GCSE (9-1) Computer Science
Mark Scheme
J277/02: Data Representation & Programming Constructs
Question Answer Marks Guidance
1a The part of the program where a variable is recognised / can be accessed. 1
Examiner's Note: LOW FREQUENCY. Students often confuse "Scope" with "Data Type". Ensure students use the term "Subprogram" or "Function" when describing local scope.
1b 1 mark for each point, 1 for expansion:
  • Memory efficiency: Local variables are removed from memory when the function ends (2).
  • Easier Debugging: Changes to a local variable won't affect other parts of the program unexpectedly (2).
 4
2a record Car
  ID : Integer
  Make : String
  Price : Real
endrecord
(Accept Python Class definition equivalent) 		3
1 mark for RECORD.
1 mark for correct fields.
1 mark for correct types.
2b showroom[5].Price = 12500.00 2
Examiner's Note: GHOST TOPIC. Rarely tested but core J277 requirement. Many students will try to use 2D array syntax showroom[5, 2]; this should receive 0 marks if the question specifies a Record.
3
  • C (1)
  • 68 (1)
  • D (1)
 3
Examiner's Note: LOW FREQUENCY. Tests the ability to treat characters as underlying integers.
4
  • 16 (1)
  • Computer (1)
  • Com (1)
  • COMPUTER SCIENCE (1)
 4
Examiner's Note: MID FREQUENCY. OCR ERL uses 0-based indexing.
5a ASCII uses 7/8 bits; Unicode uses 16/32 bits. 2
5b Unicode can represent characters from all world languages/emojis. 2
6a Type mismatch / Adding string to integer. 1
Examiner's Note: HIGH FREQUENCY. Common error.
6b num = int(input("...")) 1
7
  • False
  • False
  • False
  • True
 4
8
  • 2.5 (Real/Float) (2)
  • 2 (Integer) (2)
 4
Examiner's Note: HIGH FREQUENCY. Essential for J277 Paper 2. DIV always truncates; it does not round.
9
  • Integer
  • Real
  • Boolean
  • String
 4
Examiner's Note: ISBN must be a String because it contains hyphens and does not require calculation.
10 Prevents accidental changes to the value during runtime; makes code easier to maintain (change value in one place). 2
Focus on "accidental change" to earn the 2nd mark.
OCR 2026