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Unit 2 test
glycocalyx,cell wall,cell membrane
| Question | Answer |
|---|---|
| The ability to attach to a surface is important for many prokaryotes. One of the structures used for attachment is the glycocalyx | True |
| Which of the following are characteristics of biofilms? | true |
| Glycocalyx is made from | carbohydrate |
| Glycocalyx comes in two forms. If it is a rigid structure and tightly attached to the cell, it is called | capsule |
| A capsule is a virulence factor because it: | interferes with phagocytosis, interferes with white blood cells engulfing and killing the bacteria |
| When a white blood cell binds to lipid A, what happens? | the wbc releases chemicals which cause inflammation, the wbc releases chemicals which suppress the immune system, if a large number of wbc bind LPS, it can lead to sepsis, organ failure and intravascular coagulation |
| Match the following cell wall type to the appropriate description: most susceptible to β-lactam antimicrobials | gram positive |
| LPS is an acronym for | lipopolysaccharide |
| Which white blood cell has a receptor for lipid A? | monocyte |
| β-lactam antimicrobials kill bacteria by | interfering with peptidoglycan synthesis |
| Which component of LPS is actually embedded in the outer membrane? | lipid A |
| Match the following cell wall type to the appropriate description: least likely to lyse under hypotonic conditions | gram positive |
| Match the following species with the appropriate characteristic: cell wall includes a waxy substance called mycolic acid; causes leprosy | Mycobacterium leprae |
| A silver bullet has the following characteristics | kills the pathogen but does not harm the host, targets structures which human cells do not have |
| Bacterial cells whose cell wall is removed with chemicals will typically lyse under hypotonic conditions. Why isn’t this true for the genus of bacteria which do not have a cell wall? | they strengthen their plasma membrane with steroids like cholesterol |
| Match the following species with the appropriate characteristic: does not have a cell wall; most common cause of pneumonia in college students | Mycoplasma pneumonia |
| LPS is found: | in the outer membrane of a gram negative cell wall |
| Even in small amounts, LPS can cause a strong inflammatory response in the human body | true |
| Which antibiotic prevents the elongation of peptidoglycan and is considered the antibiotic of last resort (because bacteria are rarely resistant)? | vancomycin |
| Which component of LPS extends away from the cell surface | polysaccharide |
| Many bacteria thwart the actions of antimicrobials. To inactivate antimicrobials which target the peptidoglycan, some bacteria produce | β-lactamase |
| Many bacteria produce a cell wall which includes peptidoglycan. The prefix ‘pepti-‘ refers to the disaccharides which connect chains of short protein. The suffix ‘-glycan’ refers to the chains of short proteins | FALSE |
| Which group of antimicrobials interfere with synthesis of peptidoglycan? | penicillins, cephalosporins, β-lactams |
| Match the following cell wall type to the appropriate description: contains a thick layer of peptidoglycan | GRAM POSITIVE |
| The bacteria which incorporate mycolic acid into the cell wall have the following characteristics | they take longer to grow, the mycolic acid interferes with the movement of nutrients into the cell, they are mo |
| The cell wall helps to prevent lysis under hypotonic conditions. Which of the following is the definition of “hypotonic”?re difficult to kill by phagocytosis | water is in lower concentration outside of the cell than inside, causes osmosis of water into the cell and the cell swells |
| Which component of LPS interferes with antibody/complement killing? | polysaccharide |
| Based on our definition of a “silver bullet”, would antibiotics which attack the cell wall of a bacteria be silver bullets? | yes |
| Compared to gram negative bacteria, gram positive bacteria are more sensitive to an enzyme called lysozyme. Of the answers below, the best reason for this difference is that gram negative bacteria: | have an outer membrane |
| Match the following terms with the appropriate definition: only used on inanimate objects | Disinfectant |
| Some antiseptics disrupt the plasma membrane of bacteria and yeast, and these antiseptics can be taken orally | false |
| If a substance is transported across the membrane by facilitated diffusion, the energy for transport is from | the concentration gradient |
| The description of a prokaryote cell membrane is based on the fluid-mosaic model. Which component of the cell membrane is responsible for the mosaic character of the cell membrane? | Proteins |
| If a substance is transported across the membrane by active transport, the energy for transport is from | ATP |
| Enzymes (proteins) in or along the prokaryote cell membrane are responsible for | transporting substances across the membrane, building outer structures like cell walls and appendages performing ATP synthesis, carrying out photosynthesis |
| The term ‘fluid’ refers to: | how molecules making up the membrane can freely move around, the phospholipid molecules |
| Are membranes a good target for antimicrobials? | no |
| Because of the amphipathic character of phospholipids, when placed in water they will arrange themselves into a bilipid membrane even though they aren’t bonded to each other. | true |
| In prokaryotes, substances move across the membrane by the following mechanism(s): | simple diffusion active transport, facilitated diffusion |
| Match the following terms with the appropriate definition: may be used topically on skin or mucus membranes but not given orally | ) antiseptic |
| The term ‘mosaic’ refers to | the variety of molecules making up the membrane |
| Describe the structure of Glycocalyx (what is it made from) | carbohydrate containing substance, located outside of the cell wall |
| Name the two forms of Glycocalyx | slime layer (loosely bound), capsule(tightly bound) |
| List the functions of a Glycocalyx | attachment to environmental surfaces, virulence factor, forming community, prevent drying out, sunscreen, food resrve |
| a community of bacteria held together by glcocalyx | biofilm |
| List the characteristic of a biofilm which provide evidence that bacteria can live as a community | they exhibit cell to cell differentiation, communication and cooperation |
| chains of disaccharides connected by peptides that surround the plasma membrane | peptidoglycan |
| Which cell wall type has a thin layer | gram negative |
| Which has a thick layer? | gram positive |
| bilipid membrane of gram neg cell wall contain a substance that is an endotoxin which is a lipid/sugar combo | LPS/lipopolysaccharide |
| What effect does lipid A have on the human immune system | induces fever, activates WBC and stimulates inflammation |
| what effect does the sugar component has on the human immune system | interfere with phagocytosis and antibody component lysis |
| Explain the purpose of the cell wall | prevent lysis of hypotonic fluid |
| Compared to gram positive, explain why gram negative organisms are more susceptible to lysing under hypotonic conditions | peptoglycon is very thin and more apt to break under osmotic pressure |
| Compared to gram negative, explain why gram positive organisms are more sensitive to antibiotics which attack the peptidoglycan | they don't have the outer layer to severe as a barrier to block the antibiotic |
| Compared to gram negative, explain why gram positive organisms are more sensitive to the enzyme lysozyme | outer layer acts as a barrier die to the prions present the lysosome cant fit thru |
| Where is lysozyme found and name its substrate | variety of body fluids,peptidoglycan |
| peptidoglycan with a waxy outer layer of myoclonic acid | mycobacteria cell wall |
| what disease does Mycobacterium tuberculosis cause | tuberculosis |
| Describe what is unique about Myoplasma | strengthens cell membranes by inserting cholesterol like molecules called sterols |
| Name a medically significant species of Mycoplasma and the disease it causes | M.pneumoniae- atypical pnue |
| State the biological significance of Mycoplasma cells? | organisms are the smallest known cells |
| Explain why the cell wall is a good target for antibiotics | human cells don't provide peptoglycon |
| what type of antibiotic- contain B-lactim ring that binds and inactivates bacterial enzyme; | B lactim antibiotics |
| how do bacteria defend themselves against β-lactam antibiotics? | produce enzyme called B-lactamases which cleaves the B lactam ring |
| Explain why the membrane is called "fluid" | phosolipid molecules are not covalently bonded |
| Explain why the membrane is called a "mosaic | disverity of surface proteins |
| molecule moves from high to low concentration | Simple diffusion |
| substance cant freely diffuse thru membrane | Facilitated diffusion |
| member protein and alternative source of energy used to move substances across membrane and against concentration | Active transport |
| List the functions of the proteins found in and on the cell membrane | makes ATP, performs protein synthesis,synthesizes glycocolax and peptoglycon |
| Explain whether or not the plasma membrane is a good target for antibiotics | no, chemicals that damages pathogen will damage human cell |
| substances which are used to kill micorbes on the surface of the skin or mucus membranes | antiseptic |
| substances which are used to kill microbes on inanimate objects | disinfectant |
| what disease does Mycobacterium leprae cause | leprosy |
Created by:
bennetta78
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