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
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
Water
Unequal distribution of charge makes it polar
Polar
Water is a ________ molecule
Sulfur, and phosphate
What other chemicals are important but not as important?
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
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
Surface tension, Specific heat, Boiling point, and Heat of vaporization
The combined effect of many hydrogen bonds accounts for water's high
Covalent bonds
The number of valence electrons determines the number of _________ that can form
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
C-H , C-C
Common Nonpolar Bonds
C-O, C=O, N-H, O-H, S-H
Common polar bonds
Ribosomes
Contain both RNA and protein
Nonpolar Covalent Bonds
Hydrocarbons have?
Noncovalent bonds
Hydrogen bonds Ionic Bonds Hydrophobic interactions Van der Waals Forces
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
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
High surface tension
allows water to move upward through the conducting tissue
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)
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
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
Diverse
Carbon containing Molecules are
Hydrocarbons
Carbon molecules containing only hydrogen atoms
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?
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.
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
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.
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
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
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
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?
hydrolysis reactions
When needed, macromolecules can be broken down to monomers by
Noncovalent Bonds
also allow Molecules to Bind to others with Specificity
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