Search results for "Sequences"

Biology

CAIE2024

(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:5)(cid:44) (c) Glycogen synthase catalyses the conversion of glucose to glycogen in liver cells. The production of glycogen synthase is coded for by the gene GYS2. A mutation in GYS2 leads to a condition called glycogen storage disease type 0 (GSD0) in which glycogen is not formed efficiently. Suggest what the consequences would be if a person with GSD0 has a meal rich in glucose. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [3] [Total: 10] The boundaries and names shown, the designations used and the presentation of material on any maps contained in this question paper/insert do not imply official endorsement or acceptance by Cambridge Assessment International Education concerning the legal status of any country, territory, or area or any of its authorities, or of the delimitation of its frontiers or boundaries. Permission to reproduce items where third‑party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer‑related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge. (cid:300)(cid:209)(cid:266)(cid:190)(cid:288)(cid:180)(cid:237)(cid:200)(cid:245)(cid:207)(cid:298)(cid:197)(cid:266)(cid:222)(cid:251)(cid:182)(cid:260)(cid:215) © UCLES 2024 (cid:300)(cid:224)(cid:201)(cid:243)(cid:220)(cid:288)(cid:282)(cid:283)(cid:212)(cid:262)(cid:265)(cid:281)(cid:251)(cid:298)(cid:257)(cid:283)(cid:293)(cid:258) 9700/42/O/N/24 (cid:293)(cid:293)(cid:277)(cid:213)(cid:245)(cid:213)(cid:197)(cid:277)(cid:245)(cid:261)(cid:229)(cid:197)(cid:261)(cid:181)(cid:261)(cid:277)(cid:213)(cid:213) NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD PMT

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Biology

CAIE2023

hours You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● You may use a calculator. ● You should show all your working and use appropriate units. INFORMATION ● The total mark for this paper is 100. ● The number of marks for each question or part question is shown in brackets [ ]. DC (DE/CT) 323203/4 © UCLES 2023 PMT

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Biology

CAIE2023

2

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Biology

CAIE2023

Chloroplasts carry out photosynthesis. Fig. 1.1 shows some structural features of a chloroplast and some processes that occur within it. light CO

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Biology

CAIE2023

stroma H O

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Biology

CAIE2023

components cycle C A make up granum product B product D chloroplast envelope Fig. 1.1 (a) (i) Identify the structures labelled A in Fig. 1.1. A .......................................................... [1] (ii) Explain how the structure and appearance of the granum, and the components labelled A, relate to their function. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] © UCLES 2023 9700/43/O/N/23 PMT

Question

Biology

CAIE2023

Biodiversity can be assessed at three different levels. One of these is the genetic variation within each species. (a) Outline two other levels at which biodiversity can be measured. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2] To calculate the genetic variation that exists within a species, scientists: • obtain DNA sequences from many individuals of one species • count the number of nucleotides that differ when the sequences of two individuals are compared • repeat this with different pairs of individuals. This allows scientists to calculate the mean number of differences at every nucleotide position along the sequence (mean number of nucleotide differences per site). (b) Explain why scientists use databases and computers to calculate the mean number of nucleotide differences per site. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [3] (c) Table 2.1 shows the mean number of nucleotide differences per site of some species. Table 2.1 species mean number of nucleotide differences per site Drosophila melanogaster, fruit fly 0.0087 Anopheles gambiae, mosquito vector of malaria 0.0301 Plasmodium falciparum, malarial pathogen 0.0015 Zea mays, wild maize 0.0139 © UCLES 2023 9700/43/O/N/23 PMT

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Biology

CAIE2023

................................................................................................................................................ ...................................................................................................................................................

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Biology

CAIE2023

................................................................................................................................................ ............................................................................................................................................. [2] (c) Scientists investigated the response of stomata to changing carbon dioxide (CO )

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Biology

CAIE2023

concentrations in the beach morning glory, I. pes-caprae. The scientists placed I. pes-caprae plants in chambers. They measured the width of open stomata (stomatal apertures) after the plants had been exposed to different CO

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Biology

CAIE2023

concentrations for 40 minutes. Light intensity and temperature were kept constant. The relationship between CO concentration and the mean width of stomatal apertures is

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Biology

CAIE2023

shown in Fig. 3.2.

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Biology

CAIE2023

0

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Biology

CAIE2023

5 mean width of stomatal aperture 1.0 /μm

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Biology

CAIE2023

Fig. 3.2 © UCLES 2023 9700/43/O/N/23 PMT

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Biology

CAIE2023

In the future, climate change may reduce water availability and increase atmospheric CO concentrations in some habitats.

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Biology

CAIE2023

Suggest how the stomatal response shown in Fig. 3.2 would allow I. pes-caprae to survive the effects of climate change. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) Under certain conditions, the closure of stomata is controlled by abscisic acid. Describe how abscisic acid causes the closure of stomata. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] © UCLES 2023 9700/43/O/N/23 [Turn over PMT

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Biology

CAIE2023

0μmol of abscisic acid

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Biology

CAIE2023

2 3 4 5 6 day Fig. 3.3 © UCLES 2023 9700/43/O/N/23 PMT

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Biology

CAIE2023

carbon dioxide and water. Table 5.1 respiratory substrate formula number of oxygen molecules needed for respiration beta-hydroxybutyric acid C H O 4.5

Question

Biology

CAIE2023

hours You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● You may use a calculator. ● You should show all your working and use appropriate units. INFORMATION ● The total mark for this paper is 100. ● The number of marks for each question or part question is shown in brackets [ ]. DC (SL) 333650 © UCLES 2023 PMT

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Biology

CAIE2023

2

Question

Biology

CAIE2023

Chloroplasts carry out photosynthesis. Fig. 1.1 shows some structural features of a chloroplast and some processes that occur within it. light CO

Question

Biology

CAIE2023

stroma H O

Question

Biology

CAIE2023

components cycle C A make up granum product B product D chloroplast envelope Fig. 1.1 (a) (i) Identify the structures labelled A in Fig. 1.1. A .......................................................... [1] (ii) Explain how the structure and appearance of the granum, and the components labelled A, relate to their function. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] © UCLES 2023 9700/41/O/N/23 PMT

Question

Biology

CAIE2023

Biodiversity can be assessed at three different levels. One of these is the genetic variation within each species. (a) Outline two other levels at which biodiversity can be measured. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2] To calculate the genetic variation that exists within a species, scientists: • obtain DNA sequences from many individuals of one species • count the number of nucleotides that differ when the sequences of two individuals are compared • repeat this with different pairs of individuals. This allows scientists to calculate the mean number of differences at every nucleotide position along the sequence (mean number of nucleotide differences per site). (b) Explain why scientists use databases and computers to calculate the mean number of nucleotide differences per site. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [3] (c) Table 2.1 shows the mean number of nucleotide differences per site of some species. Table 2.1 species mean number of nucleotide differences per site Drosophila melanogaster, fruit fly 0.0087 Anopheles gambiae, mosquito vector of malaria 0.0301 Plasmodium falciparum, malarial pathogen 0.0015 Zea mays, wild maize 0.0139 © UCLES 2023 9700/41/O/N/23 PMT

Question

Biology

CAIE2023

................................................................................................................................................ ...................................................................................................................................................

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Biology

CAIE2023

................................................................................................................................................ ............................................................................................................................................. [2] (c) Scientists investigated the response of stomata to changing carbon dioxide (CO )

Question

Biology

CAIE2023

concentrations in the beach morning glory, I. pes-caprae. The scientists placed I. pes-caprae plants in chambers. They measured the width of open stomata (stomatal apertures) after the plants had been exposed to different CO

Question

Biology

CAIE2023

concentrations for 40 minutes. Light intensity and temperature were kept constant. The relationship between CO concentration and the mean width of stomatal apertures is

Question

Biology

CAIE2023

shown in Fig. 3.2.

Question

Biology

CAIE2023

0

Question

Biology

CAIE2023

5 mean width of stomatal aperture 1.0 /μm

Question

Biology

CAIE2023

Question

Biology

CAIE2023

In the future, climate change may reduce water availability and increase atmospheric CO concentrations in some habitats.

Question

Biology

CAIE2023

Suggest how the stomatal response shown in Fig. 3.2 would allow I. pes-caprae to survive the effects of climate change. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) Under certain conditions, the closure of stomata is controlled by abscisic acid. Describe how abscisic acid causes the closure of stomata. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] © UCLES 2023 9700/41/O/N/23 [Turn over PMT

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Biology

CAIE2023

0μmol of abscisic acid

Question

Biology

CAIE2023

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Mathematics

Edexcel2023

00 6.00 9.00 12.00 15.00 18.00 NH (aq) / cm3

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Biology

CAIE2023

carbon dioxide and water. Table 5.1 respiratory substrate formula number of oxygen molecules needed for respiration beta-hydroxybutyric acid C H O 4.5

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