Practice sheet Grade 9: Biology Unit: Cell Biology Criterion B: 1. A group of students were interested students to investigating the effect of surface area volume ratio on the rate of exchange of molecules across the cells by performing an agar jelly experiment. a) Outline the question or problem to be tested by this investigation. [AL: 3-4] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ b) Formulate and explain a testable hypothesis using correct scientific reasoning for this experiment. [AL: 7-8 ] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ c) State the Independent variable in this investigation [AL: 1-2] ______________________________________________________________________________ ______________________________________________________________________________ d) Explain how independent variable can be manipulated in this investigation. [AL: 7-8] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ e) State the Dependent variable in this investigation [AL: 1-2] ______________________________________________________________________________ ______________________________________________________________________________ f) Explain how the Dependent variable can be manipulated in this investigation. [AL: 7-8] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ g) State two controlled variables in this investigation [AL: 1-2] ______________________________________________________________________________ ______________________________________________________________________________ h) Describe how these Controlled variables can be manipulated in this investigation. [AL: 34] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ i) List appropriate materials and equipment required for this investigation (minimum 6). [AL:3-4] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ j) Briefly outline the methodology for the investigation. [AL:3-4] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ k) State at least two safety precautions you need to follow while doing this experiment. [AL: 1-2] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ Criterion C Table 1: Raw data table Sl.n o Size of agar cube/ Cell (cm) Time taken for color change in agar cubes (Seconds) Trail 1 Trial 2 Trial 3 1 1.0 20 25 23 2 2.0 32 32 34 3 3.0 50 60 61 4 4.0 80 85 82 5 5.0 120 123 121 Based on the data given above answer the following questions: i) Construct a processed data table (Include units also) [AL: 3-4] ii) Calculate the average time taken for the agar block/ cell size of 2 cm size [ AL: 1-2] and also the surface area volume ratio. [AL: 5-6]. Show your work. [Note: Surface area = 6 x length x length, Volume of cube= length x breadth x height Formula: Surface Area/ Volume ratio = Total surface area/ volume of cube] Worked examples: iii) Draw and plot a line graph using the processed data table. (Note to take the independent variable on X-axis and the Dependent variable on the Y-axis) [AL: 3-4). [Note use only pencil for graph plotting. Also do include the scale and title for the graph]. iv) From the graph and the data interpret and describe results using scientific reasoning [AL:5-6] _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ v) Discuss the validity of this hypothesis based on the outcome of the experiment and data obtained in the form of a graph. [AL:7 – 8] as you have mentioned in your response given in Question 1b. _____________________________________________________________________________ _____________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ vi) Evaluate the validity of the method of measuring the data obtained in this experiment [AL: 7-8] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ vii) Describe any two suggestions or improvements for this investigation. [AL: 3-4] ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ____________________________________________________________________________ Command term list: 1. 2. 3. 4. Describe- Give a detailed account or picture of a situation, event, pattern, or process. Calculate -Obtain a numerical answer showing the relevant stages in the working. Design- Produce a plan, simulation, or model. Discuss- Offer a considered and balanced review that includes a range of arguments, factors, or hypotheses. Opinions or conclusions should be presented clearly and supported by appropriate evidence. 5. Evaluate- Make an appraisal by weighing up the strengths and limitations. 6. Explain- Give a detailed account including reasons and causes. 7. Formulate- Express precisely and systematically the relevant concept(s) or argument(s) 8. Interpret -Use knowledge and understanding to recognize trends and draw conclusions from given information. 9. List -Give a sequence of brief answers with no explanation. 10. Outline- Give a brief account or summary. 11. Plot- Mark the position of points on a diagram 12. State- Give a specific name, value, or other brief answer without explanation or calculation. 13. Suggest- Propose a solution, hypothesis, or other possible answer. 14. Draw- Represent by means of a labeled, accurate diagram or graph, using a pencil. A ruler (straight edge) should be used for straight lines. Diagrams should be drawn to scale. Graphs should have points correctly plotted (if appropriate) and joined in a straight line or smooth curve. 15. Analyse- Break down in order to bring out the essential elements or structure. (To identify parts and relationships, and to interpret information to reach conclusions.) Web site: https://www.exploratorium.edu/snacks/agar-cell-diffusion You tube link: https://youtu.be/-EIuo61_aEo Photosynthesis: Photosynthesis is a process by which phototrophs convert light energy into chemical energy, which is later used to fuel cellular activities. The chemical energy is stored in the form of sugars, which are created from water and carbon dioxide. 1. State the word balanced equation for photosynthesis. [ 1 Marks] 2. Leaves play an important role in photosynthesis. The diagram given below shows the structure of leaf. Based on the diagram given below answer the following questions. a) List out the name of any two parts of leaves cells that carry out photosynthesis. [2] b) Explain how two features of leaves, visible in sections such as that shown in above figure, are adaptations for efficient photosynthesis.[3] c) Describe how photosynthesis processes help in dealing with the issue of global warming[2] d) Rate of photosynthesis is controlled by many environmental factors. Outline how Carbondioxide concentration acts as a limiting factor for photosynthesis. [2] e) Stomata plays an important role in controlling the rate of transpiration. i) Define the term transpiration [1] ii) Suggest any two environmental which effects the rate of transpiration [1]
