Biology Chapter 3 Flashcards

Questions and Answers

Why is water considered a polar molecule?

Water is considered a polar molecule because one side of the molecule has a different charge than the other side.

What is cohesion?

Cohesion occurs when hydrogen bonds hold water molecules together.

What is adhesion?

Adhesion is the clinging of one substance to another, which happens due to polar bonds in water.

What is surface tension?

Surface tension is a measure of how difficult it is to stretch or break the surface of a liquid. Signup and view all the answers

What is high specific heat?

High specific heat is the amount of heat required to change the temperature of 1 g of a substance by 1 degree Celsius. Signup and view all the answers

What is heat of vaporization?

Heat of vaporization is the quantity of heat a liquid must absorb for 1 g of it to be converted from liquid to gas. Signup and view all the answers

What is evaporative cooling?

Evaporative cooling is the property of a liquid whereby the surface becomes cooler during evaporation. Signup and view all the answers

What is a solute?

A solute is a substance that is dissolved in a solution. Signup and view all the answers

What is a solvent?

A solvent is what a solute is dissolved in. Signup and view all the answers

What is an aqueous solution?

An aqueous solution is a solution in which water is the solvent. Signup and view all the answers

What is hydrophilic?

Hydrophilic refers to any molecule that has an affinity or attraction to water. Signup and view all the answers

What is hydrophobic?

Hydrophobic refers to any molecule that has no attraction to water. Signup and view all the answers

What is a colloid?

A colloid is a substance that consists of particles dispersed through another substance, like smoke. Signup and view all the answers

What is a hydration shell?

The hydration shell is the water molecules surrounding a dissolved ion. Signup and view all the answers

What is molarity?

Molarity is the amount of solute per each liter of a solution. Signup and view all the answers

What defines an acid and a base?

An acid increases the hydrogen ion concentration of a solution, whereas a base decreases it. Signup and view all the answers

Why are apparently small changes in pH so important in biology?

Because pH is measured logarithmically and a one unit change represents a tenfold variation, which can be harmful to cell processes. Signup and view all the answers

Study Notes

Properties of Water

Water is a polar molecule, with one side having a slight positive charge and the other side a slight negative charge.
Cohesion results from hydrogen bonds between water molecules, enabling the upward movement of water through plants as it evaporates from leaves.
Adhesion is the tendency of water to cling to other substances, assisting in counteracting gravity as water travels from roots to leaves.
Surface tension quantifies the difficulty of stretching or breaking a liquid's surface; water's surface tension is enhanced by hydrogen bonds, allowing some organisms to walk on water.

Thermal Properties

Water has a high specific heat, requiring 1 calorie per gram per degree Celsius to change temperature, which helps regulate environmental temperatures beneficial for marine life.
The heat of vaporization for water is substantial; about 580 calories are required to convert 1g of water at 25°C from liquid to gas, owing to the strength of hydrogen bonds.
Evaporative cooling stabilizes temperatures in bodies of water, providing a protective thermal environment for aquatic organisms.

Solutions and Concentrations

A solute is any substance that dissolves in a solution, while a solvent is the medium (often water) in which a solute dissolves.
An aqueous solution specifically refers to a solution where water serves as the solvent.
Molarity measures the concentration of solute in a solution, expressed as moles of solute per liter of solution.

Molecular Properties

Hydrophilic molecules exhibit an attraction to water, while hydrophobic molecules do not interact with water.
A colloid consists of small particles dispersed throughout another substance, such as smoke in air.
The hydration shell forms around dissolved ions, facilitating their interaction in solution.

Acids and Bases

An acid increases the concentration of hydrogen ions in a solution, while a base decreases it.
Small changes in pH are critical in biology due to the logarithmic scale of pH measurement; a one-unit change corresponds to a tenfold variation in hydrogen ion concentration, potentially disrupting cellular processes and causing cell death.

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Explore key concepts in Biology Chapter 3 with these flashcards. This quiz focuses on understanding water as a polar molecule and the concept of cohesion in water molecules. Test your knowledge and reinforce your learning in biology!