Question 1

The smallest living things are
A) proteins.
B) cells.
C) tissues.
D) organs.
E) organ systems.

Accepted Answer

The smallest living things are cells, which are the basic building blocks of life. Proteins are macromolecules made up of amino acids and are not living entities on their own. Tissues, organs, and organ systems are all made up of cells and are larger and more complex structures.

Question 2

If someone sweats profusely and loses large amounts of water, the result will be that the blood plasma becomes ________ to the cells.
A) hypertonic
B) isotonic
C) hypotonic
D) osmotic
E) none of the above

Accepted Answer

When someone sweats profusely and loses large amounts of water, the water content of blood plasma decreases, resulting in an increase in the concentration of solutes in the plasma. This results in the plasma becoming hypertonic (having a higher concentration of solutes) in relation to the cells, which can lead to water moving out of the cells in an attempt to equalize the concentration.

Question 3

Structurally, the plasma membrane
A) contains some imbedded proteins.
B) is composed of a bilayer of lipids.
C) contains some carbohydrate molecules.
D) contains some small holes, or pores.
E) all of the above

Accepted Answer

The plasma membrane is composed of a bilayer of lipids which contains some imbedded proteins and carbohydrate molecules. The membrane also contains some small holes or pores for the passage of substances in and out of the cell. Therefore, all of the above options are correct.

Question 4

Water molecules and small ions enter a cell through
A) transport proteins.
B) receptor proteins.
C) lipid channels.
D) anchor proteins.
E) all of the above

Accepted Answer

Water molecules and small ions cannot pass through the lipid bilayer of the cell membrane due to their hydrophilic nature. Therefore, they require transport proteins to facilitate their movement into the cell. Receptor proteins and anchor proteins do not play a direct role in the movement of water and small ions into the cell. Lipid channels do not exist in the cell membrane.

Question 5

The process that occurs when a physical pressure pushes materials through a barrier is called
A) diffusion.
B) facilitated diffusion.
C) osmosis.
D) filtration.
E) active transport.

Accepted Answer

The process described in the question is filtration. Filtration is the movement of materials through a barrier driven by a physical pressure, such as blood pressure in the kidneys causing urine to be filtered out. Diffusion and facilitated diffusion involve the movement of materials from an area of high concentration to an area of low concentration, without the need for a physical pressure. Osmosis is the movement of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration. Active transport requires the use of energy to move materials against a concentration gradient.

Question 6

The cell membrane
A) is a watery gel in which structures are suspended.
B) contains the powerhouse of the cell.
C) is the central government of the cell.
D) protects the cell and acts as a filter.
E) carries the cell's hereditary information.

Accepted Answer

The cell membrane is a protective barrier that separates the interior of the cell from the external environment. It is selectively permeable, meaning it allows certain molecules to pass through while blocking others. This membrane acts as a filter, controlling what enters and exits the cell to maintain homeostasis.

Question 7

Which of the following is a concept of the cell theory?
A) Cells are the basic structural unit of life.
B) Tissues are the site of control.
C) Organelles are the basic functional unit of life.
D) Cells are produced by meiosis.
E) All of the above are correct.

Accepted Answer

The cell theory states that cells are the basic structural unit of life, which means that all living organisms are composed of cells. Tissues may be important for specialized functions, but they are not the site of control; furthermore, organelles are important functional components within cells, but they are not considered the basic unit of life. The process of meiosis is involved in sexual reproduction, but it is not a concept of the cell theory. Therefore, the correct choice is A.

Question 8

The process by which molecules such as oxygen are moved into cells along their concentration gradient directly through the cell membrane is called
A) osmosis.
B) diffusion.
C) active transport.
D) osmosis
E) exocytosis.

Accepted Answer

The process described in the question is diffusion, as it involves the movement of molecules along their concentration gradient directly through the cell membrane. Osmosis is a similar process but specifically refers to the movement of water molecules. Active transport and exocytosis both involve the use of energy to move molecules across the cell membrane in a way that is not directly along their concentration gradient.

Question 9

Which of the following is a function of the membrane proteins called transport proteins?
A) They bind to specific extracellular molecules to trigger a cellular change.
B) They regulate the passage of ions.
C) They are enzymes.
D) They serve as anchors or stabilizers for the cell membrane.
E) They are used as a source of energy.

Accepted Answer

Transport proteins are responsible for regulating the passage of ions across the cell membrane. They can either facilitate or prohibit the movement of specific ions, which is crucial for maintaining the proper balance of ions inside and outside the cell.

Question 10

Crenation occurs when a blood cell is placed in a(n)
A) isotonic solution.
B) hypertonic solution.
C) hypotonic solution.
D) holotonic solution.
E) none of the above

Accepted Answer

Crenation occurs when a blood cell is placed in a hypertonic solution, in which the concentration of solutes outside the cell is higher than inside the cell. This causes water to move out of the cell, resulting in cell shrinkage and deformation.

Question 11

Which of the following is a function of the cell membrane?
A) continuation of the cytoplasm with the extracellular fluid
B) a free passageway for materials to the environment
C) sensitivity to changes in the extracellular fluid
D) enzyme production
E) controlling movement into the nucleus

Accepted Answer

The cell membrane plays a crucial role in the sensitivity of the cell to changes in the extracellular fluid. It contains various receptors and channels that allow for communication and transport of molecules across the membrane, thus modulating the response of the cell to environmental stimuli. Choices A, B, D, and E are incorrect because the cell membrane does not serve as a continuation of the cytoplasm, a free passageway for materials, an enzymatic producer, or a controller of movement into the nucleus.

Question 12

Which of the following terms is used to define the structure that separates the contents of a human cell from its surrounding medium?
A) cell wall
B) cell layer
C) plasma membrane
D) cell boundary
E) All of the above are used.

Accepted Answer

The plasma membrane is the structure that separates the contents of a human cell from its surrounding medium. The cell wall is only present in plant cells and provides added structural support. The term cell layer is not commonly used to refer to the plasma membrane or any other structure related to cell boundaries. The term cell boundary may be used to refer to the plasma membrane, but it is less commonly used than the term plasma membrane. Therefore, the best choice is C.

Question 13

A solution with a lower-than-normal osmotic pressure is referred to as a(n)
A) isotonic solution.
B) hypertonic solution.
C) hypotonic solution.
D) holotonic solution.
E) none of the above

Accepted Answer

A solution with a lower-than-normal osmotic pressure is referred to as a hypotonic solution.

Question 14

A solution that contains a higher solute concentration than the cytoplasm of a cell is called
A) holotonic.
B) hypertonic.
C) isotonic.
D) hypotonic.
E) semitonic.

Accepted Answer

A solution that contains a higher solute concentration than the cytoplasm of a cell is called hypertonic. In this solution, water will move out of the cell, causing it to shrink or become crenated.

Question 15

The watery medium inside a cell is known as
A) cytosol.
B) protoplasm.
C) extracellular fluid.
D) cytoplasm.
E) a colloidal gel.

Accepted Answer

Cytosol is the watery medium inside a cell, which is part of the cytoplasm.

Question 16

The classes of membrane proteins that recognize extracellular structures are called
A) receptor proteins.
B) channel proteins.
C) carrier proteins.
D) anchor proteins.
E) identifier proteins.

Accepted Answer

Receptor proteins recognize extracellular structures and transmit signals into the cell. Channel, carrier, and anchor proteins are involved in transportation or stabilization of molecules in the membrane, while identifier proteins help cells differentiate between self and non-self cells.

Question 17

The phosphate group of a phospholipid is
A) hydrophobic.
B) hydrophilic.
C) polar.
D) nonpolar.
E) both B and C

Accepted Answer

The phosphate group of a phospholipid is hydrophilic and polar, allowing it to interact with water.

Question 18

The movement of water across a membrane from an area of higher water concentration to an area of lower water concentration is known as
A) osmosis.
B) active transport.
C) diffusion.
D) facilitated diffusion.
E) filtration.

Accepted Answer

This describes the process of osmosis, where water moves down its concentration gradient to equalize the concentration on both sides of the membrane. Active transport involves movement against the concentration gradient, diffusion and facilitated diffusion refer to movement of molecules other than water, and filtration involves the movement of solutes through a membrane under pressure.

Question 19

Cell membranes allow certain molecules to pass, while blocking others. This property is called
A) impermeable.
B) freely permeable.
C) selectively permeable.
D) actively permeable.
E) none of the above

Accepted Answer

Cell membranes are selectively permeable, meaning that they allow certain molecules, such as small and non-polar molecules, to pass through while blocking others, such as large or charged molecules. This is essential for maintaining proper cellular functions and regulating the flow of molecules in and out of the cell. Therefore, option C is the best choice.

Question 20

Two solutions are separated by a semipermeable membrane with the same properties as a cell membrane. Solution A is 5 percent glucose and solution B is 10 percent glucose. Under these circumstances,
A) water will move from solution A to solution B.
B) water will move from solution B to solution A.
C) glucose will move from solution A to solution B.
D) glucose will move from solution B to solution A.
E) at equilibrium the concentration of glucose will be higher in solution B.

Accepted Answer

Water moves from a lower solute concentration (solution A) to a higher solute concentration (solution B) to try to equalize the solute concentrations on both sides of the membrane, a process known as osmosis.

Quiz 3: Cell Structure and Function

The smallest living things are

If someone sweats profusely and loses large amounts of water, the result will be that the blood plasma becomes ________ to the cells.

Structurally, the plasma membrane

Water molecules and small ions enter a cell through

The process that occurs when a physical pressure pushes materials through a barrier is called

The cell membrane

Which of the following is a concept of the cell theory?

The process by which molecules such as oxygen are moved into cells along their concentration gradient directly through the cell membrane is called

Which of the following is a function of the membrane proteins called transport proteins?

Crenation occurs when a blood cell is placed in a(n)

Which of the following is a function of the cell membrane?

Which of the following terms is used to define the structure that separates the contents of a human cell from its surrounding medium?

A solution with a lower-than-normal osmotic pressure is referred to as a(n)

A solution that contains a higher solute concentration than the cytoplasm of a cell is called

The watery medium inside a cell is known as

The classes of membrane proteins that recognize extracellular structures are called

The phosphate group of a phospholipid is

The movement of water across a membrane from an area of higher water concentration to an area of lower water concentration is known as

Cell membranes allow certain molecules to pass, while blocking others. This property is called

Two solutions are separated by a semipermeable membrane with the same properties as a cell membrane. Solution A is 5 percent glucose and solution B is 10 percent glucose. Under these circumstances,