HALF YEARLY EXAMINATIONS

Transcription

1 Secondary School HALF YEARLY EXAMINATIONS FORM: 3 Biology Time: 2 hours Name: Class: Section A: Answer ALL questions in the space provided. This section carries a total of 55 marks. 1. The frog is considered to be a living organism since it performs all the characteristics of life. Complete the table below showing the characteristics of life of the frog. Characteristic of Life Definition Eat insects that are necessary for growth and build-up of energy; Reproduction Hides under a stone in the presence of predators; Frogs use their back legs to push themselves when in the water; Growth Burning of food to build energy; Removal of waste after metabolism from the frog s body. Total 7 marks Biology F3 HY Page 1 of 10

2 2. The following diagram represents the human sex cells being studied in the laboratory. These cells are considered to be specialised cells. 1.3cm Cell A Cell B a) Write down the name of cells A and B Cell A: Cell B: b) Explain the meaning of the term specialised. c) What is the function of Cell A? d) Name two other specialised cells found in the human body. e) Name the instrument used to study the above cells in the laboratory. f) The student wrote that Cell A has been magnified x250. Calculate the actual size of the part (shown above) that measures 1.3 cm. Show all your working. (3) Total 11 marks Biology F3 HY Page 2 of 10

3 3. Plants use active transport to move some substances from the soil into the root. a) Explain the term active transport. b) Which organelle is expected to be present in abundance in root cells in order to ensure success of the process of active transport? Give a reason why. Organelle: Reason: c) Why is the process of active transport necessary in roots? d) Specialised cells, known as root hair cells, are present in roots. Draw a well labelled diagram of a root hair cell. (4) e) How is the root hair cell adapted to perform its function? Total 11 marks Biology F3 HY Page 3 of 10

4 4. a) Draw a typical animal cell and label all the structures that are normally found in it. (4) b) Certain structures are found only in plant cells. List two such structures and give the function of each. (4) Total 8 marks Biology F3 HY Page 4 of 10

5 5. Many flowering plants can reproduce both sexually and asexually. a) Define the term asexual reproduction. b) State one advantage and one disadvantage of asexual reproduction for flowering plants. Asexual Reproduction Advantage Disadvantage c) Potatoes can reproduce asexually by means of tubers. This can be observed in the following diagram: Soft and shrivelled tuber Explain why the tuber becomes soft and shrivelled when a new plant grows from it. Total 6 marks Biology F3 HY Page 5 of 10

6 6. Biology students investigated the effect of size of organisms on diffusion of molecules. For the purpose of this investigation, the organisms were represented by cubes made of transparent gelatine jelly. They cut 2 cubes as follows: Cube A Sides 3 cm each Cube B Sides 1 cm each a) Calculate the Surface Area to Volume ratio for each of the above cubes. Show your working. Cube A Cube B Surface Area Volume SA:Volume ratio b) After preparing the cubes, they placed each one of them in a beaker filled with redcoloured water. They left the cubes in the beaker for 15 minutes. After removal from the beaker, the students cut through the centre of each cube and observed the diffusion of the red-coloured water into the cubes. i) Explain the term diffusion (6) ii) In which cube do you expect the red colour to diffuse faster? Explain your answer. (1,1) (continued on next page) Biology F3 HY Page 6 of 10

7 iii) Write down one precaution the students should have followed during this investigation. iv) Write down one advantage organisms represented by Cube B could have over organisms represented by Cube A. Total 12 marks Section B: Answer question ONE and ANY OTHER TWO questions on the papers provided. This section carries a total of 45 marks. 1. Germination is a process, controlled by enzymes, in which the seed begins to develop into a new young plant. Three main factors are needed for successful germination. Germination of seeds may be either hypogeal or epigeal. Biology students investigated the changes in dry mass of pea seeds as they germinated and grew into new plants. Before planting them, they allowed the seeds to soak in water for 24 hours. The planted seeds were left on a window sill for 12 days, and the dry mass of the whole germinating plant, including the seed, was measured every 2 days. The following table shows their results over a 12-day period. Time (days) Dry mass of germinating plants (g) a) Plot a graph of dry mass of germinating plants (y-axis) against time (x-axis) (5) b) Explain why there was a decrease in the dry mass of the germinating plants during the first 6 days. c) Why were the seeds soaked in water for 24 hours before planting them? d) Besides water, list two other important factors needed for successful germination. e) The students found that hypogeal germination is characteristic of pea seeds. Explain the term hypogeal. (continued on next page) Biology F3 HY Page 7 of 10

8 f) List two things that the students should have kept the same when carrying out the investigation to ensure accurate results. g) At the end of the investigation, one of the students said that if they repeated the experiment by placing the planted seeds in a dark cupboard, no growth would be observed. Is the student correct? Explain your answer. Total 15 marks 2. Seed dispersal is the movement or transport of seeds, usually far away from the parent plant. Plants have very limited mobility and so depend on a variety of dispersal methods to transport their seeds. a) The following are seeds taken from a variety of plants. For each one state the dispersal method. G0zT03GSTlE/Uqwft7cUBVI/AAAAAAAACfc/ p_ktjb25pf0/s1600/seeds+dispersal+by+animals+vs+by+wind.png A B C b) During dispersal, seeds are usually carried far away from the parent plant. List two advantages of this process. c) Draw a well-labelled diagram of a typical seed you have studied. (4) d) Seeds have the ability to remain dormant. Explain the advantage of this. e) Seeds develop from ovules. Name the structure a true fruit develops from. f) The strawberry is considered to be a false fruit. Explain this term. D (4) Total 15 marks Biology F3 HY Page 8 of 10

9 3. John, a biology student, wanted to investigate the effect of osmosis on the size of potato cubes. He cut 3 potato cubes, all of the exact size, weighed them and placed them in boiling tubes with different solutions. He left them for 30 minutes, removed them, and weighed them once more. The following table shows the results obtained: Cube Original Weight (g) Final weight (g) % Change A % B C ? a) Explain the term osmosis. b) Calculate the % Change of cube C. Show all your working. (3) c) Explain why cube B showed no change in size. d) Draw a diagram to explain the state of the potato cells found in cube C. e) Suggest why John cut the potato cubes to exactly the same size. f) Name the biological terms used to describe the state of cube A and the state of cube C g) While researching the topic, John read that in hospital, patients are never given drips (liquid that enters directly into the blood) consisting of pure water. Explain why. (3) Total 15 marks 4. Give a biological explanation for each of the following statements: a) It is incorrect to say that respiration and breathing are the same thing (4) b) Salad lettuce can be made more crisp by placing it in a bowl of water (3) c) One cannot observe mitochondria with a light microscope d) Diffusion and osmosis are both passive processes but different from each other. (3) e) An onion is part of a plant but is not green (3) Total 15 marks Biology F3 HY Page 9 of 10

10 5. The flowers of wind-pollinated flowers, such as the Ryegrass, are less colourful than the flowers of insect-pollinated flowers. The following image shows the flower of the Ryegrass. a) Why are wind-pollinated flowers less colourful than insect-pollinated flowers? b) From the above image, list two characteristics that show that the Ryegrass is wind-pollinated. c) Both wind and insect-pollinated flowers produce pollen. Pollen is the male reproductive cell. List two ways of how pollen produced by wind-pollinated flowers is different from that produced by insect-pollinated flowers. d) Besides producing pollen, insect-pollinated flowers also produce nectar. Why is this important? e) Draw a large diagram of an insect-pollinated flower. On the diagram label only the male and female reproductive structures. (4) f) Most plants use cross-pollination, however there are a number of plants, such as the peanuts, that perform self-pollination. i) Explain the term cross-pollination? ii) Why is cross-pollination considered to be better than self-pollination? iii) List a situation when self-pollination may be of an advantage to the plant. g) Describe what happens from the time of pollination to the time fertilisation takes place. Total 15 marks Biology F3 HY Page 10 of 10