Transport of Substances Through Cell Membranes

According to the provided data on chemical compositions, what is the approximate concentration of Sodium (Na+) ions in the extracellular fluid?

What is the fundamental difference between 'diffusion' and 'active transport' across a cell membrane?

How does the lipid solubility of a substance affect its rate of diffusion through the cell membrane's lipid bilayer?

What are the specialized protein pores that selectively permit the rapid passage of water through many cell membranes called?

How do voltage-gated channels open or close their gates?

What is the primary characteristic that distinguishes facilitated diffusion from simple diffusion regarding the concentration of the diffusing substance?

The glucose transporter GLUT4 is activated by which substance, leading to an increased rate of facilitated diffusion of glucose in insulin-sensitive tissues?

What is the term for the process of net movement of water across a selectively permeable membrane caused by a concentration difference of water?

According to the text, what is the approximate normal osmolality of the extracellular and intracellular fluids in the human body?

Which transport mechanism is responsible for establishing and maintaining the concentration gradients of sodium and potassium across the cell membrane?

What is the electrogenic nature of the Na+-K+ pump a result of?

In secondary active transport, where is the energy for transporting a substance against its gradient derived from?

What is the mechanism by which glucose is transported into most cells against a large concentration gradient, as depicted in Figure 4-13?

What is the mechanism for transport of a substance through a cellular sheet, such as the intestinal epithelium?

What is the approximate concentration of Potassium (K+) ions in the intracellular fluid according to Figure 4-1?

According to the text, the potassium channel's selectivity filter allows potassium ions to pass about 1000 times more readily than sodium ions. How is this high degree of selectivity achieved?

The patch clamp method, as illustrated in Figure 4-6B, is used for what purpose in cell physiology?

What does the Nernst equation calculate?

What factor primarily determines the osmotic pressure exerted by particles in a solution?

One gram molecular weight (180 grams) of glucose is equal to 1 osmole. How many osmoles is one gram molecular weight (58.5 grams) of sodium chloride (NaCl) equal to when fully dissociated?

Besides the Na+-K+ pump, what is another important primary active transport mechanism mentioned in the text?

What is the primary function of the calcium pump in virtually all cells?

Primary active transport of hydrogen ions is particularly important in which two locations in the body?

According to the formula provided, how does the energy required for primary active transport change when concentrating a substance 1000-fold compared to concentrating it 10-fold?

What is the term for secondary active transport where a substance is transported to the outside of the cell while a sodium ion moves to the inside?

What is the difference between osmolarity and osmolality?

Why do lipid-insoluble molecules like urea, which are larger than water, still penetrate the cell membrane through protein channels, albeit more slowly?

What is the primary role of the α (alpha) subunit in the Na+-K+ pump?

What is the approximate pH of the intracellular fluid as shown in Figure 4-1?

An important function of the Na+-K+ pump is to control cell volume. How does it prevent cells from swelling and bursting?

In the mechanism of facilitated diffusion illustrated in Figure 4-8, what causes the transported molecule to be released on the opposite side of the membrane?

Which type of chemical gating is described as exceedingly important for the transmission of signals from nerve cells to muscle cells?

What is the key structural feature of the sodium channel that allows it to be highly selective for sodium ions?

What does a concentration of 1 milliosmole per liter equate to in terms of osmotic pressure at normal body temperature?

What is the function of the enzyme DNA ligase in the process of DNA replication?

Which statement accurately describes the 'all-or-none' fashion of a gated channel's conductance as shown in Figure 4-6A?

What is the net rate of diffusion into a cell proportional to?

What are the two main subtypes of diffusion through the cell membrane?

What is the estimated energy expenditure for some cells, such as those lining renal tubules, for the purpose of primary active transport?

In the context of the Nernst equation (EMF (millivolts) = +/- 61 log (C1/C2)), what does the value of 61 represent?

What is a key difference between co-transport and counter-transport in secondary active transport?

Sodium-calcium counter-transport is an example of which process?

What is the reason given for why the measured osmotic pressure of body fluids (about 5500 mm Hg) is slightly less than the calculated value (about 5790 mm Hg)?

The α subunit of the Na+-K+ pump has a molecular weight of about 100,000. What is the approximate molecular weight of the smaller β subunit?

At a concentration about 10,000 times less than in the extracellular fluid, a very low intracellular concentration of which ion is maintained by primary active transport?

How many binding sites for sodium ions are located on the portion of the Na+-K+ pump that protrudes to the inside of the cell?

What is the relationship between the energy required to transport a substance and the degree to which it is concentrated?

What type of transport mechanism moves sodium ions into a tubular cell from the lumen while counter-transporting hydrogen ions into the tubule lumen in the proximal tubules of the kidneys?

When a pressure difference exists across a membrane, what causes the net movement of molecules from the high-pressure side to the low-pressure side?

Which of the following substances crosses cell membranes by facilitated diffusion?