Exam 1 Flashcards

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1
Q

A metal ion that is essential for an enzyme activity is one example of a(n):

A

cofactor

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2
Q

The general purpose of staining a bacterial smear is to :

A

increase the contrast of the specimen

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3
Q

In one group of bacteria, the outermost layer of the cell envelope contains lipopolysaccharide. This group of bacteria is:

A

Gram-negative

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4
Q

What is one consequence of lipopolysaccharide being present on the surface of the bacterial cell?

A

It triggers a strong immune response against the bacterial cell in a host.

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5
Q

Activation energy is:

A

the energy barrier that must be overcome to convert substrate to product

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6
Q

Aseptic technique refers to:

A

laboratory procedures designed to keep microorganisms contained as they are grown and transferred so as to prevent contamination

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7
Q

A DNA or RNA nucleotide is composed of an:

A

organic nitrogen-containing base, pentose sugar, and phosphate group(s)

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8
Q

What can be said about the enzyme-catalyzed reaction depicted in the diagram?

A

The reaction is exergonic because the product exists at a lower energy level than the substrate

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9
Q

A microbiologist observes that all known bacteria discovered in the past have DNA as their genetic material. Therefore, he predicts that all new bacteria discovered in the future will also have DNA as their genetic material. This type of thinking is an example of:

A

inductive reasoning

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10
Q

All of the following are functions of various proteins in the bacterial cell membrane except:

A

mitosis and meiosis

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11
Q

When an object lies inside the focal length of a convex lens, the image seen by an observer is called a(an):

A

virtual image

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12
Q

The first person to give a description of cells based on his microscopical observations was:

A

Robert Hooke

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13
Q

If you wish to improve the resolution of the compound microscope, what would be the simplest step to take in the laboratory?

A

Add a drop of immersion oil between the specimen on the microscope slide and the 100x objective.

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14
Q

What is the reason for immersion oil?

A

Resolution improves as n increases, where n is the index of refraction of the transparent medium between the microscope slide and the objective.

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15
Q

Most capsules are composed of a network of polysaccharide fibers that is called the:

A

glycocalyx

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16
Q

A catalyst:

A

increases the rate of a chemical reaction

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17
Q

The antibiotic penicillin inhibits a key step in a bacterial cell wall biosynthesis such that the resulting peptidoglycan is defective and lacks mechanical strength. The cells then lyse due to osmotic swelling. Assuming that you don’t know anything else about how penicillin works, what hypothesis could you reasonably form based on this information?

A

Two or more of the above answers are correct

18
Q

The filament of a bacterial flagellum is able to propel the bacterial cell through the water because it:

A

has a rigid helical structure

19
Q

Which on e of the following statements about culture media is true?

A

You must know something about the nutritional needs of the organism before you can select an appropriate culture medium for its growth.

20
Q

The best resolution that can be achieved by a bright-field microscope is represented by a distance between two points of a few:

A

tenths of a micrometer

21
Q

What is a known consequence of certain bacteria having inclusions called carboxysomes?

A

They concentrate carbon dioxide so that it can be incorporated (“fixed”) into organic carbon compounds.

22
Q

RNA molecules that catalyze chemical reactions are called:

A

ribozymes

23
Q

If an enzyme consists of pure protein and does not require any sort of cofactor for activity, it is called a(an):

A

There is no special name; it is called an enzyme

24
Q

Who was the first person to use agar in the cultivation of microbes?

A

Walther Hesse

25
Q

Where is the real image formed by the objective lens located?

A

Between the f1 focal point of the ocular lens and the ocular lens.

26
Q

If the true orientation of the object on the microscope slide is shown in the figure, what orientation does the observer see when looking at it through the compound microscope?

A

head facing to the right ]—-O

27
Q

If the observer removed the ocular lens and looked directly at the real image formed inside the body tube of the microscope, what orientation would he or she see?

A

head facing to the right ]—-O

28
Q

If a particular enzyme contains a coenzyme, what is it safe to conclude?

A

The coenzyme provides a chemical functionality that the protein by itself lacks.

29
Q

If dividing bacterial cells form irregular three-dimensional clusters, the correct prefix to describe this type of cell arrangement is:

A

staphylo-

30
Q

Why are Hans and Zaccharias Janssen important in the history of microbiology?

A

They are credited with the invention of the compound microscope.

31
Q

Who was responsible for proving that different fermentation reactions were associated with different types of microbes?

A

Louis Pasteur

32
Q

Protein filaments that help bacteria attach to surfaces are called:

A

Two or more are correct (pilli and fimbriae)

33
Q

What is a primary difference between the cell walls of Gram-positive and Gram-negative bacteria?

A

Gram-positive cell walls contain a much thicker layer of peptidoglycan.

34
Q

When a table lists the Gibbs free energy values of chemical reactions using the designation delta Go’, what do the superscripts indicate?

A

All of the values are adjusted to standard conditions at a pH of 7

35
Q

Niacin (vitamin B3) deficiency leads to the disease:

A

pellagra

36
Q

When a specific amino acid in an enzyme directly participates in the catalytic reaction, it is most often due to the unique chemical characteristics of its:

A

side chain

37
Q

Using Snell’s law, what is the value of the ratio sin theta1/sin theta r?

A

1.5/1= 1.5

38
Q

In the microbiology laboratory, the streak-plate technique is often used to :

A

isolate the different cell types as pure cultures when the inoculum is a mixed culture.

39
Q

The ability of the cytoplasmic membrane to act as an effective barrier against the diffusion of small, water-soluble molecules to and from the cytoplasm of the cell is based on its structure as a :

A

phospholipid bilayer with a hydrophobic interior and hydrophilic surfaces

40
Q

The location on the enzyme where the catalytic reaction takes place is called the :

A

active site