Chapter 3 Part 2 Cells the Living Units

Which of the following statements is true?

During exocytosis, substances from the inside of the cell are moved outside.

Which of the following processes allows cells to concentrate material that is present only in very small amounts in the extracellular fluid?

Receptor-mediated endocytosis

Why is the selective permeability of the plasma membrane essential for normal cell function?

Selective permeability allows cells to exclude some substances and allow others to pass into or out of the cell.

What sort of Ca2+ concentrations are maintained by the calcium pump?

The Ca2+ concentration is higher in the extracellular fluid than in the cytoplasm.

Most cancer cells have a lower intracellular ATP concentration compared to normal cells. How would you expect this to affect the Na+-K+ pump in cancer cells?

The Na+-K+ pump would work slower.

Once solid material is phagocytized and taken into a vacuole, which of the following statements best describes what happens?

A lysosome combines with the vacuole and digests the enclosed solid material.

What is the difference between active and passive transport across the plasma membrane?

Active transport is ATP dependent, whereas passive transport uses only the kinetic energy of the particles for movement across the plasma membrane.

Which of the following statements is correct regarding diffusion? The rate of diffusion is independent of temperature. The greater the concentration gradient, the faster the rate of diffusion. Molecular weight of a substance does not affect the rate of diffusion. The lower the temperature, the faster the diffusion rate.

The greater the concentration gradient, the faster the rate of diffusion.

What is the primary function of the mitochondria?

They are the main sites of ATP production.

Crenation is likely to occur in blood cells in ________.

a hypertonic solution

What triggers the release of phosphate from the Na+-K+ pump?

binding of K+ ions to the pump

A vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes _____

exocytosis

Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____.

facilitated diffusion

The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____.

facilitated diffusion

What sort of ion distributions are established and maintained by Na+-K+ pump activity?

high Na+ concentration in the extracellular fluid; high K+ concentration in the cytoplasm

What is the energy source used by the Na+-K+ pump during its normal operation?

hydrolysis of ATP

Solutions with a higher concentration of solutes than the concentration inside the cell are:

hypertonic

A primary active transport process is one in which __________

molecules move through transport proteins that have been activated by ATP

___________ is the diffusion of a solvent, such as water, across a selectively permeable membrane.

osmosis

The plasma membrane is made primarily of_________.

phospholipids

The sodium-potassium pump uses ATP to move sodium and potassium ions across the plasma membrane. This statement describes _____.

primary active transport

Which organelle is responsible for building proteins?

ribosomes

A red blood cell placed in pure water would ________.

swell and burst

What event initiates ATP attachment to the Na+-K+ pump, leading to the pump's phosphorylation?

the binding of Na+ ions to the pump

Which of the following best describes how phosphorylation affects the Na+-K+ pump?

Phosphorylation causes the pump to change shape.

Which of the following best describes why cells need active transport mechanisms?

to move solutes against their concentration gradients

A process by which large particles may be taken into the cell for food, protection of the body, or for disposing of old or dead cells is called phagocytosis.

true

Diffusion is always from areas of greater to areas of lesser concentration.

true

Facilitated diffusion always requires a carrier protein.

true