Apbio chapter 4

What is organic chemistry?

The study of carbon compounds, especially those associated with living organisms.

Why is carbon central to organic life?

Carbon can form four covalent bonds, allowing it to build diverse and complex molecules.

How many covalent bonds can a carbon atom typically form?

Four.

Why can carbon form diverse molecules?

It can form stable bonds with itself and other elements, creating chains, branches, rings, and double bonds.

What is a carbon skeleton?

The chain or framework of carbon atoms in an organic molecule.

What are hydrocarbons?

Organic molecules composed only of carbon and hydrogen.

Why are hydrocarbons generally hydrophobic?

Their bonds are mostly nonpolar, so they do not interact favorably with water.

What is a structural isomer?

A molecule with the same molecular formula as another molecule but a different arrangement of covalent bonds.

What is a geometric isomer?

A molecule with the same covalent connections as another molecule but a different spatial arrangement caused by restricted rotation.

What is a cis-trans isomer?

A type of geometric isomer in which groups are arranged on the same side or opposite sides of a double bond.

What is a cis isomer?

A geometric isomer in which specified groups are on the same side of a double bond.

What is a trans isomer?

A geometric isomer in which specified groups are on opposite sides of a double bond.

Why can a carbon-carbon double bond produce cis-trans isomers?

The double bond restricts rotation, allowing different stable arrangements of attached groups.

What is an enantiomer?

One of two molecules that are nonsuperimposable mirror images of each other.

What usually causes a molecule to have enantiomers?

A carbon attached to four different atoms or groups, creating a chiral center.

What does chiral mean?

Not superimposable on one's mirror image.

Why can enantiomers behave differently in organisms?

Biological molecules and enzymes are often specific to a molecule's three-dimensional shape.

What is a functional group?

A group of atoms that gives an organic molecule characteristic chemical properties.

What is a hydroxyl group?

An −OH group that is polar and can form hydrogen bonds.

What type of compound contains a hydroxyl group?

An alcohol, when the hydroxyl group is attached to a carbon skeleton.

How does a hydroxyl group affect solubility in water?

It often increases water solubility because it is polar and can form hydrogen bonds.

What is a carbonyl group?

A carbon atom double-bonded to oxygen, written C=O.

What is an aldehyde?

An organic compound with a carbonyl group at the end of its carbon skeleton.

What is a ketone?

An organic compound with a carbonyl group within its carbon skeleton.

How does an aldehyde differ from a ketone?

An aldehyde has a terminal carbonyl group, while a ketone has an internal carbonyl group.

What is a carboxyl group?

A −COOH group consisting of a carbonyl group and a hydroxyl group attached to the same carbon.

What is the usual behavior of a carboxyl group?

It can act as an acid by donating a proton.

What is an amino group?

A −NH2 group that can act as a base by accepting a proton.

What is a sulfhydryl group?

A −SH group that can help stabilize protein structure by forming disulfide bonds.

What is a phosphate group?

A functional group containing phosphorus bonded to oxygen atoms, often written −OPO3²− in its ionized form.

Why is the phosphate group important in biology?

It contributes negative charge and is involved in energy transfer and the structure of molecules such as ATP and DNA.

What is a methyl group?

A −CH3 group consisting of a carbon bonded to three hydrogen atoms.

How can a methyl group affect a molecule?

It can affect molecular shape, gene regulation, and the molecule's interactions with other substances.

Are methyl groups strongly polar?

No, they are generally nonpolar.

Which functional groups can act as acids or bases?

Carboxyl groups can act as acids, while amino groups can act as bases.

Which functional group is found in alcohols?

Hydroxyl.

Which functional group is responsible for the carbonyl in aldehydes and ketones?

Carbonyl.

Which functional group is characteristic of organic acids?

Carboxyl.

Which functional group commonly accepts protons?

Amino.

Which functional group can form disulfide bonds in proteins?

Sulfhydryl.

Which functional group is important in ATP energy transfer?

Phosphate.

Which functional group is written −CH3?

Methyl.

What is the difference between a carbonyl and a carboxyl group?

A carbonyl is C=O, while a carboxyl group is −COOH and includes both a carbonyl and a hydroxyl.

How can two molecules with the same molecular formula have different properties?

They may differ in their bonding arrangement, three-dimensional shape, or functional groups.

Why do functional groups matter in biological molecules?

They determine many of a molecule's chemical reactions, polarity, and interactions.