All required practicals for the AQA A-level Biology course Flashcards
How do you Test for Carbohydrates, Lipids, and Proteins?
Aim: To test for the presence of reducing sugars (Benedict’s test), starch (iodine test), proteins (biuret test), and lipids (emulsion test).
Method:
~Reducing sugars: Add Benedict’s solution and heat. Positive result = brick red.
~Starch: Add iodine solution.
Positive result = blue-black.
~Proteins: Add Biuret reagent. Positive result = purple.
~Lipids: Add ethanol, shake, then add water. Positive result = milky emulsion.
How do you investigate the Effect of pH on Enzyme Activity?
Aim: To investigate how pH affects enzyme activity, such as the breakdown of starch by amylase.
Method:
~Prepare a starch solution and add amylase.
~Measure the time it takes for the starch to be broken down using iodine.
~Vary the pH using buffers and observe the effect on reaction rate.
How do you investigate Enzyme Activity?
Aim: To measure the effect of enzyme concentration on the rate of reaction.
Method:
~Use a reaction where enzyme concentration can be varied, such as the breakdown of hydrogen peroxide by catalase.
~Measure oxygen production or change in substrate concentration over time.
How do you investigate the structure of a cell using microscopy?
Aim: To use a microscope to observe and draw plant and animal cells.
Method:
~Use prepared slides or prepare your own (e.g., onion skin or cheek cells).
~Identify organelles such as the nucleus, mitochondria, and chloroplasts.
How do you investigate Mitosis in Root Tip Cells?
Aim: To observe stages of mitosis in plant root cells.
Method:
~Use an onion root tip.
~Stain the root tips with a dye (e.g., acetic orcein) and view under a microscope.
~Count and record the number of cells in each phase of mitosis.
How do you investigate the Effect of Temperature on Membrane Permeability?
Aim: To observe how temperature affects the permeability of cell membranes (e.g., beetroot).
Method:
~Cut beetroot into uniform pieces and place them in water at different temperatures.
~Measure the release of pigment from the beetroot into the surrounding water (indicating damage to the cell membrane).
How do you investigate gas Exchanges in Humans?
Aim: To measure the effect of exercise on breathing rate.
Method:
~Measure resting breathing rate.
~After moderate exercise, measure the breathing rate again.
~Compare the two to understand how exercise affects gas exchange.
How do you investigate the Effect of pH on the Rate of Oxygen Consumption in Yeast?
Aim: To investigate the rate of respiration in yeast at different pH values.
Method:
~Set up a fermentation vessel with yeast, sugar, and a buffer solution at different pH values.
~Measure oxygen consumption (e.g., using a respirometer) to determine the effect of pH on respiration rate.
How do you investigate transpiration in Plants?
Aim: To measure the rate of transpiration in plants.
Method:
~Use a potometer to measure water uptake and calculate transpiration rate.
~Vary environmental factors like light intensity, humidity, or temperature and observe their effect.
How do you investigate DNA Extraction?
Aim: To extract DNA from plant or animal cells.
Method:
~Use detergent to break open the cell membranes and release DNA.
~Add salt and alcohol to precipitate the DNA for observation.
How do you investigate the Effect of Light Intensity on the Rate of Photosynthesis?
Aim: To investigate how light intensity affects the rate of photosynthesis in aquatic plants (e.g., using Elodea).
Method:
~Place a plant in water and vary the light intensity using a light source.
~Measure oxygen production using a gas syringe or count bubbles to determine the rate of photosynthesis.
How do you Investigate the Effect of Light on Phototropism in Plants?
Aim: To observe how light influences plant growth (phototropism).
Method:
~Place plant seedlings in a controlled environment with light from different directions.
~Measure and record growth towards or away from the light source.
How do you investigate genetic inheritance in Drosophila?
Aim: To observe inheritance patterns in fruit flies (Drosophila).
Method:
~Cross different strains of Drosophila with known phenotypes.
~Count offspring and compare the observed ratios with expected Mendelian ratios (e.g., for eye color or wing type).
How do you investigate the Effect of Mutagens on Yeast?
Aim: To determine the effect of mutagens (like UV light or chemical agents) on mutation rates.
Method:
~Expose yeast cultures to mutagens and compare mutation frequency in exposed and control groups.
How do you investigate Genetic Transformation?
Aim: To demonstrate the process of genetic transformation (e.g., using bacteria).
Method:
~Use plasmid vectors to introduce a gene into bacterial cells.
~Select for transformed bacteria using antibiotic resistance markers.
