Question 1

Prokaryotes and eukaryotes are primarily distinguished by the absence or presence of internal membrane-bound organelles. Are prokaryotic cells at an evolutionary disadvantage because they lack organelles?

Accepted Answer

Prokaryotic cells are not at an evolutionary disadvantage because they lack organelles. While eukaryotes may be more efficient due to their organelles, prokaryotes are still able to carry out necessary processes for survival and reproduction. Additionally, some prokaryotes perform photosynthesis and respiration without needing organelles.

Question 2

Certain cells in the mouth produce large amounts of the enzyme amylase, a component of saliva that hydrolyzes carbohydrate. Which of the following organelles would be expected to be especially abundant in these cells?

Accepted Answer

The rough endoplasmic reticulum (RER) is responsible for protein synthesis and modification, including the synthesis of enzymes such as amylase. Cells that produce large amounts of amylase would need a lot of RER to support the increased protein synthesis required. Chloroplasts are only present in plant cells and are responsible for photosynthesis, mitochondria are responsible for energy production, and lysosomes are involved in digestion and the breakdown of macromolecules. None of these organelles are directly involved in the production of amylase.

Question 3

The relative abundance of a specific organelle is often predictable when cell function is considered; for example, the _____ could be expected to contain more lysosomes than an average cell.

Accepted Answer

Cells that roam around the body engulfing and consuming bacteria, such as macrophages, require more lysosomes to digest the bacteria and other debris they ingest.

Question 4

The boundary that surrounds the contents of the nucleus is the

Accepted Answer

The nuclear envelope is a double membrane structure that surrounds the contents of the nucleus, separating it from the cytoplasm. It is composed of an outer and inner membrane, with a perinuclear space in between. The nuclear envelope also contains nuclear pores, which allow for the selective transport of molecules between the nucleus and cytoplasm. The plasma membrane is the boundary that surrounds the entire cell, while the cytosol is the fluid that fills the cell.

Question 5

When looking through a light microscope at a plant leaf, you notice small green organelles moving around in the cytoplasm of every cell. What organelle are you most likely seeing?

Accepted Answer

The green organelles suggest that they contain chlorophyll, which is found in chloroplasts. Chloroplasts are organelles responsible for photosynthesis in plant cells. Mitochondria are responsible for cellular respiration, lysosomes contain digestive enzymes, and ribosomes are responsible for protein synthesis.

Question 6

Molecules of _____ are consumed by mitochondria during cellular respiration.

Accepted Answer

Oxygen (O₂) is consumed by mitochondria during cellular respiration as it is the final electron acceptor in the electron transport chain, which is responsible for the majority of ATP production in the cell. Carbon dioxide (CO₂) is actually produced as a waste product during cellular respiration and is excreted from the cell. Water (H₂O) is also produced as a waste product but is not consumed. Nitrogen dioxide (NO₂) plays no role in cellular respiration.

Question 7

The smooth endoplasmic reticulum

Accepted Answer

The smooth endoplasmic reticulum is responsible for the synthesis of lipids, including phospholipids and cholesterol, and the detoxification of drugs and poisons. It does not produce energy, convert sunlight, or store water, nutrients, and enzymes.

Question 8

Which of the following would you find in the cells that produce the mucus that lines the nasal cavities?

Accepted Answer

Mucus-secreting cells would most likely contain vesicles, which are membrane-bound organelles involved in secretion and transport. Grana, thylakoids, and flagella are not typically found in these types of cells.

Question 9

Which of the following statements is true of chloroplasts?

Accepted Answer

Chloroplasts are organelles found in plant and algal cells that contain chlorophyll and are responsible for capturing energy from sunlight during the process of photosynthesis. They do not produce proteins used by other parts of the cell, give an animal cell its shape, or contain a cell's genetic material.

Question 10

Which of the following statements is true?

Accepted Answer

Different eukaryotic cells contain different numbers and types of organelles depending on the specific tasks they must perform. This is because different cells have different functions and require different organelles to carry out those functions. For example, muscle cells have a large number of mitochondria to produce energy for muscular contraction, while nerve cells have many dendrites to receive and transmit signals.

Question 11

The process of photosynthesis

Accepted Answer

The process of photosynthesis traps light energy in an energy carrier like ATP to create sugar. Sugars are not used to create ATP in photosynthesis. Carbon dioxide is one of the reactants needed for photosynthesis, not a product. Photosynthesis only occurs in plant cells, not animal cells.

Question 12

Lysosomes are organelles responsible for the breakdown of macromolecules. Why is it useful to have the lysosomal reactions compartmentalized rather than allowing them to take place freely in the cytoplasm of the cell?

Accepted Answer

Compartmentalizing lysosomal reactions within lysosomes prevents the lysosomal enzymes from breaking down cellular macromolecules that should remain intact in the cytoplasm.

Question 13

The Golgi apparatus

Accepted Answer

The Golgi apparatus is responsible for modifying, sorting, and packaging proteins and lipids into vesicles for transport to their final destination within the cell or outside of it. It does not store genetic material, capture energy from sunlight, or create energy by converting ribosomes to proteins.

Question 14

Which of the following would be the best analogy for the function of the Golgi apparatus?

Accepted Answer

The Golgi apparatus acts as a processing and packaging center for proteins and lipids that have been synthesized in the cell. Like a worker in a factory, it modifies and sorts these molecules, adds labeling molecules (such as carbohydrates), and packages them into vesicles for transport to their final destination within or outside of the cell.

Question 15

The nucleolus is

Accepted Answer

The nucleolus is a region within the nucleus of the cell and is responsible for the production and assembly of ribosomes. It is not where chromosomes are found (A), nor is it the name of the double layer of membranes that forms the boundary of the nucleus (B). It is also not a piece of DNA wrapped around proteins (D).

Question 16

Ribosomes are very small nonmembranous organelles associated with the synthesis of

Accepted Answer

Ribosomes are the site of protein synthesis within the cell. They are composed of RNA and protein and can be located in the cytoplasm or on the endoplasmic reticulum.

Question 17

Using an electron microscope, you notice an organelle that consists of stacks of membranes and appears to be producing vesicles. This organelle is most likely

Accepted Answer

The organelle with stacks of membranes and that produces vesicles is the Golgi apparatus. The Golgi is responsible for modifying and packaging proteins and lipids into vesicles for transport to other parts of the cell or for secretion out of the cell. The endoplasmic reticulum also has membranes and produces vesicles, but it does not have stacked membranes like the Golgi. The mitochondria is responsible for energy production and does not typically produce vesicles. The nucleus is responsible for storing genetic information and does not have membranes that produce vesicles.

Question 18

The inner membranes of both mitochondria and chloroplasts are folded into various arrangements. What is the advantage of having a folded membrane rather than a simple interior membrane that follows the same oval shape as the exterior membrane?

Accepted Answer

The folds in the inner membranes of mitochondria and chloroplasts create more surface area for various chemical reactions that occur across the inner membranes. This increased surface area allows for more efficient energy production and nutrient synthesis.

Question 19

Which of the following is not a function of the plant vacuole?

Accepted Answer

The plant vacuole is not involved in the production of ATP; instead, ATP is produced through cellular respiration in the mitochondria. The other choices are all functions of the plant vacuole.

Question 20

Your muscle cells need large amounts of ATP to function in the movement of your body. Which of the following organelles would you expect to be especially abundant in muscle cells?

Accepted Answer

Mitochondria are the site of cellular respiration, which produces ATP. As muscle cells require a large amount of ATP, it is expected that they would have a high number of mitochondria.

Quiz 6: Cell Structure and Internal Compartments