Search results for "Ecosystems"

Biology

CAIE2023

For Examiner's Use

Question

Biology

CAIE2023

(a) The table shows information about some organisms and their classification. Complete the table by putting the correct kingdom for each organism described. The first one has been done for you. Each kingdom may be required once, more than once or not at all. Features of organism kingdom Body composed of single isolated cells. Heterotrophic eukaryotic cells without a cell wall. Organism motile. Protoctista Body composed of a mass of undifferentiated cells. Heterotrophic eukaryotic cells with a chitin cell wall. Not motile. Body composed of a small ball of undifferentiated cells. Autotrophic eukaryotic cells with a cellulose cell wall and flagellum. Organism motile. Body complex and multicellular, differentiated into a variety of tissues and organs. Heterotrophic eukaryotic cells with no cell wall, some cells have flagellae. Organism motile. Body a string of tiny undifferentiated cells. Heterotrophic prokaryotic cells with a peptidoglycan (murein) cell wall. Not motile. Body complex and multicellular, differentiated into a variety of tissues and organs. Autotrophic eukaryotic cells with a cellulose cell wall. Not motile. [5] (b) In traditional classification there were considered to be only two kingdoms; animals were in one kingdom, and all other organisms were in the other. Suggest the advantages and disadvantages of such a two-kingdom classification compared to the five kingdom classification often used today.  UCLES 2007 9700/4/SP07 final PPMMTT

Question

Biology

CAIE2023

(b) (i) Identify the metabolic pathway labelled cycle C in Fig. 1.1. C .......................................................... [1] (ii) Explain why pathway C is described as a cycle. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (c) (i) Identify the products of photosynthesis labelled B and D in Fig. 1.1. B .......................................................... D .......................................................... [2] (ii) Suggest and explain the importance of glucose and the product labelled B in Fig. 1.1 to ecosystems. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] [Total: 13] © UCLES 2023 9700/43/O/N/23 [Turn over PMT

Question

Biology

CAIE2023

There are more than 600 plant species in the genus Ipomoea. Many species are grown for their attractive flowers, and some species are used as crop plants. (a) Fig. 3.1 shows Ipomoea purpurea, the common morning glory. Fig. 3.1 The gene that determines flower colour in I. purpurea has two alleles: • a dominant allele that results in purple flowers • a recessive allele that results in red flowers. A student recorded the flower colour of all the I. purpurea plants in a field. The student recorded 660 plants with purple flowers and 440 plants with red flowers. Assuming the Hardy-Weinberg principle applies to this population, calculate the number of plants in the field that are heterozygous. Use the equations: p + q = 1 p2 + 2pq + q2 = 1 Show your working and give your answer to the nearest whole number. number of heterozygous plants ......................................................... [3] © UCLES 2023 9700/43/O/N/23 [Turn over PMT

Question

Biology

CAIE2023

(a) Some organisms carry out respiration in anaerobic conditions when oxygen is not available or when there is a low concentration of oxygen. In yeast and some plants, this is called ethanol fermentation. In mammals, it is called lactate fermentation. Fig. 1.1 outlines ethanol fermentation and lactate fermentation. glucose pyruvate ethanol lactate fermentation fermentation A B C D B C ethanol lactate Fig. 1.1 Identify substances A–D. A ............................................................................................................................................... B ............................................................................................................................................... C ............................................................................................................................................... D ............................................................................................................................................... [3] © UCLES 2023 9700/42/O/N/23 PMT

Question

Biology

CAIE2023

1 a α α a mating a α formation of 2 zygote a α aα budding aα

Question

Biology

CAIE2023

3.841 6.635 10.828

Question

Biology

CAIE2023

When only neurone X is stimulated, an action potential will occur in the postsynaptic neurone.

Question

Biology

CAIE2023

(b) (i) Identify the metabolic pathway labelled cycle C in Fig. 1.1. C .......................................................... [1] (ii) Explain why pathway C is described as a cycle. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (c) (i) Identify the products of photosynthesis labelled B and D in Fig. 1.1. B .......................................................... D .......................................................... [2] (ii) Suggest and explain the importance of glucose and the product labelled B in Fig. 1.1 to ecosystems. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] [Total: 13] © UCLES 2023 9700/41/O/N/23 [Turn over PMT

Question

Biology

CAIE2023

There are more than 600 plant species in the genus Ipomoea. Many species are grown for their attractive flowers, and some species are used as crop plants. (a) Fig. 3.1 shows Ipomoea purpurea, the common morning glory. Fig. 3.1 The gene that determines flower colour in I. purpurea has two alleles: • a dominant allele that results in purple flowers • a recessive allele that results in red flowers. A student recorded the flower colour of all the I. purpurea plants in a field. The student recorded 660 plants with purple flowers and 440 plants with red flowers. Assuming the Hardy-Weinberg principle applies to this population, calculate the number of plants in the field that are heterozygous. Use the equations: p + q = 1 p2 + 2pq + q2 = 1 Show your working and give your answer to the nearest whole number. number of heterozygous plants ......................................................... [3] © UCLES 2023 9700/41/O/N/23 [Turn over PMT

Question

Biology

CAIE2016

(b) Outline what is meant by the term ecosystem. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [2] (c) Coral reefs are at risk of damage due to human activities. All the coral reefs in three regions were classifi ed as being at low, medium or high risk of damage. Table 1.1 shows the areas of coral reef at risk of damage in these three regions. Table 1.1 area of coral reef at risk percentage of coral of damage (× 103 km2) reef at high risk of region damage low medium high Caribbean Sea 9 8 7 29 Indian Ocean 20 15 10 Pacifi c Ocean 60 30 9 (i) Complete Table 1.1, giving your answers, to the nearest whole number. [1] (ii) Suggest how human activities could damage coral reefs. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3] [Total: 8] © UCLES 2014 9700/04/SP/16 [Turn over PPMMTT

Question

Search Past Papers