Organic Chemistry Test 4 (Ch 18,19 and 20)
Select the true statement:
You expect water to have a higher boiling point that octane
Aldehydes are reduced to form what type of compound?
A primary alcohol
The boiling point of a branched alkane is generally ____ that of the straight chain alkane with the same number of atoms
Lower than
Why do carboxylic acids have higher boiling points than similar alcohols or aldehydes?
They form dimers that are relatively stable
Acid hydrolysis of an ester produces
A carboxylic acid and an alcohol
When butanoic acid and NaOH react in a neutralization reaction, what is the name of the salt product?
Sodium butanoate
Over the counter antacids like Tums help heartburn because
Tums contain a base which neutralizes stomach acid in a neutralization reaction
What alcohol was used to form propyl butanoate, which is an ____?
1-propanol, ester
Carboxylic acids ionize in water to produce
Carboxylate ion and hydronium ion
Which statement is not true:
All lipids contain a fatty acid
In the fluid mosaic model that describes plasma membranes…
Two layers of glyercophospholipid molecules have their nonpolar sections oriented to the inside of the membrane
The name of the reaction that occurs when a fat reacts with sodium hydroxide is:
Saponification
What are the product of hydrolysis of a traicylglycerol molecule?
Glycerol and three fatty acids
A triacylglycerol that is solid at room temperature is called an oil
False
Trans fats are regarded as the best fats for human health
False
Olive oil is a triacylglycerol that contains a high percentage of saturated fatty acids
False
The family of biomolecules called lipids are all soluble in organic solvents
True
Some fatty acids are called essential because all organisms on earth can produce them
False
Waxes contain an ester functional group
True
A carboxylic acid can be neutralized with HCL
False
Methanol and ethanol are common alcohols used to produce waxes
False
Long chain carboxylic acids are also known as fatty acids
True
Products like Crisco are formed by hydrogenation of vegetable oils
True
Amines are organic compounds that contain what element?
Nitrogen
Amines are derivatives of what compound?
Ammonia
What is a primary amine?
One carbon group or none, are bonded to the nitrogen atom
What is a secondary amine?
Two carbon groups are bonded to the nitrogen atom
What is a tertiary amine?
Three carbon groups are bonded to the nitrogen atom
What is the amine ending?
-amine
What is the substituent name for amines?
Amino
What is the name of a benzene ring with an amine?
Aniline
Is the N-H bond polar or nonpolar?
Polar, because Nitrogen is strongly electronegative
What kind of amines do not participate in hydrogen bonding?
Tertiary amines
Which is more electronegative: Nitrogen or Oxygen
Oxygen
Do amines or alcohols have higher boiling points?
Alcohols because N is less electronegative compared to O
Which type of amine has the highest boiling point?
Primary amines
Are amines soluble in water?
Yes, because they participate in hydrogen bonding
Up to how many carbons are soluble in an amine?
6 carbons
Do amines react as acids or bases?
Bases
What type of base is an amine?
Bronsted-Lowry Base
Do bases accept or give hydrogens?
Accept to have a plus charge
What type of reaction is specified to be between an acid and a base, and what is the product?
Neutralization reaction, amine salt
What is a heterocyclic amine?
An organic compound that contains 1 or more hydrogen in a ring of 5 or 6 atoms other than just carbon
What is an alkaloid?
A physiologically active amine produced by plants
What is an amide?
Derivatives of carboxylic acids and amines; the hydroxyl group on a carboxylic acid is replaced by a nitrogen from the amine
What is the formation of amides called?
Amidation reaction
What is an amidation reaction?
When carboxlyic acids are heated with amines
What types of amines undergo amidation reactions?
Primary and secondary amines
Up to how many carbons is an amide soluble?
5 carbons
What is an amino acid?
Building blocks of proteins
What is a protein?
A group of amino acids linked together
How many different amino acids are used in humans?
20 amino acids
What are classifications of amino acids?
Non-polar, polar, acidic ,and basic
What makes an amino acid non-polar?
Contains an alkyl group, or an aromatic
What makes an amino acid polar?
Contains a hydroxyl, thiol, or an amide
What makes an amino acid acidic?
Contains a carboxylic acid group
What makes an amino acid basic?
Contains an amino group
What is a zwitterion?
An ion with no overall net charge, but has charges present on a molecule
What is an isoelectric point or pI?
The ph of an atom when the charge is zero, or when it is a zwitterion
Do amino acids act as acids or bases?
Both, acids donate hydrogen and bases accept hydrogen
What is a peptide bond?
An amide bond that forms between the -COO group of one amino acid and the -NH3 group of another amino acid (formed in amidation reactions)
What is the N-terminus?
The end of a peptide bond with a free amino
What is the C-terminus?
The other end of a peptide bond with a free carboxyl
What are oligopeptides?
Molcules with up to 20 amino acids
What are polypeptides?
Molecules with more than 20 amino acids
Over 50 amino acids is referred to as what?
A protein
How many levels of structure is there for proteins?
Four
What is the primary structure?
The order of amino acids
What is the secondary structure?
When amino acids form hydrogen bonds within polypeptides between 2 peptide chains; otherwise understood as the way amino acids near each other are arranged in space
What are types of secondary structure?
Alpha helix, and beta sheet
What is an alpha helix?
A right-handed corkscrew held in place by hydrogen bonds between N-H of one amino acid and the O of the C doubled bonded to the O four amino acids away
What is a beta-pleated sheet?
Polypeptides held together side by side through hydrogen bonds, backbone is extended
What is the tertiary structure?
The way secondary structures fold up to make the protein
What is the quaternary structure?
Interactions of more than one polypeptide chain
What are hydrophobic interactions?
interactions between non polar groups
What are hydrophilic interactions?
attractions between the aqueous environment and polar and or ionic side chains; found on the outer surface of a proteins 3D structure
What are salt bridges?
These are ionic bonds between basic and acidic side chains that hold positive or negative charges at pH 7
What are hydrogen bonds?
Formed between amino acids that have side chains that can h-bond
What are disulfide bonds?
covalent bonds formed between the -SH gorup of two cysteines
What is a globular protein?
A protein that is compact, with a spherical shape because secondary structures fold on top of each other
What are fibrous proteins?
Have a long, thin, fiber like shape (contains alpha and beta keratins)
What is hydrolysis?
The splitting of an amide in the presence of an acid or bas; the reverse of peptide bond formation; disrupts primary structure
What is denaturation?
A disruption of bonds that hold secondary, tertiary, or quaternary structure; does not disrupt primary structure only unfolds the protein
What is a catalyst?
An agent that speeds up a chemical reaction by lowering activation energy
What is an enzyme?
A biological catalyst
What is activation energy?
The minimum amount of energy required to initiate a chemical reaction
What is the ending for an enzyme?
-ase
Occasionally and enzyme will end in what?
-in
How many classes of enzymes are there?
6
What are the six classes of enzymes?
Oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases
What type of enzyme catalyzes oxidation-reduction?
Oxidoreductases
What type of enzyme transfers groups of atoms?
Transferases
What type of enzyme catalyzes hydrolysis?
Hydrolase
What type of enzyme adds atoms or removes atoms to form double bonds?
Lyases
What type of enzyme rearranges atoms?
Isomerases
What type of enzyme uses ATP to combine small molecules?
Ligases
What is a substrate?
The molecule that goes into an enzymes active site
What is an active site?
The part of the enzyme that interacts with the substrate; usually a small pocket on the edge of the protein
What is an absolute enzyme?
Enzymes that catalyze one type of reaction for a single substrate
What is a group enzyme?
Enzymes that catalyze one type of reaction for similar substrates
What is a linkage enzyme?
Enzymes that catalyze one type of reaction for a specific type of bond
What is the enzyme substrate complex? (ES)
When a substrate bonds with the active site
What are the two models of substrate binding to the active site?
Lock and key model, induced fit model
What is the lock and key model?
Older view that the substrate fits directly into he active site because it has the right shape, if it has the wrong shape the enzyme will not work; views that the active site is rigid and not flexible
What is the induced fit model?
Newer view that the active site adjusts to fit the shape of the substrate, working together to acquire the proper geometry
What is the activity of an enzyme?
How fast an enzyme catalyzes or how fast it turns substrate into product
What is temperature?
The average kinetic energy of a population
What is the prime temperature for enzyme to catalyze?
37 degrees, over 50 it is not possible, nor when it is too cold
What occurs when the pH goes below optimal?
Acid has been added and the protein has unfolded
What occurs when the pH goes above optimal?
Base has been added and the protein has unfolded
What is the optimum pH for most enzymes?
7.4
What is the optimum pH for pepsin and trypsin?
1.5-2
What happens when more enzymes are added?
Reaction rates increase
What is saturation?
When all enzyme active sites are full
What is an inhibitor?
Molecules that cause enzymes to lose activity
What are the two classes of enzymes?
Reversible and irreversible
What is a reversible enzyme?
Allows enzymes to regain their activity after acting with an inhibitor
What is an irreversible enzyme?
Denys enzymes to regain their activity
What is a competitive enzyme?
A reversible inhibitor that looks like the substrate and can bind in the active site of an enzyme
What is non-competitive enzyme?
A reversible inhibitor that does not resemble the substrate and does not compete for the active site but rather binds somewhere besides the active site on the enzyme and distorts shape
What makes an inhibitor irreversible?
It covalently bonds to the enzyme, losing all activity permanently
What is a cofactor?
Outside help provided by small molecules or metal ions
What is a coenzyme?
A cofactor that is an organic molecule, includes vitamins
What makes a vitamin water soluble?
Containing a polar group, eliminated from the body through urine
What makes a vitamin fat soluble?
Long chain carbon groups, limited hydrogen bonding opportunities, not eliminated from the body