Cell Membrane And transport

Question 1

What does amphipathic mean?

Answer 1

A molecule that contains both hydrophobic and hydrophilic regions. Such as the phospholipid bilayer of the cell membrane.

Question 2

What is an integral protein?

Answer 2

Proteins which are embedded in the plasma membrane. Some only protrude from one surface of the bilayer whereas most span the membrane with a hydrophobic core region that associated with the non polar core of the membrane.

Question 3

What is a peripheral protein?

Answer 3

Proteins that occur only on the cytoplasmic side of the cell membrane.

Question 4

How does cholesterol influence the cell membrane?

Answer 4

It will modify the fluidity of the membrane.

Question 5

What are the components of the plasma membrane according to the fluid-mosaic model.

Answer 5

Phospholipids, cholesterol, and proteins.

Question 6

An increase in unsaturated fatty acid residues cause bilayer fluidity to:

Answer 6

Increase.

Question 7

Cell membrane fluidity is based on the amount of:

Answer 7

Unsaturated fatty acids in the phospholipid bilayer.

Question 8

What types of molecules most easily diffuse through the plasma membrane?

Answer 8

Small, non charged particles like carbon dioxide can easily diffuse with no energy cost. Polar molecules are not able to cross.

Question 9

Interactions between the components of the cell membrane is called

Answer 9

The fluid-mosaic model

Question 10

Water is a polar molecule, how can it pass through the primarily non polar cell membrane?

Answer 10

The majority of cells have aquaporins that allow water to cross a membrane quickly. They also equalize water pressure inside and outside the cell so that the membranes don’t burst.

Question 11

What is bulk transport?

Answer 11

When large molecules are transported into and out of a cell by vesicles. It requires an input of energy to form vesicles around substances, during bulk transport processes, such as exocytosis and endocytosis take place exocytosis is when cells, release molecules and endocytosis, is when cells take in molecules 

Question 12

Describe exocytosis

Answer 12

Exocytosis is when substances are secreted or released from the cell using vesicles the vesicle in the cytoplasm fuses with the plasma membrane then the vesicle contents are released to the extracellular side of the membrane

Question 13

Describe endocytosis

Answer 13

Endocytosis is when substances are taken into the cell, using vegetcles a portion of the plasma membrane invaginates to envelop a substance the substance becomes surrounded by the plasma membrane. Then the plasma membrane pinches off to form a vesicle inside the cytoplasm containing the substance.

Question 14

What is an isotonic solution?

Answer 14

In a lab cells are normally placed in an isotonic solutions. In an isotonic solution, the solute concentration in the water concentration both inside and outside the cell are equal and therefore there is no net gain or loss of water, a .9% solution of the salt sodium chloride is known to be isotonic to red blood cells, therefore, intravenous solutions medically administered, usually have this tonicity (strength of solution)

Question 15

What is osmosis?

Answer 15

The diffusion of water across a selectively permeable membrane from high to low concentration is called osmosis. Diffusion always occurs from higher to lower concentration.

Question 16

What is diffusion?

Answer 16

The movement of molecules from a higher to a lower concentration that is down there. Concentration gradient until equilibrium is achieved, and the molecules are distributed equally.

Question 17

As temperature increases the rate of diffusion

Answer 17

Increases

Question 18

The concentration of molecules or ions in a particular area, as compared to another area, is referred to as the

Answer 18

Concentration gradient

Question 19

An aquaporin is characterized as which type of protein

Answer 19

Channel protein

Question 20

The process of using vesicles to move macromolecules into or out of the cell is called

Answer 20

Bulk transport

Question 21

What is turgor pressure

Answer 21

Turgor pressure is extremely important in plant cells for the maintenance of the plants erect position the swelling of a plant cell in a hypotonic solution creates turgor pressure when you forget to water your plants, they will due to decreased turgor pressure

Question 22

What is a solution?

Answer 22

A solution contains both a solute, usually a salad, and a solvent, which is usually a liquid

Question 23

What types of molecules can enter and exit is cell simply by diffusion without an energy cost

Answer 23

Gases are small non charged particles and can diffuse through the plasma membrane

Question 24

Is the rate of diffusion constant

Answer 24

No, the rate of diffusion is typically faster at the beginning, and slows down as the solution reaches equilibrium

Question 25

What is a hypertonic solution?

Answer 25

A solution that causes cells to shrink or shrivel due to loss of water. This refers to a solution with a higher percentage of solute, and a lower concentration of water outside the cell. If a cell is placed in a hypertonic solution and water leaves the cell.