Chapter 2

Small, uncharged molecules

can cross the lipid bilayer (no matter is polar or nonpolar)

Nonpolar Covalent Bonds

Equal sharing of electrons

Oxygen, nitrogen and carbon are the elements that most readily form multiple strong bonds.

For each of the following false statements, change the statement to make it true. Hydrogen, nitrogen, and carbon are the elements that can most readily form strong multiple bonds.

In a hydrogen bond, the partial positive charge of a hydrogen found in a polar covalent bond is attracted (electrostatically) with the negative charge of another molecule (often oxygen due to its partial negative charge but it can be other negatively charged molecules as well).

For each of the following false statements, change the statement to make it true. In a hydrogen bond, electrons are shared between hydrogen atom and two neighboring electronegative atoms

Oil droplets coalesce in water to format a separate phase because of the strong repulsive forces of the water molecules.

For each of the following false statements, change the statement to make it true. Oil droplets in water coalesce to form a separate phase because of the strong attraction of hydrophobic molecules for each other.

Water has a high specific heat compared to most molecules of similar molecular weight.

For each of the following false statements, change the statement to make it true. Water has a higher specific heat than most other liquids because of its low molecular weight.

False. When ice forms, each water molecule forms 4 bonds which places the molecules into a rigid crystalized structure. Air gets trapped in the inside of these crystals and makes ice less dense than water.

For each of these statements about water, decide whether the statement if true and describes a property that makes water a desirable component of cells (T); is true but describes a property that has no bearing on water as a cellular constituent (X); or false. For each true statement, indicate a possible benefit to living organisms. The density of water is less than the density of ice.

True. Yet it is equally important to realize that they also break and reform. This allows water to be able to absorb a lot of heat which is important in sustaining temperatures suitable for life on earth. It also allows for hydrogen bonds to form not only with water molecules but with other polar molecules, making them soluble.

For each of these statements about water, decide whether the statement if true and describes a property that makes water a desirable component of cells (T); is true but describes a property that has no bearing on water as a cellular constituent (X); or false. For each true statement, indicate a possible benefit to living organisms. The molecules of liquid water are extensively hydrogen-bonded to one another

Carbon

Life is ________ based

Bond energy

Stability is expressed as _______________ - the amount of energy required to break 1 mole (about 6x10^23) of such bonds.

Covalent Bonds

Strong, can be polar and nonpolar

Solute

something that dissolves in a solvent

Heat of vaporization

the amount of energy required to convert 1 gram of liquid into vapor

Specific heat

the amount of heat a substance must absorb per gram to increase its temperature

Hydrolysis

The addition of a water molecule that break the bond between adjacent monomers

Surface tension, Specific heat, Boiling point, and Heat of vaporization

The combined effect of many hydrogen bonds accounts for water's high

Water

Unequal distribution of charge makes it polar

Polar

Water is a ________ molecule

Polarity

Water is an Excellent Solvent because of its

spheres of hydration

Water molecules form ___________________ around Ions

Polar molecules

Water molecules form hydrogen bonds with

Carbohydrates/polysaccharides, Proteins, Nucleic Acids, and Lipids

What are the 4 macromolecules that make up living organisms?

Structure, defense, transport, catalysis, and signaling

What are the functions of protein

Hydrogen, nitrogen, oxygen, and carbon

What are the important chemicals in biology?

Makes alcohol

What happens if we could put these molecules in water? Ethanol

Water and hydrocarbons don't mix

What happens when you add water to oil?

Sulfur, and phosphate

What other chemicals are important but not as important?

hydrolysis reactions

When needed, macromolecules can be broken down to monomers by

solvent

a fluid in which another substance can dissolve

Ionic Bonds

electrostatic attraction between oppositely charged molecules (a noncovalent bond)

self- assembly

asserts that information required to specify the spontaneous folding or macromolecules and the interactions of these macromolecules to form more complex structures in inherent in the polymers themselves

Nucleic acids

Are involved in storing and expressing genetic information

Functional groups

Are specific arrangements of atoms that confer characteristic chemical properties on the molecules to which they are attached

Ionic bonds

Are strong noncovalent electrostatic interactions between two oppositely charged ions

Calories per mole (cal/mol)

Bond energies are usually expressed in

A virus

is a complex of proteins and nucleic acids.

4

Each water molecule can form up to __ hydrogen bonds

Don't mix

What happens if we could put these molecules in water? Ethane

Nonpolar Molecules

equal sharing of electrons

Calorie

is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius

Hydrophobic

molecules do not dissolve in water

75-85%

what percentage of a cell is water

Covalent Bond Energy

= the amount of energy required to break 1 mole of bonds. Expressed as kcal/mole or Joules/mole

Ions

Atoms or molecules that carry a charge (positive or negative) due to gaining or losing electrons

water

Bonds are bent rather than linear in shape

Large, uncharged polar molecules

Can diffuse across the membrane, but to a lesser extent than small molecules.

Polymers

Carbohydrates/polysaccharides, Proteins, Nucleic Acids, and Lipids are

Diverse

Carbon containing Molecules are

Hydrocarbons

Carbon molecules containing only hydrogen atoms

C-H , C-C

Common Nonpolar Bonds

C-O, C=O, N-H, O-H, S-H

Common polar bonds

Triacylglycerols (fats and oils), cholesterol, and the long chains of fatty acids. All nonpolar molecules, not polar ones.

Consider the chemical structure of benzene. Which cellular molecules would you expect to be soluble in a container of benzene?

Ribosomes

Contain both RNA and protein

If the bond were linear, then water would be a nonpolar molecule. All of the polar molecules in the cell...DNA, sugars, many proteins, etc would be insoluble and unable to interact at all.

Defend the assertion that all of life as we know it depends critically on the fact that the angle between the two hydrogen atoms in the water molecule is 104.5 and not 180

This means that the carbon-carbon bonds in the molecules that make up living organisms are stable in the presence of the electromagnetic energy that is given off by the sun. We wouldn't be able to make cellular molecules if the bonds kept breaking.

Each of the properties that follow is characteristics of the carbon atom. In each case, indicate how the property contributes to the role of the carbon atom as the most important atom in biological molecules. A carbon atom can bond to two other carbon atoms.

This allows for the formation of hydrocarbons that can be linear, branched, and rings.

Each of the properties that follow is characteristics of the carbon atom. In each case, indicate how the property contributes to the role of the carbon atom as the most important atom in biological molecules. Carbon atoms can bond to hydrogen, nitrogen, and sulfur atoms

The presence of these functional groups provide unique characteristics to the diverse shaped hydrocarbons. Of particular importance, these functional groups increase the polarity of these molecules so they can interact in water. Also allows for molecules to form noncovalent interactions with each other which allows molecular interaction.

Each of the properties that follow is characteristics of the carbon atom. In each case, indicate how the property contributes to the role of the carbon atom as the most important atom in biological molecules. Carbon-containing compounds can contain asymmetric carbon atoms

Carbon can form 4 bonds due to the presence of 4 valance electrons. These bonds can be formed as single, double, and triple bonds - all are strong due to the sharing of electrons. This is important in making stable molecules.

Each of the properties that follow is characteristics of the carbon atom. In each case, indicate how the property contributes to the role of the carbon atom as the most important atom in biological molecules. The carbon atom has a valence of four.

True. Yet it is equally important to realize that they also break and reform. This allows water to be able to absorb a lot of heat which is important in sustaining temperatures suitable for life on earth. It also allows for hydrogen bonds to form not only with water molecules but with other polar molecules, making them soluble.

For each of these statements about water, decide whether the statement if true and describes a property that makes water a desirable component of cells (T); is true but describes a property that has no bearing on water as a cellular constituent (X); or false. For each true statement, indicate a possible benefit to living organisms. Water has a high heat of vaporization

True. Yet it is equally important to realize that they also break and reform. This allows water to be able to absorb a lot of heat which is important in sustaining temperatures suitable for life on earth. It also allows for hydrogen bonds to form not only with water molecules but with other polar molecules, making them soluble.

For each of these statements about water, decide whether the statement if true and describes a property that makes water a desirable component of cells (T); is true but describes a property that has no bearing on water as a cellular constituent (X); or false. For each true statement, indicate a possible benefit to living organisms. Water has a high specific heat.

True. Being able to dissolve polar molecules is definitely important. It allows "life activities" to take place by creating a playground for these macromolecules to interact and carry on all processes.

For each of these statements about water, decide whether the statement if true and describes a property that makes water a desirable component of cells (T); is true but describes a property that has no bearing on water as a cellular constituent (X); or false. For each true statement, indicate a possible benefit to living organisms. Water is a polar molecule and hence an excellent solvent for polar compounds.

Nonpolar Covalent Bonds

Hydrocarbons have?

Noncovalent bonds

Hydrogen bonds Ionic Bonds Hydrophobic interactions Van der Waals Forces

Breaking and forming

Hydrogen bonds are constantly _________ and _________ in water

Water

Hydrogen bonds attract ________ molecules to each other

noncovalent bonding

Hydrophobic interactions are a form of

A virus

Itself is not alive; but can invade and infect a specific living host cell, take over the synthetic machinery of this cell, and use the host cell to produce more components

Hydrocarbons

Methane, Propane, Butane, and Gasoline - mixtures of hexane, octane, decane are all examples of

noncovalent bonds

Molecules are stabilized by

specific conformations

Molecules have ______________________ - one is the most stable and therefore, the most favored

Polar Molecules

Molecules that contain a polar covalent bond (unequal sharing of electrons)

Hydrophilic molecules

Molecules that readily dissolve in water

condensation reactions

Monomers are covalently linked together through

Aldehyde

Name this functional group

Amino

Name this functional group

Carbonyl

Name this functional group

Carboxyl

Name this functional group

Hydroxyl

Name this functional group

Ketone

Name this functional group

Phosphate

Name this functional group

Sulfhydryl

Name this functional group

DNA and RNA molecules

Serve a coding function

permeable

The lipid bilayer is __________ to nonpolar molecules

Most polar molecules and ions

The lipid bilayer is quite impermeable to most _____________ and is highly impermeable to ___________.

Covalent bonds

The more _________ you have the stronger it is

Covalent bonds

The number of valence electrons determines the number of _________ that can form

denaturation

The unfolding of a polypeptide under such conditions

Transport proteins

To transport theses substances into and out of the cell, biological membranes are equipped with a wide variety of

High surface tension

allows water to move upward through the conducting tissue

Noncovalent Bonds

also allow Molecules to Bind to others with Specificity

Anion

are negatively charged

Cation

are positively charged

Molecular chaperones

are proteins that facilitate the correct folding structures but are not themselves components of the assembled structure

Van der Waals interactions

are weak interactions between two atoms that occur only if the atoms are very close to one another and are oriented apporpriately

hydrophobic interactions

describes the tendency of nonpolar groups within a macromolecule to associate with each other as they minimize their contact with surrounding water molecules and with any hydrophilic groups in the same or another macromolecule

Ultraviolet radiation

has high energy and can break carbon- carbon bonds

Molecules that don't dissolve in water

includes nonpolar molecules (contain nonpolar covalent bonds) Hydrocarbons Fats and oils Purines and pyrimidines (bases in nucleic acids)

Transport proteins

is a specialized transmembrane protein that serves wither as hydrophilic channel through an otherwise hydrophobic membrane or as a carrier that binds a specific solute on one side of the membrane and then undergoes a conformational change to move the solute across the membrane

water

is excellent at forming hydrogen bonds

van der Waals Forces

may occur between two nonpolar covalent bonds

Hydrogen Bond

noncovalent bondMay occur when H is involved in a polar covalent bond

polarity

uneven distribution of charge within a molecule

Visible light

would break covalent bonds spontaneously, and life as we know it wouldn't exist if it didn't have a lower energy than a carbon carbon bond