Mark Scheme (Results)
2025 Predicted Paper
Pearson Edexcel Level 3 GCE
Edexcel AL Biology Marking Scheme 1B 2025 Predicted
PAPER 1 Advanced Level
1
, Edexcel AL Biology Marking Scheme 1B 2025 Predicted
General Marking Guidance
• All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
• Mark schemes should be applied positively. Candidates must be rewarded
for what they have shown they can do rather than penalised for omissions.
• Examiners should mark according to the mark scheme not according to their
perception of where the grade boundaries may lie.
• There is no ceiling on achievement. All marks on the mark scheme should be
used appropriately.
• All the marks on the mark scheme are designed to be awarded. Examiners
should always award full marks if deserved, i.e. if the answer matches the
mark scheme. Examiners should also be prepared to award zero marks if the
candidate’s response is not worthy of credit according to the mark scheme.
• Where some judgement is required, mark schemes will provide the principles
by which marks will be awarded and exemplification may be limited.
• When examiners are in doubt regarding the application of the mark scheme
to a candidate’s response, the team leader must be consulted.
• Crossed out work should be marked UNLESS the candidate has replaced it
with an alternative response.
2
,Edexcel AL Biology Marking Scheme 1B 2025 Predicted
3
, Edexcel AL Biology Marking Scheme 1B 2025 Predicted
Comprehensive Marking Scheme
Question 1
Contextual Overview
This section examines fundamental concepts in molecular biology, specifically protein
synthesis, protein structure, and the consequences of protein misfolding. These
topics are commonly assessed in advanced biology exams (e.g., A-Level, IB, or
university entrance exams) because they underpin a broad range of biological
processes and applications in health and disease.
• Topic Context: Questions typically cover transcription, translation, protein
folding, enzymatic catalysis, and related cellular processes.
• Historical Trends (2015-2023): Questions on these topics often test both
knowledge recall (e.g., naming components) and application (e.g., explaining
how misfolded proteins lead to diseases). Data-analysis questions about
experiments involving protein synthesis also appear periodically.
• Preparation Tips:
1. Familiarize yourself with diagrams of ribosomes, tRNA, and protein
folding.
2. Review key processes such as peptide bond formation and enzyme
catalysis.
3. Study case studies on diseases caused by protein misfolding (e.g.,
Alzheimer’s).
Detailed Mark Scheme
1(a) Describe the formation of a peptide bond during protein synthesis,
including the role of ribosomes and tRNA. (2 Marks)
Answer:
1. A peptide bond forms between the amino group of one amino acid and the
carboxyl group of another.
2. Ribosomes facilitate the positioning of tRNA molecules, each carrying a
specific amino acid, within the ribosomal active site.
3. The ribosomal RNA (rRNA) catalyzes the reaction by stabilizing the transition
state.
4. The amino acid attached to the tRNA in the P-site is transferred to the amino
acid attached to the tRNA in the A-site, forming the peptide bond.
4
2025 Predicted Paper
Pearson Edexcel Level 3 GCE
Edexcel AL Biology Marking Scheme 1B 2025 Predicted
PAPER 1 Advanced Level
1
, Edexcel AL Biology Marking Scheme 1B 2025 Predicted
General Marking Guidance
• All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
• Mark schemes should be applied positively. Candidates must be rewarded
for what they have shown they can do rather than penalised for omissions.
• Examiners should mark according to the mark scheme not according to their
perception of where the grade boundaries may lie.
• There is no ceiling on achievement. All marks on the mark scheme should be
used appropriately.
• All the marks on the mark scheme are designed to be awarded. Examiners
should always award full marks if deserved, i.e. if the answer matches the
mark scheme. Examiners should also be prepared to award zero marks if the
candidate’s response is not worthy of credit according to the mark scheme.
• Where some judgement is required, mark schemes will provide the principles
by which marks will be awarded and exemplification may be limited.
• When examiners are in doubt regarding the application of the mark scheme
to a candidate’s response, the team leader must be consulted.
• Crossed out work should be marked UNLESS the candidate has replaced it
with an alternative response.
2
,Edexcel AL Biology Marking Scheme 1B 2025 Predicted
3
, Edexcel AL Biology Marking Scheme 1B 2025 Predicted
Comprehensive Marking Scheme
Question 1
Contextual Overview
This section examines fundamental concepts in molecular biology, specifically protein
synthesis, protein structure, and the consequences of protein misfolding. These
topics are commonly assessed in advanced biology exams (e.g., A-Level, IB, or
university entrance exams) because they underpin a broad range of biological
processes and applications in health and disease.
• Topic Context: Questions typically cover transcription, translation, protein
folding, enzymatic catalysis, and related cellular processes.
• Historical Trends (2015-2023): Questions on these topics often test both
knowledge recall (e.g., naming components) and application (e.g., explaining
how misfolded proteins lead to diseases). Data-analysis questions about
experiments involving protein synthesis also appear periodically.
• Preparation Tips:
1. Familiarize yourself with diagrams of ribosomes, tRNA, and protein
folding.
2. Review key processes such as peptide bond formation and enzyme
catalysis.
3. Study case studies on diseases caused by protein misfolding (e.g.,
Alzheimer’s).
Detailed Mark Scheme
1(a) Describe the formation of a peptide bond during protein synthesis,
including the role of ribosomes and tRNA. (2 Marks)
Answer:
1. A peptide bond forms between the amino group of one amino acid and the
carboxyl group of another.
2. Ribosomes facilitate the positioning of tRNA molecules, each carrying a
specific amino acid, within the ribosomal active site.
3. The ribosomal RNA (rRNA) catalyzes the reaction by stabilizing the transition
state.
4. The amino acid attached to the tRNA in the P-site is transferred to the amino
acid attached to the tRNA in the A-site, forming the peptide bond.
4
