Lecture Quiz 1 Flashcards
What was the theory of spontaneous generation? Explain how this theory was disproved.
Discredited belief that organisms can arise from non-living matter. Discredited belief that organisms can arise from non-living matter.
Give a few uses for microorganisms that benefit humans and the environment.
In humans it helps helps immune system distinguish “friendly” microbes from those that can cause severe disease. Microorganisms recycle and ensure the availability of certain nutrients.
List a few infectious disease epidemics that have had the greatest impact on U.S. and world history.
as infectious diseases that have newly appeared in a population or have existed but are rapidly increasing in incidence or geographic range. Influenza, smallpox, plague, and polio.
Define reemerging infectious disease and give at least three examples
Infectious diseases that were under control or were irradicated but begin to spread again, resulting in increased number of cases. measles, mumps, whooping cough
What is meant when we say that certain bacteria are antibiotic-resistant?
Occurs when bacteria change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections.
What are the three Domains of Life?
- Bacteria - single-celled prokaryotes that have peptidoglycan in their cell wall
- Archea - Prokaryotic cell structure, move primarily by means of flagella, have a rigid cell wall.
- Eucarya - Eukaryotes, membrane-bound nucleus and other organelles.
Describe each of the five major groups of microorganisms?
Viruses, Bacteria, Archaea, Fungi, and Protists
What bacterial cells looks like this?
cocci (spherical)
What bacterial cells looks like this?
coccobacillus - rod so short that it can be mistaken as cocci
What bacterial cells looks like this?
vibrio - short, curved rod
What bacterial cells looks like this?
spirochete - long, helical cell with a flexible cell wall and a unique mechanism of motility
What bacterial cells looks like this?
spirochete - long, helical cell with a flexible cell wall and a unique mechanism of motility
Give several reasons why it is important to study prokaryotic cell structures.
- understanding how microbes survive
- selectively kill bacteria/inhibit growth without harming the human host.
- can be used to identify different species of bacteria
What is the main function of the cytoplasmic membrane for bacteria?
Phospholipid bilayer embedded with proteins
Proteins = gates/channels/sensors of environmental conditions.
What is osmosis?
is the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell’s partially permeable membrane.
What is a biofilm?
an assemblage of surface-associated microbial cells that is enclosed in an extracellular polymeric substance matrix. On your teeth, in sink drains and Slippery rocks
Describe passive and active transport systems in the cytoplasmic membrane
1) Passive
a) Simple Diffusion
b) Facilitated Diffusion
c) Osmosis (water only)
2) Active
a) Molecules
b) Particles
Describe the composition and structure of Gram-positive bacterial cell walls.
lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the Gram-negatives.
What is endotoxin?
a toxin that is present inside a bacterial cell and is released when the cell disintegrates.
List the four steps of gram staining and explain the purpose of each step.
- Applying a primary stain (crystal violet).
- Adding a mordant (Gram’s iodine).
- Rapid decolorization with ethanol, acetone or a mixture of both.
- Counterstaining with safranin.
what color is Gram-positive?
PURPLE!
what color is Gram-negative?
PINK!
describe the composition of the bacterial capsule.
an outer layer of polysaccharides that covers the cells of many different bacterial species. Capsules act as a sort of magic cloak, protecting bacteria from toxic compounds and desiccation
describe the structure, arrangements, and movement of bacterial flagella.
a coiled, thread-like structure, sharp bent, consisting of a rotary motor at its base and are composed of the protein flagellin.
What is the main function of
flagella for bacteria?
enables movement and chemotaxis.
describe the structure and function of pili (fimbriae) for bacteria. What role do pili play in bacterial disease?
They can have a role in movement, but are more often involved in adherence to surfaces, which facilitates infection, and is a key virulence characteristic.
Explain the function of sex pili for bacteria. How do sex pili provide one way for bacteria to acquire new
genes?
allow the transfer of DNA between bacteria, in the process of bacterial conjugation.
Describe the structure and function of ribosomes.
an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell
What are the expected staining results and observed cell shapes for each type of bacteria used in lab?
coccus, bacillus, and spiral
Explain the effects of hypertonic or hypotonic surroundings on Gram-positive, penicillin-treated bacterial cells.
ruptures the cell wall
Explain the process of binary fission.
an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA
What is meant by exponential growth of cells?
mass increase (i.e., cytoplasmic mass increase)
identify and explain what is occurring during all four phases shown on a bacterial growth curve: lag
phase, exponential (log) phase, stationary phase, death phase, and prolonged decline phase.
- LAG - initial phase is characterized by cellular activity but not growth. These cells increase in size
- Exponential - time when the cells are dividing by binary fission and doubling in numbers after each generation time.
- Stationary - decline as the available nutrients become depleted and waste products start to accumulate.
- Death - the number of dying cells continues to rise
What are the temperature conditions for growth of each of the following types of microbes?: psychrophiles, mesophiles, thermophiles, hyperthermophiles.
psychrophiles 0-20
mesophiles 25-45
thermophiles 45-60
hyperthermophiles 65-95
each of the following classes of microbes, what are a) the O2 conditions for growth and b) the metabolic process(es) for obtaining energy to make ATP:
