Ch 3B

What is the purpose if the energy extracted from ATP in this figure?

to generate a sodium concentration gradient the energy from ATP hydrolysis is used to transport sodium and potassium ions across the membrane and thereby establish concentration to each of those ions.

Concentration differences cause ionic imbalances that polarize the cell membrane.

true

I'm their resting state, all body cells exhibit a resting membrane potential; therefore, all cells are polarized.

true All cells have a resting membrane potential (RMP), such that the inside (interior surface) of the cell membrane has a net negative charge while the outside (external surface) of the membrane has a net positive charge. Given the different (opposite) charges on either side of the cell membrane, the cell is considered to be polarized. This RMP, which results from separation of charged particles (ions) across the cell membrane, can be measured in millivolts (typically ranging from −50 to −100 mV depending on the cell type).

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 In active transport, the cell provides the metabolic energy (ATP) needed to move substances across the plasma membrane (against their concentration gradient). In passive transport, substances cross the plasma membrane (down their concentration gradient) using kinetic energy, without any energy input from the cell.

Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"?

Cyclic AMP and calcium may be second messengers.

Which of the following statement is true?

During exocytosis, substance from inside of the cell are moved outside. Vesicular transport processes that eject substances from the cell interior into the extracellular fluid are called exocytosis. Exocytosis is a form of active transport; thus, it requires energy, usually in the form of ATP.

Channel-mediated diffusion is a form of active transport.

False Channel-mediated diffusion is a form of passive, not active, transport. Any type of diffusion results from substances moving down their concentration gradient, a form of kinetic energy. In order to move, or actively pump, substances against their concentration gradient, energy must be used. ATP directly, or indirectly, provides the energy for active transport.

Why is it necessary for glucose to be pumped into the cell rather than diffusing in?

Glucose may have to be moved against a concentration gradient. Glucose may in some cases be able to follow a concentration gradient into the cell, but in many cases it needs to be pumped against a concentration gradient and requires active transport.

Which of the following is a difference between primary and secondary active transport?

In primary transport, the transport protein gets phosphorylated; in secondary active transport, the transport protein is not phosphorylated

Which of the following would not be restricted (limited) by low levels of ATP?

Osmosis

A cell engulfing a relatively large particle will likely utilize?

Phagocytosis

Which vesicular transport process occurs primarily in some white blood cells and macrophages?

Phagocytosis

Which of the following is False regarding the membrane potential?

The resting membrane potential is maintained solely by passive transport processes.

What is a membrane potential?

a voltage or electrical charge across the plasma membrane The membrane potential is the electrical potential energy (measured in millivolts) resulting from the separation of oppositely charged particles (ions) across the plasma membrane. At rest, membrane potentials are typically negative, ranging from −50 to −100 mV, with more anions (than cations) concentrated along the internal surface of the membrane, and more cations (than anions) concentrated along the external surface.

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

exocytosis The term exocytosis literally means "out of the cell"

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

facilitated diffusion

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

facilitated diffusion Yes! You've got it! Facilitated diffusion is a passive transport process during which molecules move down their concentration gradients through transport proteins.

A resting membrane potential is a sign of a depolarized membrane.

false A resting membrane potential would be a sign of a polarized membrane.

Which of the following is not a factor that binds cells together?

glycolipids in the glycocalyx

A primary active transport process is one in which?

molecule move through transport proteins that have been activated by ATp Yes! You've got it! Primary active transporters, such as the sodium-potassium ATPase (or pump), are activated when ATP is hydrolyzed. This activation allows for the transport of solutes across the plasma membrane against concentration gradients.

If a cell is non-selectively engulfing samples of extracellular fluid, for example to absorb nutrients, it will likely utilize ________.

pinocytosis

if active transport establishes a concentration gradient with the use of ATP, then the concentration can be looked at as?

potential energy that can be harnessed when molecules passively diffuse down the concentration gradient

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

primary active transport Yes! You've got it! The sodium-potassium pump is activated by ATP. This activation allows the pump to transport sodium and potassium ions against their gradients.

Some hormones enter cells via ________.

receptor-mediated endocytosis

Which transport process is the main mechanism for the movement of most macromolecules by body cells?

receptor-mediated endocytosis

Active Process

secondary transport, primary transport, endocytosis, exocytosis

Passive Process

simple diffusion, facilitated diffusion, osmosis

This figure illustrates which of the following description?

the use of a sodium concentration gradient to power the pumping of glucose into the cell The sodium ion gradient is generated by the Na+-K+ pump at the left. Diffusion of sodium ions through the Na+-glucose symport transporter (shown at the right) provides the energy necessary to actively transport glucose into the cell. Such a mechanism is used by intestinal cells (to absorb nutrients) and kidney cells (to recover glucose from urine prior to excretion).