Question 1

Which of the following will have the greatest ratio of surface area to volume?

Accepted Answer

A 1×1×1 box has the greatest surface area to volume ratio because as the dimensions decrease, the ratio increases.

Question 2

Which domains of life are classified as prokaryotes?

Accepted Answer

Prokaryotes are single-celled organisms that lack a nucleus and other membrane-bound organelles. Both Bacteria and Archaea are classified as prokaryotes. Fungi, Protista, and Eukarya all have a distinct nucleus and membrane-bound organelles, and are therefore classified as eukaryotes.

Question 3

Which of the following macromolecules enter the nucleus of a eukaryotic cell through pores in the nuclear membrane?

Accepted Answer

Ribosomal proteins are synthesized in the cytoplasm and then transported into the nucleus through nuclear pores to be assembled with rRNA into ribosomal subunits.

Question 4

A newspaper ad for a local toy store indicates that an inexpensive toy microscope available for a small child is able to magnify specimens nearly as much as the more costly microscope available in your college lab. What is the primary reason for the price difference?

Accepted Answer

The primary reason for the price difference is that the toy microscope, while capable of magnifying specimens, has low resolution, resulting in poor quality images compared to the more costly college lab microscope.

Question 5

What is the explanation for how a modern transmission electron microscope (TEM) can achieve a resolution of about 0.2 nanometers, whereas a standard light microscope has a maximum resolution of about 200 nanometers?

Accepted Answer

Electron beams have much shorter wavelengths than visible light, allowing for greater resolution in the modern TEM compared to a standard light microscope.

Question 6

A newly discovered unicellular organism isolated from acidic mine drainage is found to contain a cell wall, a plasma membrane, two flagella, and peroxisomes. Based just on this information, the organism is most likely ________.

Accepted Answer

The presence of a cell wall and plasma membrane suggests that the organism is either a prokaryote or eukaryote. The presence of peroxisomes suggests that it is a eukaryote. The presence of flagella suggests that it is motile, and since prokaryotes typically have only one flagellum and archaea often have different types of flagella, the organism is most likely a motile eukaryote.

Question 7

What is the function of the nuclear pore complex found in eukaryotes?

Accepted Answer

The nuclear pore complex is responsible for regulating the movement of molecules such as proteins and RNAs into and out of the nucleus. It acts as a gateway, controlling which molecules can enter and exit the nucleus.

Question 8

Which of the following would be most appropriate method to observe the three-dimensional structure and organization of microvilli on an intestinal cell?

Accepted Answer

Scanning electron microscopy is the best choice as it provides a three-dimensional view of the surface structure of cells, which is ideal for observing microvilli. A hand lens and standard light microscopy do not provide the necessary magnification, and transmission electron microscopy would require thin sectioning of the cells, which may not accurately represent the true organization of the microvilli.

Question 9

Which of the following frequently imposes a limit on cell size?

Accepted Answer

The ratio of surface area to volume frequently imposes a limit on cell size because as a cell grows in volume, its surface area does not increase proportionally. This can result in decreased efficiency of nutrient uptake and waste removal, making it difficult for the cell to support its metabolic needs. Therefore, cells often divide when they reach a certain size to maintain a high surface area to volume ratio. The absence of a nucleus, the number of mitochondria in the cytoplasm, and the volume of the endomembrane system are not directly related to limiting cell size.

Question 10

Which of the following would be the most appropriate method to observe the movements of condensed chromosomes during cell division?

Accepted Answer

Standard light microscopy is the most appropriate method for observing the movements of condensed chromosomes during cell division, as it allows for live cell imaging and is capable of visualizing chromosomes in real-time.

Question 11

In the fractionation of homogenized cells using differential centrifugation, which of the following will require the greatest speed to form pellets at the bottom of the tube?

Accepted Answer

Ribosomes are the smallest and least dense of the listed organelles, requiring the greatest centrifugal force (highest speed) to pellet during differential centrifugation.

Question 12

Which of the following macromolecules leave the nucleus of a eukaryotic cell through pores in the nuclear membrane?

Accepted Answer

mRNA (messenger RNA) is responsible for carrying the genetic information from DNA in the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. It is a single-stranded molecule that is small enough to pass through the pores in the nuclear membrane. DNA, amino acids, and phospholipids are all larger molecules that cannot pass through the pores in the nuclear membrane.

Question 13

In bacteria, DNA will be found in ________.

Accepted Answer

Bacteria do not have a membrane-enclosed nucleus or mitochondria. DNA in bacteria is found in a region called the nucleoid, which is not surrounded by a membrane. Ribosomes are structures involved in protein synthesis, but they do not contain DNA.

Question 14

You have a cube of modeling clay in your hands. Which of the following changes to the shape of this cube of clay will decrease its surface area relative to its volume?

Accepted Answer

A sphere has the smallest surface area relative to its volume compared to any other shape. So rounding the clay up into a sphere will decrease its surface area relative to its volume.

Question 15

Which of the following would be most appropriate method to observe and measure the size of ribosomes in a eukaryotic cell?

Accepted Answer

Transmission electron microscopy (TEM) is the best choice for observing and measuring the size of ribosomes in a eukaryotic cell. TEM uses electrons to create a highly detailed image of the cell's internal structures, making it possible to visualize small organelles like ribosomes. Standard light microscopy and a hand lens do not have enough resolution to view ribosomes, while scanning electron microscopy is typically used to observe the surface of cells rather than internal organelles.

Question 16

Which of the following is the smallest structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope?

Accepted Answer

A standard research-grade light microscope can typically resolve structures down to about 200 nanometers. Mitochondria are usually about 0.5 to 10 micrometers in size, making them visible under a light microscope, whereas microtubules, ribosomes, and viruses are generally smaller than the resolution limit of a standard light microscope.

Question 17

One primary advantage of light microscopy over electron microscopy is that ________.

Accepted Answer

Light microscopy allows for the visualization of dynamic processes in living cells, such as cell division or movement, which electron microscopy cannot do because samples must be fixed and prepared before imaging.

Question 18

Which of the following is a major difference between prokaryotic cells and eukaryotic cells?

Accepted Answer

Eukaryotic cells are characterized by the presence of membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, whereas prokaryotic cells lack these distinct membrane-bound structures. The other options (A, B, and D) are not accurate in distinguishing between prokaryotic and eukaryotic cells, as cell walls may be present in both types of cells (although they may differ in composition), both prokaryotic and eukaryotic cells may have flagella or cilia, and there is no general rule that prokaryotic cells are larger than eukaryotic cells.

Question 19

Which structure is common to plant and animal cells?

Accepted Answer

Both plant and animal cells have mitochondria as the site of cellular respiration to generate ATP, the main source of energy for cellular activities. Option (A) chloroplast is only found in plant cells, (B) central vacuole is found in plant cells, but usually in a larger and more prominent form, and (D) centriole is only found in animal cells.

Question 20

Which of the following are found in plant, animal, and bacterial cells?

Accepted Answer

Ribosomes are found in all types of cells, including plant, animal, and bacterial cells. Mitochondria are found in plant and animal cells, while chloroplasts are only found in plant cells. Endoplasmic reticulum can be found in plant and animal cells, but not in bacterial cells.

Quiz 6: A Tour of the Cell