Biological molecules Questions with Correct
Answers
Name the covalent bond between two adjacent amino acids in a chain of amino acids. -
ANSWERSpeptide bond
Name the type of reaction involved in breaking this bond and describe what happens in
this reaction. (2) - ANSWERShydrolysis, water is added
Describe how an enzyme, such as pepsin, breaks down a substrate. (5) - ANSWERS-
substrate / protein is complementary to active site
- induced fit / description of induced fit
- forms enzyme-substrate complex
- destabilising of bonds in substrate forms an enzyme-product complex
- product(s) / amino acids , leave (active site)
What elements do triglycerides and cholesterol contain? - ANSWERScarbon, hydrogen
and oxygen
Describe how to do the emulsion test for lipids and how a positive result would be
identified. (2) - ANSWERS- mix sample with ethanol and water
- (goes) cloudy
Lipids form an essential part of a balanced diet. Some food, such as mycoprotein, is
produced by microorganisms.
How might the lipid content of mycoprotein differ from food that comes from animals?
(2) - ANSWERS- less overall lipids
- more unsaturated lipids
What features describe the primary level of protein structure? - ANSWERSthe
sequence of amino acids and peptide bonds
What features describes the secondary level of protein structure? - ANSWERShydrogen
bonding, and the initial folding of the polypeptide chain
, What features describe the tertiary level of protein structure? - ANSWERSthe overall 3D
shape and the type of bonding eg ionic
What features describe the quaternary level of proteins? - ANSWERSalpha and beta
sub-units
Hydrogen bonds also form between water molecules. Describe the formation of a
hydrogen bond between two molecules of water and explain why water can form these
bonds (3) - ANSWERS- hydrogen bonds form between oxygen and hydrogen on
adjacent molecules, between electronegative oxygen and electropositive hydrogen.
- water is polar
Hydrogen bonds allow water to act as a solvent.
Why is the ability of water to act as a solvent important for the survival of organisms? (3)
- ANSWERS- water is a medium for metabolic reactions, it allows for minerals, gases
and food to be absorbed and transported around the body
- able to dilute toxic substances
State the name given to the sequence of amino acids in a protein molecule. -
ANSWERSprimary structure
Draw the general structure of an amino acid - ANSWERSamine group, carboxyl group, r
group, and hydrogen attached to central carbon atom
Collagen is an important fibrous protein which forms part of the wall of blood vessels.
State one property of collagen that makes it a useful component of blood vessel walls. -
ANSWERSstrength/ toughness/ insolubility
Describe the structure of the collagen molecule. (6) - ANSWERSpeptide bonds form
between amino acids
every 3rd amino acid is glycine
made up of 3 polypeptides
triple helix structure
hydrogen bonds form between polypeptides
- adjacent molecules are joined by cross links
- crosslinks hold collagen molecule together forming fibrils
State one function of haemoglobin. - ANSWERStransport oxygen
Haemoglobin contains a prosthetic group known as haem.
Collagen does not contain a prosthetic group.
Describe three other ways in which the structure of haemoglobin differs from that of
collagen - ANSWERSHb is a globular protein
Hb has two different sub-units; alpha and beta
In Hb the hydrophilic R groups are on the outside, and hydrophobic groups are on the
inside
Answers
Name the covalent bond between two adjacent amino acids in a chain of amino acids. -
ANSWERSpeptide bond
Name the type of reaction involved in breaking this bond and describe what happens in
this reaction. (2) - ANSWERShydrolysis, water is added
Describe how an enzyme, such as pepsin, breaks down a substrate. (5) - ANSWERS-
substrate / protein is complementary to active site
- induced fit / description of induced fit
- forms enzyme-substrate complex
- destabilising of bonds in substrate forms an enzyme-product complex
- product(s) / amino acids , leave (active site)
What elements do triglycerides and cholesterol contain? - ANSWERScarbon, hydrogen
and oxygen
Describe how to do the emulsion test for lipids and how a positive result would be
identified. (2) - ANSWERS- mix sample with ethanol and water
- (goes) cloudy
Lipids form an essential part of a balanced diet. Some food, such as mycoprotein, is
produced by microorganisms.
How might the lipid content of mycoprotein differ from food that comes from animals?
(2) - ANSWERS- less overall lipids
- more unsaturated lipids
What features describe the primary level of protein structure? - ANSWERSthe
sequence of amino acids and peptide bonds
What features describes the secondary level of protein structure? - ANSWERShydrogen
bonding, and the initial folding of the polypeptide chain
, What features describe the tertiary level of protein structure? - ANSWERSthe overall 3D
shape and the type of bonding eg ionic
What features describe the quaternary level of proteins? - ANSWERSalpha and beta
sub-units
Hydrogen bonds also form between water molecules. Describe the formation of a
hydrogen bond between two molecules of water and explain why water can form these
bonds (3) - ANSWERS- hydrogen bonds form between oxygen and hydrogen on
adjacent molecules, between electronegative oxygen and electropositive hydrogen.
- water is polar
Hydrogen bonds allow water to act as a solvent.
Why is the ability of water to act as a solvent important for the survival of organisms? (3)
- ANSWERS- water is a medium for metabolic reactions, it allows for minerals, gases
and food to be absorbed and transported around the body
- able to dilute toxic substances
State the name given to the sequence of amino acids in a protein molecule. -
ANSWERSprimary structure
Draw the general structure of an amino acid - ANSWERSamine group, carboxyl group, r
group, and hydrogen attached to central carbon atom
Collagen is an important fibrous protein which forms part of the wall of blood vessels.
State one property of collagen that makes it a useful component of blood vessel walls. -
ANSWERSstrength/ toughness/ insolubility
Describe the structure of the collagen molecule. (6) - ANSWERSpeptide bonds form
between amino acids
every 3rd amino acid is glycine
made up of 3 polypeptides
triple helix structure
hydrogen bonds form between polypeptides
- adjacent molecules are joined by cross links
- crosslinks hold collagen molecule together forming fibrils
State one function of haemoglobin. - ANSWERStransport oxygen
Haemoglobin contains a prosthetic group known as haem.
Collagen does not contain a prosthetic group.
Describe three other ways in which the structure of haemoglobin differs from that of
collagen - ANSWERSHb is a globular protein
Hb has two different sub-units; alpha and beta
In Hb the hydrophilic R groups are on the outside, and hydrophobic groups are on the
inside
