Lecture Quiz 1 Flashcards

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1
Q

What was the theory of spontaneous generation? Explain how this theory was disproved.

A

Discredited belief that organisms can arise from non-living matter. Discredited belief that organisms can arise from non-living matter.

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2
Q

Give a few uses for microorganisms that benefit humans and the environment.

A

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.

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3
Q

List a few infectious disease epidemics that have had the greatest impact on U.S. and world history.

A

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.

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4
Q

Define reemerging infectious disease and give at least three examples

A

Infectious diseases that were under control or were irradicated but begin to spread again, resulting in increased number of cases. measles, mumps, whooping cough

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5
Q

What is meant when we say that certain bacteria are antibiotic-resistant?

A

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.

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6
Q

What are the three Domains of Life?

A
  1. Bacteria - single-celled prokaryotes that have peptidoglycan in their cell wall
  2. Archea - Prokaryotic cell structure, move primarily by means of flagella, have a rigid cell wall.
  3. Eucarya - Eukaryotes, membrane-bound nucleus and other organelles.
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7
Q

Describe each of the five major groups of microorganisms?

A

Viruses, Bacteria, Archaea, Fungi, and Protists

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8
Q

What bacterial cells looks like this?

A

cocci (spherical)

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9
Q

What bacterial cells looks like this?

A

coccobacillus - rod so short that it can be mistaken as cocci

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10
Q

What bacterial cells looks like this?

A

vibrio - short, curved rod

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11
Q

What bacterial cells looks like this?

A

spirochete - long, helical cell with a flexible cell wall and a unique mechanism of motility

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12
Q

What bacterial cells looks like this?

A

spirochete - long, helical cell with a flexible cell wall and a unique mechanism of motility

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13
Q

Give several reasons why it is important to study prokaryotic cell structures.

A
  1. understanding how microbes survive
  2. selectively kill bacteria/inhibit growth without harming the human host.
  3. can be used to identify different species of bacteria
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14
Q

What is the main function of the cytoplasmic membrane for bacteria?

A

Phospholipid bilayer embedded with proteins
Proteins = gates/channels/sensors of environmental conditions.

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15
Q

What is osmosis?

A

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.

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16
Q

What is a biofilm?

A

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

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17
Q

Describe passive and active transport systems in the cytoplasmic membrane

A

1) Passive
a) Simple Diffusion
b) Facilitated Diffusion
c) Osmosis (water only)

2) Active
a) Molecules
b) Particles

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18
Q

Describe the composition and structure of Gram-positive bacterial cell walls.

A

lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the Gram-negatives.

19
Q

What is endotoxin?

A

a toxin that is present inside a bacterial cell and is released when the cell disintegrates.

20
Q

How can endotoxin get into the bloodstream?

A

Plasma endotoxin may be derived from bacteria in an infected local tissue, the blood, the GI or respiratory tract, or food or other ingested matter.

21
Q

How does endotoxin affect the body?

A

disrupt humoral and cellular host mediation systems.

22
Q

List the four steps of gram staining and explain the purpose of each step.

A
  1. Applying a primary stain (crystal violet).
  2. Adding a mordant (Gram’s iodine).
  3. Rapid decolorization with ethanol, acetone or a mixture of both.
  4. Counterstaining with safranin.
23
Q

what color is Gram-positive?

A

PURPLE!

24
Q

what color is Gram-negative?

A

PINK!

25
Q

Explain how the antibiotic penicillin and the enzyme lysozyme affect Gram-positive vs. Gram-negative cells.

A

Gram-positive bacteria are more susceptible to the action of lysozyme because their cell wall contains up to 90% peptidoglycan, whereas Gram-negative bacteria are more resistant because of the smaller amount of peptidoglycan in their cell wall.

26
Q

describe the composition of the bacterial capsule.

A

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

27
Q

what does it mean to say that capsule components are antigenic?

A

any of the antigens, usually polysaccharide in nature, that are carried on the surface of bacterial capsules.

28
Q

describe the structure, arrangements, and movement of bacterial flagella.

A

a coiled, thread-like structure, sharp bent, consisting of a rotary motor at its base and are composed of the protein flagellin.

29
Q

What is the main function of
flagella for bacteria?

A

enables movement and chemotaxis.

30
Q

describe the structure and function of pili (fimbriae) for bacteria. What role do pili play in bacterial disease?

A

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.

31
Q

Explain the function of sex pili for bacteria. How do sex pili provide one way for bacteria to acquire new
genes?

A

allow the transfer of DNA between bacteria, in the process of bacterial conjugation.

32
Q

Describe the structure and function of ribosomes.

A

an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell

33
Q

What are some of the substances in storage granules of bacteria?

A

carbon, phosphate, and nitrogen

34
Q

What are the expected staining results and observed cell shapes for each type of bacteria used in lab?

A

coccus, bacillus, and spiral

35
Q

Explain the effects of hypertonic or hypotonic surroundings on Gram-positive, penicillin-treated bacterial cells.

A

ruptures the cell wall

36
Q

Explain the process of binary fission.

A

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

37
Q

What is meant by the generation time of a bacterial population?

A

the time (usually in hours or days) that it takes for bacteria to divide

38
Q

What is meant by exponential growth of cells?

A

mass increase (i.e., cytoplasmic mass increase)

39
Q

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.

A
  1. LAG - initial phase is characterized by cellular activity but not growth. These cells increase in size
  2. Exponential - time when the cells are dividing by binary fission and doubling in numbers after each generation time.
  3. Stationary - decline as the available nutrients become depleted and waste products start to accumulate.
  4. Death - the number of dying cells continues to rise
40
Q

What are the temperature conditions for growth of each of the following types of microbes?: psychrophiles, mesophiles, thermophiles, hyperthermophiles.

A

psychrophiles 0-20
mesophiles 25-45
thermophiles 45-60
hyperthermophiles 65-95

41
Q

what are the two main toxic forms of oxygen always being produced in cells?

A

Superoxide and hydroxyl ions

42
Q

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:

A
43
Q

What are the pH conditions for growth of most bacteria?

A

neutral pH close to 7.0

44
Q

What are acidophiles and alkophiles?

A

-Alkaliphiles are microbes that thrive in alkaline (pH 9-11) environments.
-Acidophilic organisms are those that thrive under highly acidic conditions (usually at pH 2.0 or below)