Homework -- Cell Structure

Transcription

1 CELL BIOLOGY UNIT 1 HOMEWORK Homework -- Cell Structure 1. Use the diagram below to complete the table which follows. (8) Structure Function 1 stores genetic information / controls cell activities Cytoplasm 2 Cell membrane 3 Cell wall 4 5 site of photosynthesis 6 stores water and minerals help support the cell, and when full it pushes outwards against the wall to help provide support Mitochondrion 7 8 site of protein synthesis

2 2. Use the diagrams below to answer the questions which follow. A B C D (i) Identify the four cells shown. (3) (ii) Name a structure which is present in cell A but absent from the others, and give its function. (2) (iii) Name a structure which is absent from cell B but is present in the others. (iv) How is the structure mentioned in part (iii) different in cell C compared to A and D? (v) Name a structure which is present in cell C but absent from the others. (vi) Why would this structure not be found in cells from the same organism which are not exposed to sunlight? (vii) Name a structure which is present in C and D but not A and B

3 3. (i) The diagram shows a number of cells as seen under a microscope at a magnification of 100X. Field of view Calculate the average length of one cell in micrometres. 1 millimetre (ii) If a cell has a length of 40 µm, how many could fit end to end across a field of view of 0.5mm? / 20

4 Transport across the Membrane Homework Exercise The diagram below shows a single-celled organisms called an amoeba. The arrows indicate the diffusion of substances in and out of the cell. A C B a) Name the substances represented by the letters A, B and C. (2) b) Which part of the cell controls movement in and out of the cell? c) Name the process by which materials enter or leave the cell.

5 2. Three cylinders of potato were carefully dried on blotting paper and weighed. Each piece weighed 3g. One piece was then placed in each tube as shown below and the tubes were left for 24hrs and then reweighed. A B C 25 cm 3 distilled water 25 cm 3 5% sucrose solution 25 cm 3 20% sucrose solution a) Which potato cylinders would be the heaviest and the lightest? (2) b) The movement of which substance was mainly responsible for the weight changes in the potato cylinders? c) Name the process which was responsible for this movement in the potato cylinders. d) Why were the surfaces of the discs dried before they were reweighed? 3. The apparatus shown in the diagram was set up by groups of students Universal indicator paper Cork Wire gauze

6 Glass Tube Ammonia-soaked cotton wool The cotton wool was soaked with ammonia solution before being placed against the wire gauze and then the tube was corked at both ends. Ammonia gas causes universal indicator paper to change colour from yellow to blue. The time taken for this to happen was recorded. The investigation was repeated with three different ammonia solutions. The results are given in the table below. Concentration of ammonia solution Pieces of universal indicator paper Time taken for colour change to occur (seconds) Molar (dilute) Molar Molar (concentrated) a) The pieces of indicator paper change colour in order. What process is taking place which makes this happen and explain why it happens. b) Look at the results for the fifth piece of indicator paper in each of the investigations. c) Suggest a reason for the different times taken for the indicator paper to change colour in each investigation. (c) The indicator paper was moistened with distilled water to make it stick to the inside of the tube. Why was distilled water used and not tap water? (d) Suggest two reasons why the tubes were corked (e) The tubes must be kept horizontal and not stood on end for these investigations. Explain why?

7 DNA Genes and Chromosomes Homework Exercise 1. Complete the passage below using the words from below: chromomsomes genes DNA nucleus (4). are found in the.. of a cell. They are threadlike structures made up of a chemical called Each chromosome is made up of sections of DNA called. Genes control different characteristics in living things. 2. Below is a diagram of a cell and the structures found within its nucleus. Using the words below, complete the diagram cell chromosomes nucleus DNA (4) From the Cell to DNA

8 National 4/5 DNA and the Production of Proteins 1. How many strands make up a molecule of DNA? 2. Name the 4 different types of bases found in DNA i. ii. iii. iv... (4) 3. The bases found in a molecule of DNA are said to complimentary. What does this mean?.. 4. The diagram below shows a molecule of DNA. Complete the diagram by inserting the correct names of the structures (2)

9 5. The diagram shows part of a single strand of DNA. T G A Draw the complimentary strand with the bases in the correct order. 6. Name the nucleic acid needed to makes proteins from DNA Explain how proteins are made from DNA....

10 Cell Division State the two uses for the new cells produced from cell division. (2) 2. What effect does cell division have on the number of cells in the body? 3. Name the structure within a cell which controls cell division. 4. Below is a diagram of a human cell. Name the structure labelled X. X 5. Complete the following sentences by deleting the incorrect word from each pair to create a correct sentence. The number of chromosomes in the new cells produced by cell division will be the same as/half that of the parent cell. During cell division each parent cell produces two/four new cells. The cells produced by cell division will be different/identical to each other. (3) 6. Cell division can be described as a controlled cycle. What might occur if cell division is uncontrolled? 7. An onion cell contains 16 chromosomes. It divides to form two new cells, which then divide again. How many chromosomes will these new cells have?

11 Cell Division Extension 9 1. The diagrams below show six stages of a cell process. The stages are shown in pairs. The diagrams in each pair are in the correct order. The three pairs of diagrams are NOT in the correct order. (a) (b) (c) (a) Name the process shown in the diagrams. (b) Write the letters of each pair in the order in which they occur in this process (c) Name the cell structure which controls this process

12 2. A cell can divide to produce two daughter cells. Each daughter cell grows and then divides. The beginning of these divisions is shown in the diagram below. 1st division 1st generation 2nd division 2nd generation Calculate the number of cells in the 4th generation. Space for calculation Answer: cells

13 3. The diagram below shows some of the stages in cell division occurring in the cells of a plant root. Describe the stages of cells division (mitosis) shown in the cells labelled X, Y, and Z. X: Y: Z: 4. Describe the meaning of the term diploid cell 5. Typical timings of the stages of mitosis are shown in the table below. Stage A B C D Time (minutes) What percentage of the total time for mitosis is taken by stage C? Space for calculation Answer: %

14 S3 Biology - Extension Cell Division 18 Homework Exercise 3 1. The diagrams below show stages in mitosis (cell division). (a) Complete the table below to place the stages in the order in which they occur. Order Stage B (2) (b) What name is given to the thread-like structures labelled X?

15 2. Scientists can grow liver tissue in the laboratory. This is done by making a few liver cells divide by mitosis to form a large mass of cells. Why is it important that the daughter cells contain the same number of chromosomes as the original mother cells? 3. A cell divides every 20 minutes. How many cells would be produced from one original cell at the end of two hours? Space for calculation cells Answer: 4. Stages of mitosis are shown in their correct order in the diagrams below. (a) Label the spindle on one of the diagrams. (b) Stage C would be followed by stage D. Describe what would happen in stage D. (c) Where in a cell would structure X normally be found? (d) Explain the importance of structure X.

16 5. Below is a list of events which occur during mitosis. Complete the table below to show the order in which these events take place. List of events A. Chromatids separate B. Two nuclei are formed C. Chromosomes replicate D. Chromatids move to opposite ends of the cell E. Chromosomes visible as pairs of chromatids F. Cells divides G. Chromatids line up along the middle of cell H. Two identical cells are formed (3) 6. The diagram below represents chromosomes at one stage of cell division Order Letter Spindle fibres P (a) Name the structure labelled P. (b) Describe what happens to the chromosomes at the next stage of cell division. (c) This cell contains 8 chromosomes.

17 (i) How many chromosomes will be present in each daughter cell when cell division is complete? (ii) Why is it important that each daughter cell has this number of chromosomes? 7. Below is a flow diagram which describes some of the stages of cell division. Stage 1 - Chromosomes become visible as pairs of chromatids Stage 2 Stage 3 - The spindle fibres contract pulling the chromatids of each chromosome to opposite poles of the cell. Stage 4 - A nuclear membrane forms around each nucleus. Stage 5 a) Describe what occurs at stages 2 and 5. (2)

18 S3 Biology Properties of Enzymes & Uses in Industry 9 Homework Exercise 1 1. What is the function of an enzyme? 2. Describe two features of enzymes. 3. All living cells require enzymes. What would happen to chemical reactions in a cell if enzymes were not present? 4. What is a substrate? 5. Enzymes can be described as being specific. Explain the meaning of the term specific. 6. Enzymes can be involved in both build-up and break down reactions. Give an example of an enzyme involved in each type of reaction. (2) 7. Enzymes are used frequently in biotechnological industries. Name two examples of these uses and describe their purpose. (2)

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22 Uses of microbes Read the following passage and answer the questions based on it. Fight for your Life! Adapted from Biological Sciences Review, September 2005 Every day there is a battle inside our bodies between invading micro-organisms and our immune system. Bacteria are present inside and out. Most are harmless but others are pathogens which cause disease. Infectious diseases are a major killer in developing countries. Vaccination programmes, public health improvements and increasing the availability of antibiotics are required to overcome them. However, there is a growing problem of resistance to antibiotics demonstrated by the super bug MRSA. The first thing a micro-organism does is to find its way into a cell in the body. Cells of the immune system have to recognise that this has happened and make the appropriate response. The first cells on the scene are neutrophils. They engulf bacteria and kill them with enzymes. The next cells to arrive are macrophages which have a variety of specialised killing mechanisms. Dendritic cells are also involved. They are able to recognise pathogens and stimulate other immune cells to react. Fortunately, our immune system has a memory. This means that when we encounter a micro-organism for the second time, a much faster response is triggered that rapidly wipes out the pathogen. Our immune system is very powerful, giving us the best chance to win the battle with these invaders. Sometimes this system breaks down and immune cells wrongly target and destroy our own body cells. This causes conditions such as rheumatoid arthritis and multiple sclerosis. (a) What name is given to micro-organisms such as bacteria which cause disease? 1 (b) Give three actions which are needed by developing countries to overcome infectious diseases (c) Why is MRSA a growing problem? 1 (d) Name three types of immune cells involved in a response to an attack by invading microorganisms. 1 2

23 3 1 (e) Why is the response of the immune system faster the second time a type of micro-organism invades? 1 (f) What causes conditions such as rheumatoid arthritis? 1 (a) During an investigation into the activity of yeast in bread making, a pupil divided a batch of dough into two equal portions. He added yeast to each portion before placing the dough into identical beakers as shown in the diagrams. The volume of dough in each beaker was measured at the start and end of the investigation. The results are shown in the table below. Volume of dough (cm 3 ) Beaker At start At end A B (i) How many times greater was the volume of dough in beaker A at the end compared to the start? times greater 1

24 (ii) The production of which substance caused the increase in the volume of the dough? 1 (iii) Give two factors, not already mentioned, which would need to be kept constant during this investigation (iv) What was the purpose of setting up control beaker B? 1 (b) What type of micro-organism is yeast? 1 (c) Give one use of yeast in a manufacturing process, other than the raising of dough. 1 (d) Bacteria are used to sour milk in the manufacturing of yoghurt. Name the process carried out by the bacteria which causes the milk to sour. 1 a) During the brewing of beer, ingredients including yeast and malted barley are added to a fermentation vessel. (i) What does the malted barley provide for fermentation which ungerminated barley does not? 1 (ii) How does sterilising the fermentation vessel before the raw materials are added help to provide optimum conditions for the yeast? 1

25 b) The concentrations of lactic acid and lactose in a milk sample were measured every two hours for 100 hours. The results are shown in the graph below. (i) What evidence from the graph suggests that lactose is converted into lactic acid? 1 (ii) What evidence from the graph supports the theory that lactose is being converted into compounds other than lactic acid? 1 c) Calculate the average hourly rate of lactose breakdown over the 100 hours of this investigation. Space for calculation g / l /hour 1

26 NATIONAL 5 BIOLOGY HOMEWORK UNIT 1 Aerobic and Anaerobic Respiration 1. Which of the following statements concerning aerobic respiration is correct? A B C D Two molecules of ATP are produced per molecule of glucose respired Lactic acid builds up in the muscles Ethanol and carbon dioxide are produced in plants Carbon dioxide and water are produced 2. Which of the following equations concerning ATP is correct? A ATP ADP + Pi + Energy B ATP + Energy ADP + Pi C ADP + Pi ATP + Energy D ADP + Energy ATP 3. What are the end products of anaerobic respiration in animal cells? A B C D ethanol + carbon dioxide + ATP lactic acid + carbon dioxide + ATP lactic acid + ATP ethanol + ATP 4. During aerobic respiration in muscle cells oxygen will combine with A B C D hydrogen to form water pyruvic acid to form lactic acid pyruvic acid to form ethanol glucose to form pyruvic acid 5. To respire anaerobically, a yeast cell needs A B C D alcohol glucose lactic acid carbon dioxide

27 6. Three clear glass containers were set up in light to investigate gas exchange by the organisms shown. Each container was air tight. The experiment was left for 12 hours. The colour change shown by the indicators are: YELLOW ORANGE RED (Amount of Carbon dioxide increasing) (Amount of Carbon dioxide decreasing) (a) Copy and complete the table below to show the expected colour change in tubes A and B after 12 hours. A B C D Initial Colour Orange Orange Orange Orange After 12 hours Orange Orange (b) Why does no colour change occur in container C? (c) Explain why the control tube D was included in the experiment.

28 7. An investigation into the effect of temperature on anaerobic respiration in yeast was carried out. 1. A glucose solution was boiled and cooled and poured into a conical flask. 2. A yeast suspension was added to the glucose solution. 3. Oil was poured over the surface of the liquid. 4. The number of bubbles of carbon dioxide produced in one minute was counted. 5. The procedure was repeated at a range of temperatures. (i) In this investigation temperature was the only variable altered. State two variables that should be kept constant when setting up this investigation. (2) (ii) Explain the purpose of the layer of oil. (iii) The results are shown in the table below. Temperature ( C) Bubbles of Carbon dioxide (number/minute) Present the results in a suitable format on the graph paper provided. (2) (iv) From the results, describe the effect of temperature on anaerobic respiration in yeast. (2) (v) Suggest one way in which the reliability of the results could be improved. (vi) In addition to carbon dioxide, what will be produced in the flask during the investigation? (vii) Explain why no carbon dioxide is produced when the temperature is 70 C.

29 8. The diagram below shows some steps in respiration in muscle cells. (a) Name process A. (b) Name the products B, C and D. (c) State the number of molecules of ATP produced from each molecule of glucose by; (i) Aerobic respiration (ii) Anaerobic respiration (2) (d) Why might a muscle cell switch from aerobic to anaerobic respiration? 9. Copy and complete the table below to compare the processes of aerobic and anaerobic respiration in yeast. Write the letters of the statements from the list into the correct columns. Statements A B C D E F Water is produced Carbon dioxide is produced 1 molecule of glucose produces 2 molecules of ATP Ethanol is produced Glucose is broken down by several enzymes Oxygen is required Aerobic Respiration Anaerobic Respiration 10. Describe the stages in Aerobic respiration. (5) (2)

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