lab quiz 4

Which of the following molecules are transported across cell membrane by facilitated diffusion? Check all that apply

glucose

A sample of cells is placed into a salt solution. The cells shrink and the membrane is distorted. Relative to the cell, the solution is probably:

hypertonic

The diagram shows a semipermeable membrane. Glucose and water have a low molecular weights (180 and 18, respectively) and are able to pass through the membrane. The nucleotides (phosphate, sugar, and nitrogen containing bases) have molecular weights ranging from 377 to 415) and are not able to pass through the semipermeable membrane. Diffusion and osmosis will proceed. Once equilibrium is reached, what would you be able to say about the total volume of solution on each side of the membrane?

The total volume of solution would be greater on the left side of the membrane than on the right

Placing phospholipids into an aqueous solution immediately results in their forming a lipid bilayer. What is the driving force causing this ordered arrangement?

Hydrophilic/hydrophobic interactions

Crossing a membrane by simple diffusion can be distinguished from facilitated diffusion because:

Simple diffusion is not saturable; rates of facilitated diffusion are limited by the number of functional membrane proteins and can be saturated

The diagram shows a semipermeable membrane. Glucose and water have low molecular weight (180 and 18, respectively) and are able to pass through the membrane. The nucleotides (phosphate, sugar, and nitrogen containing base) have molecular weights ranging from 377 to 415) and are not able to pass through the semipermeable membrane. As diffusion and osmosis proceed, which of the following molecules will move from the left side to the right side of the membrane?

The concentration of sugars will be higher on the right side of the membrane

All cells are surrounded by

a plasma membrane

At high temperatures, reaction rate decreases because the heat:

alters the active site of the enzyme

The difference in concentration of a solute across a membrane is called the:

concentration gradient

Which of the following transport processes requires the expenditure of energy?

exocytosis

Cell membrane components are synthesis in the endoplasmic reticulum, transported as vesicles to the Golgi stacks where they are modified, and then are transported to the cell surface, where they deliver their contents to the cell exterior and become part of the cell membrane in a process ______. The reverse of this process, brining nutrient containing particles from outside the cell to the inside of the cell is called_______.

exocytosis; endocytosis

Movement of a substance point of higher concentration to a point of lower concentration is known as:

passive transport

A substance is soluble in the lipid bilayer, and moves across the membrane from a point of higher concentration to a point of lower concentration. This process is known as:

simple diffusion

Substance A is a solute that readily moves across the cell membrane in the direction of its concentration gradient. This is an example of:

simple diffusion

The diagram shows a semipermeable membrane. Glucose and water have low molecular weight (180 and 18, respectively) and are able to pass through the membrane. The nucleotides (phosphate, sugar, and nitrogen containing base) have molecular weights ranging from 377 to 415) and are not able to pass through the semipermeable membrane. As diffusion and osmosis proceed, which of the following molecules will move from the left side to the right side of the membrane?

sugars and water

Which of the following accurately describes the nature of the cell membrane?

the molecules form a double layer with the polar regions facing the cell interior and the outside of the cell, and hydrophobic regions forming the interior of the cell membrane

In which of the following transport processes can a solute be moved against its concentration gradient?

transport pump

Which of the following molecules move across the cell membrane by simple diffusion? Check all that apply

water carbon dioxide oxygen