2024 ACJC H2 Bio P3 MS

This document consists of 21 printed pages. [Turn over Anglo-Chinese Junior College JC2 Biology Preliminary Examination Higher 2 CANDIDATE NAME FORM CLASS TUTORIAL CLASS I N D E X NUMBER BIOLOGY Paper 3 Long Structured and Free-response Questions Additional Materials: Free-response Question Answer Booklet 9744/03 28 August 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your Name, Class and Index number in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer any one q u e s t i o n i n t h e s p a c e s p r o v i d e d o n t h e s e p a r a t e F r e e - r e s p o n s e Question Answer Booklet. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiners’ use only 1 / 30 2 / 10 3 / 10 4 / 5 / 25 Total / 7 5

2 Anglo-Chinese Junior College 2024 J2 H2 9744 Paper 3 Preliminary Examination For Examiner Use Section A Answer all the questions in this section. 1 Lactose is the main carbohydrate found in mammalian milk and is i m p o r t a n t f o r m e e t i n g t h e nutritional needs of an infant. Lactose is a disaccharide of glucose and galactose, and has been considered healthier than other disaccharides such as sucrose and maltose. Table 1.1 shows the glycaemic index of lactose, sucrose, maltose and glucose. The glycaemic index measures the rise in blood glucose levels two hours after i n g e s t i o n o f t h e m e a s u r e d substance. Table 1.1 carbohydrate glycaemic index lactose 46 sucrose 65 maltose 105 glucose 100 (a) Suggest explanations for the following two observations: ( i ) the glycaemic index of lactose is lower than glucose Time is needed for the hydrolysis of lactose after it is ingested; …………………………………………………………………………………………............ [1] ( i i ) the glycaemic index of lactose is lower than sucrose. 1. There are fewer types of enzymes / lower concentration of enzymes in the gastrointestinal tract able to hydrolyse lactose compared to sucrose; 2. More time / metabolic steps are needed to convert galactose to glucose compared to fructose to glucose; OR More time / metabolic steps are needed to hydrolyse lactose compared to sucrose; …………………………………………………………………………………………............ [2]

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