Question 1

Figure 23-1 
-In the diagram of a bacterial cell in Figure 23-1, which type of cell is represented?

Accepted Answer

A Gram-negative bacterium is characterized by a thin peptidoglycan layer and an outer membrane, which is typically depicted in diagrams of bacterial cells.

Question 2

Figure 23-1 
-In the diagram of a bacterial cell in Figure 23-1, which numbers identify structures that are found in all prokaryotes?

Accepted Answer

Structures 5 (ribosomes) and 9 (cell membrane) are found in all prokaryotes.

Question 3

Which type of cell contains a nuclear membrane?

Accepted Answer

Eukarya are characterized by cells that contain a nucleus enclosed within a nuclear membrane, distinguishing them from Prokarya (which includes Bacteria and Archaea), whose cells do not contain a nucleus.

Question 4

Figure 23-1 
-In the diagram of a bacterial cell in Figure 23-1, which number identifies the structure that carries out protein synthesis?

Accepted Answer

The structure that carries out protein synthesis in a bacterial cell is the ribosome, which is typically identified as number 5 in diagrams of bacterial cells.

Question 5

Suppose you perform a Gram stain of a mixed culture of Gram-positive and Gram-negative cells, and afterward you realize that you omitted the iodine step. What would you expect to see if you observed the slide under the microscope?

Accepted Answer

Omitting the iodine step in a Gram stain procedure prevents the crystal violet dye from forming a complex with iodine, which is necessary for the dye to be trapped in the thick peptidoglycan layer of Gram-positive cells. Without this step, both Gram-positive and Gram-negative cells will not retain the crystal violet and will appear pink after counterstaining with safranin.

Question 6

Figure 23-1 
-In the diagram of a bacterial cell in Figure 23-1, which number identifies a structure that is composed of polysaccharides?

Accepted Answer

The structure identified by number 6 in a typical diagram of a bacterial cell is the cell wall, which in many bacteria is composed of peptidoglycan, a type of polysaccharide linked to peptide fragments. This makes option B the correct choice.

Question 7

Which of these terms refers to prokaryotes that are cylindrical?

Accepted Answer

Bacilli refer to rod-shaped or cylindrical bacteria, which is a common shape classification for prokaryotes.

Question 8

What is the composition of the genome of prokaryotes?

Accepted Answer

The answer of What is the composition of the genome...

Question 9

Where is DNA found in prokaryotes?

Accepted Answer

In prokaryotes, DNA is primarily located in the nucleoid, an irregularly-shaped region within the cell that lacks a membrane, and can also be found in plasmids, which are small, circular, double-stranded DNA molecules.

Question 10

Figure 23-1 
-In the diagram of a bacterial cell in Figure 23-1, which number identifies a structure that aids in attachment?

Accepted Answer

The answer of Figure 23-1 
-In the diagram of a...

Question 11

Over 6000 species of prokaryotes have been identified. What percentage of the total number of prokaryotic species on Earth does this represent?

Accepted Answer

The number of identified prokaryotic species represents a very small fraction of the estimated total, suggesting that the vast majority remain undiscovered or unclassified. Scientists estimate that the actual number of prokaryotic species could be in the millions, making the 6000 identified species less than 1% of the total.

Question 12

Figure 23-1 
-In the diagram of a bacterial cell in Figure 23-1, which number identifies the structure that carries supplemental genetic information?

Accepted Answer

The answer of Figure 23-1 
-In the diagram of a...

Question 13

What are the three domains of life?

Accepted Answer

The three domains of life are Archaea, Bacteria, and Eukarya, which classify all living organisms based on differences in their genetic and cellular structures.

Question 14

Figure 23-1 
-In the diagram of a bacterial cell in Figure 23-1, which number identifies the structure that facilitates movement?

Accepted Answer

The answer of Figure 23-1 
-In the diagram of a...

Question 15

Which organisms stain as either Gram-positive or Gram-negative?

Accepted Answer

The Gram stain is a method used to differentiate bacterial species into two large groups: Gram-positive and Gram-negative, based on the physical properties of their cell walls. This technique does not apply to Archaea or Eukarya, as their cell structures are significantly different from those of bacteria.

Question 16

Which of these statements best describes the type of bacteria found in your guts?

Accepted Answer

The gut microbiome is influenced by genetics, diet, and environment. It tends to be more similar among family members due to shared genetics and environment, but each individual's microbiome is unique due to personal dietary habits and other environmental factors.

Question 17

What is the correct sequence of the reagents in the Gram stain technique?

Accepted Answer

The correct sequence for the Gram stain technique is: crystal violet (primary stain), iodine (mordant), alcohol (decolorizer), and safranin (counterstain). This sequence is used to differentiate between Gram-positive and Gram-negative bacteria based on their cell wall properties.

Question 18

What is the major structural component of bacterial cell walls?

Accepted Answer

The major structural component of bacterial cell walls is peptidoglycan, which provides strength and rigidity to the cell wall, distinguishing it from plant and fungal cell walls that contain cellulose and chitin, respectively.

Question 19

What is the function of bacteria found in human guts?

Accepted Answer

Bacteria in the human gut help synthesize vitamin K, which is essential for blood clotting and bone health.

Question 20

Which of the following contain cytoplasmic organelles?

Accepted Answer

Eukarya contain cytoplasmic organelles, such as mitochondria and the endoplasmic reticulum, distinguishing them from Archaea and Bacteria, which do not have membrane-bound organelles.

Quiz 23: Bacteria and Archaea

Figure 23-1 -In the diagram of a bacterial cell in Figure 23-1, which type of cell is represented?

Figure 23-1 -In the diagram of a bacterial cell in Figure 23-1, which numbers identify structures that are found in all prokaryotes?

Which type of cell contains a nuclear membrane?

Figure 23-1 -In the diagram of a bacterial cell in Figure 23-1, which number identifies the structure that carries out protein synthesis?

Suppose you perform a Gram stain of a mixed culture of Gram-positive and Gram-negative cells, and afterward you realize that you omitted the iodine step. What would you expect to see if you observed the slide under the microscope?

Figure 23-1 -In the diagram of a bacterial cell in Figure 23-1, which number identifies a structure that is composed of polysaccharides?

Which of these terms refers to prokaryotes that are cylindrical?

What is the composition of the genome of prokaryotes?

Where is DNA found in prokaryotes?

Figure 23-1 -In the diagram of a bacterial cell in Figure 23-1, which number identifies a structure that aids in attachment?

Over 6000 species of prokaryotes have been identified. What percentage of the total number of prokaryotic species on Earth does this represent?

Figure 23-1 -In the diagram of a bacterial cell in Figure 23-1, which number identifies the structure that carries supplemental genetic information?

What are the three domains of life?

Figure 23-1 -In the diagram of a bacterial cell in Figure 23-1, which number identifies the structure that facilitates movement?

Which organisms stain as either Gram-positive or Gram-negative?

Which of these statements best describes the type of bacteria found in your guts?

What is the correct sequence of the reagents in the Gram stain technique?

What is the major structural component of bacterial cell walls?

What is the function of bacteria found in human guts?

Which of the following contain cytoplasmic organelles?