Experiment- flashcard qs.docx

**[Questions]** An educated guess based on an observation An experiment used for comparison to the test group.                A repeatable test to examine the viability of a hypothesis The things that change within an experiment, only one should change per experiment to ensure reliability. Scie...

**[Questions]** An educated guess based on an observation An experiment used for comparison to the test group.                A repeatable test to examine the viability of a hypothesis The things that change within an experiment, only one should change per experiment to ensure reliability. Scientific journals Repeats of an experiment to guarantee statistical reliability. An explanation to proving a hypothesis correct that has been tested and proven to be correct many times. A theory that has been tested and proven to be correct for a long time. An experiment whereby both the tester and patient are unsure if they are in the placebo or test group. To reduce bias in an experiment. Large sample size, use of a control group. Accidental discoveries and misinterpretation of results.  **Qualitative Food Test Questions:** 1\. What reagents or chemicals did you use to test for the presence of protein? 1. Biuret Reagent 2\. What colour indicates the presence of protein in a sample? 1. Lilac 3\. State a use of Benedict's solution in the laboratory. To test for the presence of a reducing sugar. 4\. Why was the brown paper used to test for starch allowed to dry out? 1. To make sure the stain was a lipid and not just water. 5\. What food test required the use of heat? 1. Testing for the presence of a reducing sugar. 6.What was the colour of the contents of the control tube after the test for a reducing sugar? 1. A brick-red colour 7\. What food biomolecule may be identified using Benedict's solution? 1. A reducing sugar. 8\. What type of food may be identified in the laboratory using brown paper? 1. A lipid 9\. In relation to a test for reducing sugar, which of the following is correct? No heat needed/ heat but do not boil/ boil? 1. Heat but do not boil 10\. What is the control used when carrying out these tests? 1. Water. 11\. Name a food that is rich in each of the following: Protein:Chicken Fat Butter Sugar Cake Starch Pasta 12\. Name a chemical element found in proteins that is not found in carbohydrates. 1. Nitrogen **Microscope Experiment Qs**\ \.A microscope with a blank white sheet Description automatically generated with medium confidence A= eye piece. To view the image B= coarse focus knob. To focus the image C= fine focus knob. To precisely focus the image D= objective lens. To observe the object E= stage. To place the slide on F= light. To provide light to the image. **[Ecology Experiment Questions]** **DNA Isolation questions:** What tissue did you use? Kiwi Why was salt used? The salt will cause the DNA molecules to clump together Why did you use washing-up liquid? The washing-up liquid will dissolve the cell and nuclear membranes and release the DNA from the cells Why did you finely chop the kiwi\> To increase the surface area for the experiment Why did you put the beaker in a water-bath at 60 degrees Celsius? This temperature denatures the enzymes that would normally digest DNA. Why did you heat the beaker for just fifteen minutes? If left any longer than 15 minutes, the DNA itself would break down. Why did you cool the mixture in an ice-water bath for five minutes? This slows down the breakdown of DNA Why did you blend the mixture for three minutes? This breaks down the cell walls and releases DNA What would happen if you blended the mixture for more than three seconds? Blending it for too long would break down the DNA strands.  Why did you use coffee filter paper instead of lab filter paper? Normal lab filter paper its pores are too small and the process would be very slow.  Why did you use a protease? The protease beaks down the proteins around the DNA What was the purpose of the ethanol? To cause the DNA to float to the top. Why was ice-cold ethanol used? DNA is insoluble in ice-cold ethanol but it is soluble in room temperature ethanol. **[Enzyme pH questions:]** **Question 1. ** What is an enzyme? A biological catalyst that is protein in nature **Question 2. ** Name the substrate in this experiment.  Hydrogen peroxide **Question 3. ** Why are a few drops of washing-up liquid used? To allow the oxygen to form foam.  **Question 4. ** Name a factor you kept constant in this experiment. Temperature **Question 5.** How is the rate of enzyme activity measured?  By measuring the volume of in the graduated cylinder at the experiment **Question 6. ** How did you vary the pH solutions in this activity? With different pH buffers **[Enzyme temperature questions:]** **Question 1. ** To what group of biomolecules do enzymes belong?  Proteins **Question 2.** Name the enzyme in this activity.  Catalase **Question 3. ** Name the products in this activity Water and oxygen **Question 4. ** Name the substrate in this activity. Hydrogen peroxide **Question 5.** What factor is kept constant during the activity? pH **Question 6.** How is the temperature varied during the experiment? With different temperatures of water baths **Question 7.** Why is the rate of activity not recorded after 60 degrees C? As the enzyme became denatured and had no activity **Question 8.** What is meant by the term denatured enzyme? The enzyme has lost its shape and can no longer carry out its function.  **[Enzyme immobilisation questions:]** **Question 1.** What is an immobilized enzyme? An enzyme that is attached to itself or to an inert material. **Question 2.** Why are the beads left for 15 minutes in the calcium chloride solution? To harden **Question 3. ** Give one advantage of using immobilized enzymes. They can be reused **Question 4.** Name the enzyme that you used in this activity. Yeast **Question 5.** Why did we stir the mixture as we added the beads of mixture.? To prevent clumping **[Enzyme denaturation questions:]** ** Question 1. ** Where in the cell are enzymes produced? Ribosomes. **Question 2. ** In relation to the heat denaturation experiment. Describe how the enzyme was treated in the test and the control.  Test: The enzyme was boiled for 5 mins. Control: The enzyme was not heated. **Question 3. ** Compare the results of the test investigation to that of the control.  Test: No foam was produced. Control: A large volume of foam was produced. **[Photosynthesis experiment questions:]** The lamp Temperature and use of a water bath with a thermometer. By moving the lamp by 10cm at each new run of the experiment The number of bubbles coming from the stem per minute can be easily counted? By counting the number of bubbles coming from the stem of the plant per minute. The experiment needed to reach equilibrium before the rate of photosynthesis could be measured. Prior to adding the elodea, a graduated cylinder is taken and ¾ filled with a premade 0.002% Sodium Hydrogen Carbonate and water solution. Initially, the graph increases proportionally with light intensity. However, as the light intensity becomes greater the graph levels off as the plant becomes saturated in light. Using a scalpel, cut the stalk of the Elodea at an angle near the base of the stalk. **[Respiration Experiment questions]** **[Diffusion and Osmosis Questions: ]** Name the material you used to act as a selectively permeable membrane? Why are the tied ends of the visking tubing kept out of the water?  How do you know osmosis has happened? If an animal cell was placed in the sucrose solution what would happen to it? **[The Growth of Leaf Yeast using Agar plates]** - How are fungi different to plants?  1. **Fungi** differs from plants in that their structure is made up of hyphae & the sugar present is chitin while they are also heterotrophic.  - Are fungi eukaryotic or prokaryotic? Explain your answer.  1. Fungi are eukaryotic as they have a nucleus and membrane enclosed organelles.  - Define 'parasitic fungi' and include examples in your answer.  1. Parasitic fungi feed on a living host. Examples: potato blight, athletes foot.  - Define 'saprophytic fungi' and include examples in your answer.  1. Saprophytic fungi feed on dead organic matter. Examples: rhizopus, yeast.  - Name 2 negative economic impacts of fungi 1. Cause food spoilage/ cause disease/ cause crop diseases/ cause timber rot - Name 2 positive economic impacts of fungi 1. Used to make alcohol/ used to make bread/ used to make antibiotics/ food source  - In what conditions do rhizopus reproduce sexually?  1. In unfavourable conditions (during drought, unsuitable temps)  - What is the name given to asexual reproduction in yeast? 1. Budding  - What is the function of the stolon in the rhizopus?  1. The stolon grows over the surface of the food and allows new mycelium to develop.  - What is the function of the rhizoids in the rhizopus?  1. Rhizoids increase surface area and carry out digestion of substrate and absorption of nutrients. **[Dicot Stem Observation Questions:]**                Busy lizzie.  Two seed-leaves To allow the light from the microscope to pass through. By using forceps While using the scalpel I made the cuts away from my body.  It is easier to cut the stem. Ground tissue and dermal tissue. Xylem transports water, phloem transports food,  **[The Effect of I.A.A Growth Regulator on Plant Tissue Questions:]** 1. Name the plant that you used in this experiment:  1. Radish Seeds 2\. What is IAA?  1. Indoleacetic acid (IAA) which is an auxin that contributes to plant growth. 3\. What biomolecule would you equate IAA to in an animal? 1. A hormone. 4\. State the location in a flowering plant where a growth regulator is secreted.  1. Meristems 5\. Why is a control necessary?  1. To allow for comparison to the test group. 6\. How would you make up serial dilutions of IAA?  1. Pipette 10ml of stock solution into dish A. Pipette 9ml of distilled water into a series of dishes then pipette 1ml of this stock solution into dish B and 1 ml of dish B into dish C and so on. 7\. How did you ensure that there was sufficient water for the seeds during the experiment?  1. Wetting the cotton wool. 8.  Name A in the diagram below:  1. Acetate grid What is the purpose of A in this experiment?  1. Help to measure the growth of the shoots and roots. 9\. A graph of a function Description automatically generated \(a) At what concentration of auxin is there maximum root growth?  1. Auxin concentration of 10^-4^ parts per million. \(b) At what concentration of auxin is there maximum stem growth?  1. Auxin concentration of 10 parts per million. \(c) What effect does 10^-2^ ppm have on root growth?  1. It inhibits the growth of the root. **[Germination Questions]** Water is needed by plants for germination The temperature was outside the optimum temperature for enzyme activity in the plant.  This denatured them, allowing them to be used as a control. To soften the Testa and make them easier to cut. This sterilises them and prevents the growth of microorganisms This allowed the enzymes in the seed to come into contact with the starch in the agar. This gives the enzymes time to digest the starch in the agar. Iodine tests for the presence of starch. **Effect of exercise on pulse rate** - How is the resting heart rate established? A.   participants sit with their heads on the table unmoving for two minutes before then sitting up and recording their heart rate.    ·        - How is the heart rate found?  A.    Find their pulse in their neck and count the number of beats for 15 seconds. This value is then multiplied by four to find the number of beats per minute.    ·        - What effect did exercise have on the pulse rate of a human? A.    The heart rate increased when the participants exercised, and it took a number of minutes at rest to return to the original resting heart rate.