2024 AS Level Biology A
H020/02 Depth in biology
Monday 4 June 2018 2024
FINAL UPDATE PASS A+
(a) Fig. 1.1 shows the general structure of an amino acid
State the names of the groups labelled U and V - ✔✔✔ANSWER-U-
amine group
V- carboxyl group
Fig. 1.2 shows a representation of a short polypeptide chain made from
three amino acids
, Name bond W and state what type of reaction takes place to form this
bond. - ✔✔✔ANSWER-Name of bond W- peptide bond
Type of reaction- condensation reaction
Pepsin is a protease enzyme with a polypeptide chain containing 327
amino acids.
Titin is the largest known protein. It has a polypeptide chain containing
at least 92 times more amino acids than pepsin.
(i) DNA sequences in genes code for polypeptide molecules such as
pepsin and titin.
Explain why a process known as transcription is necessary for
polypeptide synthesis - ✔✔✔ANSWER-DNA, copied to mRNA
DNA, is too large to leave nucleus
Calculate the minimum length of the DNA base sequence required to
code for titin. Show your working - ✔✔✔ANSWER-327 x 92 x 3= 90,252
* Titin is a fibrous protein. Pepsin is a globular protein. Compare the
properties and functions of fibrous proteins and globular proteins in the
human body - ✔✔✔ANSWER-Properties:
Globular-soluble, Fibrous- insoluble
Globular- tertiary structure, fibrous-no tertiary structure
Globular- Hydrophilic R groups on the outside
Fibrous- Hydrophobic R groups , strong flexible
H020/02 Depth in biology
Monday 4 June 2018 2024
FINAL UPDATE PASS A+
(a) Fig. 1.1 shows the general structure of an amino acid
State the names of the groups labelled U and V - ✔✔✔ANSWER-U-
amine group
V- carboxyl group
Fig. 1.2 shows a representation of a short polypeptide chain made from
three amino acids
, Name bond W and state what type of reaction takes place to form this
bond. - ✔✔✔ANSWER-Name of bond W- peptide bond
Type of reaction- condensation reaction
Pepsin is a protease enzyme with a polypeptide chain containing 327
amino acids.
Titin is the largest known protein. It has a polypeptide chain containing
at least 92 times more amino acids than pepsin.
(i) DNA sequences in genes code for polypeptide molecules such as
pepsin and titin.
Explain why a process known as transcription is necessary for
polypeptide synthesis - ✔✔✔ANSWER-DNA, copied to mRNA
DNA, is too large to leave nucleus
Calculate the minimum length of the DNA base sequence required to
code for titin. Show your working - ✔✔✔ANSWER-327 x 92 x 3= 90,252
* Titin is a fibrous protein. Pepsin is a globular protein. Compare the
properties and functions of fibrous proteins and globular proteins in the
human body - ✔✔✔ANSWER-Properties:
Globular-soluble, Fibrous- insoluble
Globular- tertiary structure, fibrous-no tertiary structure
Globular- Hydrophilic R groups on the outside
Fibrous- Hydrophobic R groups , strong flexible
