected by evolution |
| Organisms that are not microbes are always what: prokaryotes or eukaryotes | Pro |
| bacteria minimum need | cell membrane, bacterial, chromosome (dna), ribosomes, cytoplasm |
| bioremediation is | ability to restore or clean up toxic pollutants |
| Genetic engineering? | Deliberately alters genetics of microbes |
| Taxonomy? | The science of classifying living things (to name) |
| Nomenclature? | The assignment of names to the taxonomic categories |
| Classification? | The arrangement of organisms into a hierarchy (kingdom) |
| Identification | The process of discovering and recording traits of organisms so they can be placed in the taxonomic |
| Phylogeny | How they relate to one another |
| How large are the smallest objects that can be seen by the human eye | 1mm |
| How large are the smallest objects that can be seen by the light microscope | 1(weird n) m |
| How large is a typical bacterium? | 1and 10 (weird n) m |
| How does this compare to a typical human cell | 1(weird n)m so bacteria is atleast 10x larger |
| What is magnification | The process of enlarging the appearance. |
| What is resolution | seeing clearly |
| How does the oil with immersion lens help? | Reduces light scatter and increases resolution |
| Which part of the microscope magnify the image | Lens |
| In a typical compound microscope what are the 2 lenses and where are they located? | Ocular and objective lens, located on the nose piece |
| What set of lens on a compound microscope be rotated in and out | Torret |
| How is total magnification calculated | objective x ocular |
| Define refractive | bending light as it passes from one medium to another |
| What Is contrast | Ability to dee an object from the background |
| Why is contrast important in forming a good image? | to be able to see the item fully |
| How can contrast be increased | by using the iris diaphragm to reduce the intensity of the light |
| Categorize the types of microscope by their light source. | visible lights, UV rays, electron beam, |
| What is each microscope best-suited to viewing | bacteria and parasites, human/animal cells. |
| What are some considerations when determining how a sample is to be prepared for microscopy? | living? what do you want to see? what microscope is available? |
| What are the advantages of live preparations (“wet mounts”) and fixed, stained specimens | observed as near to their natural state as possible, provide true assessment of the size, shape, arrangement, color, and motility of cells. |
| What are some options when making a live preparation | water, saline, or broth? |
| What is heat-fixing and what is the purpose of it | Kill organisms and adhere them to the slides being used so they can take on stains. |
| What is the purpose of staining | enhance visualization under light and electron microscopy |
| what are some disadvantages of live preparations (“wet mounts”) and fixed, stained specimens | you can not view for a long time and not able to view in greater cellular detail |
| Which type of stain has colored specimens and a clear background? | positive staining |
| What are the differences between simple stains and differential stains | simple- 1 dye differential- 2 dyes |
| How do gram-positive and gram-negative bacteria appear under the microscope | positive purple negative red |
| What important microbe is detected by acid-fast staining | tuberculosis |
| Is India ink staining for capsules positive or negative staining | negative |
| How does flagellar staining work | enlarge flagella by coating outside then staining |
| Which type has a colored background and colorless specimens? | negative staining |
| ocular lenses | Magnify the image 10X. |
| body tube | Conducts light rays from objectives to oculars. |
| arm | Supports the upper part of the microscope. Use this and the base to carry the microscope. |
| nosepiece | Revolving plate used to change the objective lens being used. |
| objective lens | can be rotated in and out to give varying levels of magnification. |
| stage clips/ slide holder | Holds the slide securely in place on the stage. |
| Mechanical stage | The slide will rest on the stage. |
| condensor | Condenses light waves into a cone shape and controls the amount of light that passes through the slide. |
| Diaphragm closes | closes and opens the diaphragm |
| illuminator/ light source | Provides the light that will pass through the slide |
| fine focus adjustment knob | Used for final focusing. Use with high power and oil immersion. |
| coarse focus adjustment knob | raisinh or lower the stage. |
| base | Flat surface that rests on the table. |
| What structures do all bacterial cells have? | cell membrane, cytoplasm, ribosomes, DNA |
| Which structures do most bacterial cells have | cell wall |
| Which structures are only on certain bacterial cells | outer membrane |
| How large is a typical bacterium | 1-10 micrion |
| What are the principal bacterial shapes (hint – there are three) and what names do we use to designate them | rods, spirals, spheres |
| What is pleomorphism | due to individual vaiations in cell wall structure caused by nutritional or slight genetic differences |
| What are the terms used to describe grouped bacteria and variations on the principal bacterial shapes? | pleomorphic |
| What is a flagellum | a slender threadlike structure for swimming |
| Describe the motion of the flagellum | run and tumble |
| Name and describe the external bacterial flagellar arrangements. | Monotrichous (single) lophotrichous (small bunches same site) smphitrichous ( both poles) |
| What are running and tumbling | run: counterclockwise smooth linear direction tumble: reversal of direction cell to stop and change course |
| what is chemotaxis | movement of bacteria in response to chemical signals. |
| What are periplasmic flagella | spirichete (spiral/ corkscrew shape) |
| Which organisms have them flagalla? What type of motion do they produce? | corkscrew shape and unusual wriggly locomotion |
| What are pili and fimbriae? What are their functions | fimbriae: Small, bristle-like fibers sprouting off the surface of many bacterial cells. Pilus – Long rigid, tubular structure made of a special protein ‘Pilin’. |
| What are nanotubes/nano wires? What is their function? | Thin, long tubular extensions of cytoplasmic membrane Channels for nutrient or energy exchange |
| What are the two types of glycocalyx | slime layer capsule |
| What is the glycocalyx composed of? | made by bacteria, epithelia, and other cells |
| What roles can the glycocalyx serve? | Performs protective, adhesive and receptor functions |
| What substance makes up the bacterial cell wall? | Peptidoglycan - Repeating framework of glycans + Short peptide (protein) fragments |
| What macromolecules are combined in this substance? | peptidoglycan |
| How does damage to the cell wall affect a bacterium? | disrupts its integrity |
| Compare and contrast gram-positive and gram-negative cells. What features does each one have that the other one lacks? | positive: thick peptidoglycan, cell wall negative: think peptidoglycan but is more felxible |
| Which type of bacterium has an outer membrane | gram negative |
| What medical effect does lipopolysaccharide (LPS) have? | produce endospores |
| In the Gram staining reaction, what does each step do? What happens if a given step is skipped? | cystal violet dye, then iodine solution, a decolorizer, the counterstain.. skipped then it will be purple skipped may not get correct result |
| What are some options for atypical cell walls in bacteria and other prokaryotes? | mycobacterium, protein or polysaccharide, |
| What are the main components of the plasma/cytoplasmic membrane? What is its function and how does it accomplish this? | lipid bilayer with proteins. atp synthesis by holding enzymes |
| What is the difference between a chromosome and a plasmid? | plama is a non essential piece of double stranded DNA |
| What shape is the bacterial chromosome? where is it found? | circular nucleoid in cytoplasm |
| What is the function of ribosomes? | protein synthesis |
| What designation is used for prokaryotic ribosomes? | are attractive target for drug design found in bacteria |
| What designation is used for eukaryotic ribosomes? | found in licing (animals, plants, fungi ect.) |
| What are the differences between an endospore and a vegetative cell? | endospore- stress non stable vegetative- stable living conditions |
| What is the advantage of forming endospores | survive extreme conditions |
| Under what conditions do endospores form? | streesful conditions |
| What transforms them back into vegetative cells? | germination |
| What is the medical significance of endospores? | disease causing ability they can be pathogens |
| What are the primary differences between the two domains of prokaryotic cells? | bacteria are found everywhere archaea found in unusual environments |
| Why are prokaryotes difficult to classify? | because they share charateristics |
| How do we account for variations in a species when classifying prokaryotes? | serotype, subspecies, strain, or type to designate bacteria of the same species that have differing characteristics. |
| Briefly explain the concept of “last common ancestor” as it relates to eukaryotic cells. | common ancestor is nether eu or pro |
| How have eukaryotic organisms changed over time? | aggregate and formed colonies evolved when individual cells lost the ability to survive on their own |
| Describe endosymbiotic theory. | a large host cell & bacteria could become dependent on one another for survival, resulting in a permanent relationship. Over millions of yrs of evolution, mitochondria & chloroplasts have become more specialized & today they cannot live outside the cell. |
| What major group of eukaryotes has flagella? | unikonts |
| How are eukaryotic flagella different from prokaryotic flagella? | protozoa |
| Describe the structure and function of cilia. | Cilia are slender, microscopic, hair-like structures or organelles |
| What are the differences between cilia and flagella? | flagella- single slide past each other cilia- shorter and many, beat back and forth (oar strokes), feeding and filtering function |
| What are the functions of a eukaryotic glycocalyx? | Protection Adherence to surface Reception of signals from other cells and environment |
| Which eukaryotic groups have cell walls and which do not? | Do- fungi and algae dont- protozoa and helminths |
| What are fungal cell walls made of? | Thick inner layer of polysaccharide fibers composed of chitin or cellulose Thin outer layer of mixed glycans |
| Describe the general structure of the cytoplasmic membrane. What is its function? | Bilayer of phospholipids with proteins separates the interior of a cell from its outside environment |
| What is a hyphae? | Long thread like cells found in the bodies of filamentous fungi or molds |
| How does hyphae relate to pseudohyphae? | both in molds/fungi/ attach to one another |
| What are the differences between mold and yeast? | yeast-Round oval shaped and undergoes asexual reproduction mold- multicellular sexual or asexual |
| What term describes fungi that can switch between the two forms? | dimorphic |
| What are some clinically relevant aspects of fungi? | causes harms to humans |
| What are the active and inactive stages of a protozoan? | active/ trophozoite- feeding stage needs food and moisture inactive/cyst- unfavorable environment stress environments no eating |
| What is the advantage of forming cysts? | resistant to heat and drying chemicals |
| Why are cysts clinically relevant? | spread diseases |
| What are the major groups of protozoans based on motility? | Amoeba (sarcodina/ Pseudopods Ciliates (Cilophora) Flagellates (Mastigophora) Apicomplexans (Nonmotile) |
| What are the major groups of helminths? | flatworms and round worms |
| Briefly describe the helminth lifecycle. | egg, larva, adult. |
| describe nucleus | the central and most important part of an object, movement, or group, forming the basis for its activity and growth. |
| describe endoplasmic reticulum | a network of membranous tubules within the cytoplasm of a eukaryotic cell |
| define golgi apparatus | a complex of vesicles and folded membranes within the cytoplasm of most eukaryotic cells, involved in secretion and intracellular transport. |
| define lyosomes | an organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane. |
| describe mitrochondria | in which the biochemical processes of respiration and energy production occur. |
| chloroplasts | a plastid that contains chlorophyll and in which photosynthesis takes place. (in green plant cells) a plastid that contains chlorophyll and in which photosynthesis takes place. |
| define ribosomes | They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins. |
| define cytoskeleton | a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence. |
| When did eukaryotic cells first appear? | 2-3 billion years ago |
| when you miss a step on gram staining it will be | purple |
| gram staining is | differential |
| fungal had | chitin walls |
| staphyloccus aureus is a gram positive and | round shaped |
| stephyococcus shapes are | coccus, rod, bacillus or spiral |
| cocci are | oval shape |
| what is an organic molecule | molecule that must include at least both carbon and hydrogen |
| what is an inorganic molecule | molecule that does not contain both carbon and hydrogen |
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xokitty17xo