human morphology and function

Questions and Answers

What is the primary purpose of van’t Hoff's equation?

To measure concentration in solutions

To determine the rate of chemical reactions

To find the volume of a gas

To calculate osmotic pressure (correct)

In a physiological salt solution of 0.15 M NaCl at 37°C, what value of n is used in van’t Hoff's equation?

0.15

2 (correct)

Which term describes a solution where the number of particles is equal to 300 mOsm?

Supersaturated

Hypotonic

Isotonic (correct)

Hypertonic

What would happen to cells placed in a hypertonic solution?

Cells would crenate and shrink Signup and view all the answers

In terms of osmolarity and osmolality, which concept is highlighted as not being synonymous?

The type of solute used Signup and view all the answers

Which statement accurately describes the difference between molarity and molality?

Molarity is determined after the solvent is added to a constant volume, molality is based on mass of the solvent. Signup and view all the answers

What happens when a 300 mOs/l solution contains a lipid-soluble solute, such as glycerol?

It remains hypotonic leading to lysis. Signup and view all the answers

How does a signal transduction pathway differ from simple membrane translocation?

It requires interaction with specific receptors. Signup and view all the answers

Which membrane correctly describes the lining of the external surface of the stomach?

visceral peritoneum Signup and view all the answers

Which solution listed is hypotonic compared to a cell's internal environment?

0.15 M NaCl Signup and view all the answers

In anatomical terms, how is the left elbow positioned in relation to the left wrist?

proximal Signup and view all the answers

What type of body section is represented by the figure above?

sagittal Signup and view all the answers

When equilibrium is reached in two compartments separated by a semipermeable membrane, what is expected?

[Osm]A = [Osm]B Signup and view all the answers

What is the primary function of the cell membrane regarding solute transport?

Selective permeability to specific ions and molecules Signup and view all the answers

Which statement accurately reflects the Davson–Danielli model?

It posits that a phospholipid bilayer is combined with protein absorption on the surface. Signup and view all the answers

According to the Singer Nicholson model, how are integral proteins characterized?

They are tightly associated with the lipid bilayer and typically span it. Signup and view all the answers

What is the main characteristic of carrier-mediated transport systems?

They specifically bind to one or more solutes. Signup and view all the answers

What characteristic of the phospholipid bilayer allows it to separate aqueous compartments effectively?

The amphiphilic nature of phospholipids creating a stable barrier. Signup and view all the answers

Which transport process requires energy to function?

Active transport Signup and view all the answers

Which molecule is most likely to pass through the membrane unaided based on its characteristics?

H2O Signup and view all the answers

What property of the phospholipid bilayer varies with different membranes?

Permeability to water. Signup and view all the answers

What occurs during competitive inhibition in carrier-mediated transport?

Molecules of closely related structure compete for carrier attachment. Signup and view all the answers

How are peripheral proteins associated with the cell membrane?

They associate loosely with the membrane and can be easily removed. Signup and view all the answers

Which type of transport involves the simultaneous translocation of two or more substrates?

Coupled transport Signup and view all the answers

What type of molecules are primarily responsible for forming the lipid bilayer in cell membranes?

Amphiphilic phospholipids Signup and view all the answers

What does saturation in carrier-mediated transport refer to?

The point at which all carriers are occupied. Signup and view all the answers

In the ping pong model of carrier-mediated transport, which statement is true?

Only one solute can be attached at a time. Signup and view all the answers

What characteristic of integral proteins allows them to form transmembrane segments?

Inclusion of hydrophobic amino acids Signup and view all the answers

Which of the following describes a function of the cell membrane?

Regulating the entry and exit of substances in the cell. Signup and view all the answers

What describes the specificity of carrier-mediated transport systems?

Transport systems are group-specific but not perfectly selective. Signup and view all the answers

Which of the following describes non-competitive inhibition?

Only one solute can bind to the carrier at a time. Signup and view all the answers

What is the primary purpose of selectivity filters in channel proteins?

To determine which ions or molecules can pass through. Signup and view all the answers

What is the relationship between peripheral proteins and integral proteins?

Peripheral proteins are noncovalently bonded with integral proteins. Signup and view all the answers

Which of the following correctly describes the function of multimeric protein complexes?

They facilitate complex transport and signaling functions through non-covalent interactions. Signup and view all the answers

What is one role of membrane glycoproteins in the cell?

They serve as unique identity markers for different cell types. Signup and view all the answers

Which ions are found predominantly in the intracellular fluid according to the principle ion gradients?

K+, Mg++ Signup and view all the answers

Which statement correctly describes the concept of selective permeability of cell membranes?

Cell membranes permit the selective passage of certain ions and molecules. Signup and view all the answers

What does the term 'glycocalyx' refer to?

A surface coating on the external surface of eukaryotic cells. Signup and view all the answers

In which situation is lateral mobility of proteins limited?

When constrained by membrane domain boundaries. Signup and view all the answers

Which of the following is not a functional component of the membrane?

Storage for nutrients Signup and view all the answers

Which component primarily creates gradients within cell membranes?

Lipid bilayer permeability. Signup and view all the answers

How do membrane domains affect protein mobility?

They create static zones where proteins cannot move. Signup and view all the answers

Study Notes

Van’t Hoff Equation and Osmotic Pressure

Van’t Hoff equation: π = n R T ∆C; used for calculating osmotic pressure.
R (gas constant) = 0.082 l – atm K⁻¹ mol⁻¹; T is absolute temperature in K; ∆C is concentration difference in moles; n represents dissociable particles; π is osmotic pressure in atm.
Example calculation for 0.15 M NaCl at 37°C yields π = 7.62 atm or 5796 mmHg; NaCl dissociates into two ions.

Tonicity

Tonicity reflects the effect of solute concentration on cell volume.
Isotonic solutions (300 mOsm) maintain cell volume; hypertonic solutions (> 300 mOsm) cause cell shrinkage (crenation); hypotonic solutions (< 300 mOsm) lead to cell swelling (lysis).
Tonicity and osmolality differ; lipid-soluble solutes (like glycerol, urea) may cause hypotonic effects even at 300 mOs/l.

Membrane Transport Mechanisms

Simple (passive) transport mechanisms include diffusion through the bilayer, pores (e.g., aquaporins), and channels with selective gating.
Carrier-mediated transport involves protein carriers that specifically bind solutes and translocate them across membranes.
Transport classification: passive (facilitated diffusion) and active (energy-requiring).

Characteristics of Carrier-Mediated Transport

Features of carrier-mediated transport include saturation and specificity for certain substances; e.g., different carriers for amino acids and glucose.
Competitive inhibition occurs when closely related molecules compete for the same transport system.
Non-competitive inhibition refers to solutes competing for carrier attachment, limiting transport rate by the availability of carriers.

Types of Carriers

Uniport carriers translocate a single substrate; coupled transport facilitates simultaneous transport of two or more substrates.

Cell Membrane Structure and Function

Cell membranes compartmentalize cellular components, provide selective permeability, and act as receptors.
Composition includes a phospholipid bilayer (Davson-Danielli model), proteins (integral and peripheral), and multilayered protein complexes for transport and signaling.

Fluid Compartments

Total body fluid volume = 42 L; includes 25 L intracellular fluid and 17 L extracellular fluid (14 L interstitial, 3 L plasma).
Membranes maintain ion gradients with Na+, Ca++ in extracellular fluid and K+, Mg++, proteins, PO4⁻³ in intracellular fluid; essential for homeostasis.

Solute Movement

Gas diffusion described by examples like the Na-Ca exchanger illustrates solute transport dynamics across membranes.

Quiz Questions Review

Understand the classification of anatomical membranes; examples include parietal vs. visceral peritoneum.
Recognize hypotonic solutions; for example, 0.30 M urea is hypotonic compared to 0.15 M NaCl.
Be aware of anatomical terminology; e.g., the left elbow is proximal to the left wrist.
Identify types of sections in anatomy; frontal, sagittal, transverse classifications.
Know that equilibrated compartments separated by a semipermeable membrane will reach osmotic equilibrium.

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Description

Test your understanding of osmotic pressure and the Van’t Hoff equation with this quiz. You'll explore the relationship between concentration, temperature, and dissociable particles in understanding solutions like physiological salt. Perfect for chemistry enthusiasts and students!

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