Question 1

Which of the following is not a characteristic that chloroplasts and mitochondria share?

Accepted Answer

Chloroplasts and mitochondria are both organelles with their own DNA and the ability to reproduce themselves. However, they are not part of the endomembrane system, which includes the rough and smooth endoplasmic reticulum, Golgi apparatus, and lysosomes. Chloroplasts and mitochondria are unique organelles that have their own specialized functions within the cell.

Question 2

You arrive late to lecture and your professor is describing a feature of the nucleus that provides it with structural support. You are not sure which feature is being discussed, but because you read the book before you came to class, you are fairly certain that it is

Accepted Answer

The nuclear lamina provides structural support to the nucleus by forming a mesh-like network of protein filaments underneath the inner nuclear membrane. The nucleolus is responsible for producing ribosomes, the nucleoplasm is the liquid substance inside the nucleus, and the nuclear pore allows for transport of molecules in and out of the nucleus. None of these features specifically provide structural support to the nucleus.

Question 3

What is the function of the nuclear pore complex?

Accepted Answer

The nuclear pore complex regulates the movement of materials across the nuclear envelope, allowing certain molecules and proteins to enter or exit the nucleus while preventing others from doing so. It plays a crucial role in maintaining the integrity and function of the nucleus in eukaryotic cells.

Question 4

Which of the following is present in a prokaryotic cell?

Accepted Answer

Prokaryotic cells lack membrane-bound organelles but they do contain ribosomes, which are essential for protein synthesis. Chloroplasts, mitochondria, endoplasmic reticulum, and nuclear envelope are all found in eukaryotic cells.

Question 5

Which of the following components would you expect to find in any type of living organism?

Accepted Answer

Chromosomes contain genetic information and are present in all living organisms. The other components listed are not necessarily found in all types of organisms. Microtubules, mitochondria, and lysosomes are specific organelles found in eukaryotic cells, while prokaryotic cells do not have a nucleus.

Question 6

What is the site of synthesis of proteins for export secretion from the cell)?

Accepted Answer

Proteins that are destined for export or secretion are synthesized by ribosomes that attach to the endoplasmic reticulum, where they are then processed and transported through the Golgi complex before being secreted from the cell. Free ribosomes are involved in the synthesis of proteins that are localized within the cytoplasm or nucleus of the cell. Ribosomes that attach to the outer mitochondrial membrane are involved in the synthesis of proteins that are targeted to the mitochondria.

Question 7

Mitochondria are separated into two compartments, the matrix and the intermembrane space, by their inner and outer membranes. How does the presence of two compartments contribute to the function of mitochondria?

Accepted Answer

The two compartments of mitochondria allow for separate but complementary functions to occur within the organelle. The matrix contains enzymes responsible for the citric acid cycle and oxidative phosphorylation, while the intermembrane space contains proteins involved in electron transport and apoptosis. This separation allows for efficient energy production while also allowing for important regulatory processes to occur in the intermembrane space.

Question 8

Why are lysosomes considered part of the endomembrane system?

Accepted Answer

Lysosomes are formed from products synthesized by the endoplasmic reticulum and processed by the Golgi, hence they are considered part of the endomembrane system. Option A is incorrect because lysosomes do not deposit end-products of digestion in the endoplasmic reticulum. Option B is incorrect because lysosomes are indeed part of the endomembrane system. Option C is incorrect because lysosomes do not facilitate movement between stacks of the Golgi, rather they contain enzymes that break down and recycle cellular waste.

Question 9

What is the most likely role of a cell that contains an extensive smooth ER?

Accepted Answer

The smooth endoplasmic reticulum (ER) is responsible for the synthesis of lipids, such as phospholipids and steroids. Therefore, a cell that contains an extensive smooth ER is likely specialized in producing lipids.

Question 10

One function of peroxisomes is alcohol detoxification. In which of the following locations would you expect to find large quantities of peroxisomes?

Accepted Answer

Peroxisomes are responsible for alcohol detoxification in the liver. Therefore, in the liver tissue of people who consume large quantities of alcohol, there would be a high demand for peroxisomes to perform this function.

Question 11

What can you infer about high- molecular- weight proteins that cannot be transported into the nucleus?

Accepted Answer

High-molecular-weight proteins that cannot be transported into the nucleus lack nuclear localization signals (NLS). NLS is a sequence of amino acids that directs the protein to the nucleus. Therefore, their inability to enter the nucleus is most likely due to the lack of this signal.

Question 12

As part of our immune system, neutrophil cells engulf micro- organisms or foreign particles. The process by which the neutrophil does this is known as

Accepted Answer

Neutrophils engulf micro-organisms or foreign particles through the process of phagocytosis.

Question 13

You have a distant cousin, age 4, who is always tired and fatigued and is not able to play games and sports like other healthy children. He is most likely to have an enzyme deficiency or defect associated with which intracellular organelle?

Accepted Answer

Mitochondria are responsible for energy production in the cell through cellular respiration. An enzyme defect or deficiency in the mitochondria can lead to a decrease in ATP production and result in fatigue and weakness.

Question 14

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

Accepted Answer

Eukaryotic cells have a more complex structure than prokaryotic cells, including a nucleus, extensive inner membrane systems, and many intracellular organelles. Prokaryotic cells are much simpler in structure and lack a nucleus and membrane-bound organelles.

Question 15

How is the nuclear membrane related to the endoplasmic reticulum?

Accepted Answer

The inner and outer bilayers of the nuclear envelope are separated by a space that is continuous with the space inside the endoplasmic reticulum, thus providing direct contact between the two structures. This connection allows for the exchange of various molecules and facilitates the coordination of cellular activities between the nucleus and the cytoplasm.

Question 16

The small intestine is the site of digestion and absorption of nutrients. A single layer of epithelial cells lines the small intestine. In the duodenum the first section of the small intestine), these epithelial cells secrete large quantities of digestive enzymes. Which of the following features would be typical of these epithelial cells?

Accepted Answer

The epithelial cells in the duodenum secrete large quantities of digestive enzymes, which are proteins. Therefore, they would have large quantities of rough endoplasmic reticulum, which is the organelle responsible for protein synthesis and processing. Cells that secrete large quantities of lipids would have more smooth endoplasmic reticulum, which is specialized for lipid synthesis and processing. Large nuclei and lysosomes are not specific features of these types of epithelial cells.

Question 17

You are studying an organism and note that its proteins fail to be glycosylated. A deficiency in which of the following organelles is likely the cause?

Accepted Answer

The answer of You are studying an organism and note...

Question 18

Which of the following organelles is involved in the oxidation of fatty acids or ethanol?

Accepted Answer

Peroxisomes are involved in the oxidation of fatty acids and ethanol. In this process, hydrogen peroxide (H2O2) is generated as a byproduct, which is then broken down by catalase enzymes also found in peroxisomes. Mitochondria are involved in aerobic respiration and the production of ATP, but they do not oxidize fatty acids or ethanol. Rough endoplasmic reticulum and Golgi apparatus are involved in protein synthesis and modification, respectively, and are not involved in the oxidation of fatty acids or ethanol.

Question 19

What is a purpose of the cell wall for both prokaryotes and plant cells?

Accepted Answer

The purpose of the cell wall in both prokaryotes and plant cells is to protect the cell from the effects of a hypotonic environment, meaning an environment with a lower concentration of solutes than the cell's cytoplasm. The cell wall helps to maintain the shape of the cell and prevents it from bursting or lysing due to osmotic pressure.

Question 20

Mitochondrial DNA codes for about 13 proteins depending on the species of organism). These 13 proteins account for a small proportion of the proteins present in mitochondria. The remaining proteins are coded for by nuclear DNA. What is the most likely explanation for how these proteins find their way to the mitochondria?

Accepted Answer

The most likely explanation for how nuclear-encoded proteins find their way to the mitochondria is through the presence of signal sequences. These sequences act as a signal for the protein to be transported to the mitochondria and direct it to the correct location within the organelle.

Quiz 7: Inside the Cell