Chapter 3: The Organic Molecules of Life

Which molecule contains three fatty acids bound to a glycerol?

Triglyceride

True or false: Hydrogen bonds between the peptide bonds in a protein chain are responsible for the secondary structure.

True; Alpha helices and pleated sheets are secondary structures that form as a result of hydrogen bonding.

True or false: The primary structure of a protein is determined by its sequence of amino acids.

True; The sequence of amino acids determines the primary structure of a protein.

Select the functions of carbohydrates.

immediate energy source. structural components of organisms

peptide bond

joins adjacent amino acids together

Biological molecules such as fats, oils, and waxes are called ___________.

lipids

What are two common uses of fats in the bodies of animals?

long-term energy storage insulation

The physical structure of a protein can be considered at __________ different levels. (use a number)

4

There are __________ different amino acids used by living organisms.

20

tertiary

3D shape of a single chain of amino acids

The name of 'amino acid' is given to a particular type of organic molecule because of the presence of which of these functional groups?

An amino group and an acid group

The material that stores a cell's genetic information is called

DNA.

True or false: Two amino acids can have different R groups, but still have the same identity.

False (The R group is what gives each amino acid its unique qualities.)

Which biological molecules are composed of a long hydrocarbon chain with a carboxyl (COOH) group at one end?

Fatty acid

The six-carbon sugar that organisms breakdown and convert into energy during cellular respiration is _____.

Glucose

The amino acid sequence of a polypeptide determines what about the protein?

Its final shape

The covalent bond that forms between an amino group of one amino acid and the carboxyl group of an adjacent amino acid is what kind?

Peptide bond

What class of organic molecules plays a primary role in the structure and function of the cell?

Proteins

What group of organic molecules function as carriers or channels within cell membranes, make motion possible, and help to defend the body against disease?

Proteins

What molecules makes a complimentary copy of the DNA and carries it to the cytoplasm where proteins are made?

RNA

The intermediate step between DNA and protein is a type of nucleic acid called

RNA.

What determines the final shape of the protein molecule?

The amino acid sequence

The primary structure of a protein is formed by which of these?

The order of its amino acids

Select the components of a fatty acid.

a carboxyl group a long hydrocarbon chain

The shape of the DNA molecule can best be described as

a double helix.

The primary function of triglycerides is to serve as

a high energy storage molecule.

polypeptide

a long chain of amino acids joined together

secondary

alpha helices and beta pleated sheets

Which two of the following are types of secondary structures of proteins?

alpha helix beta pleated sheets

The building blocks, or monomers, of proteins are the __________ acids.

amino

Proteins are long chains of

amino acids joined by dehydration reactions.

A polypeptide is made of

amino acids joined together by peptide bonds.

quaternary

arrangement of more than one polypeptide

A _________ bond is needed to join two amino acids when forming a peptide bond.

covalent

A ____________ bond is needed to join two amino acids when forming a peptide bond.

covalent

To form a peptide a ______ reaction is necessary.

dehydration synthesis

Bacon, lard and butter are all forms of _____.

fats

Because of the double bonds in the carbon chain of an unsaturated fatty acid, there will be ____ hydrogens than those found in saturated fatty acids.

fewer

Human DNA contains approximately 19,000 _________ .

genes

Saturated fatty acids will contain ______ hydrogens than unsaturated fatty acids.

more

Long chains of nucleotides make up DNA and RNA, the two __________ acids.

nucleic

Which of these are the polymers of nucleotides?

nucleic acids

When TWO amino acid are joined together, a __________ is formed

peptide, dipeptide, di-peptide, or dimer

Which molecule has its structure classified as primary, secondary, tertiary or quartenary?

protein

Organic molecules composed of monomers of amino acids are called __________ .

proteins

What type of fatty acid has a hydrogen atom at every possible place along its carbon chain?

saturated

Within the DNA molecule, ______ make up the backbone of the molecule, with the ______ projecting to the inside.

sugar-phosphate groups bases

Select three typical functions of proteins.

support as regulatory hormones act as enzymes

primary

the sequence of amino acids

peptide

two or three amino acids joined together

A fatty acid that contain double bonded carbon atoms are called a(n) ________ fatty acid.

unsaturated