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(a) (i) What is the purpose of replicates in scientific experimentation? (ii) What is meant by the term hypothesis? (b) (i) When investigating the conditions necessary for seed germination, describe how you: 1 - Leaving Cert Biology - Question 9 - 2017
Question 9
(a) (i) What is the purpose of replicates in scientific experimentation? (ii) What is meant by the term hypothesis? (b) (i) When investigating the conditions n... show full transcript
Worked Solution & Example Answer:(a) (i) What is the purpose of replicates in scientific experimentation? (ii) What is meant by the term hypothesis? (b) (i) When investigating the conditions necessary for seed germination, describe how you: 1 - Leaving Cert Biology - Question 9 - 2017
Step 1
What is the purpose of replicates in scientific experimentation?
Answer
Replicates are used in scientific experimentation to ensure reliability and to verify results or to avoid bias. By having multiple trials, researchers can identify anomalies and confirm that findings are consistent, which strengthens the validity of the conclusions drawn.
Step 2
Step 3
When investigating the conditions necessary for seed germination, describe how you: 1. Provided an oxygen-free environment.
Answer
To provide an oxygen-free environment, I could use an anaerobic jar or utilize boiled water that has been cooled to eliminate oxygen. This setup prevents oxygen from entering, thereby creating a suitable condition for germination without oxygen exposure.
Step 4
When investigating the conditions necessary for seed germination, describe how you: 2. Determined that germination had taken place.
Answer
Germination can be determined by observing the development of radicles (roots) or plumules (shoots) emerging from the seeds. The presence of these structures indicates that the germination process has successfully occurred.
Step 5
In relation to an investigation you carried out to prepare and examine with a microscope a transverse section of a dicotyledonous stem, answer the following. 1. How did you prepare the section?
Answer
To prepare a dicot stem section, I cut a thin section of the stem and either added water to it or included a staining solution to enhance visibility under the microscope.
Step 6
In relation to an investigation you carried out to prepare and examine with a microscope a transverse section of a dicotyledonous stem, answer the following. 2. Why is a coverslip used?
Answer
A coverslip is used to prevent the cells from drying out and to protect the lens of the microscope. It also helps in keeping the sample flat and secure, making it easier to observe under the microscope.
Step 7
Step 8
When demonstrating osmosis: 2. What led you to conclude that osmosis had occurred?
Answer
Osmosis can be deduced by observing an increase in mass (or volume) of the more concentrated solution within the tubing. This indicates that water molecules have moved across the membrane from the less concentrated solution into the tubing.
Step 9
When isolating DNA from plant tissue: 1. Give a reason for adding salt (NaCl) to the chopped plant tissue.
Answer
Adding salt (NaCl) helps to clump DNA together or to separate proteins from DNA as it facilitates the precipitation of DNA while ensuring that proteins and other contaminants remain in solution.
Step 10
When isolating DNA from plant tissue: 2. Why was the mixture kept at 60 °C for a period of time?
Answer
The mixture was kept at 60 °C to denature DNases or to deactivate enzymes that would otherwise destroy DNA during the extraction process. This temperature helps to prevent degradation of the genetic material.