BIOLOGY AQA AS LEVEL
7401/1 PAPER 1 EXAM QUESTIONS
WITH CORRECT DETAILED ANSWERS
2026/2027 LATEST
Contrast the structures of DNA and mRNA molecules to give three
differences. -
ANS✔✔----DNA is double stranded/double helix and mRNA single-
stranded;
- DNA (very) long and RNA short;
-Thymine/T in DNA and uracil/U in RNA;
- Deoxyribose in DNA and ribose in RNA;
This fat substitute cannot be digested in the gut by lipase. Suggest why.
-
1
, ANS✔✔----(Fat substitute) is a different/wrong shape/not
complementary
- Unable to fit/bind to (active site of) lipase/no ES complex formed;
Despite being a lipid, the substitute cannot cross the cell-surface
membranes of cells lining the gut.
Give two ways in which the hydrolysis of ATP is used in cells. -
ANS✔✔----
To provide energy for other reactions/named process;
- To add phosphate to other substances and make them more
reactive/change their shape
The human cell then makes a complementary strand to the HIV DNA.
The complementary strand is made in the same way as a new
complementary strand is made during semi-conservative replication of
human DNA. Describe how the complementary strand of HIV DNA is
made. - ANS✔✔there are complementary nucleotides/bases pair
2
7401/1 PAPER 1 EXAM QUESTIONS
WITH CORRECT DETAILED ANSWERS
2026/2027 LATEST
Contrast the structures of DNA and mRNA molecules to give three
differences. -
ANS✔✔----DNA is double stranded/double helix and mRNA single-
stranded;
- DNA (very) long and RNA short;
-Thymine/T in DNA and uracil/U in RNA;
- Deoxyribose in DNA and ribose in RNA;
This fat substitute cannot be digested in the gut by lipase. Suggest why.
-
1
, ANS✔✔----(Fat substitute) is a different/wrong shape/not
complementary
- Unable to fit/bind to (active site of) lipase/no ES complex formed;
Despite being a lipid, the substitute cannot cross the cell-surface
membranes of cells lining the gut.
Give two ways in which the hydrolysis of ATP is used in cells. -
ANS✔✔----
To provide energy for other reactions/named process;
- To add phosphate to other substances and make them more
reactive/change their shape
The human cell then makes a complementary strand to the HIV DNA.
The complementary strand is made in the same way as a new
complementary strand is made during semi-conservative replication of
human DNA. Describe how the complementary strand of HIV DNA is
made. - ANS✔✔there are complementary nucleotides/bases pair
2
