Exam 1

Question 1

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

Answer 1

cofactor

Question 2

The general purpose of staining a bacterial smear is to :

Answer 2

increase the contrast of the specimen

Question 3

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

Answer 3

Gram-negative

Question 4

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

Answer 4

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

Question 5

Activation energy is:

Answer 5

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

Question 6

Aseptic technique refers to:

Answer 6

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

Question 7

A DNA or RNA nucleotide is composed of an:

Answer 7

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

Question 8

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

Answer 8

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

Question 9

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:

Answer 9

inductive reasoning

Question 10

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

Answer 10

mitosis and meiosis

Question 11

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

Answer 11

virtual image

Question 12

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

Answer 12

Robert Hooke

Question 13

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

Answer 13

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

Question 14

What is the reason for immersion oil?

Answer 14

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

Question 15

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

Answer 15

glycocalyx

Question 16

A catalyst:

Answer 16

increases the rate of a chemical reaction

Question 17

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?

Answer 17

Two or more of the above answers are correct

Question 18

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

Answer 18

has a rigid helical structure

Question 19

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

Answer 19

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

Question 20

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

Answer 20

tenths of a micrometer

Question 21

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

Answer 21

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

Question 22

RNA molecules that catalyze chemical reactions are called:

Answer 22

ribozymes

Question 23

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

Answer 23

There is no special name; it is called an enzyme

Question 24

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

Answer 24

Walther Hesse

Question 25

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

Answer 25

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

Question 26

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?

Answer 26

head facing to the right ]----O

Question 27

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?

Answer 27

head facing to the right ]----O

Question 28

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

Answer 28

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

Question 29

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

Answer 29

staphylo-

Question 30

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

Answer 30

They are credited with the invention of the compound microscope.

Question 31

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

Answer 31

Louis Pasteur

Question 32

Protein filaments that help bacteria attach to surfaces are called:

Answer 32

Two or more are correct (pilli and fimbriae)

Question 33

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

Answer 33

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

Question 34

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

Answer 34

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

Question 35

Niacin (vitamin B3) deficiency leads to the disease:

Answer 35

pellagra

Question 36

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:

Answer 36

side chain

Question 37

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

Answer 37

1.5/1= 1.5

Question 38

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

Answer 38

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

Question 39

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 :

Answer 39

phospholipid bilayer with a hydrophobic interior and hydrophilic surfaces

Question 40

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

Answer 40

active site