Question 1

What prevents water-soluble molecules from entering cells across the plasma membrane?

Accepted Answer

Water-soluble molecules cannot pass through the hydrophobic phospholipid bilayer of the plasma membrane. This is because the hydrophilic nature of the water-soluble molecules prevents them from interacting with the hydrophobic tails of the phospholipids. Therefore, other mechanisms such as membrane channel proteins or transporters are needed to facilitate the movement of water-soluble molecules across the plasma membrane. Carbohydrate chains and glycoprotein channels are not directly involved in regulating the entry of water-soluble molecules into cells.

Question 2

Which form of cell communication is used to communicate within the cell itself and with other cells in direct physical contact?

Accepted Answer

Cells communicate by using hundreds of kinds of signal molecules,for example,insulin.Cells communicate in three main ways; they display plasma membrane-bound signaling molecules (receptors)that affect the cell itself and other cells in direct physical contact.The other options do not correctly describe this process.

Question 3

All body cells are electrically polarized with the inside of the cell being more negatively charged than the outside.

Accepted Answer

This is true. The difference in electrical charge between the inside and outside of the cell is known as the membrane potential and is maintained by the movement of ions across the cell membrane.

Question 4

The function of adenosine triphosphate (ATP)is to store energy in molecules of carbohydrates,proteins and lipids,but not to transfer energy from one molecule to another.

Accepted Answer

ATP is responsible for transferring energy from one molecule to another. It stores energy in its chemical bonds and releases it when those bonds are broken, providing energy for cellular processes.

Question 5

In cirrhosis,how does cholesterol alter the fluidity of the plasma membrane of erythrocytes?

Accepted Answer

Cholesterol decreases the membrane fluidity of erythrocytes, which reduces its ability to carry oxygen. In cirrhosis, elevated levels of cholesterol can accumulate in the cell membrane of erythrocytes, leading to decreased membrane fluidity and reduced oxygen-carrying capacity. This can contribute to the development of anemia and other complications in cirrhosis.

Question 6

Lipids and proteins are the major components of the plasma membrane.

Accepted Answer

Lipids and proteins are the two main components of the plasma membrane, with lipids making up a majority of the membrane structure and proteins serving various functions such as transporters, receptors, and enzymes. Small amounts of carbohydrates and other molecules may also be present in the membrane.

Question 7

Lysosomes remain fully active by maintaining an acid pH created by pumping hydrogen ions into their interiors.

Accepted Answer

Lysosomes function best in an acidic pH, typically between 4.5 and 5.0, which is maintained by the pumping of hydrogen ions into the lysosome's interior.

Question 8

Eukaryotic cells are characterized by a lack of a distinct nucleus,whereas prokaryotic cells have intracellular compartments bordered by membranes and a well-defined nucleus.

Accepted Answer

This statement is actually false. Eukaryotic cells have a distinct nucleus, which is enclosed by a nuclear membrane, while prokaryotic cells have a nucleoid region, which is not surrounded by a membrane. Additionally, eukaryotic cells have many other membrane-bound organelles, such as mitochondria and lysosomes, which are absent in prokaryotic cells.

Question 9

Which of the following best describes the cellular function of metabolic absorption?

Accepted Answer

Metabolic absorption refers to the process by which cells take in and use nutrients from the surrounding environment. This is an essential cellular function that is required for growth, maintenance, and repair of tissues. The other choices may also describe cellular functions, but they do not specifically relate to metabolic absorption.

Question 10

The chief function of ribosomes is to provide sites for lipid synthesis.

Accepted Answer

The chief function of ribosomes is to synthesize proteins, not lipids.

Question 11

Phagocytosis is an example of exocytosis.

Accepted Answer

Phagocytosis is the process by which a cell engulfs solid particles or other cells. It is a type of endocytosis, not exocytosis. Exocytosis is the process by which a cell releases substances from inside the cell to the outside environment.

Question 12

What organic compound facilitates transportation across cell membranes by acting as receptors,transport channels for electrolytes,and enzymes to drive active pumps?

Accepted Answer

Proteins facilitate transportation across cell membranes by acting as receptors, transport channels for electrolytes (such as ion channels), and enzymes to drive active pumps (such as the sodium-potassium pump). While lipids are a major component of cell membranes, they are not capable of performing these functions. Proteolytic cascades refer to a series of enzymatic reactions that break down proteins, but they do not play a direct role in facilitating transportation across cell membranes. Carbohydrates can also be present in cell membranes, but their main role is in cell signaling rather than transportation.

Question 13

Diffusion is an example of active transport.

Accepted Answer

Diffusion is a passive transport process as it does not require energy input from the cell to move molecules from a region of high concentration to a region of low concentration. Active transport, on the other hand, uses energy to move molecules against their concentration gradient.

Question 14

Which cell component is capable of cellular autodigestion when it is released during cell injury?

Accepted Answer

Lysosomes are capable of cellular autodigestion when they are released due to cell injury. Lysosomes contain hydrolytic enzymes that are responsible for breaking down cellular components, and when released from the lysosome, these enzymes can cause damage to the cell's own structures.

Question 15

Using the fluid mosaic model,how is the cell capable of actively protecting itself against injurious agents?

Accepted Answer

The fluid mosaic model describes the cell membrane as a fluid structure with various proteins embedded in the phospholipid bilayer. These proteins include receptors that can specifically recognize and bind to harmful agents such as bacteria and antibodies. By altering the number and patterns of these receptors, the cell can actively protect itself by preventing the harmful agents from entering the cell or by initiating an immune response to neutralize them. Therefore, option B is the best choice. Options A, C, and D are incorrect as they do not describe mechanisms of protection that are consistent with the fluid mosaic model.

Question 16

Which component of the cell produces hydrogen peroxide (H₂O₂)by using oxygen to remove hydrogen atoms from specific substrates in an oxidative reaction?

Accepted Answer

Peroxisomes are responsible for producing hydrogen peroxide by using oxygen to remove hydrogen atoms from specific substrates in an oxidative reaction. Lysosomes are responsible for breaking down cellular waste and foreign material, while ribosomes are responsible for protein synthesis. Oxyhydrosomes are not a known component of the cell. Therefore, the correct answer is B.

Question 17

Understanding the various steps of proteolytic cascades such as caspase-mediated apoptosis and complement cascade may be useful in designing drug therapy for which human diseases?

Accepted Answer

Caspase-mediated apoptosis is involved in the pathology of many autoimmune and malignant disorders, while the complement cascade is involved in both autoimmune and cancer-related disorders. Understanding the steps of these pathways could lead to the development of targeted drug therapies for these diseases.

Question 18

What is the sequence of steps in the development of a digestive enzyme by the pancreas cells from the initial transcription to the release from the cell?

Accepted Answer

The correct sequence involves transcription of DNA to RNA in the nucleus, translation of RNA to protein at the ribosome, and transport of the enzyme in a secretory vesicle to the cell membrane for release.

Question 19

The primary functions of the cell nucleus are cell division and control of genetic information.

Accepted Answer

The cell nucleus is responsible for controlling the genetic information of the cell, which includes DNA replication and transcription. It also plays a vital role in cell division by controlling the separation of chromosomes during mitosis and meiosis.

Question 20

If cells are deprived of communication from extracellular chemical messengers,most cells experience apoptosis.

Accepted Answer

Extracellular chemical messengers play an important role in cell survival and proliferation. Without communication from these messengers, cells may undergo programmed cell death, or apoptosis.

Quiz 1: Cellular Biology

What prevents water-soluble molecules from entering cells across the plasma membrane?

Which form of cell communication is used to communicate within the cell itself and with other cells in direct physical contact?

All body cells are electrically polarized with the inside of the cell being more negatively charged than the outside.

The function of adenosine triphosphate (ATP)is to store energy in molecules of carbohydrates,proteins and lipids,but not to transfer energy from one molecule to another.

In cirrhosis,how does cholesterol alter the fluidity of the plasma membrane of erythrocytes?

Lipids and proteins are the major components of the plasma membrane.

Lysosomes remain fully active by maintaining an acid pH created by pumping hydrogen ions into their interiors.

Eukaryotic cells are characterized by a lack of a distinct nucleus,whereas prokaryotic cells have intracellular compartments bordered by membranes and a well-defined nucleus.

Which of the following best describes the cellular function of metabolic absorption?

The chief function of ribosomes is to provide sites for lipid synthesis.

Phagocytosis is an example of exocytosis.

What organic compound facilitates transportation across cell membranes by acting as receptors,transport channels for electrolytes,and enzymes to drive active pumps?

Diffusion is an example of active transport.

Which cell component is capable of cellular autodigestion when it is released during cell injury?

Using the fluid mosaic model,how is the cell capable of actively protecting itself against injurious agents?

Which component of the cell produces hydrogen peroxide (H₂O₂) by using oxygen to remove hydrogen atoms from specific substrates in an oxidative reaction?

Understanding the various steps of proteolytic cascades such as caspase-mediated apoptosis and complement cascade may be useful in designing drug therapy for which human diseases?

What is the sequence of steps in the development of a digestive enzyme by the pancreas cells from the initial transcription to the release from the cell?

The primary functions of the cell nucleus are cell division and control of genetic information.

If cells are deprived of communication from extracellular chemical messengers,most cells experience apoptosis.

Quiz 1: Cellular Biology

What prevents water-soluble molecules from entering cells across the plasma membrane?

Which form of cell communication is used to communicate within the cell itself and with other cells in direct physical contact?

All body cells are electrically polarized with the inside of the cell being more negatively charged than the outside.

The function of adenosine triphosphate (ATP)is to store energy in molecules of carbohydrates,proteins and lipids,but not to transfer energy from one molecule to another.

In cirrhosis,how does cholesterol alter the fluidity of the plasma membrane of erythrocytes?

Lipids and proteins are the major components of the plasma membrane.

Lysosomes remain fully active by maintaining an acid pH created by pumping hydrogen ions into their interiors.

Eukaryotic cells are characterized by a lack of a distinct nucleus,whereas prokaryotic cells have intracellular compartments bordered by membranes and a well-defined nucleus.

Which of the following best describes the cellular function of metabolic absorption?

The chief function of ribosomes is to provide sites for lipid synthesis.

Phagocytosis is an example of exocytosis.

What organic compound facilitates transportation across cell membranes by acting as receptors,transport channels for electrolytes,and enzymes to drive active pumps?

Diffusion is an example of active transport.

Which cell component is capable of cellular autodigestion when it is released during cell injury?

Using the fluid mosaic model,how is the cell capable of actively protecting itself against injurious agents?

Which component of the cell produces hydrogen peroxide (H2O2) by using oxygen to remove hydrogen atoms from specific substrates in an oxidative reaction?

Understanding the various steps of proteolytic cascades such as caspase-mediated apoptosis and complement cascade may be useful in designing drug therapy for which human diseases?

What is the sequence of steps in the development of a digestive enzyme by the pancreas cells from the initial transcription to the release from the cell?

The primary functions of the cell nucleus are cell division and control of genetic information.

If cells are deprived of communication from extracellular chemical messengers,most cells experience apoptosis.

Which component of the cell produces hydrogen peroxide (H₂O₂) by using oxygen to remove hydrogen atoms from specific substrates in an oxidative reaction?