practical workbook Flashcards
1
Q
What is the aim of Core Practical 1?
A
To investigate how changing enzyme concentration affects the rate of an enzyme-controlled reaction.
2
Q
What is the independent variable in the enzyme concentration experiment?
A
Enzyme concentration.
3
Q
What is the dependent variable in the enzyme concentration experiment?
A
Volume of oxygen produced (measured with a gas syringe).
4
Q
What safety precaution should be taken when handling hydrogen peroxide?
A
Wear goggles and gloves when handling hydrogen peroxide.
5
Q
What is the purpose of using a gas syringe in the enzyme experiment?
A
Measures oxygen production.
6
Q
True or False: A higher enzyme concentration always leads to a higher reaction rate.
A
False.
7
Q
What is the aim of Core Practical 2?
A
To prepare and observe biological samples under a light microscope and identify key cell structures.
8
Q
Fill in the blank: The stain used for onion cells is _______.
A
iodine.
9
Q
What is the purpose of using a mounted needle when preparing a slide?
A
Prevents air bubbles when placing the coverslip.
10
Q
What is the independent variable in the microscopy experiment?
A
Type of sample observed.
11
Q
What is the aim of Core Practical 3?
A
To calculate the mitotic index of a plant root tip and identify the stages of mitosis.
12
Q
What is the formula for calculating the mitotic index?
A
(Number of cells in mitosis / Total number of cells) × 100.
13
Q
What is the purpose of using hydrochloric acid in the mitotic index experiment?
A
Softens tissue for squashing.
14
Q
What is the aim of Core Practical 4?
A
To investigate how changing sucrose concentration affects the growth of pollen tubes.
15
Q
What is the independent variable in the pollen tube growth experiment?
A
Sucrose concentration (e.g., 0%, 5%, 10%, 15%, 20%).
16
Q
What is the dependent variable in the pollen tube growth experiment?
A
Length of the pollen tubes (measured under a microscope).
17
Q
What safety precautions should be taken when handling sucrose solutions?
A
Wear gloves when handling sucrose solutions.
18
Q
What is the aim of Core Practical 5?
A
To investigate the effect of temperature on the permeability of plant cell membranes.
19
Q
What is the independent variable in the temperature and membrane permeability experiment?
A
Temperature (e.g., 0°C, 10°C, 20°C, 30°C, 40°C, 50°C).
20
Q
What method is used to measure pigment leakage from beetroot?
A
Using a colorimeter to measure absorbance at a specific wavelength.
21
Q
What is the purpose of rinsing beetroot cubes with cold distilled water?
A
To remove excess pigments that could have leaked out during cutting.
22
Q
What is the biological explanation for pollen tube growth?
A
Pollen tube growth is energy-dependent, relying on nutrients like sucrose.
23
Q
What should be done to ensure the beetroot samples are treated consistently in the experiment?
A
Use separate beakers for each beetroot sample to maintain integrity.
24
Q
True or False: Higher temperatures always increase membrane permeability.
A
False.
25
What improvements can be made to increase the reliability of the pollen tube growth experiment?
* Increase the number of replicates * Use a data logger for precise measurements * Include more sucrose concentrations.
26
What is the independent variable in the investigation of pigment release from beetroot?
Temperature (e.g., 0°C, 10°C, 20°C, 30°C, 40°C, 50°C)
## Footnote
The temperature is systematically varied to assess its effect on pigment release.
27
What is the dependent variable in the beetroot pigment release experiment?
The amount of pigment released from the beetroot, measured by absorbance in a colorimeter
## Footnote
Absorbance indicates the concentration of pigment in the water.
28
List the control variables in the beetroot experiment.
* Size of beetroot cubes
* Duration of exposure to the water bath
* Volume of distilled water used
* Type of beetroot
* Light conditions
## Footnote
Control variables ensure that the experiment is fair and results are valid.
29
What safety precautions should be taken when handling knives or scalpels?
Wear gloves and use a cutting board
## Footnote
These precautions minimize the risk of cuts and injuries.
30
What is the method for measuring the absorbance of beetroot pigment?
Measure the absorbance of the solution at 520 nm using a colorimeter
## Footnote
This wavelength corresponds to the maximum absorption of betalain pigment.
31
How does temperature affect membrane permeability in beetroot cells?
As temperature increases, membrane permeability increases due to the fluidity of the phospholipid bilayer
## Footnote
Higher temperatures can disrupt the membrane structure, allowing more pigment to leak out.
32
What equipment is used to investigate gas exchange in locusts?
* Sealed respirometer
* Soda lime
* Manometer
* Thermometer
* Water bath
* Stopwatch
* Ruler
* Scissors or forceps
## Footnote
Each piece of equipment is essential for measuring respiration rates accurately.
33
What is the independent variable in the locust respiration experiment?
Environmental conditions such as temperature, light, and activity level
## Footnote
These conditions are manipulated to observe their effect on respiration.
34
What is the dependent variable in the locust respiration experiment?
Volume of oxygen consumed, indicated by the movement of the manometer fluid
## Footnote
The movement reflects the rate of respiration in the locust.
35
What is the aim of the experiment investigating environmental conditions and water uptake in plants?
To investigate the effect of environmental conditions (e.g., light, temperature, and humidity) on the rate of water uptake in plants
## Footnote
Understanding these effects can provide insights into plant physiology.
36
List the independent variables in the water uptake experiment.
* Light intensity
* Temperature
* Humidity levels
## Footnote
These factors can influence transpiration and water uptake rates.
37
What is a key biological explanation for water uptake in plants?
Water uptake is driven by transpiration, creating negative pressure that draws water into the plant
## Footnote
Factors such as temperature and humidity impact the rate of transpiration.
38
What method is used to measure the rate of aerobic respiration in yeast?
Set up a respirometer to measure oxygen consumption
## Footnote
The oxygen uptake is directly proportional to the respiration rate.
39
What is the effect of higher temperatures on the rate of respiration in locusts?
Higher temperatures usually increase the rate of respiration as enzymatic activity accelerates
## Footnote
This leads to increased energy production.
40
Fill in the blank: The __________ is used to absorb CO₂ in the respirometer setup.
sodium hydroxide
## Footnote
This ensures that only oxygen consumption is measured during the respiration experiment.
41
What is the purpose of using multiple replicates in experiments?
To improve reliability and reduce random errors
## Footnote
Replicates help ensure that results are consistent and valid.
42
What is a risk associated with handling locusts during the respiration experiment?
Potential for injury to the locust or handler
## Footnote
Careful handling is essential to ensure humane treatment of the insects.
43
How can consistency in temperature be maintained during the water uptake experiment?
Use a thermostatically controlled environment
## Footnote
This ensures that temperature variations do not affect the results.
44
What is the relationship between the rate of respiration and the absorption of CO₂?
The measurement is specific to oxygen uptake, critical for measuring aerobic respiration.
45
What factors can be manipulated to affect respiration in yeast?
Temperature, glucose concentration, oxygen availability.
46
What is the effect of temperature on enzyme activity in respiration?
Higher temperatures generally increase respiration rates until an optimum is reached.
47
How does glucose concentration influence respiration?
It directly influences the energy available for respiration.
48
Why is oxygen availability important in aerobic respiration?
It is the final electron acceptor in the electron transport chain.
49
What is the method to measure the rate of respiration?
Measure the amount of oxygen consumed over a fixed period.
50
What apparatus is used to measure gas volume in respiration experiments?
Manometer or gas syringe.
51
Why is it important to replicate experiments in respiration studies?
To ensure accuracy and reduce the chance of error or anomaly in the results.
52
What are control variables in a respiration experiment?
Type of yeast, volume of yeast suspension, glucose solution, experimental setup.
53
What precautions should be taken when handling yeast and chemicals?
Wear gloves and goggles, handle carefully to avoid contamination or spills.
54
What is the dependent variable in respiration experiments?
Rate of aerobic respiration, measured by the volume of oxygen consumed.
55
What is the aim of Core Practical 10?
To investigate how different wavelengths of light affect the rate of photosynthesis.
56
What plant is commonly used in photosynthesis experiments?
Elodea.
57
What is the independent variable in the photosynthesis experiment?
Wavelength of light.
58
How is the rate of photosynthesis measured?
By counting the number of oxygen bubbles produced or measuring the volume of oxygen produced.
59
What is a safety precaution when using electrical equipment in water?
Ensure electrical equipment is properly insulated.
60
What does the retention factor (Rf) indicate in chromatography?
It is used to identify pigments based on known reference Rf values.
61
What solvents are commonly used for pigment extraction?
Acetone or isopropanol.
62
What is the purpose of using sodium bicarbonate in the photosynthesis experiment?
To supply CO₂ for photosynthesis.
63
What are the risks associated with handling acetone or isopropanol?
They are flammable and can irritate the skin and eyes.
64
What is the biological explanation of photosynthesis?
Plants convert light energy into chemical energy, producing glucose and oxygen.
65
Which wavelengths of light are most effective for photosynthesis?
Red and blue light.
66
Fill in the blank: The type of pigment primarily involved in photosynthesis is _______.
chlorophyll.
67
What is one improvement suggested for the photosynthesis experiment?
Use a more precise method for measuring oxygen production.
68
True or False: Green light is efficiently absorbed by chlorophyll.
False.
69
What are the control variables in the chromatography experiment?
Volume and concentration of pigment extract, type of chromatography paper, amount of solvent.
70
What is the purpose of marking the solvent front in chromatography?
To measure the distance traveled by each pigment.
71
What is the importance of working in a well-ventilated area when handling volatile chemicals?
To avoid inhalation of harmful vapors and ensure safety.
72
What is the Rf value in chromatography?
The ratio of the distance traveled by the pigment to the distance traveled by the solvent.
73
How can precision be improved in chromatography experiments?
By using more accurate measuring tools and higher-quality chromatography paper.
74
What are chloroplast pigments responsible for?
Absorbing light energy for photosynthesis.
75
Which pigments are the most well-known in chloroplasts?
Chlorophyll a and b.
76
What is the purpose of using a zigzag pattern when inoculating agar?
To ensure an even distribution of microorganisms across the surface.
77
What is the independent variable in the investigation of microorganism growth?
Environmental factors such as temperature, pH, or nutrient availability.
78
What are some risks associated with handling microorganisms?
Pathogenic microorganisms, burns from hot equipment, and contamination.
79
What method is commonly used to isolate individual bacterial species?
Streak plate technique.
80
What does the streak plate method achieve?
It isolates individual bacterial cells in a mixed culture.
81
What is gibberellin's role in plants?
It is a hormone that promotes growth and can influence enzyme production.
82
What is the purpose of soaking seeds in gibberellin solution?
To assess its impact on amylase production during seed germination.
83
Fill in the blank: The dependent variable in the microorganism growth experiment is the _______.
Rate of microorganism growth, measured by colony diameter or number of colonies.
84
True or False: The incubation time must be the same for all plates in microorganism growth experiments.
True.
85
What is the significance of using a control group in experiments?
To compare and determine the effect of the experimental treatment.
86
What should be done to ensure the agar medium is free from microorganisms?
Autoclave the medium before use.
87
What is the purpose of measuring the diameter of microbial colonies?
To quantify the growth rate.
88
What is the method for testing for amylase activity?
Add amylase extract to starch solution and test for starch presence using iodine.
89
What must be done after extracting amylase from plant tissue?
Test for amylase activity by mixing with a starch solution.
90
List three control variables in the microorganism growth experiment.
* Volume and composition of the culture medium
* Initial concentration of microorganisms
* Incubation time
91
What is the purpose of subculturing isolated colonies?
To confirm the purity of the culture.
92
What type of agar medium is typically used for bacterial growth?
Nutrient agar.
93
What factors can influence microbial growth rates?
* Temperature
* pH
* Nutrient availability
94
Fill in the blank: The streak plate technique helps in isolating _______.
individual bacterial species.
95
True or False: Different bacterial species can have similar colony morphologies.
False.
96
What should be done to prevent contamination during bacterial culture handling?
Use aseptic techniques and sterilize equipment.
97
What is the optimal temperature range for most microorganisms?
Varies, but typically around 20-37°C for many species.
98
What is the purpose of using a microscope in bacterial culture observation?
To examine the characteristics of the bacterial cells.
99
What are the steps for preparing gibberellin treatment?
Dissolve gibberellic acid in water to a known concentration and soak seeds.
100
List two improvements that can be made in bacterial isolation experiments.
* Use a more sensitive microscope
* Increase the number of streaks for better isolation
101
What is the purpose of grinding the tissue in the experiment?
To break open the cells and extract amylase into the buffer solution for analysis
## Footnote
This allows for subsequent testing of amylase activity.
102
What is the first step in testing for amylase activity?
Prepare a starch solution by dissolving starch in water.
103
What happens if starch is present after adding iodine solution?
The iodine will turn blue-black.
104
What indicates that starch has been broken down by amylase?
The iodine remains yellow/brown.
105
What is the purpose of comparing amylase production in gibberellin-treated and control samples?
To assess the effect of gibberellin on amylase production.
106
What apparatus is needed for the amylase activity experiment?
* Barley seeds
* Gibberellin (GA3) solution
* Mortar and pestle
* Buffer solution
* Starch solution
* Iodine solution
* Test tubes and pipettes
* Incubator or controlled temperature environment
* Colorimeter (optional)
107
What is the independent variable in the amylase experiment?
The presence or absence of gibberellin.
108
What are the control variables in the amylase experiment?
* Seed type and age
* Concentration and volume of gibberellin solution
* Duration of treatment with gibberellin
* Temperature and time of incubation
* Volume and concentration of starch solution
* Method of grinding and extracting the enzyme.
109
True or False: Gibberellin can irritate the skin and eyes.
True.
110
What is the qualitative measurement in the amylase activity experiment?
Observe the color change in the iodine test.
111
What does a lower intensity of iodine color indicate?
More starch breakdown, hence higher amylase activity.
112
What is the Lincoln index formula used for?
To estimate population size in the capture-mark-release method.
113
Fill in the blank: The Lincoln index formula is N = (_______ × C) / R.
M
114
What is the aim of investigating different sampling methods?
To see how they affect the estimation of population size.
115
What method involves using a square or rectangular frame to estimate population density?
Quadrat sampling.
116
What is the dependent variable in the population estimation study?
The estimated population size or density.
117
What risks are associated with the capture-mark-release method?
* Handling organisms may cause harm or stress
* Some plants may cause allergic reactions
* Risk of trips or falls in fieldwork.
118
What is one improvement suggested for the population estimation experiment?
Increase the number of samples to improve accuracy.
119
What is the independent variable in the abiotic factor investigation?
The chosen abiotic factor (e.g., light intensity, temperature, or soil pH).
120
What is the purpose of measuring morphological traits in the species?
To determine how the species adapts to different abiotic conditions.
121
What does the comparison of species distribution and morphology help identify?
Trends in how the species responds to the abiotic factor.
122
What type of measurement involves counting the number of individuals in each sampling area?
Quantitative measurement.
123
True or False: The use of fixed sampling areas ensures valid and reliable comparisons.
True.
124
Fill in the blank: Different sampling methods are designed to estimate the _______ size of organisms.
population
125
What does the term 'abiotic factors' refer to?
Non-living chemical and physical parts of the environment that affect living organisms.
126
What are some instruments for measuring abiotic factors?
More accurate thermometers, light meters, pH meters
## Footnote
These instruments help in quantifying environmental conditions that affect living organisms.
127
What is the purpose of replicates in an experiment?
To repeat the experiment in different locations or times of the year for consistency
## Footnote
Increasing the number of replicates per environmental condition provides more robust data.
128
What should be controlled in an experiment to ensure accurate results?
Additional environmental factors such as humidity and soil nutrients
## Footnote
This ensures that only the chosen abiotic factor influences the species being studied.
129
How do abiotic factors influence species distribution?
They significantly influence species distribution and morphology
## Footnote
Examples include light, temperature, and soil pH.
130
What adaptive strategies might organisms use in response to abiotic factors?
Organisms may exhibit variations in morphology such as changes in leaf size or body shape
## Footnote
These adaptations help them survive in specific abiotic conditions.
131
Fill in the blank: Plants may grow ______ in low-light conditions to compete for light.
taller
## Footnote
This is an example of how abiotic factors can influence growth patterns.
132
What effect do temperature extremes have on species?
They may limit survival and reproductive success
## Footnote
Temperature is a critical abiotic factor affecting various species.
133
True or False: Only biotic factors influence species survival and morphology.
False
## Footnote
Abiotic factors also play a significant role in these processes.
134
What is the relationship between morphology and abiotic conditions?
Variations in morphology can reflect how species are adapted to specific abiotic conditions
## Footnote
This indicates the importance of environmental adaptations.
