UT Dallas BIOL 300 Exam 1 Fall 2014

Write in complete sentences.I will take off points for not using complete sentences.
You can draw diagrams to supplement your answers.

Long answer:

1a. Describe Pasteur’s experiment disproving spontaneous
generation. (6 points)

b. How might this experiment have been affected by the presence of
endospore
contamination in Pasteur’s culture media? (2 points)

2. Specifically stateeach ofKoch’s four postulates. (6 points)
Then explain how you would useeach ofKoch’s postulates to determine thatNeisseria meningitidisis a causative agent of infectious meningitis (infection
of the brain). (6 points)

3. Draw the Gram-negative cell wall and label all the components.
Write out full names of components – don’t use abbreviations. Be detailed. You
don’t need to draw chemical
structures. (7.5 points)

4. Describe and/or draw the structure ofE. colipeptidoglycan,
including any unusual features.
Write out full names of components – don’t use abbreviations. Be
detailed. You don’t need to draw chemical structures. (6 points)

5. What are the steps of the Gram stain? (4 points) Explain how it
discriminates between Gram-positive and Gram-negative cells. (4 points)

Matching: (13.5 points total)

From the list below, determine whether each statement applies to
prokaryotic cells (P),
eukaryotic cells (E), both, or neither (N). If both, write “both”
and not “B”. (1.5 points each)
______ Has a nucleus
______ Requires sources of carbon and energy for growth
______ Utilizes the processes of replication, transcription and
translation
______ Has a DNA genome
______ Has an RNA genome
_____BacteriaandArchaea
______ Has a cytoplasmic membrane
______ Transcription and translation are coupled
_____ Evolves by heritable variations in genome sequence

Short answer: Answer with 1-2 complete sentences. (17
points total)

Why can’t many nutrients, and specifically hydrophilic molecules,
pass freely through the cytoplasmic membrane? (2 points)

Why can’t ribosomal RNA sequencing be used for phylogenetic
studies of viruses? (2 points)

What is a chemolithotroph? (2 points)

Your friend went to Yellowstone this summer on a research trip.
She says she isolated a
novel hyperthermophilic microbe. She tells you that the organism
grows in the lab at
temperatures ranging from 10°C to 122°C, and grows perfectly well
at room temperature.

Explain why she is wrong about this organism being a
hyperthermophile. (2 points)

What is endotoxin, and why is it relevant to human health? (3
points)

What is one major difference between the cytoplasmic membranes ofBacteriaand
Archaea? (2 points)

What is a biofilm? (2 points)

What does the term “enrichment culture” refer to? (2
points)

True/False: Mark T or F on the line. (2 points each,
10 points total)

_____ Peptidoglycan and LPS are specific toBacteriaand
are recognized by the human immune system.
_____ There are many known species of pathogenicArchaea.
_____ All microbes on Earth have been discovered and catalogued.
____ Lipoteichoic acid is found in the cell walls of gram-negative
bacteria.
_____ All bacteria are the same size and shape asE. coli.

Multiple choice: Mark your answer on the line. (2
points each, 18 points total)

______Who was the first person to describe bacteria, using a
microscope?
A) Sergei Winogradsky
B) Antoni van Leeuwenhoek
C) Martinus Beijerinck
D) Robert Hooke

______ Which of the following features are variable among
bacteria, meaning that not all
species possess them?
A) Flagella
B) Type IV pili
C) Capsule
D) All of the above

______Most prokaryotic cells reside
A) on Earth’s surface.
B) in lakes, rivers, and oceans.
C) in and on nonprokaryotic organisms (including humans and other
animals).
D) in the oceanic and terrestrial subsurfaces. Which are largely
uncharted and which
means we know little about most prokaryotic life on Earth.

______According to our present understanding, mitochondria and
chloroplasts are ________
in origin.
A) viral
B) bacterial
C) eukaryotic
D) archaeal

______A tiny stylus positioned so close to a specimen that weak
repulsive forces are
established is used in
A) dark-field microscopy.
B) confocal scanning laser microscopy.
C) atomic force microscopy.
D) none of the above.

______Which of the following carbon sources would be appropriate
for a heterotroph?
A) CO2
B) Glucose
C) H2
D) Both A and B would be appropriate

______What is the function of theE. coliPTS
system?
A) Providing protons for flagellar motility/transport.
B) Trapping a sugar within the cell by adding a phosphate group to
it.
C) Polyhydroxyalkanoate transport and synthesis.
D) Peptidoglycan transport and synthesis.

______Which of the following statements are true about endospore
formation?
A) All bacteria can sporulate.
B) Sporulation begins when excess nutrient sources are present.
C) Endospores lack genomic DNA.
D) Dipicolinic acid and small acid-soluble proteins are present.

______Which of the following statements is not true about
flagella?
A) flagellar rotation does not require an energy source
B) some cells can change their direction of movement by temporarily
stopping or
changing the direction of flagellar rotation
C) flagella assist in swimming motility
D) flagellar motion and chemotaxis can be used to preferentially
move bacteria
towards a
desired nutrient source