Question 1

70S is the sedimentation rate of which of the following?

Accepted Answer

The 70S ribosomes are characteristic of prokaryotic cells, chloroplasts, and mitochondria, distinguishing them from the 80S ribosomes found in the cytoplasm of eukaryotic cells.

Question 2

Which of the following is true about endospores?

Accepted Answer

Endospores are highly resistant to environmental stress such as heat, drying, freezing, and radiation, which allows bacteria to survive in harsh conditions. They are not reproductive structures, are metabolically inactive, can remain viable for long periods, and are resistant to many chemicals.

Question 3

Bacteria that have flagella at both poles of the cell are described as amphitrichous.

Accepted Answer

Amphitrichous bacteria have a single flagellum or a tuft of flagella at both ends of the cell, allowing them to be highly motile.

Question 4

What happens when you place a bacterial cell into a hypertonic solution?

Accepted Answer

In a hypertonic solution, water moves out of the bacterial cell due to osmosis, causing the cell membrane to pull away from the cell wall in a process called plasmolysis. This can lead to cell shrinkage and potentially inhibit the cell's ability to function properly.

Question 5

Gram- positive bacteria stain purple when the Gram stain is complete.

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer in their cell wall that retains the crystal violet dye during the Gram staining process, resulting in a purple color.

Question 6

Which of the following does not enable bacterial endospores to be heat resistant?

Accepted Answer

Peptidoglycan is a component of bacterial cell walls, not specifically related to the heat resistance of endospores. The other options contribute to the protective and resistant properties of endospores.

Question 7

Spirochetes move in a corkscrew- rotary motion due to a specialized periplasmic flagellum.

Accepted Answer

Spirochetes are a group of bacteria characterized by their unique structure, which includes a periplasmic flagellum (also known as axial filaments) that wraps around the cell body. This specialized flagellum is located in the periplasmic space between the inner cytoplasmic membrane and the outer membrane in these bacteria. The rotation of the periplasmic flagella enables spirochetes to move in a distinctive corkscrew or rotary motion, allowing them to navigate through viscous environments such as mucous membranes or tissue.

Question 8

What term most correctly describes when energy released by the flow of an ion from high to low concentration fuels the transport of an unrelated substance from low to high concentration but in the same direction?

Accepted Answer

Symport describes the process where two substances are moved in the same direction across a membrane, one down its concentration gradient, providing the energy to move the other substance against its gradient.

Question 9

Binary fission is more complicated than mitosis.

Accepted Answer

Binary fission is a simpler process than mitosis, primarily used by prokaryotic organisms to replicate and divide into two identical cells, whereas mitosis is a more complex process involving multiple stages for the division of eukaryotic cells.

Question 10

Bacteria that have flagella distributed all over the cell surface are described as (having)

Accepted Answer

Peritrichous bacteria have flagella distributed all over the cell surface, allowing them to move in various directions.

Question 11

Which of the following is not an example of an inclusion body?

Accepted Answer

Endosomes are not considered inclusion bodies; they are part of the cell's endocytic membrane transport pathway, involved in sorting and directing vesicular contents, unlike the other options which are examples of inclusion bodies typically used for storage or other specific functions within prokaryotic and eukaryotic cells.

Question 12

The genetic material of bacteria can be found in the

Accepted Answer

The genetic material of bacteria is primarily located in the nucleoid, an irregularly-shaped region within the cell that lacks a nuclear membrane, distinguishing it from the nucleus found in eukaryotic cells.

Question 13

Which of the following structures allow bacteria to transfer genetic information through conjugation?

Accepted Answer

Pili, specifically sex pili, are structures that allow bacteria to transfer genetic material from one cell to another through a process known as conjugation.

Question 14

Prokaryotic cells that move in response to oxygen levels are said to display chemotaxis.

Accepted Answer

Chemotaxis refers to movement in response to chemical stimuli, not specifically oxygen levels. Movement in response to oxygen is called aerotaxis.

Question 15

Which of the following is false about the bacterial cytoskeleton?

Accepted Answer

The bacterial cytoskeleton does contain proteins that are functionally similar to actin and tubulin, but these proteins are not actually actin and tubulin. Instead, bacteria have their own unique cytoskeletal proteins, such as FtsZ (tubulin homolog) and MreB (actin homolog), that perform similar roles in cell division and shape maintenance.

Question 16

Short, bristle- like structures that extrude from the cell surface are called

Accepted Answer

Fimbriae are short, bristle-like structures on the surface of some bacterial cells that help in attachment to surfaces.

Question 17

What is the function of a carboxysome?

Accepted Answer

Carboxysomes are microcompartments in bacteria that enhance the efficiency of carbon fixation, particularly through the Calvin cycle, by concentrating carbon dioxide around the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO).

Question 18

Which of the following structures do not help the bacteria adhere to surfaces?

Accepted Answer

Flagella primarily function in locomotion for bacteria, not in adherence to surfaces.

Question 19

Periplasmic flagella are unlike most flagella because they

Accepted Answer

Periplasmic flagella, also known as axial filaments, are unique because they are located in the periplasmic space, which is the area between the peptidoglycan layer and the outer membrane in spirochetes. This location allows them to rotate and cause the entire bacterium to move in a corkscrew motion, different from the propulsion mechanism of other bacterial flagella.

Question 20

Which of the following is true about ribosomes?

Accepted Answer

The answer of Which of the following is true about...

Quiz 3: Introduction to Prokaryotic Cells