AP Bio Unit 1: Chemistry of Life

What are the building blocks of polymers?

Monomers

What occurs in dehydration synthesis?

One monomer forms a covalent bond to another monomer and releases a water molecule.

Glucose

a simple sugar (monosaccharide) that serves as the main source of energy for cells in living organisms

The solubility of a solute in a solvent is always the same regardless of temperature.

Answer: False

Explanation: Solubility often changes with temperature

Ex. sugar dissolves better in hot water than cold water.

A solute will always dissolve in a solvent

Answer: False

Explanation: Some solutes do not dissolve in certain solvents. Oil and water are classic examples of this

Cohesion is not affected by temperature.

Answer: False

Explanation: Temperature affects cohesion; higher temperatures can weaken cohesive forces by increasing molecular movement.

The heat of vaporization is measured in joules per gram

(J/g).

Answer: True

Explanation: The heat of vaporization is typically measured in joules per gram (J/g), indicating the energy required to vaporize one gram of a substance.

What is the heat of vaporization?

Answer: The amount of heat required to convert 1 gram of a liquid into a gas at its boiling point

Explanation: Heat of vaporization is the energy needed to turn a liquid into a gas at its boiling point.

Cohesion is the reason why water can travel up plant stems.

Answer: True

Explanation: Cohesion helps water molecules stick together as they move up plant stems through capillary action, working with adhesion.

Adhesion helps plants transport water from their roots to their leaves.

Answer: True

Explanation: Adhesion allows water molecules to cling to the walls of plant vessels, aiding in the upward movement of water through capillary action.

Adhesion is not involved in the formation of meniscus in a liquid column.

Answer: False

Explanation: The meniscus forms due to adhesion, which makes the liquid molecules stick to the container walls, resulting in a curved surface.

The heat of vaporization is an endothermic process.

Answer: True

Explanation: Vaporization is endothermic because it requires energy input to overcome intermolecular forces, absorbing heat from the surroundings.

Why does water exhibit adhesive properties?

Answer: Because of hydrogen bonding

Explanation: Water's adhesive properties are due to hydrogen bonds forming between water molecules and other substances.

What happens when a polar molecule interacts with a nonpolar molecule?

Answer: They repel each other

Explanation: Hydrogen bonds form between polar molecules, not between polar and nonpolar molecules.

Why is water considered a polar molecule?

Answer: It has a bent shape and an unequal distribution of electrons

Explanation: Water's shape is asymmetrical, which is why it is polar.

Which factor does NOT affect the heat of vaporization of a substance?

Answer: Temperature. Temperature affects the rate of vaporization but not the intrinsic heat of vaporization

Explanation: Higher molecular weight can affect the heat of vaporization.

The heat of vaporization is the amount of energy required to convert one gram of a liquid into a gas at its boiling point.

Answer: True

Explanation: The heat of vaporization is indeed the energy needed to turn one gram of liquid into gas at its boiling point, reflecting the energy required to break intermolecular forces.

In which scenario does adhesion play a crucial role?

Answer: Water forming a meniscus in a graduated cylinder

Explanation: Melting is a phase change, not related to adhesion.

Polarity in molecules affects their solubility in water.

Answer: True

Explanation: Polarity affects solubility because polar molecules, like water, can dissolve other polar substances due to their ability to form hydrogen bonds.

The heat of vaporization is the same as the heat of fusion.

Answer: False

Explanation: The heat of vaporization and heat of fusion are different; vaporization involves liquid to gas, while fusion involves solid to liquid.

The heat of vaporization is the same for all substances.

Answer: False

Explanation: Different substances have different heat of vaporization values due to varying intermolecular forces; stronger forces require more energy to vaporize.

The heat of vaporization for water is lower than that for alcohol.

Answer: False

Explanations: Water's heat of vaporization is higher because its hydrogen bonds are stronger than the intermolecular forces in alcohol, needing more energy to vaporize.

The heat of vaporization is important in regulating Earth's climate.

Answer: True

Explanation: The heat of vaporization plays a crucial role in climate regulation by absorbing heat during evaporation and releasing it during condensation, affecting weather patterns.

How does the heat of vaporization of water benefit the environment?

Answer: It stabilizes ocean temperatures

Explanation: The high heat of vaporization of water helps absorb and release heat, stabilizing ocean temperatures.

The heat of vaporization can be used to calculate the energy required to vaporize a given mass of liquid.

Answer: True

Explanation: By multiplying the heat of vaporization by the mass of the liquid, you can calculate the total energy needed to vaporize that mass.

What is covalent bonding?

The sharing of electrons.

What is polar covalent bonding?

Uneven sharing of elections (cause of partial charge)

Nonpolar covalent

Electrons that are EVENLY shared

Ionic Bonding

Transfer of electrons (this process also forms salt)

Hydrogen Bonding

Occurs between a hydrogen and an electronegative atom

This process is most commonly found in water

Is water a polar or nonpolar molecule?

Water is a polar molecule

Polarity

The relationship between two opposite charges

High heat of vaporization

The amount of energy required to convert a substance from a state of liquid to gas

High specific heat

The amount of heat required to raise the temperature of a substance by 1 degree celsius

An example of this is water.

Cohesion

“SAME”

SIMILAR particles sticking together

Adhesion

“DIFFERENT”

The joining of surfaces of DIFFERENT compositions

What is the difference between cohesion and adhesion?

Adhesion is the attraction between molecules that are DIFFERENT substances. Cohesion is the attraction of molecules that are the SAME substance.

What are the four groups of biologically important molecules?

Proteins, Lipids, Carbohydrates, and Nucleic Acids

What is a polymer?

A polymer is any large molecule that is made by the process of bonding.

How are polymers formed?

Monomers join together to form polymer chains by making covalent bonds.

How can polymers be broken apart?

Through hydrolysis (“to split water”)

What is the monomer of carbs?

Monosaccharides

What makes up lipids?

Glycerol & fatty acids

What makes up nucleic acids?

Nucleotides

What are the three groups of carbs?

Monosaccharides, Disaccharides, & Polysaccharides

What is the role of carbohydrates in living things?

Carbohydrates act as an energy source by controlling blood glucose, insulin metabolism, & help with energy consumption

What is the monomer of proteins?

Amino acids

What are the types of bonding in proteins?

Peptide, Ionic, Disulfide, Hydrogen, & Hydrophobic interactions

What are the 4 levels of protein structures?

Primary, secondary, tertiary, & quaternary structure

Formulation of peptide bonds

A peptide bond forms between the nitrogen in amino groups

Lipids

A fatty compound that is responsible for several functions in the body (soluble in organic solvents, NOT soluble in polar solvents)

Structure of triglyceride fats

A glycerol backbone is esterified with three fatty acids.

Formulation of triglyceride fats

Requires glycerol and three fatty acids

What is the difference between saturated and unsaturated fats?

Unsaturated fats contain one or two bonds & have less hydrogen atoms on their carbon chains than saturated fats

Structure of steroids

The basic structure of a steroid is called a gonane

it is composed of:

• 17 carbon atoms

• bonded in 4 fused rings (three 6 member cyclohexane rings)

Function of steroids

They are crucial components of the cell membrane and dictate the membrane fluidity by signaling molecules

Structure of phospholipids

• 2 fatty acids

• a glycerol unit

• a phosphate group

Function of phospholipids

Acts as a barrier to protect the cell against various environmental insults

What is the monomer of nucleic acids?

Nucleotides

What are the two types of nucleic acids?

DNA & RNA

What is standard deviation?

Standard deviation is a measure of how dispersed the data is in relation to the mean