UT Dallas BIOL 300 Exam 1 Fall

27 Jun UT Dallas BIOL 300 Exam 1 Fall

Question
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