AQA A-Level Biology Paper 1 2024/2025
Exam Questions and Corresponding
Answers with Surety of 100% Pass Mark
Describe the role of a ribosome in the production of a polypeptide. /3 - 🧠
ANSWER ✔✔1. mRNA binds to ribosome;
2. Idea of TWO codons/binding sites;
3. tRNA with ANTICODONS binds;
4. (Catalyses) formation of PEPTIDE bond between AMINO ACIDS (held
by tRNA molecules);
5. Moves along (mRNA to the next
codon);
Describe the structure of glycogen. /2 - 🧠 ANSWER ✔✔1. Polysaccharide
of α-glucose;
OR
polymer of α-glucose;
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
1
STATEMENT. ALL RIGHTS RESERVED
,2. (Joined by) glycosidic bonds
OR
Branched structure;
NHE3 actively transports one sodium ion into the cell in exchange for one
proton
(hydrogen ion) out of the cell.
Use your knowledge of transport across cell membranes to suggest how
NHE3
does this. /3 - 🧠 ANSWER ✔✔1. Co-transport;
2. Uses (hydrolysis of) ATP;
3. Sodium ion and proton bind to the protein;
4. Protein changes shape (to move sodium ion
and/or proton across the membrane);
Explain the curves for max protease activity over time at 50C and 60C. /4 -
🧠 ANSWER ✔✔1. Both denatured (by high temperature);
2. Denaturation faster at 60 °C due to more (kinetic) energy;
3. Breaks hydrogen/ionic bonds (between amino acids/R groups);
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
2
STATEMENT. ALL RIGHTS RESERVED
, 4. Change in shape of the active site/active site no longer complementary
so fewer enzyme-substrate complexes formed;
Describe the action of these membrane-bound dipeptidases and explain
their
importance. /2 - 🧠 ANSWER ✔✔1. Hydrolyse (peptide bonds) to release
amino acids;
2. Amino acids can cross (cell) membrane;
OR
Dipeptides cannot cross (cell) membrane;
OR
Maintain concentration gradient of amino acids for absorption;
Explain why the scientists suggested that patients should be treated with
both the current antibiotic and the new one.
Use information from Figure 2 (old antibiotic decreases number of bacteria,
new one decreases it more) and your knowledge of evolution of antibiotic
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
3
STATEMENT. ALL RIGHTS RESERVED
Exam Questions and Corresponding
Answers with Surety of 100% Pass Mark
Describe the role of a ribosome in the production of a polypeptide. /3 - 🧠
ANSWER ✔✔1. mRNA binds to ribosome;
2. Idea of TWO codons/binding sites;
3. tRNA with ANTICODONS binds;
4. (Catalyses) formation of PEPTIDE bond between AMINO ACIDS (held
by tRNA molecules);
5. Moves along (mRNA to the next
codon);
Describe the structure of glycogen. /2 - 🧠 ANSWER ✔✔1. Polysaccharide
of α-glucose;
OR
polymer of α-glucose;
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
1
STATEMENT. ALL RIGHTS RESERVED
,2. (Joined by) glycosidic bonds
OR
Branched structure;
NHE3 actively transports one sodium ion into the cell in exchange for one
proton
(hydrogen ion) out of the cell.
Use your knowledge of transport across cell membranes to suggest how
NHE3
does this. /3 - 🧠 ANSWER ✔✔1. Co-transport;
2. Uses (hydrolysis of) ATP;
3. Sodium ion and proton bind to the protein;
4. Protein changes shape (to move sodium ion
and/or proton across the membrane);
Explain the curves for max protease activity over time at 50C and 60C. /4 -
🧠 ANSWER ✔✔1. Both denatured (by high temperature);
2. Denaturation faster at 60 °C due to more (kinetic) energy;
3. Breaks hydrogen/ionic bonds (between amino acids/R groups);
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
2
STATEMENT. ALL RIGHTS RESERVED
, 4. Change in shape of the active site/active site no longer complementary
so fewer enzyme-substrate complexes formed;
Describe the action of these membrane-bound dipeptidases and explain
their
importance. /2 - 🧠 ANSWER ✔✔1. Hydrolyse (peptide bonds) to release
amino acids;
2. Amino acids can cross (cell) membrane;
OR
Dipeptides cannot cross (cell) membrane;
OR
Maintain concentration gradient of amino acids for absorption;
Explain why the scientists suggested that patients should be treated with
both the current antibiotic and the new one.
Use information from Figure 2 (old antibiotic decreases number of bacteria,
new one decreases it more) and your knowledge of evolution of antibiotic
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
3
STATEMENT. ALL RIGHTS RESERVED
