Question 1

A cell is placed in a solution of large nutrient molecules tagged with a red dye.Soon the cell is dark red,showing a concentration of the nutrient much higher than the external solution.We add a reagent that blocks the use of ATP.What result would you expect from this experiment?

Accepted Answer

The answer of A cell is placed in a solution...

Question 2

Receptor-mediated endocytosis involves all of the following EXCEPT

Accepted Answer

Receptor-mediated endocytosis is a process for internalizing specific molecules into the cell, not for secreting materials out of the cell.

Question 3

Exocytosis is carried out by proteins in the cell membrane.

Accepted Answer

The answer of Exocytosis is carried out by proteins in...

Question 4

When an intestinal cell ingests substances inside very small vesicles that can only be seen with an electron microscope,this is

Accepted Answer

Pinocytosis is the process of taking in small amounts of extracellular fluid and its solutes by forming vesicles at the plasma membrane. These vesicles are too small to be seen with a light microscope but can be visualized with an electron microscope.

Question 5

Dead plants seen alongside a salted roadway died because the salt solution caused the cells to

Accepted Answer

The salt solution caused the plant cells to undergo plasmolysis, which is the shrinking of the cytoplasm away from the cell wall due to the loss of water. This can lead to cell death and ultimately the death of the entire plant.

Question 6

In the Malpighian tubules of an insect (blind,threadlike excretory tubule attached to the gut of an insect),salt molecules are actively transferred from body fluids to the inside of the tubule.Which of the following is NOT true?

Accepted Answer

The statement "The tubules have the same tonicity as the body fluids" is not true. The Malpighian tubules have a higher salt concentration inside compared to the body fluids, which causes the active transport of salt molecules from the body fluids to the tubule. This difference in tonicity is essential for the function of the Malpighian tubules in excreting excess salt from the insect's body.

Question 7

Which membrane transport process can continue whether the cell is alive or dead?

Accepted Answer

Diffusion is a passive process that can occur whether the cell is alive or dead. It is driven by the laws of thermodynamics and does not require ATP or a living cell. The other options (A, B, C, D) all require an active process or energy input from a living cell.

Question 8

When a plant cell is placed in a hypotonic solution,the cell wall prevents

Accepted Answer

When a plant cell is placed in a hypotonic solution, water enters the cell due to osmosis. This causes the cell to swell, but the cell wall prevents it from bursting. The cell wall provides structural support and prevents the cell from expanding beyond its capacity. Therefore, option C is correct. The other options are incorrect because the cell wall does not prevent diffusion or active transport, and it does not prevent the cell from shrinking or water from entering the cell.

Question 9

Which of the following is not true regarding active transport?

Accepted Answer

Active transport can be done by animal cells, therefore, it is not true that it cannot be done by animal cells. The other options are true regarding active transport.

Question 10

A differentially permeable membrane separates a molasses solution from distilled water.Over time,the

Accepted Answer

Since there is a differential permeability of the membrane, water molecules will cross the membrane from distilled water to the molasses solution, but the larger molecules in molasses cannot pass through the membrane. This will cause the molasses solution to become more dilute over time as water continues to cross the membrane until equilibrium is reached. Therefore, option B is the correct choice.

Question 11

When a substance moves from an area of low concentration to an area of high concentration while using energy,the process is termed

Accepted Answer

The process described where a substance moves from low concentration to high concentration using energy is active transport. Diffusion (A), osmosis (B), facilitated diffusion (C), and pinocytosis (D) do not involve the use of energy to move substances against their concentration gradient.

Question 12

Molecules such as glucose and amino acids are NOT lipid soluble and therefore they

Accepted Answer

Molecules that are not lipid soluble cannot easily pass through the cell membrane by simple diffusion. Instead, they require carrier proteins to transport them across the membrane by facilitated transport. Active transport is not always necessary for molecules that are not lipid soluble, and conversion to lipids or engulfment by endocytosis is not necessary or relevant for most small molecules like glucose and amino acids.

Question 13

How can marine animals such as sharks live in salt water?

Accepted Answer

Marine animals such as sharks increase or decrease the amount of urea in their blood until the blood is isotonic with the environment. This allows them to maintain a constant level of salt concentration in their bodies despite living in a salty environment.

Question 14

Carrier molecules are required for

Accepted Answer

Carrier molecules are essential for both facilitated diffusion and active transport because these processes involve the movement of substances across cell membranes with the help of specific proteins, unlike osmosis and simple diffusion that do not require such molecules.

Question 15

Which is true of facilitated transport by carrier proteins?

Accepted Answer

Facilitated transport by carrier proteins is a type of passive transport, meaning it does not require the expenditure of chemical energy by the cell. It allows for the transport of larger or charged molecules (such as glucose) that cannot diffuse through the cell membrane on their own. The glucose carrier protein can transport hundreds of molecules per second. Options A and D are incorrect as facilitated transport is specific to certain molecules and does not require energy expenditure. Option C is incorrect as carrier proteins can transport multiple molecules.

Question 16

Macrophages,a type of white blood cells,are able to remove bacteria from our bloodstream and tissues by

Accepted Answer

Macrophages are capable of engulfing and digesting bacteria through the process of phagocytosis. The other transport mechanisms listed do not involve active ingestion of particles by the cell.

Question 17

If a cell lacks ATP,which of the following processes would cease to operate immediately?

Accepted Answer

The sodium/potassium pump requires ATP to function, so it would immediately cease to operate if there is no ATP in the cell. The other listed processes do not directly require ATP for their operation.

Question 18

In the emergency room,saline solutions are often run into a person's vein.The saline solution must be

Accepted Answer

The most commonly used saline solution in the emergency room is 0.9% NaCl solution, also known as normal saline. This solution has the same salt concentration as the human body and is used to replace lost fluids and electrolytes in cases such as dehydration, vomiting, and diarrhea. Higher concentrations of salt, such as 9% NaCl, can cause serious complications and are not used for routine fluid replacement.

Question 19

Which of the following refers to materials only leaving the cell?

Accepted Answer

Exocytosis refers to the process in which materials are released or secreted out of the cell.

Question 20

The number of mitochondria in a cell would be a general indicator of the extent of

Accepted Answer

Mitochondria are responsible for producing ATP through cellular respiration, which requires active transport of molecules. Therefore, the number of mitochondria in a cell is a general indicator of the extent of active transport.

Quiz 4: Membrane Structure and Function