General Biology I - BSC 1010C - Chapter 5: The Structure
and Function of Large Biological Molecules Questions With
Complete Solutions
Are fatty acids soluble in water? Why? Correct Answers Fatty
acids are generally hydrophobic and are not soluble in water.
This is because of the relatively nonpolar C-H bonds in the
hydrocarbon chains of fatty acids. Fats separate from water
because the water molecule hydrogen-bond to one another and
exclude the fats.
Are phospholipids soluble in water? Why? Correct Answers
The two ends of phospholipids show different behaviors with
respect to water. The hydrocarbon tails are hydrophobic and are
excluded from water, while the phosphate groups and its
attachments form a hydrophilic head that has an affinity for
water. When phospholipids are added to water, they self-
assemble into a double-layered sheet called a "bilayer" that
shields their hydrophobic fatty acid tails from water.
Are proteins soluble in water? If a protein is heated, how could
that change its solubility? Why? Correct Answers Proteins are
built up out of amino acids. All amino acids have a similar
backbone structure but differ in their side chains. These side
chains have different properties: some are hydrophobic (not
water-soluble) while others are hydrophilic (water-soluble). To
form a functional protein, the amino acid chain is folded in a
way that the hydrophobic parts end up on the inside and the
hydrophilic parts on the outside. As a result, a stable, water-
soluble protein is formed. Protein denaturation changes the 3D
shape of proteins and (parts) will unfold. Some hydrophobic side
, chains, usually buried inside the protein, are exposed, and the
protein is not soluble anymore.
How many levels of structure are present in a protein? Describe
each level in detail. Correct Answers There are four levels of
structure present in a protein: primary, secondary, tertiary, and
quaternary. The primary structure is the unique structure of
amino acids in a polypeptide; it is defined by what amino acids
are present in the chain and what order they are in. The
secondary structure is the folding or coiling of the polypeptide
into a repeating pattern, including the α helix and the β pleated
sheet, which are maintained by hydrogen bonding. The tertiary
structure is the three-dimensional shape of a polypeptide,
resulting from interactions between amino, carboxylic, and R
groups. The quaternary structure is the overall protein structure
that results from the aggregation of two or more polypeptide
subunits.
How many polypeptide chains are there in a protein? Correct
Answers There are one or more polypeptide chains in a protein.
In which form are carbohydrates stored in animal cells? In what
organ(s) do we store carbohydrates? Correct Answers
Carbohydrates are stored in animal cells as a polysaccharide
called glycogen, a polymer of glucose that is like amylopectin
but more extensively branched. Vertebrates store glycogen
mainly in liver and muscle cells.
What are lipids? Correct Answers Lipids are a group of large
biological molecules, including fats, phospholipids, and steroids,
and Function of Large Biological Molecules Questions With
Complete Solutions
Are fatty acids soluble in water? Why? Correct Answers Fatty
acids are generally hydrophobic and are not soluble in water.
This is because of the relatively nonpolar C-H bonds in the
hydrocarbon chains of fatty acids. Fats separate from water
because the water molecule hydrogen-bond to one another and
exclude the fats.
Are phospholipids soluble in water? Why? Correct Answers
The two ends of phospholipids show different behaviors with
respect to water. The hydrocarbon tails are hydrophobic and are
excluded from water, while the phosphate groups and its
attachments form a hydrophilic head that has an affinity for
water. When phospholipids are added to water, they self-
assemble into a double-layered sheet called a "bilayer" that
shields their hydrophobic fatty acid tails from water.
Are proteins soluble in water? If a protein is heated, how could
that change its solubility? Why? Correct Answers Proteins are
built up out of amino acids. All amino acids have a similar
backbone structure but differ in their side chains. These side
chains have different properties: some are hydrophobic (not
water-soluble) while others are hydrophilic (water-soluble). To
form a functional protein, the amino acid chain is folded in a
way that the hydrophobic parts end up on the inside and the
hydrophilic parts on the outside. As a result, a stable, water-
soluble protein is formed. Protein denaturation changes the 3D
shape of proteins and (parts) will unfold. Some hydrophobic side
, chains, usually buried inside the protein, are exposed, and the
protein is not soluble anymore.
How many levels of structure are present in a protein? Describe
each level in detail. Correct Answers There are four levels of
structure present in a protein: primary, secondary, tertiary, and
quaternary. The primary structure is the unique structure of
amino acids in a polypeptide; it is defined by what amino acids
are present in the chain and what order they are in. The
secondary structure is the folding or coiling of the polypeptide
into a repeating pattern, including the α helix and the β pleated
sheet, which are maintained by hydrogen bonding. The tertiary
structure is the three-dimensional shape of a polypeptide,
resulting from interactions between amino, carboxylic, and R
groups. The quaternary structure is the overall protein structure
that results from the aggregation of two or more polypeptide
subunits.
How many polypeptide chains are there in a protein? Correct
Answers There are one or more polypeptide chains in a protein.
In which form are carbohydrates stored in animal cells? In what
organ(s) do we store carbohydrates? Correct Answers
Carbohydrates are stored in animal cells as a polysaccharide
called glycogen, a polymer of glucose that is like amylopectin
but more extensively branched. Vertebrates store glycogen
mainly in liver and muscle cells.
What are lipids? Correct Answers Lipids are a group of large
biological molecules, including fats, phospholipids, and steroids,
