Viscosity and Osmolarity Concepts

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Questions and Answers

What effect does polycythemia have on viscosity?

Decreases viscosity significantly

Causes viscosity to fluctuate

Increases viscosity (correct)

Has no effect on viscosity

What is the absolute viscosity of water at 25°C?

0.5 poise

1.0 poise

2.0 poise

0.895 poise (correct)

How do surface molecules behave compared to interior molecules in a liquid?

Interior molecules are attracted only downward

Surface molecules are attracted only downward (correct)

Interior molecules experience no attraction

Surface molecules are attracted equally in all directions

What phenomenon describes the breakdown of large fat globules into smaller ones in water?

Emulsification Signup and view all the answers

Which of the following statements about viscosity is incorrect?

Viscosity is constant regardless of the substance Signup and view all the answers

How does temperature affect osmolarity?

Osmolarity decreases as temperature rises. Signup and view all the answers

What is the relationship between the concentration of a substance and the volume of water in a solution?

Higher water volume leads to lower concentration. Signup and view all the answers

If the volume of a solution is halved, what happens to the concentration of the substance?

Concentration doubles. Signup and view all the answers

Which factor primarily causes osmolarity to vary in a solution?

The temperature affecting volume. Signup and view all the answers

In a scenario where the temperature of a solution rises significantly, what impact would this have on the osmolarity?

Osmolarity will decrease. Signup and view all the answers

What is a major factor affecting the viscosity of a fluid?

Temperature Signup and view all the answers

How does an increase in solute concentration affect viscosity?

It increases viscosity Signup and view all the answers

Which of the following components contribute to blood viscosity?

Plasma proteins Signup and view all the answers

What happens to blood viscosity during conditions like anemia or hypoProteinemia?

Viscosity decreases Signup and view all the answers

What is viscosity defined as?

The resistance offered by the fluid to flow Signup and view all the answers

Study Notes

General Basis of Biochemistry

Biochemistry is the study of chemical processes within and relating to living organisms.
An element is a substance formed of only one type of atom. Elements can be metals (e.g., iron) or non-metals (e.g., chlorine).
An atom, the structural unit, contains protons (positively charged particles in the nucleus), neutrons (neutral particles in the nucleus), and electrons (negatively charged particles orbiting the nucleus).
Atomic weight (atomic mass) is the number of protons and neutrons. It determines the element's physical properties.
Atomic number is the number of protons only. It determines the element's chemical properties.
An ion is an atom with a charge. Positive ions are called cations and negative ions are called anions. For instance, removing an electron from a hydrogen atom creates a proton, a positive ion.
Isotopes are different forms of the same element with the same atomic number (same chemical properties) but different atomic weights (different physical properties).
- Stable isotopes do not emit radiation (e.g., oxygen 16, 17, 18).
- Radioactive isotopes emit radiation from the nucleus in the form of α particles (positively charged particles, the nucleus of helium, i.e., 2 protons and 2 neutrons), β particles (negatively charged electrons), and gamma rays (electromagnetic radiation).
Isotopes are used in diagnosis (e.g., thyroid gland diseases) and treatment (e.g., many cancers). Radioactive materials are also used in research to track their fate in the body.

Acids (Proton Donors)

Acids are substances that release protons (hydrogen ions) into solution. Acids can be strong (dissociate completely) or weak (dissociate slightly).
True acidity is the pH of a solution, representing the concentration of hydrogen ions.
Titratable acidity is the concentration of hydrogen ions available for ionization, even if they aren't ionized at the current time.

Alkalis (Hydroxyl Ion Donors)

Alkalis are substances that release hydroxyl ions into solution. They can be strong (dissociate completely) or weak (dissociate slightly).

Base (Proton Acceptor)

Bases are substances that accept protons (hydrogen ions) in solution.
Not all bases are alkalis.
Several examples include sodium and uracil.

Conjugate Base

A conjugate base is the part of an acid that remains after the removal of a proton.

Amphoteric Substance

An amphoteric substance can act as both an acid (proton donor) and a base (proton acceptor).

Law of Mass Action

The rate of a reversible reaction is directly proportional to the product of the concentrations of the reactants.
For the reaction A + B <=> C+D, rate 1 (V₁) is proportional to [A] x [B] and rate 2( V₂) is proportional to [C] x [D].
At equilibrium, V₁ = V₂, and the equilibrium constant (K_eq) = K₁/K₂ = [C] x [D]/ [A] x [B].

Dissociation constant of acid

Ka is dissociation constant
pK of an acid is the negative log of Ka at base 10
Strong acid means smaller pK and bigger Ka.

pH

pH is the negative logarithm (base 10) of the hydrogen ion concentration ([H+]).
A pH of 7 is neutral, lower values indicate acidity, and higher values indicate alkalinity.
Pure water has a very small amount of hydrogen and hydroxyl ions.
The dissociation constant of water (Kw) is a constant relating the concentrations of hydrogen and hydroxide ions in water.
Changes in pH can significantly affect the functions of the body, including the function of enzymes.

pH of Blood

The normal pH of blood is 7.4 ± 0.03 (7.37-7.43).
This is a very narrow range; even slight changes can affect body function.
Many biochemical processes in the body require specific pH ranges for maximum activity.

Henderson-Hasselbalch Equation

Represents the relationship between pH and pK of a weak acid.
pH = pK - log([HA]/[A-]) where [HA] is the concentration of the weak acid and [A-] is the concentration of the conjugate base.

Buffer

A buffer is a solution that resists changes in pH when an acid or alkali is added.
Buffers are mixtures of a weak acid and the salt of its conjugate base (e.g., carbonic acid and bicarbonate or H₂CO₃/NaHCO₃).

Mechanism of Action of Buffers

A buffer's mechanism of action depends on which buffer is involved. For example, when an alkali (e.g., NaOH) is added to an H₂CO₃/NaHCO₃ buffer, the hydroxide ions react with the carbonic acid to form bicarbonate and water.
If the buffer is H₂CO₃/NaHCO₃, then when an acid (HCl) is added the reaction will be with sodium bicarbonate to form carbonic acid and sodium chloride (NaCL).

Importance of Osmotic Pressure

Formation of Urine: In the glomerular capillaries, filtration forces (due to blood pressure) and reabsorption forces (due to osmotic pressure) create a net filtration pressure.
Formation and Reabsorption of Interstitial Fluid: Within blood capillaries, osmotic pressures determine fluid flow into and out of blood vessels. The presence and regulation of osmotic pressure influence gas exchange (e.g., oxygen and carbon dioxide).
Hemolysis: Red blood cells (RBCs) are isotonic in a 0.9% NaCl solution. In a hypertonic solution, RBCs lose water and shrink (crenation), while in a hypotonic solution, RBCs gain water and swell (potentially causing lysis, or hemolysis).

Solutions

Solutions: A solution is formed by dissolving a solute in a solvent.
Units of Mass and Concentration: Concentration of a solution can be expressed as molarity (moles/liter) or normality (equivalents/liter).
- A mole is the amount of substance, measured in grams, equal to its molecular weight.
- Molecular weight equals the sum of the atomic weights of the atoms in a compound.
- Molar solution = 40 gm of NaOH dissolved in 1 liter water

Units of Concentrations

Concentration can be expressed as either molarity or normality

Molar solution = 40 gm of NaOH dissolved in 1 liter water
Normal solution of H₂SO₄ = 49 gm of H₂SO₄ dissolved in 1 liter water

Crystalloids, Colloids & Suspensions

Crystalloids: Particle size < 1.0 nm.
Colloids: Particle size ranges from 1-100 nm (divisible into emulsoids and suspensoids)
Emulsoids have 2 stability factors and are difficult to precipitate.
Suspensoids have one stability factor and are easy to precipitate.
Suspensions: Particle size > 100 nm, and exhibit properties like high viscosity, reduced osmotic pressure, clear ability to form gels, and imbibition/syneresis.
Colloid properties: Tyndall effect (observable light scattering), Brownian movement (continuous and significant vibrational movement of colloidal particles), viscosity, and gel formation

Solutions Phenomena

Diffusion: The movement of molecules from an area of high concentration to an area of low concentration.
Osmosis: The movement of solvent molecules from an area of low solute concentration to an area of high solute concentration across a semipermeable membrane. Large solute particles cannot pass the membrane, while small solvent particles can.
Osmotic Pressure: Hydrostatic pressure needed to prevent osmosis. It can be affected by the number of dissolved particles (ions affecting pressure more than non-ionizable molecules). The number of ions in a substance greatly increases its osmotic pressure.
Viscosity: Resistance of a fluid to flow. It is determined by the viscosity of the fluid within the substance.
Surface Tension: Force that holds the surface molecules of a liquid together.
Emulsification: Breakdown of large fat globules in water into smaller ones to form an emulsion. Emulsifying agents (e.g., bile salts, soap, and proteins) lower the surface tension of water. Hydrotrophy (converting water-insoluble substances into water-soluble ones) and lipotropic factors (fat mobilization from the liver) are also factors.
Adsorption: Capacity of a substance to make other substances attach to its surface.
Elution: Recovery of adsorbed material from an adsorbing agent.
Dialysis: Separation of colloids from crystalloids using a semipermeable membrane.
Osmolarity: The concentration of a substance per unit volume of solution. It depends on temperature.
Osmolality: The concentration of a substance per unit mass of solvent.

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Description

This quiz explores key concepts related to viscosity and osmolarity, including the effects of temperature and concentration. It examines the behavior of molecular interactions in different states and the physiological implications in blood viscosity. Test your understanding of these fundamental principles in fluid dynamics and their applications in real-world scenarios.