Water's Functions: Dissolving, Temperature Regulation, and More

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Questions and Answers

What is the most abundant substance in living systems?

Protein

Lipid

Carbohydrate

Water (correct)

What is the geometry of a water molecule?

Linear

Tetrahedral (correct)

Triangular

Octahedral

What type of bond is a hydrogen bond?

Nonpolar covalent bond

Covalent bond (correct)

Polar covalent bond

Ionic bond

What property of water allows it to have a high heat capacity?

Polarity Signup and view all the answers

What is the function of water as a universal solvent?

It dissolves inorganic and organic molecules Signup and view all the answers

What is the consequence of hydrogen bonds being strongest when the bonded molecules are oriented to maximize electrostatic interaction?

Directional bonding Signup and view all the answers

At what temperature does water have its highest density?

4ºC Signup and view all the answers

What property of water contributes to its high cohesive and adhesive properties?

High polarity Signup and view all the answers

What is the electric charge carried by the oxygen atom in a water molecule?

-0.5 charge Signup and view all the answers

What does the course of evolution has been shaped by?

Properties of the aqueous medium Signup and view all the answers

What determines the ability of water to dissolve substances?

H-bond with polar groups in non-ionic molecules Signup and view all the answers

Which type of compounds dissolve easily in water?

Charged or polar compounds Signup and view all the answers

What is the term for molecules or groups that are insoluble in water?

Hydrophobic Signup and view all the answers

What is the function of aldosterone and antidiuretic hormone in body fluid homeostasis?

Regulating thirst and sodium and water balance Signup and view all the answers

Where is the interstitial fluid found?

Between cells not contained within blood vessels Signup and view all the answers

What is osmosis?

Bulk flow of water through a semipermeable membrane into another aqueous compartment containing solute at a higher concentration Signup and view all the answers

What is osmotic pressure?

Pressure generated by the osmotic flow of water through a semipermeable membrane into an aqueous compartment containing solute at a higher concentration. Signup and view all the answers

What is the molecular mobility related to osmotic effect?

Important factor in the life of most cells. Signup and view all the answers

What are isotonic solutions?

Solutions with osmolarity equal to that of a cell’s cytosol. Signup and view all the answers

What are hypertonic solutions?

Solutions with higher osmolarity than that of the cytosol. Signup and view all the answers

What are hypotonic solutions?

Solutions with lower osmolarity than the cytosol. Signup and view all the answers

Study Notes

Water in Living Systems

Water is the most abundant substance in living systems.

Structure of Water Molecules

The geometry of a water molecule is bent or V-shaped.
A water molecule (H2O) has a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom.
The oxygen atom in a water molecule carries a partial negative charge (δ-).

Hydrogen Bonds

Hydrogen bonds are a type of weak electrostatic attraction between molecules.
Hydrogen bonds are strongest when the bonded molecules are oriented to maximize electrostatic interaction.
Hydrogen bonds are responsible for water's high heat capacity and its ability to dissolve substances.

Properties of Water

Water has a high heat capacity due to the energy required to break hydrogen bonds.
Water has high cohesive and adhesive properties due to the strong hydrogen bonds between molecules.
Water's high surface tension and viscosity are also due to hydrogen bonds.

Water as a Solvent

Water is a universal solvent, able to dissolve a wide variety of substances.
Substances that dissolve easily in water are called hydrophilic (water-loving) compounds, such as salts, sugars, and amino acids.
Substances that are insoluble in water are called hydrophobic (water-fearing) compounds, such as oils and fats.
The ability of water to dissolve substances is determined by its polarity and hydrogen bonding ability.

Regulation of Body Fluids

Aldosterone and antidiuretic hormone (ADH) regulate body fluid homeostasis.
Aldosterone helps regulate the amount of water reabsorbed in the kidneys.
ADH helps regulate the amount of water reabsorbed in the kidneys and the permeability of the collecting ducts.

Fluid Balance and Osmosis

Interstitial fluid is found in the spaces between cells.
Osmosis is the movement of water molecules from a region of high concentration to a region of low concentration through a selectively permeable membrane.
Osmotic pressure is the pressure required to prevent osmosis.
Molecular mobility is related to the osmotic effect, as it affects the rate of water movement.
Isotonic solutions have the same osmotic pressure as the cell's internal environment.
Hypertonic solutions have a higher osmotic pressure than the cell's internal environment, causing water to leave the cell.
Hypotonic solutions have a lower osmotic pressure than the cell's internal environment, causing water to enter the cell.

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Description

Explore the importance of water in living systems, including its functions such as nutrient transportation, temperature regulation, and its role as a universal solvent. Learn about the unique properties of water and its significance in biological processes.