Microbial growth and antibiotics Flashcards

Question

What is equation for binary fission?

Answer 1

2n n is generation

Answer 2

Obtain light Oxidise chemical compound

Answer 3

Use co2 in photosynthesis

Answer 4

Use organic source in photosynthesis

Answer 5

Obtain energy using chemical compound They break down compound leading to production of ATP

Answer 6

Obtain energy by oxidising inorganic compound

Answer 7

Obtain energy by oxidising organic compound Most of bacteria

Answer 8

Batch culture Continuous culture

Answer 9

Lag phase Log/exponential phase Stationary phase Death phase

Answer 10

No or little cell division But cell may increase in size Synthesise RNA, proteins and enzymes Nutrient specific enzymes might be produced If bacteria used to environment, it might get shorter

Answer 11

Cell at maximum division rate All condition optimal for growth No limiting factor Primary metabolite formed and excreted

Answer 12

No increase in population Limiting factor appeals Secondary metabolites which is not essential might be produced and excreted

Answer 13

Unfavourable condition increase so death rate above growth rate Autolysis may often occur

Answer 14

Low temp – slow due to low kinetic energy reducing enzymes activity on metabolism High temp – most bacteria gets destroyed as enzymes denature Extremophile may be adapted

Answer 15

Extremely high or low pH would cause denature of enzymes required for metabolism

Answer 16

Depends on microbe type If obligate aerobes high concentration is ideal If obligate anaerobes low concentration is ideal

Answer 17

Obligate aerobes – live only when O2 present Obligate anaerobes – live only when no O2 present Facultative anaerobes – can live in both, prefers O2 present Aerotolerant anaerobes – prefers anaerobic but can live with O2 Microaerophiles – anaerobic condition required but low O2 concentration is fine

Answer 18

Halophiles Alkalinophiles Acidophiles Barophiles(Piezophile) Thermophiles Psychrophiles

Answer 19

Survive in high salt conc High conc of salt in cytoplasm preventing osmosis out of cells Optimal folding proteins tolerating high salt conc Cell wall is composed of glycoprotein and stabilised by sodium ions

Answer 20

Optimal in pH above 9.0(Alkali) Membrane and cell wall resist dissolution Adapted proteins Intracellural pH close to 9.0 Actively pump hydrogen ions in to use ATP synthase

Answer 21

Optimal in below pH 5.0 Acid resistant cell walls and membranes Activelly pump out excess protons

Answer 22

Preferably or exclusively at high hydrostatic pressure Barotorelant - high to 500 atmosphere Barophilic - requires high pressure, usually at 700, 800 atmosphere, not less than 400 atmosphere Increased pressure decrease binding capacity, so enzymes must be folded in such a way to minimise this Lipid bilayer is more tightly packed so provide more rigid structure and shields the inside ompH gene code for a protein at high pressure but inhibited at low, so enables uptake of wider range of nutrients

Answer 23

Optimum above 45 celcius If above 80 celcius is hyperthermophiles High saturated fatty acid in membrane for stability More chemical bonds to maintain protein shape Loops of polypeptide less or absent Less amino acids unstable at high temp Chaperones refold denatured proteins DNA use DNA-binding proteins and reverse DNA gyrase to introduce supercoils into DNA

Answer 24

Optimal at 15 celcius or below Cold adapted enzymes Increase in unsaturated fatty acid as temp reduce to control membrane fluidity Antifreeze protein bind to ice ctrystal preventing piercing of membrane

Answer 25

Total cell count(death and living cell) Viable cell count(living cell)

Answer 26

Total cell count Use chamber as haemocytometer Volume is 0.004mm3 Well mixed sample diluted Then counted, averaged and using dilution factor estimated

Answer 27

Total cell count Use colorimeter Culture medium become more turbid(cloudy) as cell increase Culture is well mixed before measure Optical density measured Cannot differentiate living and death

Answer 28

Variable cell counts Dilution factor calc is done to liquid culture Done aseptically

Answer 29

Eukaryotic Some can be unicellular They are heterotrophic(use organic matter) They can be parasitic, mutualistic or saprophytic Use extracellular digestion

Answer 30

Fine, branched thread called hyphae Hyphae forms mass called mycelium

Answer 31

Cell wall made of chitin Same as other eukaryotes Some are coenocytic, so no cross wall between each other

Answer 32

Increase in diameter mycelium - only on filamentous fungi Increase in dry mass - any microorganism

Answer 33

Used in filamentous fungi If effect of temperature on the growth measured: Agar plates containing identical concentration of nutrients are inoculated with the same quantity fungi Obtain equal sized pieces of mycelium, place in the centre of each plate Each plate is incubated at a different temperature in the range All other environmental conditions are standardised e.g. nutrient concentration and pH The increase in the diameter of the mycelium is measured and recorded daily These results can be plotted on a graph and the optimum temperature determined

Answer 34

Used in microorganisms If the effect of pH on the growth rate of a filamentous fungus measured: Set up flasks containing liquid broth media of the same volume and nutrient concentrations Inoculate each flask aseptically with the same mass of fungal mycelium Each culture is incubated at a different pH using buffers Ensure temperature is standardised and at the optimum At suitable time intervals, remove an identical volume of sample from each culture and determine the dry mass of fungus in pH culture. The dry mass is determined by placing the sample in an oven until all the water is removed. Dry mass at each pH can be plotted on a graph and the optimum pH for the growth of that particular fungus determined. For oven, heat at 100°C for an hour, remove and weigh it. Reheat for 15 minutes and reweigh it until you get two constant masses

Answer 35

Non-sterile apparatus Air Skin surface Work surface

Answer 36

Use sterile syringes/pipettes/equipment Flame top of test tube/bottle/inoculating loops Minimise exposure to the air by lifting lid of dish lightly Avoiding sterile apparatus touch skin or work surface

Answer 37

Maybe solid or liquid They must contain balanced mixture of required nutrients So desired species grow

Answer 38

Obtain energy via light during photosynthesis Light utilised by pigment e.g. bacteriochlorophyll

Answer 39

Used for wide range of microorganism growth or when no exact nutrients are known It cantains all nutrients required for growth e.g. glucose, amino acids, water, salts, vitamins, trace elements

Answer 40

Suitable for growth of specific microorganism If inoculated with mixed culture, only species the medium designed for will grow Growth of others will be supressed Condition would also be for specific spicies

Answer 41

Direct heating - Inoculating loop, neck of tubes Autoclaving - glassware, unwanted culture Burning alcohol - glass Disinfectants - inanimate objects Ultrafiltration

Answer 42

To obtain pure culture from mixed culture of bacteria

Answer 43

Use inoculating loop to move bacteria to agar plate Lift the lid of petri dish slightly to minimise air exprosure Streak the agar plate with sample Reflame loop Re-streak sample on plate at right angle from last time Incubate the plate at 25 degrees celcius for 2 days During exam include asepctic technique and how it prevent contamination of the culture

Answer 44

Using aseptic technique pick and transfer a sample from a single colony onto another agar plate and incubate

Answer 45

Determines the effectiveness of a compound by seeing compound effect on growth of microorganism Also used to screen microorganism to determine for antibiotic prodcution This is by measuring their ability to inhibit the growth of bacteria on a bacteria lawn

Answer 46

Compound produced by microorganims inhibiting or killing bacteria Can work in either in bacteriostatic or bactericidal In natural enviroment, fungus antibiotic is ecological advantage as reduce competition

Answer 47

Inhibits or prevent bacteria growth

Answer 48

Actually kill the bacteria

Answer 49

Take an agar plate seeded with bacteria Place a mycelial disc from the fungus onto centre of agar Incubate the plate If the antibiotic produced by fungus is effective against bacteria then a clear zone will result Clear zone represents inhibition of growth or death of bacteria Larger the diameter, the more effective

Answer 50

Take an agar plate seeded with the test bacterium Then place a standard volume of antibiotic into a standard sized well or use standard sized paper discs with antibiotic Incubate at 25 degree celcius for 48 hours A clear zone will be produced if the antibiotic is effective against the bacteria

Answer 51

Chemical compounds that kill bacteria, e.g. Lysol, Dettol It is possible to determine the effectiveness of a disinfectant by using bioassay

Answer 52

Chemical substances produced by microorganisms or synthetically It inhibit the growth of or kill other microorganisms Usually bacteria but few are effective against fungi They are ineffective against viruses

Answer 53

Inhibiting cell wall synthesis Cell membrane disruption Inhibiting mRNA translation Inhibiting nucleic acid synthesis

Answer 54

Penicillins and Ampicillin Inhibits enzymes involved in the syntheis of peptide cross links in the cell wall, causing it to weaken So burst as osmotic lysis happens

Answer 55

Polymyxin B Alters cell membrane structure making it more permeable and leading to cell death

Answer 56

Streptomycin and tetracyclines Inhibit protein syntheis by biding across ribosomes but not on eukaryotic cell

Answer 57

Ciprofloxacin Inhibits DNA replication

Answer 58

Effective against a wide range of bacteria May be initially used in the treatment of undetermined bacterial infections e.g. Tetracyclines

Answer 59

Effective against a small specific group of bacteria e.g. Streptomycin is used to treat infections caused by streptococcus bacteria Some antibiotics produce allergic effects in certain individuals

Answer 60

Penicillin resistance occurs as bacteria gets genetic mutation to produce enzymes penicillinase and breaks down penicillin Mutation in change of biding site of antibitic

Answer 61

Spontaneous mutation Transfer of genes for resistance from other bacteria

Answer 62

Vertical and horizontal

Answer 63

Resistance to antibiotics may arise due to a random mutation Bacteria with resistance gene survive when exposed to the antibiotic Bacteria reproduce and pass resistance gene on to future generations Repeated exposure to antibiotics (particularly when dosages of antibiotic are not correctly administered or if the patient does not complete the full course of antibiotic) leads to more bacteria surviving and passing on the gene Antibiotic resistant bacteria increase in the population lead to an increase in the frequency of the allele for antibiotic resistance

Answer 64

Antibiotic resistance gene are usually on plasmid, and plasmid can contain more than one antibitic resitance gene The donor cell produces a conjugation tube (pilus) which connects the two bacterial cells Horizontal gene transmission happens by conjugation Donor cell replicates its plasmid and passes the copy of the plasmid to the other bacterium The recipient cell receives the plasmid which may contain a gene for antibiotic resistance

Answer 65

Can pass DNA of one bacteria to other bacteria Bacteriophage insert its DNA to bacteria Bacteriophage DNA replicates and host DNA splits into bacteriophage size New bacteriophages made, some with original bacteriophage DNA some with bacteria DNA Bacteriophage with bacterial DNA attacks another bacteria Bacteria gains other bacteria DNA

Answer 66

DNA drom a lysed bacteria cell is bound to DNA binding protein in the host cell wall One DNA strands enters host cell as other strand is broken down The single strand of DNA is bound to the DNA of host cell

Answer 67

Strain of bacterium Mycobacterium tuberculosis has resistance to different antibiotics due to mutation Icomplete a course of antibiotic treatment enabled to survive and exchange their genes with other bacteria via horizontal gene transmission So multiple-antibiotic-resistant strains of TB developed So a cocktail of antibiotics is often used to treat TB Scientists are trying to develop more effective antibiotics to treat TB and other bacterial infections

Answer 68

MRSA (methicillin-resistant Staphylococcus aureus) is the name of any strain of the Staphylococcus aureus that is resistant to antibiotics MRSA is difficult to treat and is prevalent in hospitals as: Many antibiotics being used - enabling multiple-resistance to develop Close proximity of patients - ideal for transmission of infections Weak and sick individuals - more vulnerable to infection by MRSA.

Answer 69

When antibiotics is used in patients it decrease competition in body and increase and release toxin(Opportunistic bacteria)

Answer 70

Mild to severe diarrhea Severe inflammation of the bowel

Answer 71

People treated with broad spectrum antibiotics People with serious underlying illnesses Elderly

Answer 72

Hands of healthcare and other people in contact with patients or their enviromental surfaces contaminated with bacteria or spores Spores are produced when bacteria encountered with unfavolable condition They survive on clothes and surfaces for long period even when cleaned with alcohol

Answer 73

the use of specific antibiotics which will kill C. difficile (e.g. either metronidazole or vancomycin) Probiotic supplements which are designed to stimulate the growth of ‘good’ bacteria (although the evidence of their effectiveness in treating CDIs is inconclusive) Injections of immunoglobulins to enhance the production of antibodies available to fight off the infection Fecal transplantation – this treatment involves transplantation of a fecal sample from a healthy donor Serious infection may require surgery to remove a damaged section of the bowel.