dr lowry microbiology

39 flashcards · Biology · by Louise Cox

1. what is microbiology

   microbiology is the study of an organism too small to be seen by the unaided eye

2. what is the magnification on a light microscope

   up to x 1,000

3. what info does a light microscope provide

   size, shape , organisation

4. examples of simple stains

   methylene blue , malachite green ,crystal violet , safranin

5. types of bacteria shapes

   coccus ( spherical shape) >in a regular chain >irregular clumps bacillus ( rod shaped ) >cells without recognised grouping > cells in chains

6. why do we get differences in gram stains

   due to differences in thick of a peptidoglycan layer in the cell membrane between gram positive and gram negative bacteria

7. procedure for gram stain

   we collect the sample ( example urine ) . it is placed in a Petri dish . in the lab we then add a primary stain ( crystal violet ) , add a mordant ( grams iodine ) , cause rapid decolorisation with ethanol , acetone or a mix of both . then counterstain with safranin. we will then examine the sample for colour and size

8. what are the final colours of a gram stain

   it will be pink/red if it is gram negative , it will be purple if it is gram positive

9. examples of heavy metal ions that deflect electrons

   molybdenium , uranium , tungsten , lead and gold

10. cell biology of prokaryotes

    they have simple internal organisation , no membrane bound nucleus , no mitochondria , no Golgi or endoplasmic reticulum

11. function of Golgi

    Golgi are a factory in the body which proteins from the endoplasmic reticulum are further processed and sorted for transport to their eventual destination

12. role of endoplasmic reticulum

    calcium storage , protein synthesis , lipid metabolism

13. 2 types of prokaryotes

    bacteria >most human pathogens archae > enviromental organisms > inhabitants of harsh environments

14. examples of coccus diseases ( gram positive)

    staphylococcus , streptococcus , enterococcus

15. examples of bacillus diseases ( gram positive )

    anthrax , clostridium , listeria

16. coccus diseases ( gram negative )

    neisseria gonnorhea , neisseria meningitis

17. bacillus diseases ( gram negative )

    enterobacteria , legionella , bordtella

18. spirochete diseases ( gram negative )

    treponema , borrelia , leptospina

19. pleomorphic diseases ( gram negative )

    mycoplasma

20. bacteria cell essential activities

    protein synthesis , Dna replication , rna transcription , metabolic reactions

21. bacteria limited organisations

    no nucleusn tightly wound DNA no mitochondria no Golgi no endoplasmic reticulum

22. bacterial membrane contains a lipid bilayer that ....

    is 7nm thick is composed of : phospholipid , lipopolysaccharide and proteins

23. functions of a bacterial cell membrane

    >compartmentalisation >energy generation >nutrient transport >DNA replication > protein secretion > membrane wall synthesis

24. gram positive bacterial cell wall

    > 30-60 nm thick > 60-90 percent cell envelope > x link via peptide interbridge

25. gram negative cell wall

    2-3 nm thick 10-15 percent of cell envelope no interbridge

26. alternative to peptidoglycogen cell

    mycosplasmataceae

27. what are bacterial endospores

    Bacterial endospores are simplified forms of the bacteria, consisting of the DNA genome, some small amount of cytoplasm, and a specialized coating that confers resistance to heat, radiation, and other harsh external conditions.

28. what species of bacteria produce bacterial endospores

    gram positive bacteria such as genus Bacillus, the genus Clostridium, and a number other genera of bacteria, including Desulfotomaculum, Sporosarcina, Sporolactobacillus, Oscillospira, and Thermoactinomyces.

29. what is the main structural features of a bacterial endospore

    The endospore consists of the bacterium's DNA and part of its cytoplasm, surrounded by a very tough outer coating.

30. what are the main properties of bacterial endospores in respect to sterilisation and disinfwction

    Bacterial endospores are more resistant to disinfectants than are vegetative organisms due to their lower water content and slower metabolism.

31. why are bacterial endospores dangerous for human health

    The endospore survives until a variety of environmental stimuli trigger germination, allowing outgrowth of a single vegetative bacterium. Infectious diseases such as anthrax, tetanus, gas gangrene, botulism, and pseudomembranous colitis are transmitted to humans by endospores.

32. what are flagella

    flagella are organelle of motility . the consist of non-covalent polymers of proteins . their filament is helical and has a characteristic wave length

33. what are pilli

    pilli are hair like appendages on a cell surface . they are 2-40 nm in diameter . they can be up to 12 microns in length . they can be straight or curved . they present in bundles . they can be found on gram positive and gram negative spices . their expression can be variable depending on factors such as ph.

34. what important functions are carried out by pili

    the carry out adhesion . they bind to bacteria and are the first step in infection .

35. what are protists

    protists are a large diverse group of unicellular eukaryotic micro organisms

36. how do protists asexually reproduce

    binary fission , multiple fission , budding

37. how do protists sexually reproduce

    fusion of gametes and conjugation

38. what is paramecium

    paramecium is a genus of eukaryotic unicellular ciliates

39. properties of Protozoa

    1) osmotrophy - absorbitive nutrition they uptake soluble nutrients . examples = myxomycota , dictyostelida , arcrasidia 2) phagotrophy - ingestive nutrition predation on bacteria or other protists . pinocytosis ( fluid uptake ) occurs. examples= actinopoda , apicomplexa , ciliophora , flagellates .