Lecture 2 Flashcards
List the main differences between prokaryotic and eukaryotic cells.
a. Prokaryotic
i. Have cell wall
ii. No nucleus
b. Eukaryotic
i. No cell wall
ii. Have nucleus
Describe the function and/or types of a) glycocalyx, b) flagella, c) pili and fimbriae
a. Glycocalyx
i. Gelatinous coating on bacteria
1) Helps to stick to surfaces and protection against phagocytosis
b. Flagella
i. Used for motility
c. Pili and Fimbrae
Both used for adherence to surfaces. Pili used to reproduce
What is the main difference between gram positive and gram negative bacteria?
- What is the main difference between gram positive and gram negative bacteria?
a. Gram positive have thicker walls
Gram negative have thinner walls and have outer membrane
List the steps of a gram stain. List the colour of both a GPOS and GNEG at the end of each step.
a. Heat stain Both Clear Crystal violet Both purple Lugols iodine Both Purple Alcohol wash POS = purple NEG = clear Carbol fuchsin POS = Purple NEG = pink
How do bacteria reproduce and list the 4 growth phases in a broth culture?
a. Bacteria reproduce via binary fission
i. Lag phase
ii. Exponential phase
iii. Stationary phase
iv. Death or decline phase
What are: mesophiles, psychrophiles, obligate anaerobes, facultative anaerobes and carboxyphiles?
a. Mesophiles
i. 10-45 degrees (37 degrees optimal)
b. Psychrophiles
i. 0-<20 (15 or lower optimal)
c. Obligate anaerobes
i. Unable to grow in O2
d. Facaltative anaerobes
i. Can grow in presence or absence of oxygen
e. Carboxyphiles
High CO2 levels 2.5-5%
Briefly describe bacterial respiration and fermentation.
a. Respiration
i. Takes pyruvate through krebs cycle and oxidative phosphorilation
b. Fermentation
Take pyruvate and makes ATP without oxygen at low yield and with by-products like alcohol and acids
Describe glycolysis: what is the starting carbohydrate; what is the storage molecule produced; and what is the end product? How many nett energy molecules are produced from 1 carbohydrate molecule during glycolosis?
a. Glucose is starting molecule
i. ATP is produced
ii. Pyruvate is produced
2 ATP net and 2 pyruvate
Describe the terms: catabolism, anabolism, oxidation, reduction, and enzymes.
a. Catabolism
i. The breakdown of larger molecules into smaller components
b. Anabolism
i. The synthesis of larger molecules from smaller components
c. Oxidation
i. Election loss
d. Reduction
i. Election gain
e. Enzymes
i. Protein catalyst (speeds up chemical reactions)
What factors (growth & nutritional conditions) need to be considered when culturing bacteria?
a. Temperature
b. Atmosphere
c. Moisture
d. PH
e. Osmolarity
f. Nutrients
What is a “Microbial Biofilm”? Describe how plaque leads to tooth decay?
a. Complex mixture of microbes, cell debris and extracellular matrix
i. Microbes feed off food in the mouth and produce energy anaerobically. This produces alcohols and acids as a by-product and erodes the teeth.
What is a “virulence factor” and give three examples? What is the difference between and endotoxin and an exotoxin?
a. Virulence factor is a trait that gives the microbe the ability to cause disease
i. Ability to produce toxins
ii. Production and release of enzymes
iii. Production of haemolysins
iv. Production of adherence factors
Endotoxins are in the cell wall when it dies and breaks up
Exotoxins are produced by cell and released through cell
What are the three types of haemolysins seen on a blood agar plate?
a. Alpha
b. Beta
c. Gamma
Describe the function of the following parts of light microscope: condenser lens, iris diaphragm and how to calculate total magnification from the objective lenses and ocular lenses.
a. Condenser lens
i. Controls the amount of light let into the microscope
b. Iris diaphragm
i. Controls the amount of light let into the microscope
c. You multiply the ocular lens magnification with the objective lens magnification
How would you increase contrast when looking at an unstained preparation with bright field illumination?
Close the condenser diaphragm to scatter the light
What is the difference between a mixed and a pure culture, and how can you tell the difference on a culture plate?
a. Mixed has multiple different microorganisms, pure has one
b. You can tell by the colony morphologies, they are usually different colours and shapes
Explain what selective and differential media are.
a. Selective media is media that allows only one type of microbe to grow
b. Differential media highlights specific types of microbes over others
Name the four principle shapes of bacteria. Name the four types of microscopic arrangement.
a. Shape
i. Bacillus
ii. Cocci
iii. Spiral
iv. Vibrio
b. Arrangement
i. Singular / Random
ii. Cluster
iii. Chain
iv. Pairs
Apart from colony morphology and the Gram stain, what other methods could be used to identify an unknown organism?
a. Biochemical tests can identify unknown organisms
- What is the difference between the incubation period of a disease and the invasive phase?
a. Incubation has few symptoms and is gradually building numbers
b. Invasive has many symptoms and usually the highest number of microbes
What is a microaerophile?
a. Small organism requiring low levels of oxygen to grow
Which parts of the body are usually considered sterile?
a. Lower respiratory tract, blood and tissues
What is an opportunistic pathogen?
a. Pathogen that is harmful in certain environments
Define mutualism, commensalism and parasitism?
a. Mutualism
i. Both gain from relationship
b. Commensalism
i. One gains and the other isn’t effected
c. Parasitism
i. One gains and the other suffers
