Question 1

What characteristic do simple diffusion and facilitated diffusion share?
A)Both require cellular energy for the transport of substances.
B)Both move water across a semipermeable membrane.
C)Both require a special carrier molecule to move substances across the membrane.
D)Both move a substance from a region of higher concentration to one of lower concentration without using cellular energy.

Accepted Answer

Simple diffusion and facilitated diffusion both move substances across a membrane from an area of higher concentration to an area of lower concentration without using cellular energy. However, facilitated diffusion requires a special carrier molecule while simple diffusion does not. Neither process specifically moves water across a membrane, making choice B incorrect. Choice A is also incorrect, as neither process requires cellular energy.

Question 2

DNA molecules are in the nucleus
A)as free molecules.
B)complexed with protein, forming chromatin fibers.
C)complexed with protein, forming nucleoli.
D)complexed with protein on the nuclear envelope.

Accepted Answer

DNA molecules are complexed with proteins and form chromatin fibers inside the nucleus. This is essential for packaging and organization of the genetic material in the nucleus. While there are some free DNA molecules in the nucleus, the majority of DNA exists as chromatin fibers. The DNA is not complexed with proteins to form nucleoli or on the nuclear envelope.

Question 3

Red blood cells are placed in a solution of 0.9% NaCl and no diffusion or osmosis is observed. This means that the solution is ________. 
A)isotonic
B)hypotonic
C)hypertonic
D)isertonic

Accepted Answer

If there is no diffusion or osmosis observed, it means that the concentration of solutes inside the red blood cells is equal to the concentration of solutes outside the cells in the 0.9% NaCl solution. This indicates that the solution is isotonic, as there is no net movement of water into or out of the cells.

Question 4

Cells are placed in a solution that causes them to absorb liquid until they burst. When more water is removed from the solution, newly added cells do not burst. The original solutions was ________ , while the second was ________ to the cells. 
A)isotonic; hypotonic
B)isotonic; hypertonic
C)hypotonic; isotonic
D)hypertonic; isotonic

Accepted Answer

The answer of Cells are placed in a solution that...

Question 5

When there is a surplus of dietary carbohydrates, they are converted to lipids through lipogenesis. Where are they synthesized?
A)Golgi apparatus
B)Smooth endoplasmic reticulum
C)Rough endoplasmic reticulum
D)Mitochondria

Accepted Answer

Lipogenesis occurs in the smooth endoplasmic reticulum. The enzymes responsible for converting excess carbohydrates into lipids are located in this organelle.

Question 6

Salt is placed in a glass of water. Slowly the salt begins to even out in concentration due to what factor?
A)Distance gradient
B)Distance vector
C)Concentration vector
D)Concentration gradient

Accepted Answer

The even distribution of the salt in the water is due to the concentration gradient, which is the gradual change in concentration between two areas. This phenomenon causes the salt to move from areas of high concentration to areas of low concentration until it becomes evenly distributed.

Question 7

The function of the nucleus is to
A)direct the activities of the cell.
B)form mitochondria.
C)transfer energy.
D)provide cell shape.

Accepted Answer

The nucleus is considered the control center of the cell as it contains the genetic material (DNA) that directs the biochemical processes and activities of the cell. It is responsible for essential functions, such as cell division, protein synthesis, and the regulation of gene expression. The other options (B, C, and D) are incorrect as they describe the functions of other cellular organelles.

Question 8

The movement of molecules through a membrane by filtration requires
A)osmotic pressure.
B)hydrostatic pressure.
C)atmospheric pressure.
D)barometric pressure.

Accepted Answer

Filtration involves the movement of molecules through a membrane due to a pressure difference, with the molecule movement occurring from high to low pressure. This pressure difference is typically hydrostatic pressure, which is the force exerted by fluid on the membrane. Osmotic pressure refers to the pressure exerted by a concentration gradient and can result in the movement of water across a membrane, but not necessarily other molecules. Atmospheric and barometric pressure are not directly relevant to the process of filtration through a membrane.

Question 9

During cell division, the chromosomes did not separate properly. This likely means that the centrioles failed to attach to what structure?
A)Centrosome
B)Cilia
C)Nucleus
D)Microtubules

Accepted Answer

The centrioles play a critical role in cell division as they are responsible for pulling apart the chromosomes. To do this, they attach to the centrosome, which in turn connects to the microtubules that pull the chromosomes apart. If the chromosomes did not separate properly, it likely means that the centrioles failed to attach properly to the centrosome and/or microtubules. Therefore, choice A, centrosome, is the best answer.

Question 10

If a red blood cell is placed in a hypotonic solution,
A)the cell will shrink.
B)only permeable substances will leave; but concentrations in the cell do not change.
C)the cell will remain the same size and shape.
D)the cell will swell and may eventually burst.

Accepted Answer

In a hypotonic solution, the concentration of solutes is lower outside the cell compared to the inside of the cell. Therefore, water will move from an area of higher concentration (outside the cell) to an area of lower concentration (inside the cell). As a result, the cell will swell and may eventually burst due to osmotic pressure.

Question 11

The nucleolus contains
A)DNA only.
B)RNA and protein.
C)DNA and protein.
D)RNA only.

Accepted Answer

The nucleolus contains RNA and protein. While the nucleolus does contain DNA, it is not its primary component. The main function of the nucleolus is to synthesize and process ribosomal RNA (rRNA) which then combines with protein to form ribosomes.

Question 12

If the concentration of glucose in the water outside of a cell is higher than the concentration inside,
A)water will enter the cell by osmosis.
B)water will leave the cell by osmosis.
C)glucose will enter the cell by osmosis.
D)glucose will leave the cell by osmosis.

Accepted Answer

Water always moves from an area of high water concentration (hypotonic) to an area of lower water concentration (hypertonic) in order to equalize the concentrations on both sides of the membrane. In this case, since the concentration of glucose is higher outside the cell, the water concentration is lower outside the cell, making the extracellular fluid hypertonic. Therefore, water will leave the cell by osmosis, in order to try and balance the concentration on both sides of the membrane. Glucose is too large to pass through the membrane by osmosis.

Question 13

Cytoskeletal structures that are not found in all cell types are
A)microtubules.
B)microfilaments.
C)myofibrils.
D)intermediate filaments.

Accepted Answer

The answer of Cytoskeletal structures that are not found in...

Question 14

Osmosis is the movement of
A)molecules from a high concentration to a low concentration.
B)water through a selectively permeable membrane to a solution containing a higher concentration of impermeant solute.
C)water through a selectively permeable membrane to a solution containing a lower concentration of impermeant solute.
D)ions from a low pressure region to a high pressure region through a selectively permeable membrane.

Accepted Answer

Osmosis is the movement of water through a selectively permeable membrane to a solution containing a higher concentration of impermeant solute. This process results in the equalization of solute concentration on both sides of the membrane. Option A describes diffusion, which is the movement of molecules from high to low concentration. Option C is the opposite of osmosis and would result in the movement of water out of the cell. Option D describes reverse osmosis, which is the movement of water from a high pressure region to a low pressure region through a selectively permeable membrane.

Question 15

Which of following does not influence the rate of molecular movement? 
A)Distance
B)The concentration of the substance
C)The amount of energy available for transport molecules
D)The molecular weight of the diffusing molecules

Accepted Answer

The answer of Which of following does not influence the...

Question 16

Which organelle contains the nucleolus?
A)The mitochondrion
B)The endoplasmic reticulum
C)The Golgi apparatus
D)The nucleus

Accepted Answer

The nucleolus is a structure found within the nucleus of eukaryotic cells. Therefore, the correct choice is the nucleus. A, B, and C are incorrect options as they do not contain the nucleolus.

Question 17

If cells placed in a solution shrivel up, the solution is ________.
A)hypertonic
B)hypotonic
C)isotonic
D)isertonic

Accepted Answer

A hypertonic solution has a higher concentration of solutes compared to the inside of the cells. This causes water to move out of the cells, leading to shrinkage or shriveling up of the cells.

Question 18

What is the relationship of osmotic pressure to the number of solute particles in a solution?
A)The lower the number of impermeant solute particles, the greater the osmotic pressure.
B)The greater the number of impermeant solute particles, the lower the osmotic pressure.
C)The greater the osmotic pressure, the lower the number of impermeant solute particles.
D)The greater the number of impermeant solute particles, the greater the osmotic pressure.

Accepted Answer

Osmotic pressure is directly proportional to the number of impermeant solute particles in a solution. This means that the greater the number of impermeant solute particles, the greater the osmotic pressure. Therefore, option D is the correct choice.

Question 19

An isotonic solution
A)has a greater concentration of impermeant solute than a cell.
B)has more water entering than leaving a cell.
C)has the same osmotic pressure as the cells in the solution.
D)causes a cell to shrink.

Accepted Answer

An isotonic solution has the same osmotic pressure as the cells in the solution. This means that the concentration of solute inside and outside of the cell is equal and there is no net movement of water, so the cell remains the same size. Option A is incorrect as an isotonic solution has equal solute concentration. Option B is incorrect as an isotonic solution has an equal amount of water entering and leaving the cell. Option D is incorrect as the cell would remain the same size in an isotonic solution.

Question 20

A hypotonic solution
A)has a lower concentration (number)of impermeant solute than do the cells in the solution.
B)would cause cells in the solution to lose water.
C)has a higher osmotic pressure than do the cells in the solution.
D)causes cells to shrink.

Accepted Answer

A hypotonic solution has a lower concentration of impermeant solute than do the cells in the solution. This means that there is more water outside the cell than inside the cell, causing water to move into the cell, which can result in cell swelling or even bursting (lysis).

Answer: B
 A hypotonic solution would cause cells in the solution to lose water. This is an incorrect statement because hypotonic solutions have more water and less solute than the cell, causing water to enter the cell, leading to swelling or even bursting (lysis).

Answer: C
 A hypotonic solution has a lower osmotic pressure than do the cells in the solution, not a higher osmotic pressure. This is because the concentration of impermeant solute is lower in the hypotonic solution than in the cell, causing water to move into the cell.

Answer: D
 A hypotonic solution does not cause cells to shrink. In fact, it causes cells to swell or even burst (lysis) because of the higher water concentration outside the cell compared to inside the cell.

Quiz 3: Cells

What characteristic do simple diffusion and facilitated diffusion share?

DNA molecules are in the nucleus

Red blood cells are placed in a solution of 0.9% NaCl and no diffusion or osmosis is observed. This means that the solution is ________.

Cells are placed in a solution that causes them to absorb liquid until they burst. When more water is removed from the solution, newly added cells do not burst. The original solutions was , while the second was to the cells.

When there is a surplus of dietary carbohydrates, they are converted to lipids through lipogenesis. Where are they synthesized?

Salt is placed in a glass of water. Slowly the salt begins to even out in concentration due to what factor?

The function of the nucleus is to

The movement of molecules through a membrane by filtration requires

During cell division, the chromosomes did not separate properly. This likely means that the centrioles failed to attach to what structure?

If a red blood cell is placed in a hypotonic solution,

The nucleolus contains

If the concentration of glucose in the water outside of a cell is higher than the concentration inside,

Cytoskeletal structures that are not found in all cell types are

Osmosis is the movement of

Which of following does not influence the rate of molecular movement?

Which organelle contains the nucleolus?

If cells placed in a solution shrivel up, the solution is ________.

What is the relationship of osmotic pressure to the number of solute particles in a solution?

An isotonic solution

A hypotonic solution